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MDK 01.01. Fundamentals of plumbing and assembly and electrical work. Section 1 " . Locksmith, locksmith and assembly work. » Serov Valery Sergeevich master p / o
Topic. Markup 1. Essence and purpose of markup. 2. Tools, fixtures and materials used for marking. 3. Preparation of surfaces for marking. 4. Rules for performing markup techniques. 5. Typical defects in marking, their causes and ways to prevent them. 6. Mechanization of marking works. Study questions:
1. Essence and purpose of marking Marking is the operation of applying lines (marks) to the surface of the workpiece that define the contours of the manufactured part, which is part of some technological operations. Depending on the features of the technological process, planar and spatial markings are distinguished. Planar marking is used in the processing of sheet material and shaped rolled products, as well as parts on which marking risks are applied in one plane. Spatial marking is the application of scratches on the surfaces of the workpiece, interconnected by mutual arrangement.
2. Tools, fixtures and materials used for marking Pic. 2.1. Scribers: a - one-sided with a ring; b - one-sided with a handle; c - bilateral; d - double-sided with a handle Scribers are the simplest tool for drawing the contour of a part on the surface of a workpiece and are a rod with a pointed end of the working part.
Continuation of question 2 Reismas is used to apply marks on the vertical plane of the workpiece (Fig. 2.2). Rice. 2.2. Height gauge: 1 - vertical scale bar; 2 - scriber mounted on a vertical stand
Question 2 continued Marking compasses are used to draw arcs of circles and divide segments and angles into equal parts (Fig. 2.3). Rice. 2.3. Marking compasses: a - simple; b - spring
Continuation of question 2 Center punches (Fig. 2.4) are made of U7A tool steel. The hardness on the length of the working part (15...30 mm) should be HRC 52...57. 2.4. Kerner Fig. 2.5. Kerner Yu.V. Kozlovsky: 1 - building; 2 - striker; 3 - impact head; 4 - bushing; 5, 13 - springs; b, 11 - legs; 7.8 - nuts; P, 10 - replaceable needles; 12,14- screws
Continuation of question 2 Fig. 2.6. Tools for applying center holes: a - bell; b, c - square-center finder: 1 - square; 2 - ruler; g - probe-protractor: 1 - locking screw; 2 - ruler; 3 - square; 4 - protractor
Continuation of question 2 Fig. 2.7. Automatic mechanical punch: 1- punch; .2 - rod; 3,5,6 - components of the center punch; 4 - flat spring; 7, 11 - springs; 8 - drummer; 9 - shoulder; 10 - cracker Fig. 2.8. Electric center punch: 1 - sleeve; 2 - rod; 3 - center punch; 4,7 - springs; 5 - coil; b - drummer; 8 - body; 9 - electrical circuit
Continuation of question 2 Fig. 2.9. Special punch: a - without load; b-with cargo; 1 - stand; 2 - center punch; 3 - rack; 4 - screw; 5 - legs; b - cargo
Continuation 2 questions Marking plates (Fig. 2.10) are cast from gray cast iron, their working surfaces must be accurately machined. Rice. 2.10. Marking plate: a - on a stand; b - on the table
Question 2 continued Marking prisms (Fig. 2.11) are made with one or two prismatic recesses. By accuracy, prisms of normal and increased accuracy are distinguished. Rice. 2.11. Marking prisms: type I - one-sided; type II - quadrilateral; h, h 1, h 2, h 3, h 4 - depth of V-shaped grooves
Question 1 continued When marking stepped shafts, prisms with a screw support (Fig. 2.12) and prisms with movable cheeks, or adjustable prisms (Fig. 2.13) are used. Rice. 2.12. Prism with screw support Fig. 2.13. Adjustable prism
Continuation of question 2 Squares with a shelf (Fig. 2.14) are used for both planar and spatial markings. Rice. 2.14. Square with a shelf: a - square; b, c - examples of use
Question 2 continued Marking boxes (Fig. 2.15) are used for installation on them when marking workpieces of complex shape. Rice. 2.15. Marking box: a - general form; b - example of use
Question 2 continued Marking wedges (Fig. 2.16) are used when it is necessary to regulate the position of the marked workpiece in height within a small range. Rice. 2.16. Marking wedge
Question 2 continued Jacks (Fig. 2.17) are used in the same way as adjustable wedges for adjusting and aligning the position of the marked workpiece in height, if the part has a sufficiently large mass. Rice. 2.17. Jacks with ball (a) and prismatic (b) workpiece support
Question 2 continued In order for marking marks to be clearly visible on the surface of the marked workpiece, this surface should be painted. For painting the marked surfaces, the following is used: a solution of chalk in water with the addition of wood glue, which ensures reliable adhesion of the coloring composition to the surface of the marked workpiece, and a desiccant, which contributes to the rapid drying of this composition; copper sulphate, which is copper sulphate and, as a result of ongoing chemical reactions, ensures the formation of a thin and durable layer of copper on the surface of the workpiece; quick-drying paints and enamels.
3. PREPARATION OF SURFACES FOR MARKING. Preparatory work for marking includes the preparation of dyes, the preparation of surfaces for painting and the painting itself. Chalk with the addition of wood glue and desiccant is diluted to the consistency of liquid sour cream. Copper sulphate is dissolved in water in a ratio of 1:10 or solid copper sulphate is used, which is rubbed on the surface of the workpiece to be marked. Varnishes and enamels are used in finished form. Before painting, the surface to be marked must be cleaned of dirt, dust, traces of scale and degreased. Coloring is performed by applying the composition to the surface of the workpiece evenly, in a thin layer. To apply the coloring composition, use a brush and swab.
Continuation of 3 questions Then markup is performed. First, the base from which the risks will be applied is determined. Marking risks are usually applied in the following order. First all horizontal, then vertical, then slanted, and last - circles, arcs and fillets. After making sure that the markup is correct, all lines are punched so that they are not erased when processing the part. Cores should be shallow and divided by marking risks in half. Marking is done in several ways: according to the drawing, according to the template, according to the sample and in place.
4. Rules for performing markup techniques. one . The layer of the coloring composition applied to the surface of the workpiece must be thin, uniform in thickness and completely cover the surface to be marked. 2. When drawing risks, accurately align the ruler with the original marks on the part and press it tightly against the workpiece. 3. Before drawing the risk, you should make sure that the scriber (compass) is well sharpened. 4. Draw a risk with one continuous movement of the scriber along the ruler, do not apply the risk twice in the same place, as this leads to its bifurcation.
Question 4 continued 5. When punching marking marks: make sure that the punch is sharpened correctly, re-sharpen if necessary; punching should be done with light hammer blows on the center punch so that the depth of the core recess is approximately 0.5 mm. lines of large circles with a diameter of more than 15 mm are punched evenly in 6 ... 8 places, arcs in mates should be punched with smaller gaps between the recesses than in straight sections; the points of conjugation and intersection of the risks must be necessarily punched; the center of the hole or arc is punched deeper than the risk, the diameter of the hole should be approximately 1.0 mm.
Continuation of question 4 6 . When marking a hole or arc, accurately set the compass opening to the required size, firmly fix the compass opening with the clamping screw of the compass arc. When drawing the arc, tilt the compass slightly in the direction of movement. 7. If, when pairing rectilinear and curvilinear marks, they did not match, repaint the marked place of the part and repeat the markup. 8. When marking according to the template (sample), press it firmly against the part, make sure that it does not move during the marking process. 9. When marking the center at the end of a cylindrical part with a center finder (bell), monitor the installation of the center finder strictly along the axis of the part, check the marking accuracy with a sliding center finder.
Question 4 continued 10. When marking the center at the end of a cylindrical part with a center finder, make sure that the center finder shelves fit snugly to the cylindrical part of the part. 11. When marking the center of the hole in the part with the help of a sliding center finder, make sure that the wooden block is perpendicular to the plate with the axis of the hole. 12. When marking "from the edge" of the machined part, firmly press the square shelf with a wide base to the edge of the part. 13. When marking "from the center lines", the dimensions are counted from two control core recesses located at the edges of these lines.
5 . TYPICAL DEFECTS IN MARKING, CAUSES OF THEIR APPEARANCE AND MEANS OF PREVENTION Defect Cause Prevention method Bifurcated risk The ruler was weakly pressed against the part. The risk was carried out twice in the same place. The marking was carried out with a blunt scriber. Press the ruler tightly against the part, at risk only once. Sharpen the scriber The core hole is not at risk When installing the center punch, its tip was not at risk. Punching was done with a blunt center punch. The center punch has shifted from the marks before hitting with a hammer. Place the center punch precisely into the recess of the marks, hold it firmly when punching. If necessary, sharpen the center punch Forked or displaced risk of a marked arc or circle The supporting (fixed) leg of the compass is blunt. The shallow depth of a core hole at the center of a circle or arc. Strong pressure on the movable leg of the compass in the process of marking Mark out only with compasses with sharply sharpened legs, smooth, not strong movements of the compass, tilting it in the direction of movement
Continuation of the 5th question Risks are not related to each other Inaccurately set the risk line. Displacement of the ruler during the application of the risk. The size of the compass is inaccurately set; the support leg of the compass jumped out of the core hole during the drawing of the risk Accurately follow all the marking rules. Hold the ruler and compass firmly during the marking process Non-parallel or non-perpendicular marks to each other The core depressions on the original marks are displaced. The ruler for risks and arcs is not exactly set. The clamping screw of the compass is loose. Set the ruler precisely according to the initial marks. Firmly press it against the part. Follow the clamping of the legs of the compass. The angles between the risks do not correspond to the data. The core depressions on the initial risks are displaced. The sequence of constructing the corner is broken. The ruler is inaccurately set according to the marks and core depressions. Apply core depressions only to the deepening of the risks. Follow the sharpening of the center punch and scriber. Accurately set the ruler according to the risks and core depressions The marked contour does not correspond to the template The template during the marking was loosely pressed to the surface of the workpiece, as a result of which it shifted when marking marks were applied Press the template tightly to the surface of the workpiece during the marking process. If possible, fix the template on the workpiece with a clamp
Continuation of the 5th question When marking with a thickness gauge, the risk is not straight The part to be marked is set unstable. The depth gauge needle is loosely fixed on the stand. Dirt got on the marking plate under the base of the flight masa Check the strength (without pitching) of the installation of the part on the marking plate. Thoroughly wipe the marking plate before marking. Firmly fasten the marking needle on the thickness rod The centers of the holes and the cylindrical parts of the parts do not match The centers of the holes and the cylindrical parts of the part are not well defined Check the marking of the centers
6. MECHANIZATION OF MARKING WORKS 2.18. Coordinate marking machine with digital display (all dimensions are in millimeters): 1 - measuring head; 2 - traverse; 3 - marking silt; 4 - table; 5 - bed
Continuation of question 6 Fig. 2.19. Coordinate marking machine for small parts (all dimensions are in millimeters): 1 - measuring head; 2 - traverse; 3 - marking needle; 4 - table; 5 - bed
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GBPOU SMT "SORMOVSK MECHANICAL TECHNICIUM NAMED AFTER THE HERO OF THE SOVIET UNION P.A. SEMENOV" MDK 01.01. “Fundamentals of metalwork, assembly and electrical work” TOPIC: CUTTING OF METAL Developed by Serov V.S. master of p / o, the highest category
CUTTING OF METAL 1. The purpose and purpose of metalwork cutting. 2. Tools used in felling. 3. Sharpening of the cutting tool. 4. Basic rules and methods of performing work during felling. 5. Manual power tools. 6. Typical defects during felling, their causes and ways of prevention Training questions:
1. The purpose and purpose of metalwork cutting Cutting is the operation of removing a layer of material from the workpiece, as well as cutting metal (sheet, strip, profile) into pieces with cutting tools (chisel, crosscut or groove with a hammer). Cutting perform the following work: removal of excess layers of material from the surfaces of workpieces (cutting off castings, welds, cutting edges for welding, etc.); trimming edges and burrs on forged and cast blanks; cutting into pieces of sheet material; punching holes in sheet material; cutting oil grooves, etc.
2. TOOLS USED FOR CUTTING 1. Bench chisel: a - general view of the chisel and its working part; b - taper angle and action of forces; c - cutting elements during cutting; P - cutting force; w 1 , w 2 - components of the cutting force; β, β 1 , β 2 - taper angles; γ - front angle; a - rear corner; δ - cutting angle A metalwork chisel (Fig. 1) consists of three parts: working, middle, shock. As with any cutting, the cutting part of the tool is a wedge (Fig. 1a).
Continuation of question 2 Kreutzmeysel (Fig. 2) differs from a chisel in a narrower cutting edge. Kreuzmeysel is used for cutting grooves, cutting keyways and similar work. Rice. 2. Kreutsmeysel Groover (Fig. 3.) is used for cutting lubrication grooves in bushings and bushings of plain bearings and profile grooves for special purposes. Rice. 3 . ditcher
Continuation 2 questions Locksmith hammers (Fig. 4.) are used when cutting as a percussion tool to create a cutting force and are of two types - with a round (Fig. 4, a) and square (Fig. 4, b) striker. Rice. 4. Locksmith hammers: a - with a round striker; b - with a square striker; in - ways of fastening the handle
3. SHARPENING THE CUTTING TOOL The sharpening of the cutting tool is carried out on grinding machines. 5. Grinding machine: a - grinding unit of the machine; b - a template for controlling sharpening angles; 1 - protective screen; 2 - casing; 3 - handguard
4. BASIC RULES AND METHODS FOR PERFORMING WORK DURING CUTTING 1. When cutting sheet and strip metal up to 3 mm thick at the level of the vise jaws, the following rules should be observed: the part of the workpiece that goes into the chips must be located above the level of the vise jaws; the risk on the workpiece must be exactly at the level of the jaws of the vise, the warp of the workpiece is not allowed; the workpiece should not protrude beyond the right end of the vise jaws; cutting according to the level of the vise should be performed by the middle of the cutting edge of the tool, placing it at an angle of 45 ° to the workpiece (Fig. 6 b). The angle of inclination of the chisel, depending on the angle of sharpening of the working part, is from 30 to 35 ° (Fig. 6 a).
Continuation of question 4 Fig. 6. Cutting according to the level of the vise: a and b - the angle of inclination of the chisel, respectively, in the vertical and horizontal plane
Continuation of question 4 2 . When cutting strip (sheet) material on a plate (anvil), the following requirements should be met: the cutting edge of the chisel should not be sharpened straight, but with some curvature (Fig. 7.); cut sheet material in a straight line, starting from the far edge of the sheet to the front, while the chisel should be located exactly at the marking risk. When cutting, move the sheet in such a way that the impact point is approximately in the middle of the plate; when cutting out a curved profile blank from sheet material (Fig. 8.), leave an allowance of 1.0 ... 1.5 mm for its subsequent processing, for example, by filing;
Continuation of the 4th question, cut the strip along the markings on both sides by about half the thickness of the strip, then break it in a vice or on the edge of the slab (anvil); adjust the impact force depending on the thickness of the cut material. Rice. 7. Cutting of sheet material Fig.8. Punching a workpiece from sheet material
Question 4 continued 3. When cutting a metal layer on a wide surface of a part, first cut grooves with a depth of 1.5 ... 2.0 mm using a cross cutter along the entire surface of the part (Fig. 9 a), then cut off the remaining protrusions with a chisel (Fig. 9 b). Rice. 9. Cutting material from a wide surface: a - cutting grooves; b - cutting ledges
Question 4 continued 4. Cutting curved grooves on the workpiece should be performed with a groover in one or several passes, depending on the material being processed and the requirements for the quality of processing. The volume of material to be cut is regulated by the inclination of the groover and the force of impact on the tool. 5. When sharpening the tool, the following requirements must be met: install the tool rest of the grinding machine in such a way that the gap between the tool rest and the grinding wheel does not exceed 3 mm; press the tool with the cutting part to the periphery of the grinding wheel, while leaning on the handpiece; periodically cool the tool with water, lowering it into a special container.
Continued 4 questions check the sharpening angle of the tool according to the template; monitor the symmetry of the tool blade relative to its axis. 6. When cutting and sharpening the cutting tool, the following safety measures must be observed: install a protective screen on the workbench; firmly fix the workpiece in a vise; do not use a hammer, chisel, groover, kretzmeisel with a flattened striker; do not use a hammer that is loosely attached to the handle; perform cutting only with a sharpened tool; use personal protective goggles or a protective shield installed on the machine to avoid injury to the eyes.
5. MECHANIZED HAND TOOLS ten . Manual pneumatic hammer: 1 - handle; 2 - fitting; 3 - starting device; 4 - valve; 5 - air distribution device; b - bushing; 7 - drummer; 8 - trunk; 9 - chisel shank; 10 - end sleeve According to the nature of the main movement, mechanized tools with reciprocating and rotational motion are distinguished.
Continuation of question 5 Fig. 11. Pneumatic grinder: 1 - spindle; 2 - casing; 3 - body; 4 - trigger; 5 - handle; b - grinding wheel Pneumatic grinders are used to clean welds and prepare surfaces for further processing.
6. TYPICAL DEFECTS IN CUTTING, CAUSES OF THEIR APPEARANCE AND MEANS OF PREVENTION Defect Cause Method of prevention Cutting of sheet steel in a vise The cut off edge of the part is curved The part is weakly clamped in the vise Firmly fix the part in the vice Sides of the cut part are non-parallel Distortion of marking lines. Misalignment of the workpiece in the vise Follow the marking rules, accurately place the workpiece in the vice according to the marking mark “Jagged” edge of the workpiece The cutting was carried out with too strong blows or a blunt chisel Before cutting, make sure that the chisel is sharpened correctly. Adjust the force of impacts depending on the thickness of the workpiece. The angle of inclination of the chisel must be at least 30°
Continuation of the 6th question Cutting grooves “Ragged” edges of the groove Incorrect sharpening of the cross-cutting tool Sharpen the cutting edge with undercutting of the cutting edge The depth of the groove is not the same along its length During the cutting process, the slope of the cross-cutting tool was not adjusted When cutting, the thickness of the cut layer of material, and therefore the depth of the groove, should be adjusted by tilting the cross cutting tool Chips at the end of the groove The chamfer on the part has not been cut off Before starting cutting (especially for brittle metals), it is imperative to chamfer the edge of the workpiece at the exit point of the crosscut
Question 6 continued Cutting off a metal layer on a wide surface Rough blockages and cuts on the processed surface Cutting was carried out with a blunt chisel. Incorrect setting of the chisel during cutting. Irregularity in the force of blows with a hammer on a chisel during cutting. Adjust the thickness of the layer to be removed by tilting the chisel Chips on the edge of the part Not chamfered on the part
Continuation of question 6 Cutting sheet, strip and bar steel on a plate Indirectly linear edge from the chopped part Violation of the rules for marking the part. The cutting was not carried out according to the marking risk. Monitor the straightness of the marking risk. Setting the chisel accurately is at risk The edge of the chopped part has deep cuts and chips Incorrect sharpening of the chisel. Inaccurate setting of the chisel on the marking line. The chipping was carried out with too weak impacts with "tapping" or a blunt chisel For cutting sheet metal, the chisel should be sharpened slightly rounded. Cutting should be done with energetic blows without “tapping”. Hold the chisel firmly at the marking risk
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GBPOU SMT "SORMOVSK MECHANICAL TECHNICIUM NAMED AFTER THE HERO OF THE SOVIET UNION P.A. SMYONOV" MDK 01.01. "Fundamentals of locksmith and assembly work" TOPIC: BENDING OF METAL Developed by Serov V.S. master p / o, the highest category
BENDING OF METAL 1. Essence and types of bending. 2. Tools, fixtures and materials used in bending. 3. Mechanization during bending. 4. Rules for performing work during manual bending of metal. 5. Typical defects during bending, their causes and methods of prevention. Study questions:
1. Essence and types of bending Bending (bending) is an operation, as a result of which the workpiece takes the required shape (configuration) and dimensions by stretching the outer layers of the metal and compressing the inner ones. The total length of the workpieces when bending with roundings is calculated according to the following formula: where is the length of the straight sections of the workpiece; r 1 ,...., r n - radii of the corresponding curves; a 1 ..., and n - bending angles. Bending can be done manually, using various bending devices and using special bending machines.
2. TOOLS, DEVICES AND MATERIALS USED IN BENDING one . Bending on a mandrel: a-c - the sequence of the operation. As tools for bending sheet material with a thickness of 0.5 mm, strip and bar material with a thickness of up to 6.0 mm, steel metalwork hammers with square and round heads weighing from 500 to 1000 g are used , hammers with soft inserts, wooden hammers, pliers and round nose pliers.
Continuation of question 2 Fig. 2. Pliers Fig. 3 . Round-nose pliers Pliers and round-nose pliers are used for bending profiled rolled products with a thickness of less than 0.5 mm and wire.
Continuation of question 2 Fig. four . Device for bending the frame of a hacksaw: a, b - schemes for using the device; c - finished frame; 1 - lever; 2 - roller; 3 - blank; 4 - mandrel; A, B - respectively, the upper and lower positions of the lever
Continuation of question 2 Fig. 5 . Device for bending rings Hot bending of pipes is performed after preheating with high frequency currents (HF), in flame furnaces or forges, with gas acetylene burners or blowtorches directly at the place of bending. Fillers for pipe bending are selected depending on the pipe material, its dimensions and the bending method. As fillers use: sand or rosin.
3. MECHANIZATION IN BENDING Fig. 6. Sheet bending rolls: 1 - drive mechanism; 2 - top roll; 3 - bending sheet; 4 - plate; 5 - lower roll
Continuation of question 3 Fig. 7. Press brake: a - general view; b - structural diagram; in - forms of a bent profile; 1 - slider frame; 2 - punch; 3 - matrix; 4 - lining; 5 - plate
Continuation of question 3 Fig. eight . Roller bending machine: a - three-roller: 1 - handle; 2 - top roller; 3,4 - pressure rollers; 5 - clamps; b - four-roller: 1 - frame; 2.8 - handles; 3, 5 - leading rollers; 4.7 - pressure rollers; b - blank
Continuation of question 3 Fig. 9 . Pipe bending machine with heating by high frequency currents: 1 - frame; 2 - longitudinal feed mechanism; 3 - extension; 4 - bent pipe; 5 - sponges; b, 10 - carriages; 7 - guide rollers; 8 - inductor holder; 9 - inductor; 11 - pressure roller; 12 - pressure roller carriage; 13 - cross feed screw; 14 - cross feed mechanism; 1 5 - limit switch; 16 - cooling system; 17 - lead screw; 18, 20 - handles; 19 - roller
4. Rules for performing work during manual bending of metal. one . When bending sheet and strip material in a vice, the marking risk must be positioned exactly, without distortions, at the level of the vise jaws in the direction of bending. 2. When bending from strips and bars of parts such as corners, brackets of various configurations, hooks, rings and other parts, you should first calculate the length of the elements and the total length of the part development, marking the bending points. 3. In the mass production of parts such as brackets, it is necessary to use mandrels, the dimensions of which correspond to the dimensions of the elements of the part, which excludes the current marking of bending points.
Question 4 continued When bending sheet and strip metal in fixtures, it is necessary to strictly adhere to the instructions attached to them. 5. When bending gas or water pipes by any method, the seam must be located inside the bend.
5. TYPICAL DEFECTS IN BENDING, CAUSES OF THEIR APPEARANCE AND MEANS OF PREVENTION Defect Causes Method of prevention When bending an angle from a strip, it turned out to be skewed. Check the perpendicularity of the strip to the jaws of the vice with a square. The dimensions of the bent part do not correspond to the specified ones. Inaccurate calculation of the development, the mandrel is incorrectly selected. Accurately mark bending points. Use mandrels that exactly match the given dimensions of the part Dents "(cracks) when bending the pipe with filler The pipe is not tightly packed with filler Place the pipe vertically when filling with filler (dry sand). Tap the pipe from all sides with a hammer
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GBPOU SMT "SORMOVSK MECHANICAL TECHNICIUM NAMED AFTER THE HERO OF THE SOVIET UNION P.A. SEMENOV Serov V.S., master of p / o, the highest category of MDK 01.01. “Fundamentals of metalwork and assembly and electrical work” TOPIC: METAL STRAIGHTENING
Topic 5. EDIT OF METAL 1. Essence, purpose and methods of editing. 2. Tools and fixtures used in straightening. 3. Mechanization when editing. 4. Basic rules for performing work when editing. 5. Typical defects during editing, their causes and ways to prevent them. Study questions:
1. Essence, purpose and methods of dressing Editing is an operation for straightening a bent or warped metal, which can only be applied to ductile materials: aluminum, steel, copper, brass, titanium. Editing is carried out on special straightening plates, which are made of cast iron or steel. Editing small parts can be done on blacksmith anvils. Dressing of metals is carried out with hammers of various types, depending on the state of the surface and the material of the part being dressed.
Continuation of question 1 Editing is carried out in several ways: by bending, stretching and smoothing. Straightening by bending is used when straightening round (rods) and shaped material, which have a sufficiently large cross section. In this case, hammers with steel heads are used. Pull straightening is used to straighten sheet material that has bulges or undulations. Such editing is carried out with hammers with soft metal strikers or mallets. Burnishing straightening is used in cases where the workpiece has a very small thickness. Smoothing is carried out with wooden or metal bars.
2. TOOLS AND DEVICES USED IN STRAIGHTENING Pic. one . Correcting plate On such plates, profile blanks and blanks from sheet and strip material, as well as rods from ferrous and non-ferrous metal, are corrected.
Continuation of question 2 Fig. 2. Hammers with soft inserts: a - with prismatic; b - with a cylindrical: 1 - pin; 2 - striker; 3 - handle; 4 - body Sledgehammers are hammers of large mass (2.0 ... 5.0 kg) and are used for straightening round and profile rolled products of large cross-section in cases where the impact force applied by a conventional metalwork hammer is insufficient to straighten a deformed workpiece .
Question 2 continued Mallets are hammers, the impact part of which is made of hard wood, they are corrected by sheet material made of highly ductile metals. Feature mallet adjustments in that they practically do not leave marks on the straightened surface. Metal or wooden trowels (made of hardwood: beech, oak, boxwood) are designed for straightening (smoothing) sheet material of small thickness (up to 0.5 mm). This tool during processing, as a rule, does not leave traces in the form of dents.
3. MECHANIZATION DURING STRAIGHTENING Fig. 3 . Hand press: a - editing in the centers; b - straightening on prisms The simplest device for mechanization of straightening is a manual press (Fig. 3), with the help of which straightening of shaped rolled products and bar material is carried out.
Continuation of question 3 Fig. four . Straightening machine: a - general view; b - editing scheme; Р - editing force Fig. 5 . Correct rollers
4. BASIC RULES FOR PERFORMING WORK DURING STRAIGHTENING 1. When dressing strip and bar material (round, square or hexagonal section), the straightened part must touch the straightening plate or anvil at least in two points (Fig. 6). Rice. 6. Straightening of strip and bar material
Continuation 4 questions 4. Editing of sheet material with a thickness of 0.5 ... 0.7 mm must be done using wooden hammers - mallets (Fig. 7). 5. When straightening strips bent along the edge (straightening), as well as sheet material with significant deformations, it is necessary to use the stretch straightening method (Fig. 8). Rice. 7. Editing sheet material with a mallet Fig. eight . Editing a strip bent along an edge
Question 4 continued 6. Straightening of strips with a helical bend must be carried out in manual vices (Fig. 9, b). Rice. 9 . Editing a strip with a helical bend: a - a strip with a double bend; b - editing the strip in manual vices
Question 4 continued 7. Quality control of dressing should be carried out depending on the configuration of the workpiece and its initial state: on the “eye” (Fig. 10) - visually, with a ruler, rolling over the plate; "on a pencil" (Fig. 11) - by rotating the straightened shaft in the centers of the manual screw press. 8. When dressing strip and bar material on a plate (anvil), it is necessary to use Fig. ten . Editing control visually Fig. eleven . Control editing "on a pencil" with gloves, editing with a hammer or a sledgehammer, firmly mounted on the handle.
