Editing and bending of metal

Bending a strip in thickness around a circle, we get a cylindrical ring; moreover, the outer part of the metal is somewhat stretched, and the inner part is compressed. Therefore, the length of the workpiece will correspond to a circle that comes in the middle between the outer and inner circles of the ring.

In a cold state, pipes of small diameter up to 20 mm are bent. Bending of pipes with filler in the hot state is carried out with a pipe diameter of more than 100 mm. Bending of pipes in a hot state with a filler is carried out in the following order:

1. One end of the pipe is closed with a stopper.

2. To prevent crushing, bulging and cracking during bending of pipes, they are filled with fine, dry, river sand, which is sieved through a sieve with 2 mm mesh size, and too fine sand is not suitable.

3. The second end of the pipe is closed with a wooden stopper, which must have openings or grooves for the gas to escape when the pipe is heated.

5. Wear gloves.

6. Install the pipe.

7. Heat the pipe with a blowtorch or flame of a gas burner to a cherry red color over a short length of 6 diameters.

8. Bend the pipe along the copier.

9. Check the bending of the pipe with a template.

10.At the end of bending, beat out the cork or burn out and pour out sand.

It is recommended to bend the pipe with one heating, as repeated heating affects the quality of the metal. When heating, pay attention to sand warming. Do not allow excessive overheating of individual sections. Scale bounces off a very hot part of the pipe. In the event of overheating, the pipe is cooled to a cherry red color before bending. If the pipe is bent at an angle of 90 degrees, then a section equal to 6 pipe diameters is heated, if the pipe is bent at a angle of 60 degrees, then a section equal to 4 pipe diameters is heated, if at an angle of 45 degrees, then 3 pipe diameters.

Welded pipes must be positioned during bending so that its weld is located in the neutral layer, otherwise it may diverge. When bending, the following defects are possible: oblique bends and mechanical damage to the treated surface, as a result of incorrect marking of the sludge and clamping of the part in a vice, as well as the application of strong blows.

Round rods with a diameter of more than 30 mm, shafts and pipes are controlled by screw presses, by pressing with a twist with a prismatic tip. Check is made by the indicator. Deviation of the indicator arrow will show the magnitude of non-linearity.

Safety when editing metal:

· Hammer handles must be crack-free with fasteners firmly attached to them.

· The hammer head must have a smooth, polished with a slightly convex surface.

· When editing, be sure to work in mittens.

· Workpieces must be securely fastened.

· When editing a strip or bar, they must touch the plate at least at two points.

Safety measures when bending metal.

· Securely fasten parts in a bench vise or fixtures.

· Work only on working equipment and fixtures.

· Locksmiths must have good handles and be tightly set.

· When working on bending machines, strictly observe the safety rule set out in special instructions.

· When bending pipes when hot, work in their hands.

Types of locksmith work
Locksmiths are widely used in various types of production. Depending on the type of work performed, there are specialties: locksmith-toolmaker, locksmith-healer, locksmith for fixtures, etc., which are particularly demanding. So, the list of work performed by a toolmaker includes mechanical marking and filing of complex profiles of dies and molds, mechanical and manual grinding and polishing of their planes, engraving and chasing of products. Each type of work corresponds to a certain accuracy class of machined parts:
  works requiring marking of planes, cutting, cutting and bending of metal, filing and fitting of simple parts in the repair of appliances, dies and molds, 13-12;
  works of medium complexity, requiring filing and fitting during assembly of relatively complex parts of dies and molds, 13-11;
  complex work requiring fine-tuning and fitting during assembly of parts of dies and molds, 11-9;
  more complex work requiring careful adjustment and refinement of the surfaces of parts of dies, molds, casting lengths and investment casting forms; making
  brand, 9-6;
  very complex work, requiring particularly careful tuning and fitting of the mating contours and planes, the manufacture of complex brands of knurled rollers; engraving on bronze and steel with a shtikhel, 6-5.
  The tool fitter does the work that cannot be done on precise and perfect equipment: for example, manufacturing complex conjugate profiles of dies and punches, dies and molds, processing and engraving of relief images on dies, etc. The tool fitter must be technically competent, fluent read the drawings and know the characteristics and characteristics of the processing of metals and alloys; used in tool manufacturing. When working in a single production, he needs to possess related professions, such as a turner, milling machine operator or grinder.