6. TYPICAL DEFECTS DURING STRAIGHTENING, CAUSES OF THEIR APPEARANCE AND MEANS OF PREVENTION Defect Cause Method of prevention After straightening the machined part, it has dents Editing was carried out by hitting a hammer or sledgehammer directly on the part straightening machined cylindrical parts to install on prisms After straightening the sheet material with a mallet or a hammer through a wooden adapter, the sheet is significantly deformed Insufficiently effective straightening methods were used Apply the straightening method by stretching the metal along the edges of the bulge, alternating this method with straightening by direct blows After straightening the strip is not straight along the edge The dressing process is not completed Finish the dressing by hitting the edges of the strip, turning it over 180° during the dressing process
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GBPOU SMT "SORMOVSK MECHANICAL TECHNICIUM NAMED AFTER THE HERO OF THE SOVIET UNION P.A. SEMENOV" MDK 01.01. “Fundamentals of metalwork and assembly and electrical work” TOPIC: METAL SAWING Developed by Serov V.S. master of p / o, the highest category
SAWING METAL 1. The essence and purpose of the operation of filing. 2. Tools used for filing. 3. Devices for filing. 4. Surface preparation, main types and methods of filing. 5. Rules for manual filing of flat, concave and convex surfaces. 6. Mechanization of work when filing. Tools for the mechanization of filing work. Rules for performing work with mechanized filing. 7. Typical defects in metal filing, their causes and prevention methods. Study questions:
1. The essence and purpose of the filing operation Filing is an operation to remove a layer of material from the surface of the workpiece using a cutting tool - a file, the purpose of which is to give the workpiece a given shape and size, as well as to provide a given surface roughness. In locksmith practice, filing is used to process the following surfaces: - flat and curved; - flat, located at an external or internal angle; -flat parallel under a certain size between them; - shaped complex profile. In addition, filing is used to process recesses, grooves and protrusions. Distinguish between rough and fine filing.
2. TOOLS USED FOR SADDING 1. Types of notches: a - single; 6 - double; c - rasp The main working tools used in filing are files, rasps and needle files.
Continuation of question 2 Fig. 2. Forms of the teeth of the file: a - notched: β - cutting angle; γ - front angle; δ - taper angle; α - back angle; b - milled; c - stretched Files are classified depending on the number of notches per 10 mm of file length into 6 classes. The notches have numbers from 0 to 5, while the smaller the notch number, the greater the distance between the notches and, accordingly, the larger the tooth.
Continuation of question 2 Fig.3. Cross-sectional shapes of files and processed surfaces: a, b - flat; c - square; g - trihedral; d - round; e - semicircular; g - rhombic; h - hacksaw
Continuation of question 2 Fig. 4. Rasps: a - flat blunt; 6 - flat pointed; c - round; g - semicircular; L is the length of the working part; / - handle length; b - rasp width; h is the thickness of the rasp; d - rasp diameter
Continuation of question 2 Fig. 5. Files: a, b - flat; c - square; d, d - trihedral; e - round; g - semicircular; h - olive-shaped; and - rhombic; to - trapezoidal; l - fillet
Continuation 2 questions The profile of the cross section of the file is selected depending on the shape of the surface being filed: flat, flat side of the semicircular - for filing flat and convex curved surfaces; square, flat - for processing grooves, holes and openings of rectangular section; flat, square, flat side of the semicircular - when filing surfaces located at an angle of 90 °; trihedral - when filing surfaces located at an angle of over 60 °; hacksaw, rhombic - for filing surfaces located at an angle of more than 10 °; trihedral, round, semicircular, rhombic, square, hacksaw - for sawing holes (depending on their shape).
Continuation 2 questions The length of the file depends on the type of processing and the size of the surface being processed and should be: -100 ... 160 mm - for filing thin plates; 160 ... 250 mm - for filing surfaces with a processing length of up to 50 mm; 250...315 mm - with processing length up to 100 mm; -315 ... 400 mm - with a processing length of more than 100 mm; -100 ... 200 mm - for sawing holes in parts up to 10 mm thick; -315 ... 400 mm - for rough filing; -100 ... 160 mm - when finishing (needle files). The notch number is selected depending on the requirements for the roughness of the machined surface.
Continuation of question 2 Fig. 6. File handle Fig. 7. Quick-change file handle: 1 - sleeve; 2 - spring; 3 - glass; 4- nut; 5 - body
3. Devices for filing Fig. 8. Frame: 1 - partition; 2 - working plates; 3 – screws Fig. 9. Plane-parallel basting: a - basting; b - basting in a vice with a workpiece; 1,2 - beads; 3 - working plane; 4 - workpiece
Continuation of question 3 Fig. 10. Sliding parallels a - rectangular; b – angular Fig. 11. Conductor: 1 - conductor; 2 - workpiece
Continuation of question 3 Fig. 12. Filing prism: 1 - body; 2 - clamp; 3-gon; 4 - ruler; 5-threaded hole; A - guiding plane of the prism
Question 3 continued When working with a file, the cut becomes clogged with sawdust, so the file must be cleaned before further use. The method of cleaning files from sawdust and other processing products depends on the type of material being processed and the condition of the file surface: - after processing wood, rubber and fiber, the file should be dipped in hot water for 10 ... 15 minutes, and then cleaned with a steel trimming brush; - after processing soft materials (lead, copper, aluminum) with files, the notch is cleaned with a trimming brush; - oiled files are rubbed with a piece of charcoal, then cleaned with a trimming brush. Oil from the surface of the file can be removed with a solution of caustic soda, followed by rinsing and cleaning.
4. Surface preparation, main types and methods of filing Preparation of surfaces for filing includes cleaning from oil, dirt, molding sand, scale. Cleaning is carried out with trimming brushes, as well as cutting off the remains of the gating system and flash with a chisel, followed by cleaning with coarse sandpaper. The oil is removed with various solvents. The position of the worker when filing is most convenient when his body is turned at an angle of 45 ° to the vise jaws (Fig. 13, a). The left leg should be extended forward and be at a distance of approximately 150...200 mm from the front edge of the workbench, and the right leg should be 200...30 mm away from the left so that the angle between the feet is 60...70° (Fig. 13b).
Continuation of question 4 Fig. 13. The position of the worker: a - the position of the hands and body; b - position of the legs
Continuation of question 4 Fig. 14. The position of the hands when filing: a - on the handle; b - on the toe; c - when filing
Continuation of question 4 Fig.15. Distribution of efforts during filing (balancing) The working stroke during filing is the movement of the file forward from the worker, the return stroke is idle, without pressure. Movements during the working stroke should be uniform, smooth, rhythmic, while both hands should move in a horizontal plane. When reversing, it is not recommended to tear off the file from the workpiece being processed.
Continuation of question 4 Fig. 16. Grip the file with a “pinch” Fine filing is carried out with personal files (no. 2 and 3) with less effort, which ensures the removal of small chips and a high quality surface. Finishing the surface after processing is carried out to improve its appearance with a personal file, which is taken with a “pinch”.
Question 4 continued Finishing and polishing is done with short personal and velvet files (No. 4 and 5). The pressure on the file in this type of processing should be minimal. Sawing narrow flat surfaces is usually done across, which ensures greater processing performance. When filing wide flat surfaces, three methods are used: - after each double stroke of the file, it is moved in the transverse direction to a distance slightly less than the width of the file; - the file makes a complex movement forward and to the side across the workpiece; - cross filing, in which processing is carried out alternately along the diagonals of the surface being processed, and then along and across this surface.
5. Rules for manual filing of flat, concave and convex surfaces 1. Before starting work, it is necessary to check the conformity of the configuration and dimensions of the workpiece with the requirements of the drawing. 2. It is necessary to firmly fix the workpiece in a vise. 3. When performing fine finishing operations of filing, it is necessary to use false sponges. 4. The number, length and section of the file should be selected in accordance with the technical requirements for processing.
Continuation of the 5th question Rules for filing flat surfaces 1. Choose a method of filing, taking into account the surface being processed: - transverse stroke - for narrow surfaces; - longitudinal stroke - for long surfaces; - cross stroke - for wide surfaces; - capturing the file with a “pinch” - when finishing filing, finishing under the ruler and under the size of long narrow surfaces; - the edge of a trihedral file - when finishing the inner corner of the mating surfaces. 2. A check tool to check the flatness of the surfaces should be used during filing. 3. It is necessary to start fine filing of a flat surface only after the rough filing of this surface is done exactly under the ruler.
Continuation of question 5 4. A checking tool for controlling the angle between the mating surfaces should be used only after finishing filing the base surface. 5. The tool for checking the size between parallel surfaces should only be used after a fine filing of the base surface. 6. When checking the flatness, angles and dimensions, observe the following rules: - before checking, it is necessary to clean the treated surface with a sweeping brush or rags, but in no case by hand; - to check the workpiece after processing should be released from the vice; - the workpiece with the test tool should be placed between the eyes and the light source;
Continuation of the 5th question - do not tilt the test (curve) ruler during the flatness control using the "light gap" method; - do not move checking and measuring tools on the surface of the workpiece in order to avoid their premature wear; - measurements of dimensions should be made only after the surface is well filed and checked with a ruler; - measurements of the part should be made in three or four places in order to increase the accuracy of measurements. 7. The final processing of flat narrow surfaces must be done with a longitudinal stroke.
Question 5 continued When filing curved surfaces, the following rules must be observed: 1. Correctly choose a file for filing curved surfaces: - flat and semicircular - for convex; - semicircular - for concave with a large (more than 20 mm) radius of curvature; - round - for concave with a small (up to 20 mm) radius of curvature. 2. Observe the correct coordination of movements and balancing of the file: - when filing a cylindrical roller (rod) fixed horizontally: at the beginning of the working stroke - the toe of the file is lowered down, the handle is raised up; in the middle of the working stroke - the file is located horizontally; at the end of the working stroke - the toe of the file is raised up, the handle is lowered down (Fig. 17, a);
Question 5 continued - when filing a cylindrical roller (rod) fixed vertically: at the beginning of the working stroke - the toe of the file is directed to the left; at the end of the working stroke - the toe of the file is directed forward (Fig. 17, b); - when filing a concave surface with a large radius of curvature during the working stroke, it is necessary to move the file along the surface to the right or left, slightly turning it; - when filing concave surfaces with a small radius of curvature during the working stroke, it is necessary to perform a rotational movement with a file; Rice. 17. Filing a round rod: a - located horizontally; b - located vertically
Continuation of the 5th question - finishing (finishing according to the template) of convex and concave surfaces should be done with a longitudinal stroke, holding the file with a “pinch”. 4. The convex surfaces of flat parts must first be filed on a polyhedron with an allowance of 0.5 mm, and then filed according to the markup and template. 5. Finishing should be done only after preliminary (rough) sawing of the surface according to the template.
6. Mechanization of work when filing. Rice. 19. Filing discs 20. Burs
Continuation of question 6 Fig. 21. Grinding heads: a - semicircular; b - round; c, d, e - conical; e - reverse conical; g - cylindrical
Continuation of question 6 Fig.22. Electric filing machine with flexible shaft: 1 - chuck; 2- tool; 3.5 - pulleys; 4 - belt. 6- flexible shaft. 7-electric motor; 8 - bracket; R - support.
Continuation of question 6 Fig. 23. Pneumatic filing machine: 1 - tool; 2 - cartridge; 3 - piston; 4 - rotary sleeve; 5 - piston box; 6- hose; 7- cover; 8 - trigger
Continuation of question 6 Fig. 24. Filing machine with abrasive tape: 1 - bracket; 2 - lamp; 3 - endless abrasive belt; 4 - table; 5 - base; b - power button
Continuation of question 6 Fig. 25. Stationary filing and cleaning machine: a - general view of the machine; b - executive unit; 1 - bed; 2 - casing; 3.5- brackets; 4 - rack; 6 - stock; 7 - file; 8 - blank; 9 - table; 10, 12 - screws; 11 - starting pedal
Question 6 continued Rules for performing work in mechanized filing 1. It is necessary to choose the right tool for mechanized filing of curved surfaces: - cutter cutter - for removing a large layer of metal or rough cleaning of a raw surface and burrs; - figured round files - for precise (up to 0.05 mm) surface treatment; - grinding shaped heads - for final cleaning of the processed surfaces. 2. The shape of the tool should be selected depending on the shape of the surface to be machined. 3. Surface treatment with round rotating files must be carried out by fixing them with a shank in the chuck of a manual drilling machine with a power of at least 0.5 kW.
7. TYPICAL DEFECTS IN METAL FILLING, CAUSES OF THEIR APPEARANCE AND MEANS OF PREVENTION Defect Cause Warning method "Blocks" in the rear part of the plane of the part The vice is set too high Adjust the height of the vise according to growth "Blocks" in the front of the plane of the part The vice is set too low The same “Blocks” of a sawn wide plane of the part Sawing was performed in only one direction When sawing a wide flat surface, sequentially alternate longitudinal, transverse and cross filing
Continuation of question 7 Defect Cause Prevention Cannot be filed the mating flat surfaces under the square The rules for filing the mating flat surfaces were not followed First, accurately, under the ruler, and cleanly file the base flat surface of the part, and then saw the mating surface along it flat surface The square does not fit snugly against flat surfaces mated at an internal angle Poorly finished corner at the mating Finish the corner between the mating flat surfaces with the edge of a trihedral file or needle file, make a slot in the corner of the surfaces mating Unable to file parallel flat surfaces but to each other The rules for filing flat surfaces are not observed. First, accurately, under the ruler, and cleanly file the base plane of the part. Filing of the mating plane is carried out by alternating from the very beginning of work a regular check of its flatness with a ruler and the size of the caliper with a compass. Places of sawing should be determined by the clearance between the jaws of the caliper and the sawn surface, as well as by comparing the measurement results
Continuation of question 7 Rough final finishing of the sawn surface Finishing was carried out with a “bastard” file. Incorrect methods of surface finishing were used. Surface finishing should be done only with a personal file after high-quality filing to the surface ruler with a coarser file. Surface finishing should be done with a longitudinal stroke, using a “pinch” grip on the file. The sawn round rod is not cylindrical (ovality, taper, cutting ) Irrational sequence of filing and control When filing, more often measure the dimensions of the rod in different places and from different sides.If it is necessary to remove a significant layer of metal, first file the rod into a polyhedron, checking the size and parallelism, and then bring it to cylindricity
Question 7 continued Defect Cause Warning method The filed curved surface of a flat part does not match the profile of the control template The rules for filing curved surfaces of flat parts are not observed When filing convex surfaces, first file on a polyhedron with a finishing allowance of 0.1 ...0.2 mm, then finish with a longitudinal stroke with regular control of the surface according to the template. When filing a concave surface with a small radius of curvature, the diameter of the round file should be less than twice the radius of the notch. The filed mating contour of the part does not match the profile of the control template. Finish processing by filing the concave parts of the surface, carefully watching the filing of the mating points. Finishing with a longitudinal stroke
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GBPOU SMT "SORMOVSK MECHANICAL TECHNICIUM NAMED AFTER THE HERO OF THE SOVIET UNION P.A. SEMENOV" Section 1 ". Locksmith, locksmith and assembly work. » TOPIC: SAWING Developed by Serov V.S. master of p / o, the highest category
Sawing and fitting 1. The essence of sawing and fitting. 2. Basic rules for sawing and fitting parts. 3. Typical defects in sawing and fitting parts, their causes and ways to prevent them. Study questions:
1. The essence of sawing and fitting Sawing is a kind of filing. When sawing, a hole or opening is processed with a file to ensure the specified shape and size after this hole or opening is previously obtained by drilling, drilling the contour, followed by cutting out jumpers, sawing an open contour (opening) with a hand saw, stamping, etc. The peculiarity of the sawing operation is processing quality control (size and configuration) is carried out with special testing tools - templates, workings, inserts, etc. (Fig. 1) along with the use of universal measuring tools.
Continuation of question 1 Fig. one . Template and insert: a - template; b - production; c - liner Fitting is a locksmith operation for mutual fitting by means of filing two mating parts (pairs). Fitted contours of pairs of parts are divided into closed (such as holes) and open (such as openings). One of the attached parts (with a hole, an opening) is called an armhole, and the part included in the armhole is called an insert.
2. Basic rules for sawing and fitting parts Rules for sawing 1 . It is rational to determine the method of preliminary formation of sawn openings and holes: in parts with a thickness of up to 5 mm - by cutting out, and in parts with a thickness of more than 5 mm - by drilling or reaming, followed by cutting out or cutting jumpers. 2. When drilling, reaming, punching or cutting out jumpers, it is necessary to strictly monitor the integrity of the marking marks, leaving a processing allowance of about 1 mm. 3. You should follow a rational sequence for processing openings and holes: first, process straight sections of surfaces, and then - curved sections associated with them.
Question 2 continued 4. The process of sawing openings and holes must be periodically combined with checking their contours according to a control template, insert or working. 5. The corners of openings or holes must be finished with a file edge of the corresponding cross-sectional profile (No. 3 or 4) or needle files, checking the quality of processing by workings. 6. Finishing the surfaces of the holes should be done with a longitudinal stroke. 7. For the final calibration and finishing of the hole, punching, broaching and flashing on a screw or pneumatic press should be used (Fig. 2). Rice. 2. Cylindrical firmware
Question 2 continued 8. The work should be considered completed when the control template or liner completely, without pitching, enters the opening or hole, and the clearance (gap) between the template (liner, working) and the sides of the opening (hole) contour is uniform. Fitting rules: 1. The fitting of two parts (pairs) to each other should be carried out in the following order: first, one part of the pair (usually with external contours) is made and finished - an insert, and then, according to it, as in a template, it is marked and fitted (fitted ) another mating part is an armhole. 2. The quality of the fit should be checked by clearance: in the gap between the parts of the pair, the clearance should be uniform. 3. If the contour of a pair of parts - an insert and an armhole - is symmetrical, they should, when edging 180 °, be mated effortlessly, with a uniform gap.
3. Typical defects when sawing and fitting parts, their causes and ways to prevent Defect Cause Prevention Misalignment of the opening or hole in relation to the base surface of the part Misalignment when drilling or reaming. Insufficient control when sawing Carefully monitor the perpendicularity of the tool to the base surface of the workpiece when drilling and reaming the opening (hole). In the process of work, systematically check the perpendicularity of the plane of the opening (hole) being sawn to the base surface of the part. Non-observance of the shape of the opening (hole) Sawing was performed without checking the shape of the opening (hole) according to the template (shu inserts). "Gouges" for the marking when cutting out the contour First, sawing should be carried out according to the marking (0.5 mm to the marking line). The final processing of the opening (hole) is carried out with a thorough check of its shape and dimensions with measuring tools or a template (insert)
Question 3 continued Non-coincidence of the symmetrical contours of the fitted pair (insert and armhole) when they are turned over by 180° One of the parts of the pair (counter-template) is not made symmetrically Carefully check the symmetry of the insert during marking and manufacturing One of the parts of the pair (armhole) is loose adjoins another (insert) in the corners Obstructions in the corners of the armhole Follow the rules for processing parts. Cut through the corners of the armhole with a hacksaw or saw with a round file.
1. Essence and methods of cutting Cutting is an operation associated with the separation of materials into parts using a hacksaw blade, scissors and other cutting tools. Depending on the tool used, cutting can be carried out with or without chip removal.
2. TOOLS AND DEVICES USED FOR CUTTING Pic. one . One-piece hacksaw: 1 - machine; 2 - handle; 3 - pins; 4 - hacksaw blade; 5 - head for fastening a hacksaw blade; b - tension screw with nut Hand saws are designed mainly for cutting long and profile rolled products manually, as well as for cutting thick sheets and strips, cutting grooves and slots in screw heads, cutting workpieces along the contour and other works.
Continuation of question 2 Fig. 2. Sliding hacksaw Fig. 3 . Hacksaw blade: a - geometrical parameters of the hacksaw blade: γ - rake angle; α - back angle; β - taper angle; δ - cutting angle; b - tooth wiring; in - wiring on the canvas
Continuation of question 2 Fig. four . Scissors are manual: and - right; b - with curved blades; c - finger Hand scissors (Fig. 4) are right and left. For right scissors, the bevel on the cutting part on each of the halves is on the right side, and for the left, on the left.
Continuation of question 2 Fig. 5 . Geometrical parameters of scissor blades: a - clearance angle; β - taper angle; φ - angle between blades Fig. 6. Chair scissors
Continuation of question 2 Fig. 7. Power scissors: 1 - knife; 2 - screw; 3 - hinge link; 4 - notched handle; 5 - handle with plastic tip; b - axis; 7 - lever; 8 - washer eight . Desktop manual lever scissors: 1 - base; 2 - handle; 3 - knife; 4 - table-knife
Continuation of question 2 Fig. 9 . Pipe cutters: a - roller: 1 - clamp; 2 - screw; 3 - screw lever; 4 - bracket; 5 - bracket; b - cutting rollers; 7 - pipe; b - collar; in - chain; g - incisive: 1 - pressure screw; 2 - cutting cutter; 3 - screw
Rules for performing work when cutting materials. Basic rules for cutting metal with a hacksaw 1. Before starting work, it is necessary to check the correct installation and tension of the blade. 2. The marking of the cutting line must be made along the entire perimeter of the bar (strips, parts) with an allowance for subsequent processing of 1 ... 2 mm. 3. The workpiece should be firmly fixed in a vise. 4. Strip and corner material should be cut at the wide end. 5. In the event that the length of the cut on the part exceeds the size from the blade to the frame of the hacksaw, cutting must be done with a blade fixed perpendicular to the plane of the hacksaw (hacksaw with a turned blade). 6. Sheet material should be cut directly with a hacksaw if its thickness is greater than the distance between the three teeth of the hacksaw blade. Thinner material to be cut must be clamped in a vise between wooden blocks and cut along with them.
7. The gas or water pipe must be cut, securing it in the pipe clamp. When cutting thin-walled pipes, fix them in a vice using profiled wooden spacers. 8. When cutting, the following requirements must be observed: - at the beginning of cutting, tilt the hacksaw away from you by 10 ... 15 °; - when cutting, keep the hacksaw blade in a horizontal position; - in work, use at least three quarters of the length of the hacksaw blade; -working movements should be performed smoothly, without jerks, approximately 40 ... 50 double strokes per minute; - at the end of cutting, loosen the pressure on the hacksaw and support the cut part with your hand. 9. When checking the size of the cut off part according to the drawing, the deviation of the cut from the marking line should not exceed 1 mm to the greater side.
Labor safety rules 1 . Do not cut with the blade too loose or too tight, as this may break the blade and injure your hands. 2. To avoid breaking the blade and injuring your hands when cutting, do not press the hacksaw hard down. 3. It is forbidden to use a hacksaw with a loose or split handle. 4. When assembling the hacksaw, use pins that fit tightly, without pitching, into the holes of the heads. 5. If the teeth of the hacksaw blade are chipped, stop work and replace the blade with a new one. 6. To prevent the handle from jumping off and injuring the hands during the working movement of the hacksaw, do not hit the front end of the handle on the part being cut. Continuation of 3 questions
Basic rules for cutting sheet metal up to 0.7 mm thick with hand scissors 1. When marking the part to be cut, it is necessary to provide for an allowance of up to 0.5 mm for subsequent processing. 2. Cutting should be done with sharpened scissors in gloves. 3. Place the sheet to be cut strictly perpendicular to the blades of the scissors. 4. At the end of the cut, the scissors should not be completely brought together to avoid tearing the metal. 5. It is necessary to monitor the condition of the axis-screw of the scissors. If the scissors begin to "crumple" the metal, you need to slightly tighten the screw. 6. When cutting material with a thickness of more than 0.5 mm (or when pressing the handles of the scissors is difficult), one of the handles must be firmly fixed in a vise. 7. When cutting a curved part, for example a circle, the following sequence of actions must be observed: - mark the contour of the part and cut the workpiece with a straight cut with an allowance of 5 ... 6 mm; -cut the part according to the markup by turning the workpiece clockwise. 8. Cutting should be done exactly along the marking line (deviations are allowed no more than 0.5 mm). The maximum amount of "gouge" in the corners should not exceed 0.5 mm. Continuation of 3 questions
Basic rules for cutting sheet and strip 1 . Cutting must be done with gloves to avoid cuts to the hands. 2. Cutting of a significant sheet material (more than 0.5x0.5 m) should be done by two people (one should support the sheet and move it away from you along the lower knife, the other should press the scissors lever). 3. In the process of work, the material being cut (sheet, strip) must be placed strictly perpendicular to the plane of the movable knife. 4. At the end of each cut, do not bring the knives to full compression in order to avoid "tearing" the material being cut. 5. After finishing work, it is necessary to fix the scissors lever with the fixing pin in the lower position. Continuation of 3 questions
Basic rules for cutting pipes with a pipe cutter 1 . The cut line should be marked with chalk around the entire perimeter of the pipe. 2. The pipe must be firmly secured in a pipe clamp or vise. Fixing the pipe in a vice must be done using profiled wooden spacers. The cutting point should be located no further than 80 ... 100 mm from the clamping jaws or vise. 3. In the process of cutting, the following requirements must be observed: lubricate the cutting site; - monitor the perpendicularity of the pipe cutter handle to the pipe axis; - carefully monitor that the cutting discs are located exactly, without distortion, along the cut line; - do not apply great efforts when rotating the screw of the pipe cutter handle to feed the cutting discs; - at the end of cutting, support the pipe cutter with both hands; make sure that the cut piece of pipe does not fall on your feet. Continuation of 3 questions
Fig. 4. Manual mechanized tool. ten . Mechanical hacksaw: 1 - drum; 2 - body; 3 - finger; 4 - slider; 5 - bracket; b- hacksaw blade
Continuation of question 4 Fig. eleven . Manual electrovibrating scissors: 1 - eccentric roller; 2 - body of the cutter head; 3 - body; 4- bracket; 5 - lower knife; 6 - upper knife; 7 - lever; 8 - finger; 9 - connecting rod
Fig. 5. Stationary equipment for cutting metals. 12 . Stationary mechanical hacksaw: 1 - bed; 2 - table; 3 - vice; 4 - frame; 5 - trunk; 6 - branch pipe of the cooling system; 7 - electric motor; 8 - interchangeable nozzles
Continuation of question 5 Fig. 13 . Universal circular saw: 1 - electric motor; 2, 4,5,9 - handles; 3 - bracket; b- vertical column; 7- bed; 8 - cutting disc
Continuation of question 5 Fig. fourteen . Pendulum saw: 1 - bed; 2 - table; 3 - cutting disc; 4 - handle; 5 - pulley; 6 - swinging trunk; 7 - bracket; 8 - support bar
Continuation of question 5 Fig. fifteen . Band saw: 1 - casing; 2 - flywheel; 3 - table; 4 - bed; 5 - cutting blade
Continuation of question 5 Fig.16. Guillotine shears: 1 - table; 2 - hydraulic clamps; 3 - side guides; 4 - electric motor; 5 - bed; 6 - control pedal; 7 - stand
Continuation of question 5 Fig. 17 . roller scissors
Continuation of question 5 Fig. eighteen . Disc shears
Continuation of question 5 Fig. 19 . Vibrating shears: 1 - electric motor; 2 - bracket; 3 - emphasis; 4 - head of the bracket; 5 - upper knife; 6- lower knife; 7- table; 8 - bed
5. TYPICAL DEFECTS IN CUTTING METAL, CAUSES OF THEIR APPEARANCE AND MEANS OF PREVENTION Defect Cause Method of prevention Cutting with a hacksaw Skewed cut Weakly tensioned blade. The cutting was carried out across the strip or the flange of the square Tension the blade in such a way that it is tight when pressed with a finger from the side Chipping of the teeth of the blade Incorrect selection of the blade. Blade defect on - blade overheated Blade should be selected in such a way that the tooth pitch is no more than half the thickness of the workpiece, i.e. so that two or three teeth participate in the work. Ductile metals (aluminum and its alloys) should be cut with blades with a finer tooth, thin material should be fastened between wooden blocks and cut along with them Blade breakage Strong pressure on the hacksaw. Weak tension on the canvas. The canvas is overstretched. Uneven movement of the hacksaw when cutting Loosen the vertical (transverse) pressure on the hacksaw, especially when working with a new one, as well as a heavily stretched blade. Loosen the pressure on the hacksaw at the end of the cut. Make movements with a hacksaw smoothly, without jerks. Do not attempt to correct a misaligned cut by misaligning the blades. If the blade is dull, then it needs to be replaced.
Continuation of question 6 Cutting with hand shears When cutting sheet material, the scissors crumple it Dull scissors. The hinge of the scissors is loose. Cut only with sharp-sharpened scissors. Before starting cutting, check and, if necessary, tighten the hinge of the scissors so that the extension of the handles is carried out smoothly, without jamming and pitching “Tears” when cutting sheet metal converged completely, as this leads to "tearing" of the metal at the end of the cut
Continuation of the 6th question Defect Cause Prevention method Deviation from the marking line when cutting with electro-vibration shears Non-observance of cutting rules moving (feeding someone's) scissors. When cutting workpieces with curved contours (especially for small workpiece sizes), feed by moving the workpiece Injury to the hands Work was carried out without gloves Work with scissors only in canvas gloves (primarily on the left hand supporting the sheet being cut)
Continuation of question 6 Cutting pipes with a pipe cutter Gross tears at the points of pipe fixing Violation of the rules for fixing pipes Securely fix the pipe in the pipe clamp so that it does not rotate during the cutting process. When fixing the pipe in a vise, use wooden spacers. “Ragged” end of the cut pipe. Non-observance of the rules for cutting pipes. Accurately install the pipe cutter disks according to the marking marks. During the cutting process, carefully monitor the perpendicularity of the pipe cutter handle to the pipe axis (under this condition, the cutting discs of the pipe cutter do not move and the cutting line does not warp). With each turn of the pipe cutter, tighten its screw by no more than half a turn. Copiously lubricate the axes of the cutting discs and the cutting points
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Developed by Serov V.S. master p / o, the highest category MDK 01.01. "Fundamentals of metalwork and assembly and electrical work" GBPOU SMT "SORMOVSK MECHANICAL TECHNICIUM NAMED AFTER THE HERO OF THE SOVIET UNION P.A. SEMENOV"
Lesson topic: Drilling
Objective: to develop knowledge and skills in the application of drilling skills Students should be able to: perform basic drilling techniques avoid defects when making holes follow the rules for safe work when drilling use theoretical knowledge in practice
Drilling is the formation of holes in a solid material by removing chips using a drill that performs rotational and translational movements about its axis.
Drilling is used for: placing fasteners (screws, bolts, etc.) cutting internal threads improving hole quality by countersinking and reaming
mechanized and manual equipment for drilling: vertical drilling machine 2N125L desktop vertical drilling machine 2M112
Mechanized and manual drilling equipment: Radial drilling Electric drill Hand drill machine 2H55
Drilling techniques: Drilling blind holes to a given depth: A - along the sleeve stop B - along the measuring ruler
Drilling techniques: Drilling holes Drilling A- in a plane located A- an incomplete hole with an angle to another plane using an attachment plate B- on a cylindrical surface B- holes in an angle C- in hollow parts
Types of drills: A, B - spiral, V - with straight grooves, G - feather, D - gun, E - single-edged with an internal outlet, G - two-edged for deep drilling, Z - for ring drilling, I - centering
Defects in the processing of holes, their causes and methods of prevention Defect Cause Prevention Misalignment of the hole Chips getting under the workpiece. Wrong pads. Clean the table and workpiece from dirt and chips. Fix or replace pads. Hole offset Pull drill to the side. Incorrect markup when drilling on markup. Check the correct sharpening of the drill. Correctly mark the workpiece. Oversized hole diameter Different lengths of cutting edges. Offset transverse cutting edge. Regrind the drill correctly Increasing the depth of the hole Incorrect setting of the depth stop Accurately set the stop to the specified depth of cut
Drilling Safety Rules Keep your hair under a hat Close the cuffs on your sleeves carefully Do not: 1. Drill a loose workpiece 2. Press the drill feed lever hard 3. Lean close to the drilling site to prevent chips from getting into your eyes 4. Blow chips
Task for the lesson Produce: drilling blind holes drilling through holes drilling a shank
Checklist #1 What is drilling used for? No. 2 What equipment is used for drilling? No. 3 What drilling techniques do you know? No. 4 How to avoid defects in holemaking? No. 5 What safety precautions must be observed when working with power tools for drilling?
Thank you for your attention!
Fitting and assembly work. Connection types
All types of connections of parts used in metalwork and assembly work are divided into two main groups: detachable and one-piece. Detachable connections are those that can be disassembled into their component parts. This group includes threaded, keyed, splined, pin and wedge connections. One-piece, respectively, those connections, the disassembly of which is possible only with the destruction of the fastening or the parts themselves. This group includes press, riveting, welded and adhesive joints.
Assembly of threaded connections
When trying to disassemble any mechanism or plumbing structure, whether it is the engine of a washing machine or an object of plumbing equipment, you will notice that most of all the joints of the parts are threaded. And this is not accidental: threaded connections are simple, reliable, interchangeable, and easy to adjust.
The assembly process of any threaded connection includes the following operations: installation of parts, baiting, screwing, tightening, sometimes tightening, if necessary, installation of locking parts and devices that prevent self-unscrewing.
When baiting, the part to be screwed must be brought to the threaded hole until the axes coincide and screwed into the thread by 2-3 threads. Anyone who has worked with small screws knows how inconvenient it can be to hold a screw in hard-to-reach places, such as from below. Professionals in such cases use magnetic and other special screwdrivers. But if they are not there, you should not despair and curse the stubborn screw with strong words, the problem can be solved with the help of a simple device that is easily made in just a few seconds. From a thin soft wire, you need to make a small hook and support the screw with it until it enters the threaded hole for several threads. Then you just need to pull on the wire - the loop will open and release the screw for further screwing with the tool.
After baiting, an assembly tool (wrench or screwdriver) is installed on the part and rotational movements are imparted to it (screwed). Screwing is completed by tightening, which creates immobility of the connection.
Tightening is carried out when the part is fastened with several bolts (screws). For example, when attaching the cylinder head (in a car engine), the bolts are screwed in without pre-tightening, and after they are all installed, they are tightened. This is carried out in a certain order - according to the so-called spiral method (Fig. 50).
Rice. 50. Scheme of a possible sequence of tightening (tightening) of bolts (screws, nuts).
Threaded connections in mechanisms that are subjected to a pulsating load (vibration) during operation often unscrew themselves, which can cause an accident. Therefore, when assembling such mechanisms, they resort to locking threaded connections.
The simplest, fairly reliable and not requiring any special devices locking method is locking with a lock nut. It is screwed on after tightening the main fixing nut and tightened until it is in full contact with its end. The locking mechanism with this method is based on an increase in the friction surfaces in the thread and on the surfaces of the nuts.
Locking with lock washers is also widespread (Fig. 51).
Rice. 51. Ways of locking threaded connections: a - lock washer; b - stopper; c - wire; d - welding or punching.
Such a washer has either a nose, which is bent to the edge of the nut after it is tightened, or a foot, which is inserted into a specially drilled hole in the part body. Screws (bolts) with open heads can be locked with wire. Holes in the heads of screws (bolts) for wire in this case are drilled before they are installed in the assembly. The wire should be inserted into the holes in such a way that the tension of its ends creates a screwing moment.
Locking by welding or punching, in fact, turns a detachable connection into a one-piece.
Quite often, threaded connections use studs, which, unlike a bolt or screw, do not have a head. In order to ensure a tight fit of the stud into the body of the part, you can use one of the proposed methods: the stud tension is formed due to thread run-out (see the chapter on external threading) or is provided with a tight thread with interference along the average diameter of the turns. If the part body is made of a material less durable than the stud, then a spiral insert made of rhombic steel wire is used: it is inserted into the thread of the part body before the stud is screwed in. This method not only increases the strength and wear resistance of the connection (due to an increase in the surface of the thread cut in the body part), but also contributes to a tight fit of the stud. To form a sealed, hydro-tight connection, a gasket made of an easily deformable material (copper-asbestos, paronite, etc.) is placed between the parts to be joined.
In some cases, it is required to obtain a connection of special strength, which cannot be achieved using ordinary low-grade metal bolts, since they simply break under large transverse loads. Buying special high-strength bolts is expensive, and you can’t always find them in stores. In such cases, it is possible to apply an adhesive layer of epoxy resin on the surfaces of the parts that will be in contact before assembly. The connection will turn out to be very strong even when using ordinary cheap bolts.
Assembly of keyed-spline connections
Another type of fixed detachable connections are keyed-slotted, which are formed by rods - dowels. Keyed connections are mainly used in mechanisms for torque transmission. Depending on the load on such connections and the operating conditions of the mechanism, wedge, prismatic and segment keys are used (Fig. 52).
Rice. 52. Varieties of keyed connections: a - wedge key.
Rice. 52 (continued). Types of key connections: b - feather key; in - segment key; g - slotted; d - pin.
Rice. 52 (continued). Types of keyed connections: e - correctly assembled connection; g - defect of the increased gap; h - defect from misalignment of the axis of the keyway.
As a rule, such a connection consists of a shaft, a key and a wheel or bushing.
A type of keyway connection is spline, when the key is one with the shaft. Due to the fact that not three, but two parts are involved in this connection, the connection is more accurate.
When assembling keyed connections, a pin can be used instead of a key. The pin connection is more technologically advanced (which is ensured by the interchangeability of parts), but requires additional processing: in the female part and on the shaft, it is necessary to jointly drill and expand the hole for the pin with a conical reamer.
The assembly sequence of the keyed connection is as follows: the shaft is fixed in a vice, a key is installed in the groove of the shaft and the female part is put on. In this case, the connection of the key with the shaft must be tight (the key is installed in the groove of the shaft with an interference fit), while the key is installed more freely in the groove of the hub.
When mounting the female part (wheels, bushings, etc.) on the shaft, it is necessary to ensure that the axes of the shaft and the part coincide. Incorrect keying leads to deformation and destruction of the key. The main reason for such a defect is the increased clearance or misalignment of the keyway axis. In order to avoid joint defects, the groove is adjusted by scraping, and the dimensions of the grooves and keys are adjusted, and the misalignment of the axes is controlled.
Soldered connections. Tinning
Soldering allows you to combine elements from different metals and alloys with different physical and mechanical properties into a single product. For example, the method of soldering can be used to connect low-carbon and high-carbon steels, cast iron parts with steel, hard alloy with steel, etc. Particularly noteworthy is the possibility of joining parts made of aluminum and its alloys by soldering. The method of soldering plates is widely used hard alloy to holders in the manufacture of cutting tools.
In a home workshop, soldering is the most accessible form of the formation of fixed, one-piece joints. During soldering, a molten filler metal, called solder, is introduced into the gap between the heated parts. Solder, which has a lower melting point than the metals to be joined, wetting the surface of the parts, connects them when cooled and solidified. In the process of soldering, the base metal and solder, mutually dissolving in each other, provide a high strength of the connection, the same (with high-quality soldering) as the strength of the entire section of the main part.
The process of soldering differs from welding in that the edges of the parts to be joined are not melted, but only heated to the melting temperature of the solder.
To make solder joints, you need: an electric or indirectly heated soldering iron, a blowtorch, solder, flux.
The power of an electric soldering iron depends on the size of the parts to be joined, on the material from which they are made. So, for soldering copper products of small sizes (for example, a wire with a cross section of several square millimeters), a power of 50–100 W is sufficient; when soldering electronic devices, the power of an electric soldering iron should be no more than 40 W, and the supply voltage should not exceed 40 V; large parts require a power of several hundred watts.
The blowtorch is used to heat the indirectly heated soldering iron and to heat the parts to be soldered (with a large soldering area). Instead of a blowtorch, you can use a gas burner - it is more productive and reliable in operation.
The most commonly used solder alloys are tin-lead alloys with a melting point of 180–280 °C. If bismuth, gallium, cadmium are added to such solders, then low-melting solders with a melting point of 70–150 ° C are obtained. These solders are relevant for soldering semiconductor devices. In ceramic-metal soldering, a powder mixture is used as solder, consisting of a refractory base (filler) and low-melting components, which provide wetting of the filler particles and the surfaces to be joined. On sale there are also alloys in the form of bars or wire, which are a symbiosis of solder and flux.
The use of fluxes in the soldering process is based on their ability to prevent the formation of an oxide film on the surfaces of parts when heated. They also reduce the surface tension of the solder. Fluxes must meet the following requirements: maintaining a stable chemical composition and activity in the solder melting temperature range (that is, the flux under the action of these temperatures should not decompose into components), the absence of chemical interaction with the soldered metal and solder, the ease of removal of the products of interaction between the flux and the oxide film ( washing or evaporation), high fluidity. Soldering various metals is characterized by the use of a specific flux: when soldering parts made of brass, silver, copper and iron, zinc chloride is used as a flux; lead and tin require stearic acid; sulfuric acid is suitable for zinc. But there are also so-called universal solders: rosin and soldering acid.
Parts that are supposed to be connected by soldering should be properly prepared: cleaned of dirt, removed with a file or sandpaper the oxide film formed on the metal under the influence of air, pickled with acid (steel - hydrochloric, copper and its alloys - sulfuric, alloys with a large nickel content - nitrogen), degrease with a swab dipped in gasoline, and only after that proceed directly to the soldering process.
You need to heat up the soldering iron. Heating is checked by immersing the tip of the soldering iron in ammonia (solid): if the ammonia hisses and blue smoke comes from it, then the heating of the soldering iron is sufficient; Under no circumstances should the soldering iron be overheated. If necessary, its nose should be cleaned with a file from the scale formed during the heating process, immerse the working part of the soldering iron into the flux, and then into the solder so that droplets of molten solder remain on the tip of the soldering iron, heat the surfaces of the parts with a soldering iron and tin them (that is, cover them with a thin layer molten solder). After the parts have cooled down a bit, tightly connect them together; warm up the soldering place again with a soldering iron and fill the gap between the edges of the parts with molten solder.
If it is necessary to connect large surfaces by soldering, then they act somewhat differently: after heating and tinning the place of soldering, the gap between the surfaces of the parts is filled with pieces of cold solder and at the same time the parts are heated and the solder is melted. In this case, it is recommended to periodically process the tip of the soldering iron and the place of soldering with flux.
The fact that it is unacceptable to overheat the soldering iron has already been said, but why? The fact is that an overheated soldering iron does not hold droplets of molten solder well, but this is not the main thing. At very high temperatures, the solder may oxidize and the joint will be fragile. And when soldering semiconductor devices, overheating of the soldering iron can lead to their electrical breakdown, and the devices will fail (which is why soft solders are used when soldering electronic devices and the effect of a heated soldering iron on the soldering point is limited to 3–5 seconds).
When the soldering site has completely cooled down, it is cleaned of flux residues. If the seam turned out to be convex, then it can be leveled (for example, with a file).
The quality of the soldering is checked: by external inspection - in order to detect unsoldered places, by bending at the place of the soldering - no cracks are allowed (strength test); brazed vessels are checked for tightness by filling with water - there should be no leakage.
There are soldering methods that use hard solder - copper-zinc plates 0.5-0.7 mm thick, or rods with a diameter of 1-1.2 mm, or a mixture of sawdust of copper-zinc solder with borax in a ratio of 1: 2. Soldering iron not used in this case.
The first two methods are based on the use of plate or rod solder. Preparing parts for hard soldering is similar to preparing parts for soft soldering.
Next, pieces of solder are superimposed on the place of soldering and the parts to be soldered together with solder are twisted with a thin knitting steel or nichrome wire (0.5–0.6 mm in diameter). The place of soldering is sprinkled with borax and heated until it melts. If the solder has not melted, then the place of soldering is sprinkled with brown a second time (without removing the first portion) and heated until the solder melts, which fills the gap between the soldered parts.
In the second method, the place of soldering is heated red-hot (without pieces of solder), sprinkled with borax and a solder bar is brought to it (continuing heating): the solder melts and fills the gap between the parts.
Another soldering method is based on the use of a powder mixture as a solder: the prepared parts are heated red-hot at the place of soldering (without solder), sprinkled with a mixture of borax and solder sawdust and continue to heat until the mixture melts.
After soldering by any of the three proposed methods, the soldered parts are cooled and the place of soldering is cleaned from the remnants of borax, solder and binding wire. The soldering quality is checked visually: to detect non-soldered places and strength, the soldered parts are lightly tapped on a massive object - with poor-quality soldering, a kink is formed in the seam.
Varieties of solder joints are shown in fig. 53.
Rice. 53. Designs of soldered joints: a - overlap; b - with two overlaps; in - end-to-end; g - oblique seam; d - end-to-end with two overlaps; e - in Taurus.
In most cases, the parts are first tinned, which makes subsequent soldering easier. The scheme of the tinning process is shown in fig. 54.
Rice. 54. Scheme of tinning with a soldering iron: 1 - soldering iron; 2 - base metal; 3 - zone of fusion of solder with the base metal; 4 - flux; 5 - surface layer of flux; 6 - dissolved oxide; 7 - flux pairs; 8 - solder.
However, tinning can be used not only as one of the stages of soldering, but also as an independent operation, when the entire surface of a metal product is covered with a thin layer of tin to give it decorative and additional performance.
In this case, the covering material is not called solder, but semi-solder. Most often they are tinned with tin, but in order to save money, lead can be added to the half-day (no more than three parts of lead to five parts of tin). The addition of 5% bismuth or nickel to the tin gives the tinned surfaces a beautiful sheen. And the introduction of the same amount of iron into the half-day makes it more durable.
Kitchen utensils (dishes) can only be tinned with pure tin half, the addition of various metals to it is dangerous to health!
The half-day lies well and firmly only on perfectly clean and fat-free surfaces, therefore, before tinning, the product must be thoroughly cleaned mechanically (with a file, scraper, sandpaper to a uniform metallic sheen) or chemically - hold the product in a boiling 10% caustic soda solution for 1–2 minutes, and then etch the surface with a 25% hydrochloric acid solution. At the end of cleaning (regardless of the method), the surfaces are washed with water and dried.
The tinning process itself can be carried out by rubbing, dipping or galvanizing (such tinning requires the use of special equipment, so galvanic tinning at home, as a rule, is not carried out).
The rubbing method is as follows: the prepared surface is covered with a solution of zinc chloride, sprinkled with ammonia powder and heated to the melting point of tin.
Then you should attach a tin rod to the surface of the product, distribute the tin over the surface and grind it with clean tow until a uniform layer is formed. Re-lubricate untinned places. Work should be done in canvas gloves.
In the dip tinning method, tin is melted in a crucible, the prepared part is grasped with tongs or pliers, immersed for 1 minute in a solution of zinc chloride, and then for 3-5 minutes in molten tin. The part is removed from the tin and the excess of the tin is removed by strong shaking. After tinning, the product should be cooled and rinsed with water.
Welding
To create fixed, permanent joints, welding is also widely used, by means of which an interatomic bond is established between the parts to be joined.
Depending on the form of energy used in the formation of a welded joint, all types of welding are divided into three classes: thermal, thermomechanical and mechanical (Table 1).
Table 1. Classification of types of welding
Of course, not all types of welding can be done in a home workshop. Most of them require sophisticated equipment. Therefore, we will consider in more detail those types of welding that are most accessible to the home master.
But first, about the preparation of parts that are intended to be joined by welding: oily places should be washed with a solution of caustic soda, and then with warm water, the welding spots should be treated with a file and an organic solvent, the edges should be sawed off or milled to form a chamfer.
Most often in living conditions gas welding is used (Fig. 55, a). The principle of gas welding is as follows: gas (acetylene), burning in the atmosphere, forms a flame beam that melts the filler material - wire or rod. The molten rod fills the gap between the edges of the parts, resulting in a weld. Gas welding can weld both metals and plastics.
Rice. 55. Types of welding: a - gas: 1 - filler material; 2 - welding torch; b - consumable electrode arc welding: 1 - consumable electrode; 2 – electrode holder; c - electric arc welding with a non-consumable electrode: 1 - electrode holder; 2 - non-consumable electrode, 3 - filler material; d - scheme of explosion welding: 1, 2 - welded plates; 3 - explosive charge; 4 - electric detonator.
Electric arc welding is also widespread (Fig. 55 b, c). It can be produced both with a consumable electrode and non-consumable - coal or tungsten (in this case, filler material is additionally introduced into the zone of the melting arc).
Medium-, high-carbon and alloy steels belong to the category of metals with limited weldability. To avoid cracks when welding parts made of these materials, they are preheated to a temperature of 250–300 °C. Details from sheet steel up to 3 mm thick can be welded by gas welding.
The scheme of explosion welding is shown in fig. 55, d: one of the plates to be welded is fixedly mounted on the base, a second plate is placed above it at a height h, on which an explosive charge is placed. The electric detonator explodes the charge, as a result of which the detonation wave, which has a high speed and high pressure, informs the second plate of the impact speed. At the moment of contact of the plates, they are welded.
It is difficult to carry out other types of welding at home (devices for diffusion, laser, electron beam and other types of welding are not as widely available as welding machines for arc or gas).
Assembly of rivet joints
If the assembly unit (joint assembly) during operation will be subjected to large dynamic loads and the soldering method is not applicable due to the fact that the parts are made of metals with poor weldability, then in these cases riveted joints are used.
The rivet is a metal rod of circular cross section, with a head at the end, which is called a mortgage and is semicircular, secret and semi-secret in shape (Fig. 56).
Rice. 56. Types of rivets: a - with a countersunk head; b - with a semicircular head; in - with a flat head; g - with a semi-secret head; e - explosive rivet: 1 - recess filled with explosive.
Rivets are drilled with a drill having a diameter larger than the diameter of the rivet shaft. The dimensions of the rivets depend on the thickness of the parts to be riveted.
The riveting operation itself is preceded by the preparation of parts for the implementation of this type of connection. First you need to mark the rivet seam: if the riveting will overlap, then the upper part is marked, for butt riveting, the overlay is marked.
In this case, it is necessary to observe the step between the rivets and the distance from the center of the rivet to the edge of the part. So, for a single-row riveting t = 3d, a = 1.5d, for a double-row riveting t = 4d, a = 1.5d, where t is the pitch between the rivets, a is the distance from the center of the rivet to the edge of the part, d is the diameter of the rivet.
Next, drill and countersink holes for the rivet rods. When choosing the diameter of the drill, it should be noted that for rivets with a diameter of up to 6 mm, a gap of 0.2 mm must be left, with a rivet diameter of 6 to 10 mm, the gap should be 0.25 mm, from 10 to 18 mm - 0.3 mm. When drilling holes, it is necessary to strictly observe the angle between the axis of the hole and the planes of the parts at 90 °.
In the direct method, blows are applied from the side of the closing head, and for good contact of the riveted parts, their tight compression is necessary. With the reverse method, blows are applied from the side of the insert head, and a tight connection of the parts is achieved simultaneously with the formation of the closing head.
Riveting is carried out in the following sequence (Fig. 57):
- select rivet rods with a diameter depending on the thickness of the sheets to be riveted:
where d is the required diameter, s is the thickness of the sheets to be riveted. The length of the rivets should be equal to the total thickness of the parts to be riveted plus the allowance for the formation of the closing head (for countersunk - 0.8–1.2 rivet diameter, for semicircular - 1.25–1.5);
- rivets are inserted into the extreme holes of the riveting seam and the embedded heads are supported on a flat support, if the heads should be countersunk, or on a spherical one, if the heads should be semicircular;
- upset the parts at the place of riveting until they fit snugly;
- upset the rod of one of the extreme rivets with a hammer striker and flatten it with the hammer nose;
- further, if the head should be flat, then the hammer striker aligns it, if it is semicircular, then the side impacts of the hammer give it a semicircular shape and, using a spherical crimp, achieve the final shape of the closing head;
- in the same way, the second extreme rivet is riveted, and then all the rest.
Rice. 57. Process sequence hand forged: a - rivets with countersunk heads.
Rice. 57 (continued). The sequence of the manual riveting process: b - rivets with semicircular heads.
The connection of parts (mostly thin) in hard-to-reach places is carried out with explosive rivets with an explosive in the recess (Fig. 56, e). To form a joint, the rivet is put in place in a cold state, and then the embedding head is heated by a special electric heater for 1-3 seconds to 130 ° C, which leads to an explosion of the explosive filling the rivet. In this case, the closing head acquires a barrel-shaped shape, and its expanded part tightly tightens the sheets to be riveted. This method is characterized by high productivity and good riveting quality.
It is necessary to introduce explosive rivets into the holes by smooth pressing, without impacts. It is forbidden to remove varnish, discharge rivets, bring them to fire or hot parts.
When riveting by hand, a bench hammer with a square head is often used. The mass of the hammer to ensure a quality connection must correspond to the diameter of the rivets. For example, with a rivet diameter of 3–4 mm, the weight of the hammer should be 200–400 g, and with a diameter of 10 mm, 1 kg.
If the diameter of the drill for making a hole for rivets, the diameter and length of the rivet itself is incorrectly selected, if other operating conditions are violated, rivet joints may have errors (Table 2).
Table 2. Marriage in rivet joints and its causes
If defects are found in rivet joints, incorrectly set rivets are cut or drilled and riveted again.
Pneumatic riveting hammers with a spool air distributor greatly facilitate riveting. With a small consumption of compressed air, they are characterized by high performance.
Gluing
Bonding of parts is the last type of assembly of fixed, one-piece joints, in which a layer of a special substance is introduced between the surfaces of the parts of the assembly unit, capable of holding them motionless - glue.