One of the issues of the scientific organization of labor in metalwork and instrumental work is the rational organization of workplaces aimed at ensuring the high quality of instrumental work at the minimum cost of working time and material resources. The organization of jobs in tool production should be constantly improved.
  By the rational organization of jobs of toolmakers should be understood:
  a) specialization for the performance of certain works;
b) rational equipment with technological equipment, as well as technological and organizational equipment;
  c) a rational layout taking into account the techniques, methods and modes of work, a rational working posture, convenient access to equipment and providing an overview;
  d) compliance with normal working conditions, rules and safety requirements;
  f) ensuring an uninterrupted supply of tools and material.
  The division of labor at the workplace should be carried out both by type of work (manufacturing dies and punches of dies, processing the forming surfaces of dies and punches of molds), and by operations depending on the technological process.

Receptions and methods of work. The working movements of the toolmaker should be economical, easy and smooth, that is, the worker should only make those movements that are necessary to perform a given operation or reception; hand movements should be synchronous, which contributes to the balance of the body and the even distribution of muscle effort. When performing metalwork and instrumental work, labor movements should be performed in the optimal zone, and the last movement should be the beginning of the next. Saving the working movements of the toolmaker is achieved by the correct placement of the tool and fixtures on the workbench table. A tool or device, often used, should lie close and in a comfortable position: on the right, what is taken with the right hand, on the left, what is taken with the left. The quality of metalwork and instrumental work is affected by their optimal pace and rhythm. Both at an underestimated and an overestimated pace of work, attention is weakened, the quality of work and the accuracy of movements are reduced. When determining the rhythm of the work of a tool-maker, it is necessary to take into account that operations that require concentration of attention should not alternate with operations in which fast movements are used.
  To eliminate the monotony of work, it is necessary to introduce regulated intra-shift breaks into the labor process, the first break should be carried out when signs of fatigue appear, the second - an hour and a half before the end of the shift. Lunch break should be 3-4 hours after the start of work.

Working pose. For toolmakers, due to the increased accuracy of work, it is recommended that the working posture be "sitting" and, in some cases, "standing"; the pose should be free and comfortable. The choice of a working posture depends on the size of the workplace, working area, tension of vision, etc. The working posture should ensure the rational use of muscle work, for which it is advisable to use armrests, back rests, which allow saving muscle effort and creating conditions for relaxation. For prolonged work at the workbench, it is recommended that the working chair has a backrest that allows it to periodically straighten. The back should be located above the waist of the worker, so that when you straighten the body, it can spring and lean back.
  For the convenience of work and to prevent fatigue of the toolmaker, a removable bracket with an armrest for supporting the right hand is installed under the cover of the workbench. When changing the position of the legs or turning the chair, the bracket can be extended and retracted. The position of the body when sitting is determined by the height of the chair seat. At the same time, the landing should be without tension of the muscles of the back and lower back. When the right hand is resting on the armrest and resting, the left makes light movements, directing the file along the plane of the workpiece. The right leg should rest on a stand at the bottom of the workbench. With signs of fatigue, it is recommended to change the position of the body and the support of the legs.
  Small metalwork and instrumentation work, such as filing the internal profiles of dies or molds, is also performed while sitting.

Lighting.

The workplace of the tool-maker should be adequately lit: a) the illumination must be stable; b) the light source should be on the left or in front so that the shadow does not fall on the assembled product; c) the light should not blind eyes; d) mixed lighting (fluorescent and incandescent lamps) cannot be used. Illumination is affected by the degree of reflection of the internal surfaces of the production room.
  When determining the lighting standards, the nature of the work (especially accurate, accurate, high precision, low accuracy, rough, etc.), the size of the instrument or products to be assembled, the background, the contrast of the object with the background should be taken into account