This type of connection has a number of advantages: firstly, the possibility of obtaining assembly units from dissimilar metals and non-metallic materials; secondly, the gluing process does not require elevated temperatures (as, for example, welding or soldering), therefore, deformation of parts is excluded; thirdly, the internal stress of materials is eliminated.
In fitting and assembly work, adhesives are usually used: EDP, BF-2, 88N (Table 3).
Table 3. Grade of glue and its scope
Like all other types of joints, the quality of glued joints largely depends on the correct preparation of the surfaces for the gluing process: they should not be stained with dirt, rust, traces of grease or oil. Cleaning of surfaces is carried out with metal brushes, abrasive skins, the material for removing grease and oil stains depends on the brand of glue used: when gluing parts with 88N glue, gasoline is used, for EDP and BF-2 glues - acetone.
The process of gluing parts consists of the following operations:
- prepare the surfaces of the parts and select the brand of glue (see above);
- apply the first layer of glue on the surfaces at the joints (this operation can be done with a brush or watering), dry, apply a second layer of glue, connect the parts and press them together with clamps (here it is important to monitor the exact match of the parts and their tight fit);
– withstand the glued knot and clean the seams from glue smudges.
Drying mode of the first adhesive layer: EAF is applied in one layer and does not require drying; BF-2 requires drying for 1 hour at a temperature of 20 ° C (“tack-free”); 88N - 10-15 minutes in air. After applying the second layer, hold for 3-4 minutes and only then connect the parts.
Holding time for glued joints: when using EDP glue - 2–3 days at a temperature of 20 °C or 1 day at a temperature of 40 °C; glue BF-2 - 3–4 days at a temperature of 16–20 °C or 1 hour at a temperature of 140–160 °C; glue 88N - 24-48 hours at a temperature of 16-20 ° C under load.
When assembling machines and mechanisms, sometimes combined glued joints are used - glue-welded: a layer of VK-9 glue is applied to the mating surface of one of the parts, and the second part is welded by spot welding on this layer.
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PC 1.2. Manufacture of fixtures for assembly and repair;
The results of the intermediate certification show the level of development of professional and general professional competencies.
Indicators of the result of mastering professional and general professional competencies.
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Professional competencies. |
Indicators for evaluating the result of mastering professional competencies. |
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PC 1.1. Perform bench fitting and soldering of parts and assemblies of varying complexity during the assembly process; |
Compliance with the algorithm of working methods when describing the technology of metalwork and metalwork - assembly work. Accuracy in determining the tool, fixtures, material necessary to perform metalwork and metalwork - assembly work. The accuracy of the choice of variant of solving problems. Accuracy in the definition of concepts, formulations. Justification of the choice of solder when connecting wires of various brands by soldering; Justification of the choice of methods and use of materials in tinning; Demonstration of knowledge of the technology of performing soldering with various solders and tinning; |
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PC 1.2. Manufacture fixtures for assembly and repair |
Demonstration of practical skills in making fixtures for assembly and repair Justification of the chosen device. |
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General professional competencies. |
Indicators for evaluating the result of mastering general professional competencies. |
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Understand the essence and social significance of your future profession, show a steady interest in it. |
Possession of a culture of thinking, the ability to generalize, analyze, perceive information, set a goal and choose ways to achieve it. Able to improve and develop his intellectual and general cultural level, achieve moral and physical improvement of his personality |
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Organize your own activities, based on the goal and ways to achieve it, determined by the leader. |
Rationality of planning and organization of activities for the implementation of control tasks. Timely delivery of assignments, reports, etc. Argumentation of the choice of methods for controlling one's knowledge. Discipline, responsibility. Ability to get the job done. Self control. Introspection. |
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Analyze the working situation, carry out current and final control, evaluate and correct their own activities, be responsible for the results of their work. |
Demonstration of the ability to make decisions in standard and non-standard situations and take responsibility for them Responsibility for the results of your work Demonstration of the ability to independently learn new research methods, to change the scientific and scientific-production profile of one's professional activity, to change the socio-cultural and social conditions of activity |
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Search for information necessary for the effective performance of professional tasks. |
Demonstration of skills to use normative and reference documents in the course of work |
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Use information and communication technologies in professional activities. |
Demonstration of the skills of searching for reference material on the Internet. Possession of skills of work in professional applied programs. |
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Work in a team, communicate effectively with colleagues, management, customers. |
Correct interaction with students, teachers; |
Tasks
for the final control for the first half of the year
(differentiated score)
Written test
according to MDK 01.01 Basics of metalwork and assembly and electrical work
Option 1
1. Name the universal measuring tools for dimensional control used in plumbing.
2. What is markup?
3. Name the operations performed before marking the part.
4. What operation does the locksmith perform before cutting and sawing the material?
5. What is filing?
6. Name the types of drills depending on their design.
7. How is a broken drill removed from a hole in metal?
8. What tools are used to cut the helical surface on the outer cylindrical surface of the part?
9. What are the file handling requirements?
Option 2
1. What holes are used for riveting?
2. What tools, besides scrapers, are used for scraping?
3. Describe the sequence of blackening?
4. Explain the main difference between soft and hard solders.
5. What is the sequence of assembling parts and assemblies?
6. Who is allowed to service lifting and transport mechanisms, cranes and welding equipment?
7. What should be done immediately before proceeding with the assembly of parts into assembly kits and assemblies?
8. List the safety rules for grinding.
9. Name some simple special dimensional control tools used in plumbing.
10. Describe the technology of this contact connection.
Option 3
1. Name the types of markup.
2. What is the difference between flat and spatial layout?
3. What is a marking base?
4. What should be done with the blade if the teeth break?
5. Name the filing tool.
6. What elements does the working part of the drill consist of?
7. What tool and when is countersinking performed?
8. Name the tool for threading holes.
9. How to avoid accidents when filing?
10. Describe the technology of this contact connection.
Option 4
1. Name the types of rivet joints.
2. When is scraping used?
3. What is lapping?
4. What is coloring?
5. In what form is the solder produced?
6. What is dismantling machine?
7. How should the facility be prepared for renovation?
8. What is a universal caliper, what is it intended for and what elements does it consist of?
9. What safety rules must be observed when plating, tinning and soldering, as well as when gluing?
10. Describe the technology of this contact connection.
Option 5
1. What is the difference between flat and spatial layout?
2. What is punching?
3. How can I cut pipes with a hacksaw?
4. What types of files are divided into depending on their shape?
5. What is drilling and what is it based on?
6. What is the cutting part of the twist drill?
7. Name the types of countersinks.
8. What elements does the tap consist of?
9. How should the site be prepared for renovation of the facility?
10. Describe the technology of this contact connection.
Option 6
1. What should be done before scraping?
2. Name the tools and equipment that can be used to obtain permanent metal joints by soldering.
3. What is machine repair?
4. Name the types of rivet seams.
5. Describe the specifications for riveted and bolted connections.
6. What is the compass for?
7. Name the methods of spatial marking.
8. What is the markup technique for the template?
9. What safety rules should be followed when lapping and finishing surfaces?
10. Describe the technology of this contact connection.
Option 7
1. When cutting material, what should be done if the cutting line is at an angle to the surface or if the blade slides over the material?
2. How are files classified according to the density and size of the notches?
3. Where is drilling used?
4. What determines the angle at the top of the drill?
5. What is a sweep and when is it used?
6. What is a thread profile?
7. What riveting methods are used?
8. Name the tool and material used for scraping the paint.
9. What are the main conditions for dismantling?
10. Describe the technology of this contact connection.
Option 8
1. Name the types of laps.
2. What is soldering?
3. What is tinning and galvanizing?
4. What is machine assembly?
5. What specifications must the axles and shafts as well as the mounted bearings meet?
6 What is a square and in what plumbing operations is it used?
7. What is required for markup?
8. What is markup accuracy?
9. What tool is used to cut hard materials and why?
10. Describe the technology of this contact connection.
Option 9
1 Name the types of file notches.
2. What types of processing are used to obtain round holes in the material, depending on the required accuracy?
3. What should be done with the drill if it does not drill well?
4. Name the types and types of sweeps.
5. Name the types of threads depending on the profile.
6. Name the tool used for manual and mechanical riveting.
7. Explain the process of scraping paint.
8. Name the materials used for grinding.
9. What safety rules should be followed when scraping?
10. Describe the technology of this contact connection.
Option 10
1. What materials, tools and fixtures are needed for tinning and galvanizing parts?
2. What tool is used to remove the rolling bearing, gears and pulleys from the shaft?
3. List the technical conditions for the installation of friction and gear drive mechanisms.
4. Name the patterns frequently used by the locksmith.
5. Name the marking tool and the main devices necessary for marking.
6. What is the thickness of the sheet cut by different scissors?
7. How are files used depending on their shape?
8. What types of work are performed on drilling machines?
9. How should the machine or equipment be handled to ensure that it is in good working order?
10. Describe the technology of this contact connection.
Option 11
1. When are expandable and adjustable reamers used?
2. How should the threading rod be prepared?
3. What are the disadvantages and advantages of scraping?
4. What is an abrasive mineral and what does it serve?
5. Name the types of soldering irons.
6. What is a bearing alloy and where is it used?
7. Name the types of repair of machinery and equipment
8. How are permanent connections disassembled?
9. What should be done before drilling?
10. Specify the elements of the power cable.
Option 12
1. List the specifications for assembling clutches.
2. Name the measuring aids.
3. Name measuring tools for marking
4. What should be the sharpening angle of hand scissors?
5. Name the tools and fixtures for drilling.
6. Name the defects during drilling.
7. What elements does a sweep consist of?
8. Name the causes of marriage during threading.
9. When filing, what is the importance of correctly and securely fixing the material in a vice or fixture?
10. Give a description of the connection of parts
Option 13
1. Name soft solders and their melting point.
2. What is polishing?
3. What determines the choice of bearing alloys, what types of alloys are used?
4. Where is the repairman's job?
5. How are parts or assembly units of detachable connections dismantled?
6. What should be done after assembling the machine or machinery?
7. Name auxiliary locksmith tools and auxiliary materials.
8. What safety rules should be observed when riveting?
9. Name the tools and materials for soldering.
10. Determine the height of the head of the threaded bolt M 12 × 1.25
Option 14
1. Name the auxiliary materials for marking.
2. What is called cutting and sawing metal?
3. What else, besides familiar tools and equipment, can cut the material?
4. How should non-metallic material, as well as products made of artificial or non-metallic materials, be fixed to avoid surface damage?
5. Name the maximum diameters of drills that can be used to drill holes on conventional types of drilling machines.
6. What is a drilling jig?
7. Name the coolant used when reaming holes in various materials.
8. What is a riveting?
9. What is scraping?
10. When repairing, it is necessary to cut a slot in the screws M8 × 1.25 with a cylindrical head. Determine the width and depth of the slot.
Option 15
1. What is grinding?
2. Name hard solders and their melting point.
3. How is liquid bearing alloy produced?
4. List the tools, equipment and fixtures required for the repair of machinery and equipment.
5. What should be done with the parts after they are disassembled?
6. Why should the object be painted after the repair?
7. Tell about the purpose and types of wrenches.
8. Name simple marking and measuring tools used in plumbing work.
9. What operation is performed after inspecting the machine or mechanism?
10. It is necessary to drill 4 holes in the beam for M36 × 4 bolts Determine the diameter of the holes.
Option 16
1. What operation should be performed after flushing?
2. List the auxiliary materials used in the repair.
3. What is sputter plating and where is it used?
4. Name common means for cleaning and etching surfaces during soldering.
5. What is matting?
6. What is the purpose of grinding?
7. What tools are used for scraping?
8. Name the types of rivets depending on the shape of the head and their area of application.
9. What safety requirements should be followed when working on drilling machines?
10. To lock the oil pump cover, it is necessary to drill holes in the bolts for 1.8 mm cotter pins. Determine the drill diameter.
Option 17
1. What is the purpose of drilling cooling and what coolants are used?
2. When is a drilling ratchet used?
3. What should be the height of the vise and what should be the position of the locksmith when filing?
4. What is a pipe cutter and how to use it?
5. What is the purpose of the puller and what parts does it consist of?
6. On the basis of what is the marking of the part carried out?
7. Name the main parts that make up a hand saw.
8. What is file recovery and what is it based on?
9. What are the safety precautions for cutting and sawing material?
10. Two sheets 3 and 5 mm wide are riveted. Determine the diameter of the rivets.
Option 18
1. What is a drill?
2. How are holes with a diameter of more than 30 mm made in metal?
3. What is threading?
4. What parts does a rivet consist of?
5. Name the types of scrapers.
6. Name what defects can occur during grinding.
7. What is oxidation?
8. What is zinc chloride and how to use it?
9. Name the types of assembly.
10. The truss is riveted with a single-row seam with steel rivets with a diameter of 25 mm. Determine riveting pitch
STANDARDS OF ANSWERS
Option 1
1. Name the universal measuring tools for dimensional control used in plumbing.
folding measuring metal ruler or metal tape measure, universal caliper, normal caliper for external measurements, normal caliper for measuring diameter, simple rod depth gauge, universal goniometer, square, compasses.
2. What is markup?
Marking is the operation of drawing lines and dots on a workpiece intended for processing. The outline of lines and points serves as a processing boundary for the worker.
3. Name the operations performed before marking the part.
cleaning the part from dirt and corrosion, degreasing the part, inspecting the part in order to detect defects (cracks, cavities, distortions); verification of overall dimensions, as well as allowances for processing; determination of the marking base; covering with white paint the surfaces to be marked and applied to them with lines and dots; definition of the axis of symmetry.
4. What operation does the locksmith perform before cutting and sawing the material?
prepare the material, mark it with a scriber or mark it with punching.
5. What is filing?
Filing is the process of removing the allowance with files, needle files or rasps. It is based on manual or mechanical removal of a thin layer of material from the treated surface.
6. Name the types of drills depending on their design.
According to the design of the cutting part, the drills are divided into spade, with straight flutes, spiral with helical flutes, for deep drilling, centering and special.
7. How is a broken drill removed from a hole in metal?
You can remove a broken drill from the drilled hole by turning it to the side, the reverse spiral of the broken part, with tongs, if there is a protruding part of the drill. If the broken drill is inside the material, then the drilled part is heated together with the drill until it turns red, and then gradually cooled. The released drill can be unscrewed special device or drill with another drill.
8. What tools are used to cut the helical surface on the outer cylindrical surface of the part?
Round split and non-cut dies, as well as four- and hexagonal plate dies, pipe threading dies.
9. What are the file handling requirements?
Files must be protected from moisture to prevent corrosion, they should not be thrown or placed on other files, tools or metals to prevent damage to the cut. The surface of the files is protected from oil or grease, as well as from dust from grinding wheels. A new file should be used first on one side, and after it has become dull, on the other. Do not use personal and velvet files for filing soft metals (tin, lead, copper, zinc, aluminium), as well as brass.
The file during and after work should be cleaned with a steel brush. After finishing work, it is placed in a box or cabinet.
- The veins are cleaned to a metallic sheen.
- Aluminum conductors are overlapped, their ends are connected with a double twist or formed into a ring with round-nose pliers.
Option 2
1. What holes are used for riveting?
When riveting, drilled, pierced or punched holes are used.
2. What tools, besides scrapers, are used for scraping?
When scraping, cast-iron plates, flat and trihedral rulers, prisms, plates in the form of a rectangular parallelepiped, control rollers, probes are used.
3. Describe the sequence of blackening?
The blackening of a steel part is carried out in the following sequence: surface polishing, degreasing with Vienna lime, washing, drying, coating with an etching solution. After coating with an etching solution, the part is dried at a temperature of 100 ° C for several hours, after which it is exposed to steam and hot water. Then it is cleaned wet with a wire brush.
4. Explain the main difference between soft and hard solders.
Soft solders are used for the permanent connection and sealing of metals with low requirements for the strength and endurance of the joint in tension and impact, hard solders are used for permanent and hermetic joints of high strength and endurance in tension and impact.
5. What is the sequence of assembling parts and assemblies?
The sequence of assembly of parts and assemblies must be opposite to the sequence of disassembly. Assembly must be carried out in accordance with the technological maps assemblies. Proper preparation of parts for assembly speeds up the assembly process and improves its quality.
6. Who is allowed to service lifting and transport mechanisms, cranes and welding equipment?
Persons with the necessary qualifications are allowed to service lifting and transport mechanisms, cranes, welding and other equipment. They must be well trained and familiar with the maintenance and operation of this type of equipment, and must also be authorized to perform these types of work,
7. What should be done immediately before proceeding with the assembly of parts into assembly kits and assemblies?
make an external inspection of all parts included in the assembly kit or assembly, make sure that these parts correspond to the assembled assembly or assembly unit and can be installed in the appropriate places. Before assembly, they must be thoroughly rinsed and covered with a thin layer of lubricant (if necessary). Before assembly, a number of parts that determine the appearance of the product must be primed and prepared for painting after assembly.
8. List the safety rules for grinding.
When grinding, it is necessary to correctly select the appropriate grinding wheel, balance it and set the calculated speed of its rotation. The grinding wheel must be correctly fixed and protected with a casing. For grinding parts that are held in the hands, use an emphasis located at a distance of 2-3 mm in front of the grinding wheel. It is necessary to use unbreakable glasses when grinding. Grinding must be carried out in accordance with the instruction manual for the machine.
9. Name some simple special dimensional control tools used in plumbing.
Simple special tools for dimensional control include: an angular ruler with a double-sided bevel, a rectangular ruler, a threaded template, a probe, a one-sided assembly cork, a two-sided limit cork, a one-sided limit clamp and a double-sided limit clamp
10. Describe the technology of this contact connection.
- The veins are cleaned to a metallic sheen.
- Aluminum conductors are overlapped, their ends are connected with a double twist or formed into a ring with round-nose pliers.
- The veins are cleaned to a metallic sheen.
- Aluminum conductors are overlapped, their ends are connected with a double twist or formed into a ring with round-nose pliers.
- When soldering aluminum conductors, the twist is heated by a gas burner flame, while simultaneously introducing a solder rod into the flame.
- After heating the wires to the melting temperature of the solder, rub the groove and the twisting point on one side with a solder rod. As a result of friction, the oxide film is destroyed, the groove and the twist are tinned and filled with solder. Similarly solder the other side of the twist.
Option 3
1. Name the types of markup.
There are two types of markup: flat and spatial.
2. What is the difference between flat and spatial layout?
3. What is a marking base?
A marking base is a specific point, an axis of symmetry or a plane, from which, as a rule, all dimensions on a part are measured.
4. What should be done with the blade if the teeth break?
interrupt sawing, remove the blade from the frame and grind the crumbled teeth, after that you can use the blade further.
5. Name the filing tool.
Sawing can be done with files, needle files or rasps.
6. What elements does the working part of the drill consist of?
The working part of the drill consists of a guide and a cutting part.
7. What tool and when is countersinking performed?
8. Name the tool for threading holes.
taps
9. How to avoid accidents when filing?
You should pay special attention to the condition of the handle and its correct attachment to the file (the handle is mounted along the axis of the file). When inserting the handle, do not lift the file up. Files without a handle should not be used. Be especially careful when working with small files. The end of a long file should not be held with your fingers. The material must be fixed correctly and firmly.
10. Describe the technology of this contact connection.
- The veins are cleaned to a metallic sheen.
- Aluminum conductors are overlapped, their ends are connected with a double twist or formed into a ring with round-nose pliers.
- The veins are cleaned to a metallic sheen.
- Aluminum conductors are overlapped, their ends are connected with a double twist or formed into a ring with round-nose pliers.
- When soldering aluminum conductors, the twist is heated by a gas burner flame, while simultaneously introducing a solder rod into the flame.
- After heating the wires to the melting temperature of the solder, rub the groove and the twisting point on one side with a solder rod. As a result of friction, the oxide film is destroyed, the groove and the twist are tinned and filled with solder. Similarly solder the other side of the twist.
Option 4
1. Name the types of rivet joints.
Rivet connections are: overlap, butt with one overlay, butt with two overlays symmetrically, butt with two overlays asymmetrically
2. When is scraping used?
Scraping is used when it is necessary to remove traces of processing with a file or other tool, and also when they want to obtain a high degree of accuracy and low surface roughness of machine parts connected to each other.
3. What is lapping?
Lapping is the removal of the thinnest layers of metal by means of fine-grained abrasive powders in a lubricating medium or diamond pastes applied to the surface of the tool (lapping).
4. What is coloring?
Painting is the coating of a surface with a layer of paint or varnish in order to prevent corrosion and give a part or product presentation.
5. In what form is the solder produced?
Solder is available in the form of sheet, tape, rods, wire, meshes, blocks, foils, grains, powders and solder paste.
6. What is dismantling machine?
Dismantling is the operation of disassembling a machine or equipment into assembly units, assemblies and parts. In this case, the disassembly of the detachable
connections, and in some cases permanent connections,
7. How should the facility be prepared for renovation?
Before starting repairs, the object should be cleaned of dirt, grease, if necessary, of old paint (when repairing car bodies, wagons, ships, etc.). Machines or mechanisms to be repaired, sent for repair to specialized repair enterprises, must be exempt from special types of equipment, tools and auxiliary equipment.
equipment beyond repair. The transfer of an object for repair is documented by an appropriate acceptance document, which indicates the type of repair required and the completeness of the equipment handed over for repair.
8. What is a universal caliper, what is it intended for and what elements does it consist of?
The universal caliper is a measuring tool used for internal and external measurements of length, diameter and depth.
9. What safety rules must be observed when plating, tinning and soldering, as well as when gluing?
An employee performing plating, tinning or soldering operations comes into contact with molten metal, acids, alkalis and vapors of various caustic and harmful substances. The rooms in which the above operations are carried out must be well ventilated. Workers must wear protective clothing, goggles and gloves. The blowtorch must be technically sound. When pumping fuel, high pressure must not be created, nor can fuel be added to a heated lamp. Acids and alkalis should be kept in glass bottles, and they must be diluted by adding acids to water, and not vice versa. The workplace should be free of rags, spilled oil and grease.
10. Describe the technology of this contact connection.
- The veins are cleaned to a metallic sheen.
- Aluminum conductors are overlapped, their ends are connected with a double twist or formed into a ring with round-nose pliers.
- The veins are cleaned to a metallic sheen.
- Aluminum conductors are overlapped, their ends are connected with a double twist or formed into a ring with round-nose pliers.
- When soldering aluminum conductors, the twist is heated by a gas burner flame, while simultaneously introducing a solder rod into the flame.
- After heating the wires to the melting temperature of the solder, rub the groove and the twisting point on one side with a solder rod. As a result of friction, the oxide film is destroyed, the groove and the twist are tinned and filled with solder. Similarly solder the other side of the twist.
Option 5
1. What is the difference between flat and spatial layout?
The marking is called flat when lines and points are applied to a plane, spatial - when marking lines and points are applied to a geometric body of any configuration.
2. What is punching?
Piercing is the operation of drawing small dots-recesses on the surface of a part.
3. How can I cut pipes with a hacksaw?
Sawing pipes of large diameter must be performed with a gradual turn of the pipe. A thin pipe should be fixed in a vice or devices with compression along its radius with a slight clamping force. For sawing pipes, use a saw blade with fine, sharp teeth.
4. What types of files are divided into depending on their shape?
locksmith flat blunt, round, semicircular, square, trihedral, flat pointed, hacksaw, oval, lens, rhombic, round wide, rasps.
5. What is drilling and what is it based on?
Drilling is the execution of a round hole in a product or material using a special cutting tool - a drill, which, during drilling, simultaneously has rotational and translational motion along the axis of the hole being drilled.
6. What is the cutting part of the twist drill?
The cutting part of the twist drill consists of two cutting edges connected by a third edge - the so-called transverse jumper.
7. Name the types of countersinks.
Countersinks can be solid cylindrical, conical, shaped, welded with a welded shank, solid and shell-mounted prefabricated. Countersinks of small diameters are usually made solid, and large diameters are welded or mounted. Cone countersinks have vertex angles of 60, 75, 90 and 120°.
8. What elements does the tap consist of?
The elements of the tap are the working part, consisting of the cutting and calibrating parts and the shank. The working part has a spiral cut and longitudinal grooves for chip removal. Cutting edges are obtained at the intersection of helical cutting and longitudinal grooves for removing chips. The tail end ends with a square head for installation in the cartridge.
9. How should the site be prepared for renovation of the facility?
The place of repair of the object should be cleaned of dirt, metal scrap and shavings, unnecessary material and means of organizing the workplace (bedside tables, racks, roller tables, etc.). The floor must be level and clean, without any traces of grease or oils on it. The approach or driveway to the repair site must be free, and there must be sufficient free space around the object to be repaired so that repairmen can move freely and place parts and assemblies removed during dismantling from the object. The room where the repair is to be carried out must have sufficient lighting from both natural and artificial sources. The room should have both general and local lighting with a voltage of 220 and 24 V. When repairing large objects, an appropriate point or first-aid kit should be provided at the repair site to provide first aid to a worker injured during repairs, as well as fire protection equipment (fire extinguisher, bucket, axe, hook, etc.). When repairing an object in the open air, in addition to the above measures, an awning or ceiling should be provided to protect workers from precipitation and direct sunlight, and under conditions winter period temporary insulation of the repair site should be provided.
10. Describe the technology of this contact connection.
- The veins are cleaned to a metallic sheen.
- Aluminum conductors are overlapped, their ends are connected with a double twist or formed into a ring with round-nose pliers.
- The veins are cleaned to a metallic sheen.
- Aluminum conductors are overlapped, their ends are connected with a double twist or formed into a ring with round-nose pliers.
- When soldering aluminum conductors, the twist is heated by a gas burner flame, while simultaneously introducing a solder rod into the flame.
- After heating the wires to the melting temperature of the solder, rub the groove and the twisting point on one side with a solder rod. As a result of friction, the oxide film is destroyed, the groove and the twist are tinned and filled with solder. Similarly solder the other side of the twist.
Option 6
1. What should be done before scraping?
check the degree of surface roughness and places of roughness to be scraped.
2. Name the tools and equipment that can be used to obtain permanent metal joints by soldering.
soldering iron, in a gas flame, soldering in furnaces, in a "bath" by a chemical method, autogenous soldering, etc.
3. What is machine repair?
Machine repair is the restoration of working capacity, accuracy, power, speed and other parameters of the machine that determine its purpose.
4. Name the types of rivet seams.
Rivet joints are divided into longitudinal, transverse and oblique. They can be single-row, double-row and multi-row (parallel and staggered rivets). Seams may be complete or incomplete.
5. Describe the specifications for riveted and bolted connections.
use well and correctly manufactured parts, carefully carry out preparatory and basic operations, use serviceable and appropriate tools for these operations. Depending on the operating conditions of the part, assembly or assembly unit, nuts in threaded connections must be installed on split washers, cottered, locked, fixed with a folding washer mustache or wire twist.
6. What is the compass for?
The compass is used to draw circles, curved lines, or to sequentially transfer the position of points on a line when marking out parts. There are spring compasses and with an arc installation.
7. Name the methods of spatial marking.
Spatial marking can be done on a marking plate using a marking box, prisms and squares. With spatial marking, prisms are used to rotate the marked workpiece (Fig. 9).
8. What is the markup technique for the template?
Marking using a template is used in the manufacture of a significant number of identical parts. The template is superimposed on the flat surface of the part and outlined with a scriber along the contour.
9. What safety rules should be followed when lapping and finishing surfaces?
The materials and pastes used in lapping contain, among other substances, those which are harmful and poisonous. Therefore, you should follow
general precautions (if possible, do not touch them with your fingers, wash your hands. Tools and machines must be technically sound and used in accordance with the operating instructions. Paints must be stored in fireproof boxes. When painting, spraying and polishing, fire safety measures should be provided. The worker should wear protective clothing and a respirator.Intensive ventilation should be provided when performing these operations in enclosed spaces.
10. Describe the technology of this contact connection.
- The veins are cleaned to a metallic sheen.
- Aluminum conductors are overlapped, their ends are connected with a double twist or formed into a ring with round-nose pliers.
- The veins are cleaned to a metallic sheen.
- Aluminum conductors are overlapped, their ends are connected with a double twist or formed into a ring with round-nose pliers.
- When soldering aluminum conductors, the twist is heated by a gas burner flame, while simultaneously introducing a solder rod into the flame.
- After heating the wires to the melting temperature of the solder, rub the groove and the twisting point on one side with a solder rod. As a result of friction, the oxide film is destroyed, the groove and the twist are tinned and filled with solder. Similarly solder the other side of the twist.
Option 7
1. When cutting material, what should be done if the cutting line is at an angle to the surface or if the blade slides over the material?
If the cut line went at an angle to the metal surface, you should interrupt the sawing on this side and start on the other. To avoid sliding the blade over the material, you need to make the initial cut with a trihedral file.
2. How are files classified according to the density and size of the notches?
According to the size and density of the notches, depending on the number of notches per 10 mm length, the files are divided into bastard files No. 0 and I, personal No. 2 and 3 and velvet files No. 4 and 5.
3. Where is drilling used?
Drilling is primarily used when making holes in parts connected during assembly.
4. What determines the angle at the top of the drill?
The value of the angle of inclination of the helical groove of the drill depends
on the type of material being processed
5. What is a sweep and when is it used?
A reamer is a multi-blade cutting tool used to finish holes to produce a hole with a high degree of accuracy and a surface with little roughness. Reamers are divided into draft and finishing.
6. What is a thread profile?
A thread profile is a contour obtained by cutting a helical surface with a plane passing through the axis of the screw. The thread profile consists of protrusions and cavities of the turns. The axis of the shaft is the axis of the helical surface
7. What riveting methods are used?
Depending on the diameter of the rivet, the need and the type of riveting, manual and mechanical riveting is used. The closing head is obtained by impact riveting and pressure riveting. Impact riveting is universal but noisy, pressure riveting is better and quieter.
8. Name the tool and material used for scraping the paint.
To scrape parts onto the paint, use a plate or ruler, as well as paint.
As a paint for scraping, a mixture of machine oil with Parisian blue or ultramarine, which has the consistency of a light paste, is used. Sometimes a mixture of engine oil with soot is used,
9. What are the main conditions for dismantling?
Before proceeding with dismantling (dismantling), it is necessary to conduct an external inspection of the repair object or get acquainted with it on the basis of technical documentation(drawings, specifications, etc.). After getting acquainted with the object of repair, they begin to disassemble it. Dismantling is carried out in accordance with the sequence specified in the technical documentation (technology and drawing).
First, the machine or mechanism is disassembled into separate assembly units or units, which, in turn, are disassembled into parts. In order to comply with a certain order at the workplace during repairs, each repairman must have a metal box of light construction or a basket, in which the parts are folded in a certain order when disassembling the parts. This method of dismantling facilitates the preservation of parts, checking their suitability, and protects against possible losses.
10. Describe the technology of this contact connection.
- The veins are cleaned to a metallic sheen.
- Aluminum conductors are overlapped, their ends are connected with a double twist or formed into a ring with round-nose pliers.
- The veins are cleaned to a metallic sheen.
- Aluminum conductors are overlapped, their ends are connected with a double twist or formed into a ring with round-nose pliers.
- When soldering aluminum conductors, the twist is heated by a gas burner flame, while simultaneously introducing a solder rod into the flame.
- After heating the wires to the melting temperature of the solder, rub the groove and the twisting point on one side with a solder rod. As a result of friction, the oxide film is destroyed, the groove and the twist are tinned and filled with solder. Similarly solder the other side of the twist.
Option 8
1. Name the types of laps.
Lappings are divided depending on the types of grinding. There are two types of lapping: lapping with an abrasive (penetrating into the surface of the lap) abrasive lapping with a non-charging abrasive.
In accordance with the specified types of lapping, lappings are divided into manual, machine-manual, machine (mechanical) and assembly.
2. What is soldering?
Soldering is the process of creating a permanent bond between metals using a filler bonding material called solder, whereby the solder is brought to a liquid state during the soldering process. The melting point of the solder is much lower than the metals being joined.
3. What is tinning and galvanizing?
Tinning is the coating of the surface of metal products with a thin layer of tin or a tin-based alloy. Galvanizing is performed by cold electrolytic or hot coating of metal products with a thin layer of zinc.
4. What is machine assembly?
The assembly of a machine is the operation of connecting parts into assembly units and assemblies in such a way that, after assembly, they constitute a machine that is fit for use and meets its official purpose.
5. What specifications must the axles and shafts as well as the mounted bearings meet?
Axles and shafts must be made in accordance with the drawing. The bearing journals must be made in accordance with the established tolerance and the value of the permissible roughness indicated on the drawing, there must be no radial and axial play. Shaft mounted rolling bearings are not
must have play and cracks in the clips. Bearing alignment must be maintained. Plain bearings should be designed like this
and adjusted by scraping so that the bearing with its entire inner surface rests against the surface of the trunnion, and with its entire outer surface against the surface of the seat in the housing. Holes and grooves for lubrication must be built in accordance with the drawing in such a way that grease is reliably and constantly supplied to the bearings.
6. What is a square and in what plumbing operations is it used?
An angle template, called a square, is used to check or draw angles on the plane of the workpiece.
Squares are flat (regular and curved), as well as flat with a wide base. A 90 ° square is a steel template of a right angle.
Often used steel squares with an angle of 120°, 45° and 60°.
7. What is required for markup?
For flat and spatial marking, a drawing of a part and a workpiece for it, a marking plate, a marking tool and universal marking devices, a measuring tool and auxiliary materials are required.
8. What is markup accuracy?
Markup accuracy is the accuracy of transferring the dimensions of the drawing to the part that is being marked out.
9. What tool is used to cut hard materials and why?
Hard materials are usually sawn with mechanical frame, band or circular saws. Manual sawing of these materials is very laborious, and sometimes simply impossible. With mechanical sawing, an even cut is obtained.
10. Describe the technology of this contact connection.
- The veins are cleaned to a metallic sheen.
- Aluminum conductors are overlapped, their ends are connected with a double twist or formed into a ring with round-nose pliers.
- The veins are cleaned to a metallic sheen.
- Aluminum conductors are overlapped, their ends are connected with a double twist or formed into a ring with round-nose pliers.
- When soldering aluminum conductors, the twist is heated by a gas burner flame, while simultaneously introducing a solder rod into the flame.
- After heating the wires to the melting temperature of the solder, rub the groove and the twisting point on one side with a solder rod. As a result of friction, the oxide film is destroyed, the groove and the twist are tinned and filled with solder. Similarly solder the other side of the twist.
Option 9
1 Name the types of file notches.
Files come in single and double cut
A single notch can be inclined to one side, inclined at intervals, wavy, rasped. When filing soft metal surfaces
2. What types of processing are used to obtain round holes in the material, depending on the required accuracy?
Depending on the required degree of accuracy, the following types of processing are used: drilling, reaming, countersinking, reaming, boring, countersinking, centering.
3. What should be done with the drill if it does not drill well?
If the drill does not drill well, it should be sharpened. Sharpening can be done manually or by machine. Correct sharpening of the drill makes it possible to obtain the required angles, extends the life of the drill, reduces effort, and also makes it possible to obtain correctly made holes.
The selection of the cutting angles required for a given material and sharpening on special drill grinders provide the correct sharpening angles and the position of the transverse edge in the center of the drill. After sharpening, you can check the sharpening angles using a goniometer or template.
4. Name the types and types of sweeps.
There are the following types of reamers: according to the method of use - manual and machine, according to the form - with a cylindrical or conical working part, according to the accuracy of processing - roughing and finishing, according to the design - with a cylindrical shank, with a conical (Morse taper) shank and mounted. Attached reamers can be solid, with plug-in knives and floating. Manual reamers can be solid and expandable. Reamers can have simple and helical teeth.
5. Name the types of threads depending on the profile.
Depending on the profile, the threads are divided into: triangular, trapezoidal symmetrical and asymmetrical, rectangular and rounded
6. Name the tool used for manual and mechanical riveting.
For hand riveting, hammers are used to form the head of the rivet, crimp, supports, clamps and tongs.
For mechanical riveting, pneumatic or electric hammers, riveting tongs, supports for rivet heads, consoles are used. Large industrial enterprises use eccentric and hydraulic riveting machines.
7. Explain the process of scraping paint.
The paint is applied in a thin layer on a slab or ruler with a brush or frequent rags, after which the slab or paint is applied to the surface of the part intended for scraping. After several circular movements of the plate or reciprocating movements of the ruler over the part or part on the plate, the part is carefully removed from the plate. Painted spots that appear on the part indicate irregularities protruding on the surface of the part. These irregularities are removed by scraping.
8. Name the materials used for grinding.
Lapping materials are divided into pastes, lapping powders and cloth.
Diamond, white and normal electrocorundum, boron carbide, glass, polishing crocus, abrasive mineral, quicklime are used as charcoal powders. Products made of non-ferrous metals and alloys are rubbed with non-charging abrasives.
9. What safety rules should be followed when scraping?
First of all, cleanliness and order must be observed around the workplace, otherwise the worker may slip and fall, and ultimately be injured. The tool must be used carefully and with skill, during the break between work and after its completion, you need to put the tool in the box. The scraper must always be held so that the cutting part is facing away from the worker.
The scraper must be well sharpened. When scraping, be sure to remove sharp edges from parts.
10. Describe the technology of this contact connection.
- The ends of the cores are inserted into molds (sleeves) 2 so that the joint of the cores is in the middle of the mold (for cores with ends cut at an angle of 55 °, the gap between the ends is about 2 mm). Detachable molds are fastened with soft steel wire bandages, roofing steel molds are fastened with a lock.
- The entry point of the cores into the mold is sealed with a winding of asbestos cord 7. The molds are installed horizontally to ensure complete filling with solder, protective screens 5 are put on the cores (Appendix 29). When connecting cores with a cross section of 120 mm2 or more, it is recommended to additionally install coolers. In this case, the length of the first step of the cut end of the cable increases from 40 to 55 mm
- The flame of the burner 3 heats the mold (sleeve) with the tinned ends of the cores inserted into it. At the same time, a stick of solder 4 is introduced into the flame, the melt of which should fill the mold to the top. The molten solder 6 is mixed with a stirrer and slags are removed, then heating is stopped and the solder is compacted by light tapping on the mold.
Option 10
1. What materials, tools and fixtures are needed for tinning and galvanizing parts?
For tinning and galvanizing, depending on the part and its purpose, you need to have pure tin, zinc or their alloys, a blowtorch or a gas burner, cleaning agents necessary for degreasing and cleaning surfaces subjected to tinning or galvanizing, baths for melting tin or zinc, wiping material and pliers.
2. What tool is used to remove the rolling bearing, gears and pulleys from the shaft?
Rolling bearings, gears and pulleys are removed using special pullers. Pullers come in a variety of designs, with three-arm pullers being the most common.
3. List the technical conditions for the installation of friction and gear drive mechanisms.
The condition for the normal operation of friction and gear drive mechanisms is the alignment of the shafts and bearings. Parts of friction mechanisms during their assembly must adjoin each other with their entire machined surface. The installation of gear cylindrical wheels must be carried out in such a way that the correct engagement of the gear teeth is ensured. Correct engagement must
be ensured by the constancy of the distance between the axes of the shafts on which the gears are mounted, the strict parallelism of the axes and the location of the shafts and axes in the same plane.
4. Name the patterns frequently used by the locksmith.
Templates often used by a locksmith include squares, threading templates, probes, templates for shaped surfaces.
5. Name the marking tool and the main devices necessary for marking.
The marking tool includes: a scriber (with one point, with a ring, double-sided with a curved end), a marker (there are several types), a marking compass, center punches (regular, automatic, for a stencil, for a circle), a caliper with a conical mandrel , hammer, center compasses, rectangle, marker with a prism.
Marking devices include: marking plate, marking box, marking squares and bars, stand, thickness gauge with scriber, thickness gauge with moving scale, centering device, dividing head and universal marking grip, rotary magnetic plate, double clamps, adjustable wedges, prisms , screw supports.
6. What is the thickness of the sheet cut by different scissors?
Manual scissors are used for cutting tin and iron sheets up to 1 mm thick, as well as for cutting wire. Sheet material up to 5 mm thick is cut on lever shears, and material more than 5 mm thick is cut on mechanical shears. Before cutting, the cutting edges should be lubricated with oil.
7. How are files used depending on their shape?
The shape of the files is chosen depending on the configuration of the treated area. Flat files are used for filing flat, curved, convex and outer spherical surfaces; square files - for filing square and rectangular holes; trihedral - for processing trihedral surfaces, for sharpening saws, as well as for filing flat surfaces located at an acute angle; hacksaw - for filing the edges of sharp corners, as well as for making narrow grooves; rhombic - for processing very complex contours of products; round - for making semicircular and round holes, oval - for filing oval holes; semicircular and lens - for processing curved and concave surfaces.
8. What types of work are performed on drilling machines?
The following operations can be performed on drilling machines: drilling, reaming to a larger diameter of a previously drilled hole, countersinking, reaming, facing, countersinking, countersinking, threading.
9. How should the machine or equipment be handled to ensure that it is in good working order?
In order to ensure the technical serviceability of machinery and equipment, it is necessary to systematically monitor its technical condition and maintain it in accordance with the operating and repair instructions. In addition, the terms of preventive inspections and scheduled preventive repairs should be strictly observed.
10. Describe the technology of this contact connection.
- When soldering by pouring pre-molten solder, the crucible 11 with molten solder is installed somewhat away from the place of soldering, so that the heat generated by it does not additionally heat the cores and ignite the cable impregnating composition. To drain excess solder between the place of soldering and the crucible, a tray 10 is installed, which is attached to the bare cores so that it does not touch the paper insulation.
Option 11
1. When are expandable and adjustable reamers used?
Expanding and adjustable reamers are used in repair work to ream holes that have different tolerances, as well as to minimize the increase in an already completed hole.
2. How should the threading rod be prepared?
Before threading, the bar must be cleaned of rust, and its end surface must be chamfered on its end surface.
3. What are the disadvantages and advantages of scraping?
The disadvantages of scraping are too slow processing and significant labor intensity, which requires great precision, patience and time from the locksmith. The advantage of this type of processing is the possibility of obtaining high precision (up to 2 µm) with simple tools. The advantages also include the possibility of obtaining accurate and smooth curly surfaces, processing closed surfaces and surfaces to the stop. Cast iron and steel surfaces of low hardness are well scraped. Hardened steel surfaces should be ground.
4. What is an abrasive mineral and what does it serve?
The abrasive mineral, commonly referred to as emery, is a fine-grained dark-colored natural corundum. An abrasive mineral, in the form of free grains or grains glued to an elastic substrate (cloth, paper), is used for polishing and lapping. The grain size is determined in the same way as in other abrasive materials. The coarser the grain, the higher the number that indicates the abrasive mineral.
5. Name the types of soldering irons.
A soldering iron is a hand tool of various shapes and weights. The part of the soldering iron that is directly soldered is made of copper, the heating of the copper part of the soldering iron can be done using electricity (electric
soldering iron), over a gas flame (gas soldering iron) or in a furnace.
To heat soldering irons and some warm-up of the metals to be joined, gasoline blowtorches can be used.
6. What is a bearing alloy and where is it used?
Bearing alloy is an alloy of metals (tin, lead, copper, antimony, etc.), which is used for the manufacture of plain bearing shells by pouring.
In bearing alloy bushings, when the shafts rotate in them, very little friction occurs,
7. Name the types of repair of machinery and equipment
There are the following types of repairs, technical inspection, scheduled preventive (current), medium and major repairs.
8. How are permanent connections disassembled?
Machine parts or assembly units and units of permanent joints are disassembled using a chisel and hammer, welding equipment, a hacksaw, or by riveting parts. These operations must be carried out carefully so as not to damage the surfaces of parts that will be reused later.
9. What should be done before drilling?
Before you start drilling, you need to properly prepare the material (mark and mark the drilling sites), the tool and the drilling machine. After fixing and checking the installation of the part on the table of the drilling machine or in another device, as well as after fixing the drill in the machine spindle, drilling is started in accordance with the instructions and labor safety requirements. We must not forget about the cooling of the drill.
10. Specify the elements of the power cable.
1 - outer cover 2 - armor 3 - pillow 4 - sheath 5 - belt insulation 6 - core insulation 7 - neutral core 8 - current-carrying core
Option 12
1. List the specifications for assembling clutches.
The condition for the normal transmission of rotational motion from one shaft to another is the correct assembly of the shafts and subcouplings at the output ends of the shafts. Shaft trunnions should be tightly seated in the bearing seats, and there should be no runout. The shafts must be aligned and the coupling halves must be balanced.
2. Name the measuring aids.
Auxiliary measuring devices include: plates, rulers, prisms, measuring rolling pins, sine rulers, levels, measuring stands and wedges for measuring holes
3. Name measuring tools for marking
Measuring tools for marking are:
ruler with divisions, gage gauge, thickness gauge with moving scale, caliper, square, goniometer, caliper, level, control ruler for surfaces, probe and reference tiles.
4. What should be the sharpening angle of hand scissors?
The angle of sharpening of the cutting parts of the scissors depends on the nature and brand of the metal and material being cut. The smaller this angle, the easier the cutting edges of the scissors cut into the material and vice versa. However, with a small taper angle, the cutting edges quickly crumble. Therefore, in practice, the sharpening angle is chosen in the range of 75–85 °. The dull edges of the scissors are sharpened on a grinding machine. The correctness of sharpening and wiring between the edges is checked by cutting the paper.
5. Name the tools and fixtures for drilling.
To perform the drilling operation, drills with a conical or cylindrical shank, conical adapter bushings, wedges for knocking out are used.
drills, two- and three-jaw self-centering drilling chucks, handles for fastening drills in chucks, quick-clamping chucks, spring chucks with automatic shutdown of the drill, machine vise, boxes, prisms, clamps, squares, hand vices, inclined tables, as well as various types of fixtures, manual and mechanical drilling machines and drills.
6. Name the defects during drilling.
Defects during the drilling process are different: it can be a breakage of the drill, chipping of the cutting edges, deviation of the drill from the axis of the hole, etc.
7. What elements does a sweep consist of?
The reamer has the following elements: working part, neck and shank (conical or cylindrical).
8. Name the causes of marriage during threading.
Causes of defective threading are as follows: hole or shank diameter mismatch to the thread being cut, tool damage, threading without lubrication, blunt tool, poor clamping or poor tool setup, and inability to thread
9. When filing, what is the importance of correctly and securely fixing the material in a vice or fixture?
Proper and secure clamping of the material in a vise or fixture ensures accurate processing of the material, minimal worker effort and labor safety.
10. Give a description of the connection of parts
Detachable fixed connection.
Option 13
1. Name soft solders and their melting point.
Soft solders are tin-lead (with or without the addition of antimony). The melting temperature of these solders is from 183 to 305 ° C.
2. What is polishing?
Polishing is a finishing treatment in which surface irregularities are smoothed out mainly as a result of their plastic deformation and, to a lesser extent, by cutting off microroughness protrusions.
Polishing is used to give the surface of the part a shine. As a result of polishing, the surface roughness is reduced and a mirror shine is achieved. The main purpose of polishing is a decorative surface treatment, as well as reducing the coefficient of friction, increasing corrosion resistance and fatigue strength.
3. What determines the choice of bearing alloys, what types of alloys are used?
The selection of the bearing alloys most suitable for these conditions is carried out, taking into account their physical and mechanical properties, in particular, antifriction properties, the ability to withstand certain pressures and temperatures, hardness, toughness, casting qualities, etc. The properties of a bearing alloy are determined by its main component. There are bearing alloys on tin, lead, aluminum, cadmium, zinc, copper (bronze, brass) and other bases. Most often, bearing alloys based on tin, lead or copper are used.
4. Where is the repairman's job?
The place of work of a repairman is located at the object to be repaired (near the machine, equipment, mechanism, etc.).
5. How are parts or assembly units of detachable connections dismantled?
Dismantling and disassembly of parts and assembly units of detachable connections are carried out using all kinds of keys, punches, various types and designs of pullers, as well as other tools. Disassembly of screw connections can be facilitated by lubricating the threaded parts with kerosene, oil, or by heating the nuts for a short time.
6. What should be done after assembling the machine or machinery?
After assembling the machine or mechanism, it is necessary to inspect them. The purpose of the inspection is to control the correctness of the assembly, to eliminate the noticed shortcomings, to check the filling of various mechanisms with oil or lubrication of power transmissions, to remove the remaining forgotten tool, various parts and auxiliary materials from the assembled machine or mechanism.
7. Name auxiliary locksmith tools and auxiliary materials.
Auxiliary locksmith tools and auxiliary materials are: a hand brush, a metal brush for cleaning files, a marking tool, cleaning materials, chalk, vice cheek pads, wooden pads, oils and lubricants, marqueo-astal - numerical and alphabetic, rasp for wood, monter's knife, wooden mallet, rubber mallet, emery cloth, brushes, spoon for melting tin, crucible for melting low-melting alloys of non-ferrous metals, oil and insulating tape, red lead, paints.
8. What safety rules should be observed when riveting?
For riveting, first of all, you need to use a serviceable tool. Wear gloves on your hands and protect your eyes with goggles. The head of the rivet should be correctly installed in the support or console, and the crimp should be correctly installed on the body of the rivet. During riveting, do not touch the crimp with your hand.
9. Name the tools and materials for soldering.
Soldering requires soldering irons, materials called solders, and products that clean, etch, and prevent surface oxidation during soldering.
10. Determine the height of the head of the threaded bolt M 12 × 1.25
h=0.7×12=8.4mm
Option 14
1. Name the auxiliary materials for marking.
To auxiliary materials markings include:
chalk, white paint (a mixture of chalk diluted in water with linseed oil and the addition of a compound that prevents the oil from drying out), red paint (a mixture of shellac with alcohol and the addition of a dye), lubricants, detergents and etching
materials, wooden blocks and slats, small tins for paints and a brush.
2. What is called cutting and sawing metal?
Cutting is the operation of dividing a material (object) into two separate parts using hand scissors, a chisel or special mechanical scissors.
Sawing is the operation of separating a material (object) using a manual or mechanical hacksaw or a circular saw.
3. What else, besides familiar tools and equipment, can cut the material?
In addition to the tools and equipment known to us, an oxy-acetylene flame can be used to cut the material, while cutting is carried out using a special torch.
4. How should non-metallic material, as well as products made of artificial or non-metallic materials, be fixed to avoid surface damage?
In order to avoid damage to the surface of products or materials fixed in a vice, pads should be used. Pads made of soft metals (copper, zinc, lead, aluminium, brass), wood, artificial material, felt, cleaning material or rubber are placed on the jaws of the vise. The product or material is inserted between the linings, and then fixed.
5. Name the maximum diameters of drills that can be used to drill holes on conventional types of drilling machines.
On vertical drilling machines (depending on the type) it is possible to drill holes with drills up to 75 mm in diameter, on bench drilling flocks - with drills up to 15 mm in diameter, on bench drilling machines -
drills up to 6 mm in diameter. Electric hand drills (depending on the type) can drill holes up to 25 mm in diameter, pneumatic hand drills can drill holes up to 6 mm in diameter.
6. What is a drilling jig?
A drilling jig is a fixture with a jig plate for processing a large number of identical workpieces with identically spaced
holes without pre-marking. Locksmith conductors can be of different designs. They can be mounted on a part and fastened directly to the part, they can be a fixture with a jig plate into which the part is installed and clamped. In this case, suitably arranged holes are located in the jig plate with drill bushings inserted into them with a certain hole diameter, through which the drill is guided into the part clamped in the drilling fixture. In some cases, the jig plates have holes without jig bushings.
7. Name the coolant used when reaming holes in various materials.
Coolants are used to cool the tool, reduce friction, and increase tool life.
8. What is a riveting?
Riveting is the operation of obtaining a permanent connection of materials using rods called rivets. A rivet ending in a head is installed in the hole of the materials to be joined. The part of the rivet protruding from the hole is riveted in a cold or hot state, forming a second head.
9. What is scraping?
Scraping is the process of obtaining the accuracy of shapes, sizes and relative position of surfaces required by the conditions of work to ensure a snug fit or tightness of the connection. When scraping, thin chips are cut from uneven surfaces that have already been previously processed by cutting processes with a file or other cutting tool.
10. When repairing, it is necessary to cut a slot in the screws M8 × 1.25 with a cylindrical head. Determine the width and depth of the slot.
h=0.2×8=1.6 mm
Option 15
1. What is grinding?
Grinding is the processing of parts and tools using rotating abrasive or diamond grinding wheels, based on cutting the wheel grains from the surface of a very thin layer of material in the form of tiny chips.
2. Name hard solders and their melting point.
The hardness of the solder is determined by the brand and chemical composition of the metals used for soldering. They are divided into solders based on copper, brass, silver, nickel and aluminum. In addition, there are heat-resistant and stainless solders based on nickel, manganese, silver, gold, palladium, cobalt and iron. The melting temperature of hard solders is from 600 to 1450°C.
3. How is liquid bearing alloy produced?
Liquid bearing alloy is obtained in a graphite or cast iron crucible. The crucible is heated with a blowtorch, on a forge or with a flame of gas burners. The casting temperature of bearing alloys based on tin or lead is from 450 to 600 ° C. The melting temperature of bronze is from 940 to 1090 ° C. Crushed charcoal is poured onto the molten bearing alloy before pouring, which protects the alloy from oxidation.
4. List the tools, equipment and fixtures required for the repair of machinery and equipment.
However, the following tool is common for any type of repair: locksmith - hammers, fixed and sliding keys, chisels, files, hacksaws, screwdrivers, punches, various kinds of pullers, scrapers; universal measuring - rulers, calipers, etc.; electric and pneumatic - drills, wrenches, etc. When repairing equipment, you may need blowtorches and a soldering tool. In some cases, repairs may require equipment for gas or electric welding and cutting, riveting tools, devices for bending, crimping and expanding pipes,
as well as vibration machines for cutting metal. In all cases, workbenches with a vise are necessary for the work of repairmen. When repairing heavy and large machines for objects, lifting equipment is used (tripods with hoists, winches, mobile or stationary cranes, electric or forklifts, carts or other types of lifting vehicles).
5. What should be done with the parts after they are disassembled?
After disassembly, the parts should be degreased and thoroughly rinsed. For this purpose, kerosene is used, as well as special alkaline or other compounds and chemical solutions. Parts are washed in special tanks or baths, using brushes or compressed air. In specialized repair shops or in areas, in some cases, special washing machines are used with a supply of washing liquid under pressure. After washing the parts in a cleaning solution, they must be washed again in hot water and dried in a stream of warm air. Parts should be washed with protective clothing and goggles, being careful.