Equipping the workplace of a tool-maker with technological and organizational equipment should ensure the economy of movements and high-quality performance of the production task at the lowest labor costs. Tooling should be convenient to use; have a device with quick-acting clamping devices for fixing parts on drilling machines, which ensures an increase in labor productivity by 20-30%. The power tool should lie on a table or be fixed on a hinged stand with a cable. Two or more tools should be combined, since turning a two-sided tool at the other end is more convenient than taking another tool. The design of the devices should ensure the execution of operations with a minimum investment of time.
  Power tools must have reliable insulation of conductive parts. The number of tools and fixtures should be minimal. Tooling must ensure safety in work.
  Turn the equipment on and off with the foot pedal. High requirements are imposed on auxiliary and non-standard equipment, as well as on overhead transporting vehicles: a) the exclusion of the possibility of falling transported goods and the contact of moving elements with the worker; b) ensuring freedom of action for the locksmith during the work; c) the minimum number of movements and costs of physical forces during the reception of cargo (heavy dies or molds). When choosing equipment for toolmakers, the height and weight of the worker should be taken into account; racks and boxes for storing parts, tools and fixtures should be compact, stable and guarantee the tool from damage, the workplace of a locksmith should be equipped with a tablet for storing technical documentation, which must be mounted on the right on a workbench or in the center, opposite the one working; the size of the working area should be calculated for a person with a height of 185 cm, taking into account the height of the body.
  The height of the working area is determined by the distance between the part and the eyes (mm):
  The distance between the part and the eyes. . 250-300 to 500
  The height of the working area ... 900 800
The workplace of a tool-maker should be equipped with special working furniture. The chair or chair should be stable, sized to ensure the correct working position and height adjustment. The back of the chair should be movable in two directions, and in shape to correspond to the back of the worker: the angle of inclination of the back is chosen depending on the working conditions. The height of the backrest is 150-180 mm from the seat. When designing a chair, it is necessary to take into account the use of armrests and exclude the position of the hands “on weight”.
  The design of the seat should include foot rests with an area twice the footprint of the foot. The distance from the top edge of the seat to the supporting area of \u200b\u200bthe legs should be equal to the distance from the popliteal fossa to the heel plus 45-50 mm.
  The design and dimensions of industrial furniture in tool production should provide the most rational movement of the worker, ease of work; reduce fatigue; the placement of furniture should help to increase productivity and a culture of work. The appearance of organized equipment must meet the requirements of technical aesthetics.

Metal editing

Editing is an operation to straighten a curved or warped metal, which can only be subjected to plastic materials: aluminum, steel, copper, brass, titanium. Editing is carried out on special regular plates, which are made of cast iron or steel. Editing of small parts can be done on blacksmith anvils. The dressing of metals is carried out with hammers of various types, depending on the condition of the surface and the material of the piece to be dressed.

When dressing workpieces with an unfinished surface, hammers with round strikers weighing 400 g are used. A round striker leaves less traces on the surface than a square one.

When dressing workpieces with a machined surface, hammers are used that have hammer strips with soft inserts (made of copper, aluminum) that do not leave marks on the surface. When editing sheet material, wooden hammers are used - mallet, very thin sheets are ruled by wooden or metal bars - smoothing machines.

Editing is carried out in several ways: by bending, stretching and smoothing.

Bending editing is used when straightening round (rods) and profile material, which have a sufficiently large cross section. In this case, they use hammers with steel strikers. The workpiece is positioned on the correct plate with the bend up and strikes inflicted on convex places, bending the workpiece in the direction opposite to the existing bend. As the workpiece straightens, the impact force is reduced.

Editing by pulling is used when straightening sheet material having a bulge or waviness. Such editing is carried out with hammers with soft metal dies or mallets. In this case, the workpiece is laid on a regular slab with bulges upward and frequent light blows are applied, starting from the bulge border, towards the edge of the workpiece. The strength of the blows gradually decreases. In this case, the metal is drawn to the edges of the workpiece and the bulge is straightened due to this traction.

Editing by smoothing is used in those cases when the workpiece has a very small thickness. Smoothing is carried out with wooden or metal bars. The workpiece is smoothed on the correct plate, pulling the material with the help of trowels from the edge of the roughness to the edge of the workpiece, and by pulling the material, the surface of the workpiece is aligned.

Heat-treated (hardened) workpieces rule (straighten) with special straightening hammers.

Depending on the design of the workpiece, various dressing methods are used.

Tools and devices used during dressing

Regular plates (Fig. 2.31) are made of gray cast iron with working surfaces of 1.5x5.0; 2.0x2.0; 1.5x3.0; 2.0x4.0 m. On such plates profile blanks and blanks from sheet and strip material, as well as rods from ferrous and non-ferrous metal, rule.

Leveling headstock (Fig. 2.32) is used, as a rule, for dressing and straightening workpieces made of high hardness metals or pre-hardened metals. Leveling headstock is made of steel billets with a diameter of 200 ... 250 mm, their working part has a spherical or cylindrical shape.

  Fig. 2.31. Correct plate Fig. 2.32. Tailstock

Fig. 2.33. Hammers with soft inserts: a - with prismatic; b - with a cylindrical: 1 - pin; 2-side; 3 - handle; 4 - case

The dressing hammers are used to apply force at the dressing site. Different types of hammers are selected depending on the physicomechanical properties of the workpiece and its thickness. When editing workpieces from bar and strip material, square and round striking hammers made of U8A steel are used.

Hammers with soft inserts made of aluminum and its alloys or of copper (Fig. 2.33) are used to dress the treated surfaces. The hammer 2 is mounted in the housing 4 using a pin 1, the hammer is mounted on the handle 3 in compliance with the same requirements as when mounted on the handle of hammers with steel strikers.

Sledgehammers are hammers of large mass (2.0 ... 5.0 kg) and are used to straighten round and profile rolled products of a large cross section in cases where the impact force applied by a conventional bench hammer is insufficient to straighten the deformed workpiece.

Hammers are hammers, the impact part of which is made of hardwood, they are ruled by sheet material of metals of high plasticity. A characteristic feature of editing with mallet is that they practically do not leave marks on the straightened surface.

Metal or wooden smoothing machines (made of hard wood: beech, oak, boxwood) are intended 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.

Mechanization during editing

For mechanization of work during editing, various correct machines are used.

The simplest device for the mechanization of dressing is a hand press (Fig. 2.34), with the help of which dressing of rolled sections and bar material is carried out. The editing of bar material on this press is carried out in the centers (Fig. 2.34, a) or on prisms (Fig. 2.34, b). Profile rental rule only on prisms.

Fig. 2.35. The correct machine: a - general view; b - editing scheme; P - dressing force

  In most cases, special straightening machines are used to straighten sheet and profile steel (Fig. 2.35, a), in which the main working bodies are straightening rolls (Fig. 2.35, b). When editing, the sheet is fed into the rolls and, due to the friction force arising between the rolls and the sheet, is drawn between them. Passing between the rolls, the sheet is bent to one side, then to the other side, and its fibers are aligned. To correct, the sheet is passed through the rolls repeatedly, sometimes up to five times or more.

Fig. 2.34. Manual press: a - editing in the centers; b - editing on prisms

Basic rules for performing work when editing

When editing strip and bar material (round, square or hexagonal section), the straightened part must touch the correct plate or anvil at least at two points (Fig. 2.37). In this case, the editing of the deformed workpiece must be carried out due to its bending in the direction opposite to the existing deformation.

Distribute the force of blows with a hammer or sledgehammer along the length of the deformed section and adjust depending on the cross-sectional area of \u200b\u200bthe material to be edited and the amount of deformation.

When dressing the machined shafts in order to avoid dents on the machined surface, it is necessary to use supporting prisms and soft metal gaskets (Fig. 2.38).

  4. Amendment of sheet material
  0.5 ... 0.7 mm thick must be produced with
  wooden hammers - mallet
  (Fig. 2.39). In the absence of a cue
  nock allowed
  ordinary steel hammer but
  it is necessary between mo
  tray and straightened over
  put wooden
  spacer.

5. When editing strips curved along the edge (straightening), as well as sheet material with significant deformations, it is necessary to apply the method of editing by stretching (Fig. 2.40).

6. Editing of strips with a helical bend must be performed in manual vise (Fig. 2.41, b).

7. Quality control of dressing should be done depending on the configuration of the workpiece and its initial state: on the “eye” (Fig. 2.42) - visually, with a ruler, rolling on a plate; “By pencil” (Fig. 2.43) - by rotating the straightened shaft in the centers of a hand screw press.