6. Why should the object be painted after the repair?
In the process of repairing an object, its outer surfaces or individual parts may lose their presentation, their resistance to corrosion may decrease. To protect a repaired machine or mechanism from corrosion and to give it a marketable appearance after repair and testing, they are painted, and parts that cannot be painted are subjected to special treatment to make them corrosion resistant.
7. Tell about the purpose and types of wrenches.
Wrenches are used to tighten and unscrew nuts and bolts, as well as to hold the bolt when tightening the nuts. There are two types of keys: unregulated and adjustable universal.
Non-adjustable wrenches have a fixed opening size for a hexagon of a nut or bolt, universal adjustable wrenches have a opening of the wrench mouth that can be changed within certain limits.
Non-adjustable wrenches are divided into flat one-sided and double-sided overhead one-sided straight and double-sided curved straight and curved end wrenches and hook
8. Name simple marking and measuring tools used in plumbing work.
Simple marking and measuring tools used in plumbing work are:
hammer, scriber, marker, ordinary punch, square, compasses, marking plate, ruler with divisions, caliper and caliper.
9. What operation is performed after inspecting the machine or mechanism?
After inspecting and checking the readiness of the machine or mechanism for work, you should proceed to check the object at idle, while observing the rules of labor protection and safety. After checking the machine or mechanism at idle, a re-inspection of both the entire machine and its individual components and the most critical parts is carried out. Defects identified during the inspection must be eliminated.
10. It is necessary to drill 4 holes in the beam for M36 × 4 bolts Determine the diameter of the holes.
d=1,×36= 36.9 mm
Option 16
1. What operation should be performed after flushing?
The cleaned, washed and dried part must be checked for compliance with its drawing requirements. Checking and evaluating the technical condition of the part will show
can it be used in the car again. To this end, an external inspection of the part should be carried out, its dimensions checked, and it should also be established whether
the actual dimensions of the surfaces of the part within the tolerances in which this part can work. Verification is usually carried out using a universal measuring tool.
2. List the auxiliary materials used in the repair.
Auxiliary materials used in the repair include cleaning and detergents (kerosene, alkaline solutions, washing solutions, etc.), oils, rags, wood, asbestos, gasoline, coolants, zinc chloride, paints, felt, rubber, filler material for soldering, red lead, lubricants, coke, coal, petroleum jelly, chalk, hydrochloric acid, etc.
3. What is sputter plating and where is it used?
Spray plating is the application of a metal coating to the surface of a product by spraying molten metal under pressure.
This operation is performed using special pistols. Metallization is used to protect products from corrosion, as well as to repair worn parts of machines, to correct defective castings, as well as to correct defects resulting from machining.
4. Name common means for cleaning and etching surfaces during soldering.
Chemical cleansing and etching agents include: hydrochloric acid, zinc chloride, borax, boric acid, ammonia. Can clean the surface by mechanical means, abrasive material or file, or wire brushes. During soldering, the surface is protected from oxidation by means such as stearin, turpentine and rosin.
5. What is matting?
Matting is the giving of a matte ash-gray color to a metal surface. This operation is performed mechanically on small forged, cast, sawn or cast parts using steel or copper wire brushes that rotate. Before proceeding to matting, the metal surface is moistened with soapy solutions.
6. What is the purpose of grinding?
The purpose of grinding is to obtain surfaces of parts with slight roughness and very precise dimensions.
7. What tools are used for scraping?
Scraping is done with tools called scrapers.
8. Name the types of rivets depending on the shape of the head and their area of application.
The following types of rivets are used to make riveted joints: round head, countersunk head, semi-counter head, tubular,
explosive, split, flat head, flat head, cone head, cone head and preparation, oval head.
9. What safety requirements should be followed when working on drilling machines?
The drilling machine must be turned on and operated in accordance with the instruction manual for the equipment, as well as in accordance with the requirements of labor safety. Special working clothes should be used, be sure to pick up hair under a headdress, especially for women. Parts must be correctly and securely fixed in a vice or fixture that is in good technical condition. When drilling small holes, the left
the hand holding the workpiece must offer resistance opposite to the direction of rotation of the spindle. During the working stroke of the drilling machine spindle, it is impossible to hold or brake the spindle, change speeds and feeds, clean the table or workpiece from chips. The drill needs to be cooled with coolant with a brush or watering. Cooling with wet rags or rags is not allowed. The drilling machine must be turned on or stopped with dry hands.
10. To lock the oil pump cover, it is necessary to drill holes in the bolts for 1.8 mm cotter pins. Determine the drill diameter.
The drill diameter should be 2 mm.
Option 17
1. What is the purpose of drilling cooling and what coolants are used?
The cutting fluid (coolant) performs three main functions: it is a lubricant to reduce friction between the cutting tool, drill, workpiece metal and chips; is a cooling medium that intensively removes heat that occurs in the cutting zone and facilitates the removal of chips from this zone.
Coolants are used in all types of metal cutting.
Good coolant does not cause corrosion of tools, fixtures and parts, does not have a harmful effect on human skin, does not have an unpleasant odor and removes heat well.
2. When is a drilling ratchet used?
Drill ratchets are used for drilling holes in hard to reach places in steel structures. The manual drive, provided by the oscillatory movement of the ratchet lever, creates the rotation of the drill and its feed along the axis of the hole. The disadvantage of drilling with a ratchet is the low productivity and high labor intensity of the process.
3. What should be the height of the vise and what should be the position of the locksmith when filing?
The installation height is of great importance for the correct processing of the product, labor productivity and the well-being of the locksmith.
The height of the vise installation should be selected in accordance with the height of the worker. In practice, choose this height, leaning with your elbows on the cheeks of the vise (fist when vertical
in the calic position, the hands should reach the chin of the worker standing straight). If the vice is installed below this position, then gaskets are placed, and if the installation height of the vice is high, then the gaskets are removed, or a stand or ladder is placed under the locksmith's feet. The worker at the vise should be in such a position that the feet are at an angle of 45 ° to each other,
moreover, the left leg should be put forward at a distance of 25-30 cm from the axis of the foot of the right leg. The axis of the left foot in relation to the working axis of the file should be at an angle of about 30 °. This position guarantees
productive and safe work of a locksmith and reduces his fatigue.
4. What is a pipe cutter and how to use it?
A pipe cutter is a tool for cutting pipes. Pipe cutters come in many varieties; one-, two- and three-knife, as well as chain.
In a pipe cutter, the role of the cutting part is performed by a roller, the edges of which are sharpened. A three-knife pipe cutter consists of a cheek, in which there are two roller knives, a clip, in which one roller is installed, handles and levers. A pipe cutter is placed on a pipe fixed in a vice or gripping device and, using the handle, is tightened to the stop. oscillatory or rotational
the movement of the lever and the gradual convergence of the knives-rollers cut the pipe. A uniform and clean pipe cutting line can be obtained with a chain pipe cutter.
5. What is the purpose of the puller and what parts does it consist of?
A puller is a bench tool for removing gears, couplings, pulleys, bearings, levers, etc. from the shafts. The puller for bearings consists of two or three clamps (cheeks) and a clip connecting the shoulders of the clamps, bushings with internal thread, as well as from a hex or square head screw or handle.
6. On the basis of what is the marking of the part carried out?
Flat or spatial marking of the part is carried out on the basis of the drawing.
7. Name the main parts that make up a hand saw.
A hand saw consists of a fixed or adjustable frame, a handle, a hacksaw blade. The canvas is attached to the frame with two steel pins, a bolt and a wing nut. Bolt with nut is used for tension
canvases in a frame
8. What is file recovery and what is it based on?
File restoration is the restoration of its cutting ability after it has been worn out by removing dull teeth and applying a new notch to it. Restoration is carried out by annealing it, grinding off the old notch and making a new one (manually or mechanically), followed by hardening again. The file can be restored several times, but each time it becomes thinner and more prone to cracks.
9. What are the safety precautions for cutting and sawing material?
For safety reasons, you should first check the tool. Then you need to correctly and securely fix the material in a vice or fixtures, as well as correctly and firmly upset the handle of the frame saw. Dangerous places near mechanical shears are covered with a casing or shields. Mechanical scissors are serviced according to the operating instructions by a specially trained worker.
10. Two sheets 3 and 5 mm wide are riveted. Determine the diameter of the rivets.
d=√2×(3+5) = 4 mm
Option 18
1. What is a drill?
A drill is a cutting tool used to make cylindrical holes.
2. How are holes with a diameter of more than 30 mm made in metal?
To obtain holes with a diameter of more than 30 mm in metal or parts, double drilling should be used. The first operation is performed with a drill with a diameter
10-12 mm, and then with a drill of the required diameter (reaming). When drilling with two holes or drilling, reaming and countersinking, cutting forces and operation times are significantly reduced.
3. What is threading?
Threading is the formation of a helical surface on the outer or inner cylindrical or conical surfaces of a part.
4. What parts does a rivet consist of?
The rivet consists of a head and a cylindrical rod called the body of the rivet. The part of the rivet that protrudes from the other side of the material to be joined and is intended to form the closing head is called the leg.
5. Name the types of scrapers.
There are manual and mechanical scrapers, and they can be flat one-sided and two-sided, solid and with inserted plates, triangular solid and triangular one-sided, semicircular one-sided and two-sided, spoon-shaped and universal
6. Name what defects can occur during grinding.
As a result of the wrong choice of depth and feed, negligence in the supply of the grinding wheel to the part (or vice versa, the part to the wheel), damage and even rupture of the grinding wheel or part can occur, and burns may also appear, indicating structural changes in the surface of the material. When grinding, the use of cooling is mandatory. Soda solution is used as a coolant.
7. What is oxidation?
Oxidation is the production of a blue or dark blue oxide layer on the surface of a steel part or product. The most common method of oxidation in locksmith work is based on coating a well-derusted object with a thin layer of linseed oil and heating it in a furnace on hot coke.
8. What is zinc chloride and how to use it?
Zinc chloride is a chemical compound of hydrochloric acid with zinc. It is obtained by placing pieces of zinc in dilute hydrochloric acid.
After the end of the reaction (hydrogen ceases to evolve), zinc chloride should be poured into another vessel, leaving the precipitate in the former vessel, and the liquid for cleaning or pickling metals is ready. Acid must be diluted by adding water to it, and not vice versa.
9. Name the types of assembly.
There are assembly based on full interchangeability, partial interchangeability, selective selection of parts, fitting, and assembly with adjustment.
10. The truss is riveted with a single-row seam with steel rivets with a diameter of 25 mm. Determine riveting pitch
CRITERIA FOR EVALUATION
The control task for each option contains 10 questions.
Each question is worth 10 points. (Total 100 points).
If the answer to the question is given, in fact, correctly, but there are minor shortcomings, or the answer is incomplete, it is scored 7 points.
0.7- 0.8 70 - 80 3 beats
0.81- 0.9 81 - 90 4 chorus
0, 91- 1.0 91 - 100 5 ex.
1. What work is called metalwork? What kind of work is called locksmith and assembly? Give examples.
Locksmith's work is a cold working of metals by cutting, performed manually (file, hacksaw, marking, metal cutting, etc.), or mechanized (hand press, electric drill, etc.) method.
FITTING AND ASSEMBLY WORKS is a production process, as a result of which raw materials and semi-finished products are converted into finished products.
2. What is called a part, assembly, mechanism, machine? Give examples. Which of these elements can be called "assembly"?
A PART is a product made of a material that is homogeneous in name and brand.
ASSEMBLY is a product that is obtained as a result of connecting individual elements together. An assembly can consist of only parts or parts and smaller assemblies.
MACHINE - a device that performs mechanical movements in order to convert energy, materials or information
A MECHANISM is the internal structure of a machine that drives it.
ASSEMBLY is a set of jointly working parts, which are separate units, united by one purpose
3. What is the technological process? operation? Transition? Reception? Give examples.
A TECHNOLOGICAL PROCESS is an ordered sequence of interrelated actions that are performed from the moment the initial data arises until the desired result is obtained.
The assembly process is divided into operations, transitions and techniques.
ASSEMBLY OPERATION - this is a completed part of the assembly process, performed during the manufacture of a product at a separate workplace by one or more workers. The operation may consist of a series of transitions, which are characterized by the constancy of the tool used.
RECEPTION is called a part of the transition, consisting of a number of simple working movements performed by one worker.
4. Name and describe the types of assembly according to the form of organization and the relative position of jobs. Give examples.
There are two BASIC ORGANIZATIONAL ASSEMBLY FORMS: stationary and mobile.
STATIONARY ASSEMBLY is carried out at a stationary workplace, to which all the necessary parts, materials and smaller assembly units are supplied, the assembly of which can be performed at separate workplaces (according to the principle of division of operations), which reduces the process time.
MOBILE ASSEMBLY is performed only according to the principle of dismemberment of operations. The product in the assembly process moves from one workplace to another. Workplaces are equipped with the necessary tools and devices. This type of assembly allows assemblers to specialize in certain operations and increase labor productivity.
DEPENDING ON THE LOCATION OF WORKPLACES relative to each other, the assembly is distinguished IN-FLOW AND NON-FLOW.
With mobile in-line assembly, jobs are located in the sequence of operations of the assembly process, and the entire process is divided into separate operations, approximately equal or multiple in terms of execution time. Assembled products leave the production line at certain intervals, called tact. In-line assembly can be carried out both with a movable and a fixed object being assembled.
In the production of large products, in-line assembly on fixed stands is used, in which a worker or a team of workers perform the same operation, moving from one stand to another. After the last operation, the finished product is removed from each stand.
5. What is a workplace? What is workplace organization? What are the basic requirements for the organization of the locksmith's workplace (before, during and after work).
WORKPLACE is an area equipped with the necessary technical means, in which the labor activity of the performer or a group of performers, jointly performing one job or operation, is performed.
ORGANIZATION OF THE WORKPLACE is a system of measures to equip the workplace with means and objects of labor and their placement in a certain order.
MAIN REQUIREMENTS FOR ORGANIZING THE WORKPLACE:
The most convenient (normal) reach zone is determined by semi-
Proper arrangement of tools, fixtures, etc.
Cleaning up the workplace after finishing work
FITCHWORK EQUIPMENT is a complex of various devices that are used for the correct and efficient organization of workplaces. For example, a locksmith's workbench.
A DEVICE is a structure, device, mechanism, device, etc., designed to perform certain work, certain actions. For example, a screw clamp (clamp).
FITTING TOOL is a set of tools designed for manual processing such materials.
7. How is the quality control of metalwork and metalwork and assembly work carried out? Name the controls used, give examples
.
Quality control of assembly and assembly work is carried out visually, as well as with the help of various devices (for example, a bench square, probe) or tools (for example, a ruler, caliper).
8. Planar marking: definition, purpose, execution technology with a detailed step-by-step description.
LAYOUT – this is the operation of drawing lines (rises) on the workpiece, which determine, according to the drawing, the contours of the part and the places to be processed.
Markup:
planar
spatial.
Markup technology:
study of documentation
preparation of the surface of the workpiece for marking
cleaning (sandpaper)
if necessary, coating with special solutions (for untreated surfaces of castings from ferrous and non-ferrous metals - chalk diluted in water to the state of milk, and 50 g of wood glue per 1 liter of water (glue is diluted separately, then it is boiled with chalk; for treated steel surfaces and cast iron - copper sulfate (2-3 teaspoons per glass of hot water) or rubbing the wetted surface with powder blue vitriol. Non-ferrous and steel rolled products, as well as precious metals, are not painted, since the marking lines are clearly visible. In some cases, for a clearer drawing of the drawing, the marking lines are painted with white watercolor paint).
punching (core, hammer) and drawing marks (scriber, ruler).
Control (self-control) of the quality of marking (square, ruler)
9. Metal cutting: definition, purpose, execution technology with a detailed step-by-step description
CUTTING - locksmith operation performed when cutting, cutting and cutting into parts of metal and various solid materials (textolite, getinax, etc.).
In repair practice, cutting operations are performed:
Hand scissors consist of two halves connected by a screw.
Each half of the scissors is one piece: a knife and a handle.
The industry manufactures right and left scissors. On the right scissors, the upper cutting edge of the blade is located to the right of the lower blade, and on the left, on the left side.
H 
Figures a and b show the correct grip of the scissors depending on the conditions of the technological operation.
R 
manual cutting with a hacksaw
The hacksaw blade must be fixed in the machine so that it is not stretched too tight or too loose, the teeth of the hacksaw blade must be directed “away from you”, i.e. in the direction of the hacksaw movement forward.
AT 
during cutting, the hacksaw should be kept in a horizontal position; the normal length of the hacksaw stroke should be such that at least 2/3 of the length of its blade is involved in the work.
Cutting parts with straight edges from sheets up to 40 mm thick, as a rule, is carried out on guillotine shears .
The sheet to be cut is inserted between the lower and upper knives until it stops and is clamped with a clamp. The upper knife, pressing on the sheet, produces chipping.
10. Metal cutting: definition, purpose, execution technology with a detailed step-by-step description
CUTTING is a locksmith operation, during which, with the help of a cutting and impact tool, a layer of metal is removed from the surface or workpiece to be treated, or the metal is cut into pieces.
Cutting is one of the rough plumbing operations with an accuracy of 0.5 - 1 mm.
And 
felling tools
CHISEL
To 
MANUFACTURER
To 
REITSMESSEL
P 
CUTTING ROOMS
T
CUTTING TECHNOLOGY1
1. Metal filing: definition, purpose, execution technology with a detailed step-by-step description
SAWING is the removal of a layer of metal from the surface of the workpiece being processed by means of a special cutting tool - a file.
filing:
preliminary (draft)
final (finishing and finishing)
Bastard files - used for rough processing of a metal surface.
Personal files - applicable for final fine processing and obtaining a clean, not jagged surface.
Velvet - used for the final processing of metal.
Round file - processing of round, oval and concave surfaces;
Semicircular files - has two sides, flat and round, one side processes planes, the other concave and semicircular surfaces;
Triangular files - processing of surfaces and holes inaccessible to flat files;
Square files - processing narrow straight surfaces inaccessible to flat files;
Flat files with oval ribs - used for processing various kinds roundings.
METAL FILING RIMS During operation, the file makes reciprocating movements: forward - working stroke, backward - idle. During the working stroke, the tool is pressed against the workpiece; during the idle stroke, it is driven without pressure. The tool must be moved strictly in a horizontal plane. The pressing force on the tool depends on the position of the file. At the beginning of the working stroke, the left hand presses a little harder than the right. When the middle part of the file is brought to the workpiece, the pressure on the toe and the handle of the tool should be approximately the same. At the end of the working stroke, the right hand is pressed harder than the left.
There are several ways of filing: transverse, longitudinal, cross and circular. Cross filing (rice a) is performed when removing large allowances. With longitudinal sawing of workpieces (Fig. b), the straightness of the machined surface is ensured. It is better to combine these two filing methods: first, filing is done across, and then along. When filing with a cross stroke (Fig. C), good self-control over the progress and quality of work is ensured. First, they file with an oblique stroke from left to right, then, without interrupting work, with a direct stroke, and finish filing again with an oblique stroke, but from right to left. Circular filing (Fig. D) is performed in cases where frequent irregularities must be removed from the treated surface.
P 
When filing planes located at right angles, first one of the surfaces is completely filed, and then the second surface is processed at right angles to the first. The filing of surfaces along the inner right angle is carried out so that the edge of the file, on which there is no notch, is facing the second surface.
The correctness of filing is checked with a ruler or a square for clearance (see figure): if there is no clearance, the surface is flat. The durability of files largely depends on how you care for them.
From long-term use, the notch of the file crumbles and is erased, as a result of which the tool loses its cutting ability. To prolong the life of the file, it is rubbed with chalk, which prevents the notch from clogging with small chips. If the notch of the file is still clogged with sawdust, it must be cleaned with a steel brush.
12. Bending and straightening of metals: definition, purpose, execution technology with a detailed step-by-step description.
G 
Metal bending is the effect of pressure on the metal to give the desired shape.
As a result of such an impact, one part of the metal workpiece is bent relative to the other by the required angle. To get good results, you need to properly apply pressure to the metal. It is very important that the metal blank does not lose its strength during the bending process. To maintain strength, only plastic deformation should be applied to the metal, which does not turn into a rupture of the metal.
For bending at right angles, it is convenient to use a vise (the thicker the metal, the more massive the vise should be so as not to break them). The workpiece is clamped in a vice between the miter corners along the marking line and bent towards the fixed jaw with hammer blows.
If it is required to bend sheet metal of small thickness (up to 1 mm), then in the conditions of a home workshop, along with a vice, additional devices are used. In this case, it is also desirable to clamp the sheet material on both sides. To avoid dents when bending relatively thin sheets, it is recommended to use not an ordinary metal hammer, but mallet.
E 
If you need to bend large sheets, then use the simple frames shown in the figure.
The corner is attached to the front edge of the workbench. The metal sheet is placed on the workbench in such a way that the line of the intended bend is exactly above the edge of the workbench, where the frame is fixed. Next, they press the sheet from above with their hand and bend the sheet of metal with a mallet, evenly striking successively along the bending line.
The middle frame has a square section and is also used for a number of techniques, including metal bending.
The last frame of circular section is designed to obtain curves of a rounded shape. It is often used to make pipes from thin sheets of iron.
Editing is a locksmith operation that is used to eliminate mechanical defects in the workpiece.
It is possible to dress small parts using an anvil and a hammer (sledgehammer). If you need to straighten thin sheets of metal or soft parts made of non-ferrous metals, hammers made of soft material are used accordingly: copper, brass, wooden. Sheets and plates are ruled by hammer blows on convex places, turning the sheet over if necessary.
Editing thin sheets is a more complicated operation: when hitting bulges, the bulge will bend in the opposite direction and stretch even more. The meaning of the operation here is to stretch the margins of the sheet, thereby restoring the plane. Therefore, blows are applied mainly along the edges of the sheet. The blows are needed not strong but frequent. To obtain good results, straightening practice and understanding of the mechanical essence of the process of straightening and bending sheet metals is necessary.
After finishing editing and in the process, the evenness of the part is checked by eye or with a ruler (for more accurate checks, a marking plate is needed).
1
3. Making holes: definition, purpose, execution technologies with a detailed step-by-step description (including finishing holes).
DRILLING is one of the types of obtaining and processing holes by cutting using a special tool - a drill.
A twist drill consists of a working part, a shank and a neck. The working part of the drill, in turn, consists of a cylindrical (guide) and cutting parts.
The shank is designed to secure the drill in a drill chuck or machine spindle and can be cylindrical or conical. The tapered shank has a foot at the end, which serves as a stop when pushing the drill out of
The neck of the drill, connecting the working part with the shank, serves to exit the abrasive wheel in the process of grinding the drill during its manufacture. On the neck, the brand of the drill is usually indicated.
On the guide part there are two helical grooves, along which chips are removed during the cutting process.
Drilling is a necessary operation to obtain holes in various materials during their processing, the purpose of which is:
Making holes for threading, countersinking, reaming or boring.
Making holes (technological) for placing electric cables, anchor bolts, fasteners, etc.
Separation (cutting off) of workpieces from sheets of material.
Mechanical drills: drilling using human muscle power.
Electric drills: drilling on installation with portable power tools (including percussion rotary drilling).
Perforators
Study of documentation, preparation of necessary materials and tools
Preparing the surface of the workpiece for processing
markup
drilling
Drilling Quality Check
Countersinking is the processing of the upper part of holes in order to obtain chamfers or cylindrical recesses, for example, under a countersunk head of a screw or rivet.
Countersinking is the processing of holes obtained; casting, stamping or drilling, to give them a cylindrical shape, improve accuracy and surface quality.
REAMING is the finishing of holes. In essence, it is similar to countersinking, but provides higher accuracy and low surface roughness of the holes.
14. What is a detail? Classify parts according to purpose, give examples.
Parts are the simplest elements, each of which is made without the use of assembly.
Parts are combined into nodes, nodes into mechanisms, mechanisms into machines.
Parts classification
By appointment
Fasteners: nut, washer, bolt, screw, screw, nail, rivet, etc.
Transmission: shaft, key, pulley, belt, sprocket, gear, etc.
Case: beds, instrument cases, covers, casings
Rotations: axles, shafts
Elastic elements: springs
Shafts are parts that not only support rotating parts, but also transmit torques (work in bending and torsion)
Body parts are parts that enclose the mechanisms of machines, support the mechanisms, are the basis for the relative position of the main units, form the contour of the machine or its individual units.
P 
spring - an elastic element designed to accumulate and absorb mechanical energy By type of perceived load:
compression springs
extension springs
torsion springs
bending springs
tension springs- designed to increase in length under load. In the unloaded state, they usually have closed turns. There are hooks or rings at the ends to secure the spring to the structure. Compression springs- Designed to shorten length under load. The coils of such springs do not touch each other without load. The end turns are pressed against the neighboring ones and the ends of the spring are ground. Long compression springs, in order to avoid loss of stability, are placed on mandrels or glasses.
15. Name and describe the main technological, economic and operational requirements for assemblies (machines and mechanisms).
Technological requirements:
MANUFACTURABILITY - the manufacture of a product with minimal labor, time and money in full compliance with its purpose.
ECONOMY - the minimum cost of production and operation of the power plant.
RELIABILITY according to GOST 27.002–89 is the property of an object to keep in time within the established limits the values of all parameters characterizing the ability to perform the required functions in specified modes and conditions of use, Maintenance, repairs, storage and transportation
RELIABILITY - the ability to maintain its operational performance for a given operating time without forced interruptions.
FAILURE - a phenomenon associated with a partial or complete loss of product performance.
DURABILITY (RESOURCE) - the ability to maintain the specified indicators to the limit state with the necessary breaks for repairs and maintenance.
REPAIRABILITY - the ability of a product to prevent, detect and correct failures and malfunctions through maintenance and repair.
STORAGE - the ability to maintain the required performance after the specified period of storage and transportation.
The connections of parts in the EU are:
Detachable
One-piece
Detachable connections are those that can be disassembled without destroying the parts or the elements that hold them together.
For example, threaded connections.
One-piece connections are those that cannot be disassembled without destroying the parts or the elements that hold them together.
For example, welded, soldered, glued, riveted.
17. What connection is called threaded? What is a thread, name the types of thread and its characteristics. Describe the technology for making a threaded connection (with a detailed step-by-step description).
THREADED CONNECTION, connection of parts with a thread.
THREAD - a surface formed during the helical movement of a flat contour along a cylindrical or conical surface.
Threads are classified according to the following criteria
L 
THREAD - formed by a contour rotating counterclockwise and moving along the axis in the direction from the observer.
RIGHT THREAD - formed by a contour rotating clockwise and moving along the axis in the direction from the observer.
THREAD PARAMETERS
Thread profile - thread contour in a plane passing through its axis.
Profile angle - the angle between the sides of the profile.
The thread pitch P is the distance between adjacent profile flanks of the same name in a direction parallel to the thread axis.
The thread stroke Рh is the distance between the nearest identical sides of the profile, belonging to the same helical surface, in a direction parallel to the thread axis. Thread stroke - the value of the relative axial movement of the screw (nut) per revolution.
External thread diameter (d - for a bolt, D - for a nut) - the diameter of an imaginary cylinder described around the tops of the external thread or the troughs of the internal thread.
The inner diameter of the thread (d1 - for a bolt, - for a nut) is the diameter of an imaginary cylinder inscribed in the troughs of an external thread or at the tops of an internal thread.
The average thread diameter (d2 - for a bolt, D2 - for a nut) is the diameter of an imaginary coaxial cylinder with a thread that intersects the threads in such a way that the width of the thread ledge and the width of the cavity (groove) are equal.
Reading from left to right
Letter(s) - thread type
MK - metric conical
G - pipe
Tr - trapezoidal
S- persistent
The number after the letter(s) is the thread diameter (in mm)
The number after the dash is the thread pitch (in mm)
Letters after the thread pitch - thread type (according to the method of winding)
Fractional alphanumeric designation - thread fit: in the numerator - the tolerance field of the internal thread, in the denominator - the tolerance role of the external thread.
M12 x 1 - 6N/6g
M - metric thread (triangular)
Outer thread diameter - 12 mm
Thread pitch - 1mm
Thread Fit - 6N/6g
Technology for making a threaded connection (for example, a bolt-nut connection):
alignment of elements to be joined to establish tolerance of holes
install bolt
installation of washers (if necessary)
nut installation
Welding is a technological process for obtaining a permanent connection by establishing interatomic and intermolecular bonds between the parts of the product to be welded during their heating (local or general), and / or plastic deformation.
Types of welding:
thermal class (fusion welding using thermal energy): arc, electric arc, plasma, laser
thermomechanical class (types of welding carried out using thermal energy and pressure): contact, diffusion, forging, friction
mechanical class (types of welding carried out using mechanical energy and pressure): explosion, ultrasonic, cold
Cold welding according to the principle is a method of forming one-piece press joints. Cold welding occurs due to the plastic deformation of the metals being welded in the joint zone under the influence of mechanical force.
Before welding, the surfaces to be welded are cleaned of contaminants by degreasing, processing with a rotating wire brush, and scraping. When butt welding, the wires are only cut off the ends. After that, the parts to be joined are placed between the clamps and squeezed with the help of punches.
19. What is soldering? What is solder, flux? Give examples. Describe the technology for performing one of the types of soldering (with a detailed step-by-step description).
SOLDERING is a technological operation used to obtain a permanent connection of parts from various materials by introducing a molten material (solder) between these parts, which has a lower melting point than the material (materials) of the parts to be joined.
SOLDER is a metal or alloy whose melting point is much lower than that of the products being joined.
Depending on the melting temperature, the following types of solders are distinguished:
soft (fusible) - melting point not more than 450 °C
solid (medium-melting) - 450-600 ° С
high-temperature (high-melting) - over 600 °C.
POS40 - tin-lead solder with a tin content of 40%
POSK 2-18 - tin-lead solder with a tin content of 2%, a cadmium content of -18%, the remaining 80% is lead.
The numbers at the end of the marking can indicate the melting temperature of the solder
#, Ni63 W Cr Fe Si B 970-1105
FLUX - a substance that cleans surfaces and solder from oxides and contaminants and prevents the formation of oxides, as well as increasing the flow of molten solder.
FLUX TYPES
Non-corrosive (protective) fluxes for soldering have only a protective effect. Due to their low activity, they are unable to dissolve the oxide film of most metals and can be used mainly for soldering copper and its alloys, as well as steel products coated with silver, copper, tin or cadmium. These fluxes include rosin and its solutions in alcohol or in organic solvents, as well as wood resins, wax, stearin, petroleum jelly. With the use of protective fluxes, only low-melting solders can be soldered.
Slightly corrosive soldering fluxes are more active than non-corrosive ones and consist of animal fats, mineral oils, organic acids (lactic, citric, oleic, stearic, benzene, oxalic and others), their solutions in water or alcohol or in derivatives of organic acids and bases (hydrohalides, chlorides and fluorides of amines). To weaken the corrosive action, rosin or other components that do not cause corrosion are added to them. Slightly corrosive fluxes easily evaporate, burn or decompose when heated. They are used for soldering with low-melting solders.
Corrosive soldering fluxes are composed of inorganic acids, metal chlorides and fluorides. They are used in the form of aqueous solutions in a solid and pasty state. Corrosive fluxes are capable of destroying resistant oxide films of ferrous and non-ferrous metals. These fluxes are effective in soldering most metals by any method.
Rosin (colophon resin) is a brittle, vitreous, amorphous substance from dark red to light yellow. It is part of the resins of coniferous trees and is obtained from resin (resinous substance (turpentine) released when coniferous trees are injured) after extraction of crushed wood with organic solvents or distillation of crude tall oil.
SOLDERING TECHNOLOGY:
Reasonable choice of materials, tools, fixtures
Preparation of soldered elements for soldering
Soldering
Solder Quality Check
20. What is gluing? Name the types of adhesives, give examples of their use in EU. Describe the technology of gluing (with a detailed step-by-step description).
GLUING is the operation of performing a permanent connection of elements made of homogeneous or non-homogeneous materials using glue.
In many of the requirements placed on adhesives in the electrical industry, they are comparable to structural adhesives used in other industries. Additional requirements take into account the possibility of not only mechanical destruction of the system, but also the violation of its electrical conductivity. Working temperature modern electrical equipment often excludes the use of almost all thermoplastic resins as the basis of adhesives, replacing them usually with adhesives based on thermosetting resins.
Adhesives used in electrical equipment should have all or only some of the following properties: good electrical characteristics, such as low volume resistance and low dielectric constant; chemical resistance; moisture resistance; non-toxicity; non-susceptibility to the formation of traces on the surface under the action of leakage currents and resistance to the action of irradiation.
Adhesives are used in the manufacture of electrical equipment of the following types: transformers, switch parts, capacitors, microwave devices, motors, generators and insulators. Adhesives are also used, for example, when assembling belt drives (to connect the ends of the belt).
State Autonomous Vocational Educational Institution
"Krasnokamensk Mining and Industrial College"
Agreed at the PCC meetingProtocol No. _____ "____" _________________ 2018
Chairman of the PCC
Kiseleva T.M.
I approve:
Director of GAPOU "KGPT"
S.N. Epifantseva
"_____" _________________2018
MDK.01.01. Basics of metalwork and assembly and electrical work
by profession of secondary vocational education
13.01.10 Repair and maintenance electrician
electrical equipment (by industry).
Compiled by: Alexey Morozov
Lecturer GAPOU "KGPT"
Krasnokamensk 2018
Content
1. Introduction
2. Explanatory note
3. List practical work
4. Instructions for the implementation of practical work
Introduction
The academic discipline "Fundamentals of metalwork, assembly and electrical work" is studied by students in the second year. Guidelines for the implementation of practical work ensure the implementation of the work program on the technology of electrical work.
The implementation of the program will ensure the competence of future specialists in the field of life safety as an integral part of their professionalism during the period of entry into independent life.
Explanatory note
The leading didactic goal of practical classes is
formation of practical skillsrequired insubsequent learning activities and life.In accordance with the leading didactic purpose of the content
practical training is to solve various kinds of problems, includingprofessional (analysis of problem situations, solutionsituational taskswork with measuring instruments, personal protective equipment, training simulator for resuscitation, work with normative documents, instructivematerials, guides).On practical
In the classroom, students master the initial skills and abilities that they will use in their professional activities and life situations.Along with the formation of skills and abilities in the process of practical training, theoretical knowledge is generalized, systematized, deepened and concretized, the ability and willingness to use theoretical knowledge in practice are developed, and intellectual skills are developed.
As a result of studying academic discipline in the field of life, the student must
know:Main types, operations, purpose, tools, equipment and materials used in electrical work;
Purpose, physical and chemical bases, methods of soldering with soft and hard solders;
Types of connecting wires of various brands by soldering;
Purpose, methods, materials used in tinning;
Physiological and hygienic foundations of the labor process;
Labor safety requirements in organizations;
Norms and rules of electrical safety;
Measures and means of protection against electric shock.
be able to:
Perform soldering with various solders;
tinker;
Apply necessary materials, tool, equipment;
Apply electrical safety rules and regulations.
List of practical works
p/nTopic of practical work
watch
Practice #1
Practice #2
Practice #3
Practice #4
Practice #5
Practice #6
Performing the connection of wire cores using crimping.Practical lesson No. 7 Fastening and insulation of electrical appliances.
Practice #8
Wire cutting.Total:
Practice #1
Performing operations of planar marking, cutting, cutting, filing and drilling of metal."Markup"
Target: Use the necessary tool for planar marking. Learn how to apply mutually parallel and perpendicular lines
Time: 2 hours.
Equipment and materials
.1. Metal ruler 50 cm, metal sheet 20x10 cm, 1 mm thick, scriber, compasses.
2. Educational literature.
Exercise.
1. Fix the workpiece to be marked on the workbench.
2. Make a markup.
Applying parallel lines.
Learning task 1.
Application mutually parallelmarks at an arbitrary distance from each other using a square, ruler and scriber.The marking task is performed on plates (at least 200X100 mm in size) from
sheet steel in the following order.
1. The plate is placed on the marking plate so that the machined edge,
taken as a base, was addressed to the worker; while the workpiece is shifted to the edge
marking plate, which ensures a snug fit of the square.
2. A square with a wide base is applied to the base edge and carried out
scriber to the first risk, while the scriber should be tilted towards her
moving and at the same time away from the edge of the ruler.
Risking techniques.
During the application of scratches, the pointed end of the scriber is continuously pressed against
side of the ruler, while the ruler is pressed tightly against the workpiece. The risk is carried out with slight pressure only once - repeated risk is unacceptable. Risks must be clear, subtle and continuous.
Two types of scribers are used for drawing marks: round or with an insertion needle made of hard alloy.
3. The square is moved along the edge of the plate at arbitrary distances and
inflict a number of risks.
Drawing marks (lines)
a - parallel, at an arbitrary distance using a square; b - parallel, spaced at a certain distance, using a measuring ruler; c - parallel, spaced at a certain distance, with the help of a compass and ruler.
Then, along the ruler, connecting the applied marks, draw a line. Through other pairs of labels, straight lines are also drawn, which will be parallel.
To draw marks parallel to a given straight line at a certain distance, using a compass and a ruler from arbitrary points a and b, arcs of radius R are drawn on the straight line AB. The straight line CD, tangent to these arcs, will be parallel to the given straight line AB and separated from it at a distance R.
Exercise 2.
Application of mutually perpendicular marks1. Draw a line AB of arbitrary length on the surface to be marked (Fig. d).
2. In the middle (approximately) of the AB risk, mark point 1, on both sides of which, with a compass solution set to the same size, make notches 2 and 3 on the AB risk and score them.
4. Set the fixed leg of the compass 3. Set the compass to a size greater than half the size between points 1-2 and 1-3 and set the fixed leg of the compass to point 2 and draw an arc "ab" crossing the risk.
to point 3 and apply the arc "vg".
5. Draw through the points of intersection of the arcs and point 1 the risk "PC", which will be perpendicular to the line AB.
Test questions:
1. What tools are used for planar marking?
2. What methods are used to fix the workpiece on the workbench?
3. Tell us the sequence of planar marking
and drawing mutually parallel and perpendicular marks."Cutting"
Target: Learn to produce cutting material according to the level of the vise jaws, according to marking risks
Equipment and materials
.1. Metal of various profiles, locksmith's workbench, vise, workpieces, chisels.hammers
3. Educational literature.
Exercise.
1. Cut the metal according to the level of the vise jaws, according to the marking risks.
Tool selection. Pick up and check the hammer: the density and strength of its attachment to the handle; correct wedging of the handle in the hole with steel wedges; ovality of the cross section of the handle with a uniform thickening towards the end; absence of knots, cracks and chips on the handle; smoothness and slight convexity of the surface of the hammer head; lack of cracks and chips in the hammer and striker; the mass of the hammer (40 g per 1 mm of the width of the chisel) and the length of its handle (500-600 mm). Pick up a chisel and check: no cracks or chips; roundness and cleanliness of the sides and middle part; smoothness and convexity of the shock part; sharpening angle depending on the hardness of the metal being processed (35, 45, 60, 70°).
1. A wrist blow with a hammer is performed by swinging only due to the bending of the hand (Fig. c); used for light work, removing thin layers of metal.
Techniques for gripping a tool and striking when cutting metal.
2. Elbow blow is used in normal cutting, when you have to remove a layer of metal of medium thickness. With an elbow strike, the arm bends at the elbow, so it is stronger than the carpal one (Fig. b).
3. Shoulder impact is used when cutting a thick layer of metal and processing large planes. The hand moves in the shoulder, and this results in a large swing and a blow of maximum force - a blow from the shoulder (Fig. c). It must be accurate so that the center of the hammer striker falls into the center of the chisel head.
4. The location of the fingers on the handle when hit with a hammer: grasp the handle with four fingers and press it against the palm of your hand; put the thumb on the index finger and squeeze all fingers tightly, they remain in this position both during the swing and during the impact; at the beginning of the swing, when moving the hand up, grasp the handle of the hammer with all fingers. In the future, as the hand is raised up, the little finger, ring and middle fingers gradually unclench and support the hammer tilted back (Fig. g); then squeeze the unclenched fingers and accelerate the downward movement of the hand - as a result, a strong and well-aimed blow with a hammer is obtained. The blows should be accurate (falling straight on the top of the rounded part of the chisel) and uniform - at a speed of about 60 beats per minute for light cutting and 40 blows for heavy cutting. Exercises. Cutting, cutting metal and cutting grooves. Cutting planes and cutting grooves: 1. Cutting along the marking lines at the level of the vise jaws (blank 50X30X4 mm): apply a marking line to the surface of the workpiece; clamp and align the workpiece in a vice so that the marking line is parallel to the vise jaws and higher by the size of the part of the workpiece that goes into the chips; check the hammer and chisel (hammer handle attachment, absence of broken corners, broken strikers, burrs on the hammer and chisel; take the correct working posture; install the chisel correctly;
chop with the middle of the chisel, striking it correctly and removing chips 2-3 mm thick; f) check the cut line with a scale ruler - it must be straight (permissible deviation ± 0.5 mm). 2. Cutting along the marking marks above the level of the vise jaws (blank 150X30X4 mm): a) apply parallel marking marks to the surface of the workpiece (the distance between them is 1 mm); b) install the marked workpiece, align and clamp it between the vise jaws in the middle part so that the marking mark on which you need to cut is parallel to the vise jaws and 10-15 mm higher than them; correctly install the chisel; chamfer on the side of the workpiece opposite to the one from which the cutting begins; make a chamfer according to the size of the metal layer to be removed; cut the surface with the middle of the chisel along the marking risks; the thickness of the layer to be removed must be the same along the entire length (no more than 0.5 - 1.0 mm, and in case of final cutting - 0.2 - 0.5 mm); risk is not cut down; check the cutting line with a scale ruler; it must be straight (tolerance ± 0.5 mm).
Test questions:
1. List the rules for safe work when cutting metal.
2. Name the tools for cutting metal.
3. What is the difference between a chisel and a cross cut?
4. In what cases is a wrist strike used? Shoulder punch?
5. Why, when cutting in a vice, the marking line should be 1.5 ... 2 mm below the level of the jaws?
"Metal cutting"
Target: Learn to use metalwork tools and cut metal parts
Equipment and materials
.1. Metal for cutting, locksmith's workbench, hacksaw for metal and various blades for it, metal shears, pipe cutter, bench vise.
3. Educational literature.
Exercise.
1.Cut parts from various metals.
2. Answer security questions.
1. Metal cutting
During locksmith and procurement work, metal is cut in cases where it is necessary to separate a part of a certain size or a given shape from a billet of sectional, shaped steel or pipes. This operation differs from felling in that it is performed not by shock, but by pressing forces, and the adjacent ends of the main and separated parts of the metal have straight planes without bevels. Strip round, angle or other steel is cut with hand hacksaws in a vice, and pipes are cut in a clamp.
Before cutting pipes, they are marked on a workbench into blanks of the required length. For precise marking, a metal ruler up to 3 m long is fixed on the edge of the workbench with a stop at one end. The locksmith moves the pipe with one end to the stop and marks the length of the workpiece along the ruler.
Slicing (cutting)
- This is an operation associated with the separation of materials into parts using a hacksaw blade, scissors, pipe cutters.2. Tools and fixtures used for cutting
Hand saws
designed mainly for cutting bar and profile steel by hand, as well as for cutting thick sheets and strips, cutting grooves in screw heads, cutting blanks to the office and other work. The most common hacksaw blades are 13 and 16mm wide. With a thickness of 0.5 to 0.8 mm and a length of 250-300 mm. There are two types of hacksaws: solid and sliding, allowing you to install a hacksaw blade of different lengths in the machine.Hand scissors
designed to cut material in a straight line or in a large radius arc.Hand scissors are right and left. Hand shears can cut sheet steel up to 0.7 mm thick, roofing iron up to 1.0 mm thick, copper and brass sheets up to 1.5 mm thick.
Power shears
designed for cutting sheet steel up to 2.5 mm thick.Table manual lever scissors
used for cutting sheet steel with a thickness of up to 4 mm, aluminum and brass - up to 6 mm.Pipe cutters used for cutting pipes of various diameters instead of a metal saw, as well as for better cutting pipes. A pipe cutter is a special device in which steel disk cutters-rollers serve as a cutting tool. The most common roller, clamp and chain pipe cutters (for cutting large diameter pipes).
Clamps used for clamping steel pipes and pipe blanks with a diameter of 15 to 50 mm when cutting pipes manually.
3. Basic rules for cutting metal with a hacksaw (strip, sheet, bar material; shaped steel; pipes)
1. Before starting work, it is necessary to check the correct installation and tension of the blade.
2. The marking of the cutting line must be made along the entire perimeter of the bar (strips, parts) with an allowance for subsequent processing of 1 ... 2 mm.
3. The workpiece should be firmly fixed in a vise.
4. Strip and corner material should be cut at the wide end.
5. In the event that the length of the cut on the part exceeds the size from the blade to the frame of the hacksaw, cutting must be done with a blade fixed perpendicular to the plane of the hacksaw (hacksaw with a turned blade).
6. Sheet material should be cut directly with a hacksaw if its thickness is greater than the distance between the three teeth of the hacksaw blade. Thinner material to be cut must be clamped in a vise between wooden blocks and cut along with them.
7. The gas or water pipe must be cut, securing it in the pipe clamp. When cutting thin-walled pipes, fix them in a vice using profiled wooden spacers.
8. When cutting, the following requirements must be observed:
at the beginning of cutting, tilt the hacksaw away from you nV 10..15º;
when cutting, keep the hacksaw blade in a horizontal position;
in work, use at least three quarters of the length of the hacksaw blade;
perform working movements smoothly, without jerks, approximately 40..50 double strokes per minute;
at the end of cutting, loosen the pressure on the hacksaw and support the cut part with your hand.
9. When checking the size of the cut off part according to the drawing, the deviation of the cut from the marking line should not exceed 1 mm in the larger direction.
4. Basic rules for cutting sheet metal up to 0.7 mm thick with hand scissors
1. When marking the cut out part, it is necessary to provide for an allowance of up to 0.5 mm for subsequent processing.
2. Cutting should be done with sharpened scissors in gloves.
3. Place the sheet to be cut strictly perpendicular to the blades of the scissors.
4. At the end of the cut, the scissors should not be completely brought together to avoid tearing the metal.
5. It is necessary to monitor the condition of the axis-screw of the scissors. If the scissors begin to "crumple" the metal, you need to slightly tighten the screw.
6. When cutting material with a thickness of more than 0.5 mm (or when pressing the handles of the scissors is difficult), one of the handles must be firmly fixed in a vice.
7. When cutting a curved part, for example, a circle, the following sequence of actions must be observed:
mark the contour of the part and cut the workpiece with a straight cut with an allowance of 5..6mm;
cut the part according to the markup by turning the workpiece clockwise.
8. Cutting should be done exactly along the marking line (deviations are allowed no more than 0.5 mm).
The maximum value of "gouge" in the corners should not be more than 0.5 mm.
5. Basic rules for cutting sheet and strip material with lever shears
1. Cutting must be done with gloves to avoid cuts to the hands.
2. Cutting of a significant sheet material (more than 0.5 × 0.5 m) should be done by two people (one should support the sheet and move it in the “away from you” direction along the lower knife, the other should press the scissors lever.
3. During operation, the cut material (sheet, strip) must be placed strictly perpendicular to the plane of the movable knife.
4. At the end of each cut, do not bring the knives to full compression in order to avoid "tearing" the material being cut.
5. After finishing work, it is necessary to fix the scissors lever with the fixing pin in the lower position.
6. Basic rules for cutting pipes with a pipe cutter
1. The cut line should be marked with chalk around the entire perimeter of the pipe.
2. The pipe must be firmly secured in a pipe clamp or vise. Fixing the pipe in a vice must be done using profiled wooden spacers. The cutting point should be located no further than 80..100mm from the clamping jaws or vice.
3. During the cutting process, the following requirements must be observed:
lubricate the cut;
monitor the perpendicularity of the pipe cutter handle to the pipe axis;
carefully monitor that the cutting discs are aligned exactly, without distortion, along the cut line;
do not apply great effort when rotating the screw of the pipe cutter handle to feed the cutting discs;
at the end of cutting, support the pipe cutter with both hands; make sure that the cut piece of pipe does not fall on your feet.
7. Typical defects in metal cutting, their causes and methods of prevention
Cutting with a hacksaw
DefectCause
Warning method
Cut skew.
The fabric is loosely stretched.
Cutting was carried out across the strip or shelf of the square.
Stretch the canvas so that it is tight when pressed with a finger from the side.
crumbling
blade teeth.
Wrong choice of canvas. Blade defect - the blade is overheated.
The blade should be selected in such a way that the tooth pitch is no more than half the thickness of the workpiece, that is, so that two or three teeth participate in the work. Ductile metals (aluminum and its alloys) should be cut with blades with a finer tooth, thin material should be fixed between wooden bars and cut along with them.
Canvas breakage.
Strong pressure on the hacksaw. Weak web tension. The fabric is stretched. Uneven movement of a hacksaw when cutting.
Loosen the vertical (transverse) pressure on
a hacksaw, especially when working with a new one, as well as a heavily stretched blade. Release pressure on the hacksaw at the end of the cut. Make movements with a hacksaw smoothly, without jerks. Do not attempt to correct a misaligned cut with a misaligned hacksaw. If the blade is dull, then it needs to be replaced.
Test questions:
1. What caused the need to use gloves when cutting metal with scissors?
2. Why do you need to lubricate the teeth of the hacksaw blade when working?
3. How far from the edge of the jaws of the vise or clamp should be the marking line when cutting the pipe with a hacksaw or pipe cutter?
4. What defects are encountered when cutting metal?
5. What safety rules must be observed when cutting metal
5. For what purpose are the teeth of the hacksaw blade bred?
6. There is a marking on the hacksaw blade: 250; 13; 1.6; P9. Decode it.
Sheet metal bending
"Drilling Holes"
Target: Learn to use metalwork tools and drill metal blanks
Equipment and materials
.1. Workpieces for drilling,drilling machine, drills, countersinks
3. Educational literature.
Exercise.
1. Drill metal blanks on a drilling machine.
2. Answer security questions.
1. Types and techniques of drilling
drilling - this is an operation for the formation of through and blind holes in a solid material, performed using a cutting tool - a drill.
There are manual drilling - manual pneumatic and electric drilling devices (drills) and drilling on drilling machines. Manual drilling devices are used to obtain holes up to 12 mm in diameter in materials of low and medium hardness (plastics, non-ferrous metals, etc.). For drilling and processing holes of large diameter, increasing labor productivity and processing quality, desktop drilling and stationary machines are used - vertical drilling.
Holes drilled:
According to preliminary marking (made with a marking tool), single holes are drilled according to the marking. Preliminarily, axial risks are applied to the part, then the recesses in the center of the hole are punched. The core hole of the circle is made deeper to give a preliminary direction to the drill. Drilling is carried out in two steps - first, test drilling is performed, and then the final one.
By template - the use of a template saves time, since the contours of the holes previously marked on the template are transferred to the workpiece.
Large diameter holes drilled in two steps - first with a drill of a smaller diameter, and then with a drill of the required diameter.
Drilling blind holes to a given depth carried out on the sleeve stop on the drill or measuring ruler. For measurement, the drill is brought up to contact with the surface of the part, drilled to the depth of the drill cone and mark the initial position on the ruler by the arrow (pointer). Then, the specified drilling depth is added to this indicator and a figure is obtained to which drilling must be carried out.
Drilling partial holes (half holes) in cases where the hole is located at the edge, a plate of the same material is attached to the workpiece, clamped in a vice and a full hole is drilled, then the plate is removed.
Drilling under a carving and under development.
There are general rules for drilling (both on the machine and with a drill):
* in the process of marking work, the center of the future hole must be marked with a center punch, then during operation the drill is installed in the core, which contributes to greater accuracy;
* when choosing a drill diameter, its vibration in the chuck should be taken into account, as a result of which the hole is slightly larger in diameter than the drill. The deviation is quite small - from 0.05 to 0.3 mm - and is important in the case when special accuracy is required;
* when drilling metals and alloys, as a result of friction, the temperature of the cutting tool (drill, countersink) rises significantly, which leads to its rapid wear. In order to increase the durability of tools, drilling fluids are used, in particular water;
* blunt cutting tools not only form poor-quality holes, but also fail faster themselves, so they should be sharpened in a timely manner: drills - at an angle (at the top) 116-118º, conical countersinks - 60, 90, 120º. Sharpening is done manually on a grinding machine: the drill is attached to the circle of the grinding machine with one of the cutting edges at an angle of 58-60º and smoothly rotated around its axis, then the second cutting edge is sharpened in the same way.
In this case, it is necessary to ensure that both cutting edges are sharpened at the same angle and have the same length;
for drilling blind holes on many drilling machines there are automatic feed mechanisms with limbs, which determine the drill stroke to the desired depth. If your machine is not equipped with such a mechanism or you are drilling with a hand drill, then you can use a drill with a sleeve stop;
* if you need to drill an incomplete hole located at the edge of the part, then place a plate of the same material on the part, fix the entire package in a vise and drill a hole. The plate is then removed;
* when it is necessary to drill a hole in a complete part (for example, in a pipe), the hole is pre-clogged with a wooden plug. If the pipe is large in diameter, and a through hole is required, then you have to drill from both sides.
In this case, to facilitate the markup and make it most accurate, you can use a special tool. It consists of two completely identical prisms, between which the pipe is clamped. Each prism has counter-punching screws, precisely aligned against each other, clamped in their opposite vertices. The prisms are also precisely aligned with the side cheeks. When the pipe is clamped between the prisms, small, opposite holes from the punch screws remain on it. After drilling according to this marking, the holes in the pipe will correspond to each other with much greater accuracy;
* You can get stepped holes in two ways: the first way: first, a hole of the smallest diameter is drilled, then (to the desired depth) a hole of a larger diameter and the last hole of the largest diameter is drilled; the second way: exactly the opposite: first, a hole of the largest diameter is drilled to the desired depth, then a smaller one, and at the end - the smallest diameter;
* if you need to drill a hole on a curved plane or a plane located at an angle, then first you should make (cut out, cut out) a platform perpendicular to the axis of the future hole, punch the center, and then drill a hole;
* holes with a diameter of more than 25 mm are drilled in two steps: first, a hole is drilled with a drill of a smaller diameter (10 ... 20 mm), and then it is reamed with a drill of the desired diameter;
* when drilling parts with a large thickness (with deep drilling), when the depth of the hole is more than five diameters of the drill, it must be periodically removed from the hole and the chips blown out, otherwise the tool may jam;
* composite (consisting of several dissimilar layers) materials are difficult to drill, primarily because cracks appear on them during processing. This can be very avoided in a simple way: before drilling, such material must be filled with water and frozen - cracks in this case will not appear;
* high-strength materials - steel, cast iron - conventional drills are not taken. For their drilling, locksmiths are very popular with drills with tips from the so-called win. It was obtained in Russia in 1929, it consists of 90% tungsten carbide and 10% cobalt. For the same purpose, you can also get a diamond drill, the tip of which is made using synthetic diamonds - it significantly increases the speed of drilling metal.
Test questions:
1. What determines the various shapes and angles of sharpening the cutting part of the drill?
2. What determines the wear of the cutting core tool for holemaking?
3. What determines the cutting speed when machining a hole?
4. What equipment is used for drilling?
5. What safety precautions must be observed when drilling with a hand drill?
6. In what sequence is the drill sharpened?
7. How to reduce friction when drilling?
8. What types of drills are used in plumbing?
9. What defects can occur and how to eliminate them when machining holes?
10. What safety precautions must be observed when drilling with an electric drill?
11. How to determine the suitability of the workpiece?
12. What safety precautions must be observed when drilling parts?
Filing a part
Target: Learn to use a metalwork tool and file a part
Equipment and materials .
1. Metal blanks, a metal workbench, a vice, a set of files
2. Detail drawing
3. Educational and technical literature.
Exercise:
1. Study the theoretical foundations
2. File the workpiece
3. Answer security questions
Theoretical basis
In table. 1. The roughness classes and the heights of the surface microroughnesses corresponding to them, obtained with different types of metalwork, are given.
Table 1
Surface roughness obtained with different types of metalwork
Correct and reliable fastening of the material in a vice or fixture during filing ensures accurate processing of the material, minimal worker effort and labor safety.
To avoid damage to the surfaces of non-metallic materials and products fixed in a vise, pads should be used. Linings made of soft metals (copper, zinc, lead, aluminum, brass), wood, artificial material, felt or rubber are applied to the cheeks of the vise. The product or material is inserted between the linings, and then fixed.
The height of the vise when filing should be selected in accordance with the height of the worker. In practice, the height of the installation of the vise is determined by resting the elbows on the cheeks of the vise (the fist in the vertical position of the hand should reach the chin of the worker standing straight). If the vice is installed below this position, then gaskets are placed, and if the installation height of the vice is high, then the gaskets are removed or a stand or ladder is placed under the locksmith's feet. The person working at the vise should take such a position that the feet are at an angle of 45 ° to each other, and the left leg should be put forward at a distance of 25–30 cm from the axis of the foot of the right leg. The axis of the left foot in relation to the working axis of the file should be at an angle of about 30 °. This position ensures productive and safe work of the locksmith and reduces his fatigue.
The restoration of the cutting ability of a file after wear is ensured by removing dull teeth and applying a new notch to the file. Restoration is carried out by annealing the file, grinding off the old notch and making a new one (manually or mechanically) followed by hardening. The file can be restored several times, but each time it becomes thinner and more prone to cracks.
Files must be protected from moisture to prevent corrosion; to avoid damage to the cuts, they should not be thrown or placed on other files, tools or metals. The surface of the files is protected from oil or grease, as well as from dust from grinding wheels.
A new file should be used first on one side, and after it has become dull, on the other. Do not use personal and velvet files for filing soft metals (tin, lead, copper, zinc, aluminum, and brass). The filings of these metals clog the grooves of the file notches and make it impossible to process the surfaces of other metals.
The file during work and after work should be cleaned with a steel brush. After finishing work, it is cleaned in a drawer or cabinet.
You should pay special attention to the condition of the handle and its correct attachment to the file (the handle is mounted along the axis of the file). When inserting the handle, do not lift the file up. Files without a handle should not be used. Be especially careful when working with small files. The end of a long file should not be held with your fingers. The material for filing must be fixed correctly and firmly.
Test questions:
1. What are the ways to clean files
2. TB when working with files
3. In what order is the restoration of the cutting ability of the file carried out?
4. Give examples of surface roughness obtained with different types of metalwork?
Practice #2 Perform soldering operations for aluminum and copper wires.
Target: Learn to perform operations on soldering aluminum conductors and wires.
Time: 2 hours.
Equipment and materials .
1. Solder, soldering irons, copper and aluminum conductors.
3. Educational literature.
Exercise. Carry out soldering.
Information from the theory
Soldering - this is the process of obtaining a permanent connection of materials with heating below the temperature of their autonomous melting by wetting, spreading and filling the gap between them with molten solder and their adhesion during the crystallization of the seam.
Soldering is widely used in various industries. In mechanical engineering, it is used in the manufacture of turbine blades and disks, pipelines, radiators, air-cooled engine fins, bicycle frames, industrial vessels, gas equipment, etc.ATIn the electrical industry and instrument making, soldering is in some cases the only possible method of connecting parts. It is used in the manufacture of electrical and radio equipment for televisions, parts of electrical machines, fuses, etc.
The advantages of soldering include: slight heating of the parts to be joined, which preserves the structure and mechanical properties of the metal; the purity of the compound, which in most cases does not require further processing; preservation of the dimensions and shapes of the part; connection strength.
Modern methods allow brazing carbon, alloy and stainless steels, non-ferrous metals and their alloys.
Solders. The quality, strength and operational reliability of a solder joint primarily depend on the correct choice of solder. Not all metals and alloys can serve as solders.
Solders must have the following properties:
have a melting point below the melting point of the soldered materials;
in the molten state (in the presence of a protective medium, flux or in a vacuum), it is good to wet the soldered material and easily spread over its surface;
provide sufficiently high adhesion, strength, plasticity and tightness of the solder joint;
have a coefficient of thermal expansion close to the corresponding coefficient of the brazed material.
Depending on the melting temperature, solders are classified as follows: hard (refractory) - high-strength, having a melting point above 500 ° C; soft (fusible) - less strength, having a melting point below 500 ° C.
Low-melting solderswidely used in various industries and households; they are an alloy of tin and lead. Different quantitative ratios of tin and lead determine the properties of solders.
Tin-lead solders, compared to others, have a high wetting ability, good corrosion resistance. When soldering with these solders, the properties of the metals being joined practically do not change.
Refractory soldersare refractory metals and alloys. Of these, copper-zinc and silver are widely used. To obtain certain properties and melting points, tin, manganese, aluminum, iron and other metals are added to these alloys.
The addition of small amounts of boron increases the hardness and strength of the solder, but increases the brittleness of the solder joints.
Fluxes. With an increase in temperature, the rate of oxidation of the surface of the soldered parts increases significantly, as a result of which the solder does not stick to the part. To remove the oxide, chemicals are used calledfluxes.Fluxes improve the conditions for wetting the surface of the brazed metal with molten solder, protecting the surface of the brazed metal and molten solder from oxidation during heating and during the soldering process, dissolve the oxide films present on the surface of the solder metal and solder.
There are fluxes for soft and hard solders, as well as for soldering aluminum alloys, stainless steels and cast iron.
Soldering iron device . 1 - tip; 2, 6 - nuts; 3 - tube; 4 - thermocouple; 5 – ceramic tube; 7 - base; 8 - screw; 9 - bushing; 10 - heat-resistant insulating tubes; 11 - handle; 12 - holder (plate); 13 - harness of power wires, thermocouples and grounding; 14 - heating element; 15 - wire for grounding.
Preparing the soldering iron for work . The new soldering iron is first “fired” so that the threads, various inclusions in the best, oil coating, etc. burn out in it. To do this, the soldering iron is connected to the mains for 1-2 hours with the voltage indicated on the soldering iron. The tip of the sander should have the shape of a wedge with an angle of 55 ... 60 °, which is best obtained by forging to create hardening. Plaque slows down the dissolution of copper in rosin and prevents the appearance of shells on the sting. After that, the sting is filed down with a file so that the edges are smooth and a rear angle of 10 ... 15 ° is formed on the sting. This shape of the tip helps the solder flow into the solder joint.
A sawn or dirty soldering iron must be tinned, that is, covered with a thin layer of solder. To do this, after sufficient warming up, the soldering iron tip must be immersed in rosin and brought to the edge along a piece of solder. If the soldering iron is normally warmed up, but not tinny, all operations should be repeated.
soldering technology. The soldering process is as follows. Pre-cleaned conclusions of parts, wires, etc. are covered with a thin layer of solder (tinned). Then solder the parts tightly applied to each other. The required amount of solder and rosin is taken on the soldering iron. The soldering iron is applied to the part with more mass in such a way as to provide the best heat transfer. After spreading the molten solder, it is distributed with a smooth movement of the soldering iron. It is recommended to have two buy rosin: the first one is for cleaning the soldering iron, the second one is for soldering.
To provide reliable contact connection when soldering, the following requirements must be met:
1. The tip of the soldering iron must be free of pits and well tinned.
2. The soldering iron should be well warmed up. A sign of sufficient warming up is the boiling of rosin (but not combustion) and copious emission of smoke.
3. The amount of flux applied to the soldering area should be kept to a minimum. Flux should not spread beyond the soldering point.
4. The amount of solder introduced into the place of soldering is determined empirically in such a way that the holes are filled and the contours of the parts are visible.
5. The place of soldering should be sufficiently warmed up with soldering irons until the solder is completely spread.
6. The parts to be joined must be stationary untilfloorsolidification of the solder.
7. Soldering time of one contact connection - no more than 5 seconds.
To increase the mechanical strength, the tinned conductor is mechanically fixed at the contact, and soldering provides electrical conductivity between the soldered parts. Overlay or butt soldering is allowed only in laboratory layouts. When overheated, the soldering turns out to be dark and rough, and when underheated, it is fragile, and a lot of time is spent on its implementation.
Quality control of soldered joints . The quality of soldering is checked by external inspection, if necessary, using a magnifying glass. Well-made soldering should be considered one on which the contours of the connected parts (coils, rings, bends) are clearly visible, but all the slots are filled with solder. The soldering has a glossy surface, without cracks, sags, sharp bulges.
The mechanical strength of the soldering is checked with tweezers with polyvinyl chloride tubes put on its ends. The tensile force along the wire axis should be no more than 10 N. It is forbidden to bend the wire near the soldering point. All soldered cores of wires and conclusions of electrical and radio components are subject to verification. The ambassador of soldering control and acceptance of the joint is painted with a transparent colored varnish applied to the joint in the form of a small stroke with a soft brush.
Safety . When soldering and tinning, certain safety requirements must be observed.
Workplaces intended for soldering small parts must be equipped with local exhaust devices that provide directly at the soldering site with an air speed of at least 0.6 m/s.
In rooms where soldering work was carried out, floors should be washed (dry cleaning of the floor is not allowed).
Storage of clothing in rooms where soldering is carried out is prohibited.
In the immediate vicinity of the workplaces intended for performing work on soldering small parts with soft solders, the following should be installed: a washbasin; tank with 1% solution acetic acid for preliminary washing of hands; easy-to-clean portable containers for collecting paper or cotton napkins and rags. There should always be soap, brushes and napkins for wiping hands near the washbasin (the use of shared towels is not allowed).
The preparation of metals and the soldering process are associated with the release of dust, as well as harmful vapors of non-ferrous metals and salts, which cause irritation of the mucous membrane of the eyes, skin damage and poisoning. Therefore, when soldering and tinning, the following safety rules must be observed:
the workplace of the solderer must be equipped with local ventilation;
work in gas-polluted premises is not allowed;
at the end of work and before eating, wash your hands thoroughly with soap and water;
chemicals must be poured carefully, in small portions, avoiding splashes (acid getting into the eyes can cause blindness; acid fumes are also very harmful);
manual operations (washing, wiping products, bottling, etc.) are not allowed, in which direct contact of the skin of the worker with dichloroethane (flammable poisonous liquid) or mixtures containing it is possible;
when heating the soldering iron, the general rules for safe handling of the heat source should be observed;
it is necessary to conduct a visual inspection of tools and equipment, to make sure it is in good condition;
for an electric soldering iron, the handle must be dry and non-conductive;
the student's landing should be straight, the elbows should touch the plane of the table, the distance from the place of soldering to the eyes should be 350 ... 400 mm, the soldering iron must be held like a pencil.
Test questions:
1. What are the ways to get a contact connection?
2. Give a description of the brands of soldering fluxes known to you.
3. Solders for soldering. General requirements.
4. Give a description of solder brands known to you and their areas of application.
5. Give a description of the methods known to you for removing fluxes after soldering.
Practice #3 Performing external and internal threading operations.
Target: Learn to use a metalwork tool and cut external and internal threads
Time: 2 hours.
Equipment and materials .
1. Blanks for cutting internal and external threads, taps, dies, wrenches, oilers
3. Educational literature.
Exercise.
2. Cut the internal metric thread M10 and evaluate the quality of the thread
3. Answer security questions.
Information from the theory
Tapping of internal threads
The internal thread is cut with taps by hand. The tap consists of a working part and a shank. The shank ends with a square, on which a collar is put on during threading. The working part consists of intake and calibrating parts. The intake, (conical) part of the tap removes the bulk of the chips and forms a thread in the hole. The calibrating part calibrates the cut thread. For the formation of cutting edges on the taps, three or four longitudinal grooves are made; the number of grooves depends on the size of the tap. Large taps have four grooves, small taps have three. Chips flow down these grooves during operation.
Tap (appearance and main elements).
The cylindrical part of the shank is usually marked with the dimensions of the tap and its number in the kit. For metric threads, indicate the outer diameter and pitch, for example: M 8x1.25: this means that the thread is metric with an outer diameter of 3 mm with a pitch of 1.25 mm.
Currently, for the main fastening metric thread up to 26 mm, two-set taps are produced, i.e. a set of such taps consists of two pieces. The first, preliminary tap, is called a rough tap, the second is a finish tap and has two risks on the shank. The first tap, in addition, has a longer chamfer than the second tap and a blunt thread. The second tap on the gauge part has a full thread profile. The thread is cut first with a rough and then with a finishing tap.
Before threading with a tap, a thread hole must be drilled in the workpiece. The diameter of the drill for drilling such a hole is selected depending on the size of the thread according to special tables. The diameter of the drill should be less than the outer diameter of the thread and slightly larger than its inner diameter. So, for example, for threads M8, M10, M12 and MI6 when machining steel, drills for threads are selected, respectively 6.7; 8.5; 10.2 and 14 mm. The size of the drill will also depend on the material being processed. For cast iron and bronze, the size will be smaller than for steel and brass. If the hole size is made smaller than required, then the tap may break when threading. Larger holes may result in incomplete threads.
The threading process is carried out by the following working methods:
1. The tap moistened with oil is inserted with a shank into one of the square holes in the wrench, and then set in a vertical position;
2. Keeping the vertical position of the tap, and pressing the knob with your hands, turn the tap clockwise until the tap cuts into the metal (1.5-2 turns);
3. Without applying vertical force, changing the position of the hands, turn the tap half a turn clockwise, then a quarter turn back counterclockwise, etc. to complete threading with the first tap;
4. Similarly, cut the thread with a fine tap. A finishing tap is inserted into a pre-cut hole without much effort, after which a knob is put on it and the thread is cut.
Thread control is carried out with a thread gauge or a mating part (bolt). 
Methods for cutting internal threads.
In plumbing, dies of various designs are used. The most widespread are round scarves.
A round die is a kind of "nut" made of tool steel. It has a number of holes for chips drilled in it, which form the cutting edges on the bump. They perform the same role as the grooves in the tap. On both sides of the die there are intake cones, one or two threads long.
From the outer cylindrical surface of the die, four conical recesses are drilled and one longitudinal cut is made at an angle of 60°. Conical recesses are used to fix the die with screws in the die holder
When cutting external threads with dies, the diameter of the "threaded" rod must be less than the outer diameter of the thread by 0.2 of the profile height. So for example, for threads M8, M10, MI2 and Ml6, the rods should have a size of 7.85, respectively; 9.80; 11.82 and 15.76 mm. The end of the rod should be sawn perpendicular to the axis and sawed off with a receiving chamfer to facilitate insertion of the die.
Tool for cutting external threads.
For: threading, the rod in a vertical position is clamped in a vice to the required height, then a die fixed in the die holder is applied to the end of the rod. Keeping the position of the die holder perpendicular to the axis of the rod, the die is turned clockwise with force until it cuts 1-2 threads. Then a lubricant is applied to the rod. Keeping the same direction of movement as the tap (half a turn clockwise and a quarter of a turn counterclockwise), a thread is cut into the shank. No vertical force is applied to the plate.
Fig.37. Techniques for cutting external threads.
Applied in can be divided into 2 main groups: detachable and one-piece. A detachable connection of parts is also a connection in which its constituent parts can be disassembled. One-piece - this is a connection of parts, in which disassembly of the assembly is possible only if the fastening or the parts themselves are destroyed. Detachable connections include threaded, keyed, slotted, pin and wedge connections; to one-piece - riveted, welded, press and adhesive joints.
Threaded connections
To threaded include connections in which mating parts are connected using threads or threaded fasteners (bolts, nuts, screws, studs, etc.).
Test questions:
1. In what sequence is an internal thread cut by hand?
2. In what cases are sets of two and three taps used?
3. What causes thread stripping when threading?
4. What types of marriage are possible when working with blunt tools?
5. What safety rules must be observed when cutting threads by hand
Practice #4 Connection of conductors of wires using bolt clamps.
Target: learn to connect wire cores using bolt clamps.
Time: 2 hours.
Equipment and materials .
1. wire cores, terminals, bolted connections, couplings.
3. Educational literature.
Task: Connect the wires using a bolt clamp.
1. Connecting wires using bolt terminals.
Bolted terminal blocks are insulated terminals to which wires are attached using bolts. They are widely used when connecting different fixtures.
Everything is simple here. We clean the cable cores to half the width of the terminal itself, insert them from both sides and tighten the screws.
Here it is necessary to correctly select the size of the terminal block for the corresponding wire section. The option that was available in the nearest store may not be suitable, since a thin wire in an oversized terminal may fall to the side between the bolt and the terminal wall. This will lead to poor contact and heating of the connection.
The disadvantages of such a connection are:
The insulating housing may crack, which I often encountered.
You can break the thread on the screw, because you want to tighten it more securely. As a rule, in such situations, many tighten the screw to the tightest position and leave it that way, because there is no other bolt or terminal block to replace. This also leads to poor contact.
The screw can strongly crush the aluminum wire, which can subsequently break quickly.
Not convenient to put in a junction box.
The pluses include the fact that with their help you can connect the load to very short wires sticking out of the wall.
2. Bolted connection
Another type of connection of electrical wires with solid experience is bolted. It is called so because a bolt, nut and several washers are used to connect the wires. Contact through the use of washers is good, but the whole structure takes up a lot of space and is inconvenient to install. It is mainly used if it is necessary to connect conductors from different metals - aluminum and copper.
Connection assembly order:
washer (it rests on the head of the bolt);
one of the conductors;
another puck;
second conductor;
third puck;
We clean the wires from insulation.
From the cleaned part we form a loop, the diameter of which is equal to the diameter of the bolt.
We put on the bolt in the following sequence
We tighten everything with a nut.
Test questions:
1. In what sequence are the wires connected?
2. Wire stripping methods?
5. What safety precautions must be observed when connecting wires.
Practice #5 Tinning and soldering wires and cables.
Objective: To study the design and technology of obtaining one-piece connections. Gain practical skills in soldering, tinning.
Time: 2 hours.
Equipment and materials .
1. Power tools, fluxes.
2. Samples for work
Task: Perform soldering and tinning of wires.
Theoretical information
Soldering. It is a process of joining parts using a special filler fastening material - solder and an auxiliary protective material - flux.
Low-melting and refractory solders are used.
Low-melting solders (soft) are made on the basis of an alloy of tin (O) with lead (C) and are designated by the letters POS with numbers showing the tin content as a percentage. Their melting point is less than 500 ° C: They are used for soldering steel, copper, zinc, lead, tin, gray cast iron, aluminum, ceramics, glass, etc. Connections made with low-melting solders are tight, but not particularly strong. To obtain special properties, antimony, bismuth, cadmium and other metals are added to tin-lead solders. In locksmith work, POS-40 solder is most often used.
Refractory solders (solid) have a melting point of more than 500 ° C, are designed to obtain strong joints that are resistant to temperature and corrosion conditions. They solder steel, cast iron, copper, nickel and their alloys. They are divided into copper-zinc (PMC grades) and silver solders.
Fluxes are designed to ensure the wetting of the surface of metals with solder, to protect the surface of metals and solder from oxidation during heating, and to dissolve oxide films.
There are fluxes for soft low-melting solders (zinc chloride, ammonia, rosin, pastes, etc.), for hard refractory solders (borax, boric acid, etc.), as well as for soldering aluminum alloys (mixtures of sodium fluoride, lithium chloride, potassium, zinc chloride, etc.), of stainless steel(mixtures of borax and boric acid), cast iron (mixture of borax with zinc chloride).
The process of soldering metals includes the preparation of the product, the soldering iron for soldering and the soldering of the product itself.
Preparation of the product consists in cleaning its surface from dirt, fats, oxides, corrosion, scale.
Such cleaning can be carried out: – mechanically using sandpaper, files, metal brushes, grinding wheels, steel or cast iron shot; - by chemical degreasing with the help of Viennese lime diluted with water, applied with a brush to the products; - by chemical etching when the product is immersed in solutions of sulfuric, hydrochloric and other acids; – using ultrasound in a solvent bath.
The preparation of the soldering iron (Fig. 3.6) includes filling the working part at an angle of 30 ... 40 ° with blunting the top, cleaning it from scale and applying (tinning) to the end part of the solder.
When soldering, do not allow underheating and overheating of the soldering iron. In the first case, the solder cools quickly, forming an unstable joint, in the second case (above 500 ° C), scale forms and tinning of the working part on the soldering iron is difficult.
On tightly fitted parts, liquid flux is applied with a brush, and solid (rosin) is applied by rubbing while heating the soldering point with a soldering iron. With a tinned soldering iron, 2 ... 3 drops of molten solder are taken from the solder bar and transferred to the place of soldering, covered with flux. After heating the metal, the solder spreads when moving the soldering iron, filling the gaps in the seam. Cooled solder has a shiny surface. The protrusions on the solder are removed with a file.
In mass production, parts can be soldered by immersion in a bath of molten solder.
Tinning. The essence of this locksmith operation is to apply a thin layer of tin or tin alloys (with lead, zinc, bismuth, etc.) to the part in order to protect surfaces from corrosion and oxidation, to give them the necessary properties, for example, for decorative surface treatment in the manufacture art products or surface preparation of bearings before casting with babbitt, before soldering. This layer is called the half-day.
Fig.1. Soldering iron preparation:
a - refueling of the working part; 6 - cleaning of the working part with zinc chloride; c - application of solder; 1 - zinc chloride; 2 - solder
Before tinning, the surfaces of the parts are treated to a pure metallic sheen either by a non-chemical method (files, a steel or hair brush with wet sand, grinding) or a chemical method for the purpose of degreasing (in a solution of caustic soda at a boil, Vienna lime, gasoline, etc.) and etching ( in hydrochloric acid solution with heating). The tinning process is carried out in two ways (Fig. 2): by immersion in a semi-dish (a), poured into a clean dish, with pieces of charcoal (to protect against oxidation) and rubbing, by first applying tow to the surface of the zinc chloride part and then applying it from a rod with heated solder (c) and rubbing it with tow (b). After tinning, the parts are washed with water and dried.
Rice. 2. Tinning of the part: a - by immersion; c - application of solder; b - rubbing solder with tow; 1 - pieces of charcoal on the floor; 2 - solder
Safety
An employee performing plating, tinning or soldering operations comes into contact with molten metal, acids, alkalis and vapors of various caustic and harmful substances.
The rooms in which the above operations are carried out must be well ventilated.
Workers must wear protective clothing, goggles and gloves. The blowtorch must be technically sound. When pumping fuel, high pressure must not be created, nor can fuel be added to a heated lamp. Acids and alkalis should be kept in glass bottles, and they must be diluted by adding acids to water, and not vice versa. The workplace should be free of rags, spilled oil and grease.
Test questions:
1. What is soldering?
2. Describe the tinning process and the materials used in this process
3. List the solders and fluxes used in soldering
5. What safety rules must be observed when plating, tinning and soldering.
Practice #6 Connecting wire cores with
crimping.
Objective: Connect the wires using crimping.
Time: 2 hours.
Equipment and materials .
1.Wires
2. Crimping
3. Educational and technical literature
Exercise: Terminate a stranded copper core using stamped lugs.
Theoretical information
ending - this is the design of the end of a conductive core for inclusion in an electrical circuit.
Crimping - this is a method of connecting the conductive cores of wires and cables using sleeves or terminating the cores of wires and cables using lugs.When crimpinga core of wire or cable is inserted into the tubular part of the tip or specialcial sleeve and compressed by a matrix and a punch. At the same time, contactthe pressure created between the sleeve and the core ensures reliableelectrical connection
Termination of single-wire copper conductors 1…2.5 mm or stranded up to 1.5 mmperform a ring or a pin, depending on the design of the clamps.
The sequence of technological operations during installation:
removal of insulation at a length of 10 ... 15 mm for a pin and at a length of 30 ... 35 mm for a ring;
stripping the core to a metallic sheen;
compaction of the strand of wires in the core;
twisting the core into a ring with round-nose pliers in accordance with the diameter of the screw;
fastening around the core;
coating the ring or pin with flux;
immersion in molten solder for 1 ... 2 seconds or soldering with a soldering iron;
insulation with adhesive tape of the bare part of the core with an overlap of 5 ... 10 mm of the main insulation.
Stranded copper termination and aluminum conductors with a cross-sectional area of 1.5 ... 240 mm 2 are performed with cable lugs by crimping (table 3.2).
The tip is selected according to the cross-sectional area of \u200b\u200bthe core, its inner cylindrical part is cleaned with a steel ruff to a metallic sheen and coated with rosin. From the end of the wire to the length of the cylindrical part of the tip plus 10 mm, the insulation is removed, degreased with a cloth soaked in gasoline, cleaned to a metallic sheen, covered with rosin and tinned. A tip is put on the core, 1 ... 3 layers of asbestos cord are wound under its end to prevent solder from flowing out. Core and lug with wire cross-sectional area up to 10 mm 2 heated with a soldering iron, and with a larger one - with a blowtorch or a propane-butane torch to the melting temperature of the solder. The solder is fused into the sleeve. At the same time, they make sure that it penetrates between the wires of the core. With a cloth moistened with soldering ointment, solder smudges are smoothed over the surface of the tip. After the tip has cooled down, the asbestos winding is removed and the end is isolated
Table 1. Examples of termination of conductors of wires and cables with cable lugs using the crimping method
Explanatory drawings
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