8. When dressing strip and bar material on a stove (anvil), you must use gloves, dressing should be done with a hammer or sledgehammer firmly mounted on the handle.

Typical defects during editing, the reasons for their appearance and methods of prevention are given in table. 2.3.

Fig. 2.36. Straight Rollers

In addition, in the right rollers, you can edit and profile hire. Rollers for straightening profile rolled products practically do not differ from rollers for straightening sheet material. The difference lies in the design of straightening rollers, which should have a profile corresponding to the profile of the material being edited (Fig. 2.36).

Editing processed

shafts: a - with a mallet; 6 - with gasket

Fig. 2.39. Editing sheet material with a mallet

Editing a Curved Strip

Editing a strip with a helical bend:

a - strip with a double bend; b - strip editing

in manual vise

* securely fasten the workpiece in a bench vise or other devices;

* work only on working equipment;

* hand hammers should have good handles, be tightly planted and wedged;

* Do not put mandrels and tools on the edge of the workbench;

* when bending the wire, do not keep your left hand close to the place of bending;

* Do not stand behind the worker;

* Work carefully, so as not to damage the fingers;

* Work in mittens and buttoned robes.

CONCLUSION

So, the tools must be selected based on how difficult the work that you are going to do.

But you always need to remember that the more perfect one or another tool, the better you can do the work, and, in addition, it will be easier and more pleasant for you to create or repair something yourself, using the perfect technique.

The student must know:  purpose and methods of performing metal bending; tools and fixtures; technical equipment; organization and rules of the workplace; basics of industrial sanitation.

The student must be able to:  bend rods, strip steel, rolled angle steel in the correct sequence; bend pipes in cold and hot condition; properly organize the workplace; comply with safety regulations; eliminate defects that occur when bending metal.

Test questions:

1. Why is the calculation of the length of the workpiece for subsequent bending produced in a neutral line?

2. Why are there no deformations when using filler when bending pipes?

3. In what cases and why are bending hammers with soft inserts used?

4. What is considered when choosing a percussion instrument for bending?

5. Why when using special bending devices when bending pipes is not required

filler application?

6. What phenomena occur during bending?

7. What methods of pipe bending are used in practice?

8. What defects are encountered during metal bending and how to eliminate them?

9. What tools and devices are used for bending metal and what do they serve for?

10. What safety rules must be observed when bending metal?

Plumbing

Workplace organization

A workplace is a part of the production area of \u200b\u200ba workshop or site with all the necessary equipment, tools, devices that are used by an individual worker or team to carry out a production task. An area of \u200b\u200b6 - 10 m 2 is allocated for each workplace.

Organization of a locksmith’s workplace means the proper arrangement of equipment, the most advantageous arrangement of tools and parts in the workplace, and the planned supply of parts and spare parts.

At present, standard designs for the workplace of a locksmith based on the principles of the scientific organization of labor have been developed.

The main equipment and the permanent workplace of the locksmith is a workbench with a vise installed on them. The workbench is made strong and stable, well lit, covered with a metal sheet. The height of the workbench is considered correct if the hand of a straight locker bent at an elbow at an angle of 90 ° is at the level of the jaws of a vice. In the drawers of the workbench they store all the necessary tools that are grouped by purpose (i.e., files should be stored in one place, a measuring tool in another, etc.).

At each workplace, a platform is provided for shelving, supports and pyramids for storing parts, spare parts with good access to them.

The necessary tool, devices should be positioned so that you can quickly and conveniently take the right ones.

1. At the workplace should be only what is required for work;

2. Tools, parts are located at arm's length on the left and on the right or front, depending on which hand the tool is taken;

3. The tool and parts are laid out in a strict sequence of their application;

4. Files, drills, taps and other cutting tools are placed on wooden supports to prevent damage.

1.1. Benchmarking.

Markup  they call the process of transferring the shape and dimensions of the part or its part from the drawing to the workpiece to indicate places and boundaries of processing on the workpiece. The processing boundaries separate the material that must be removed from the material that forms the part.

The markup is performed using various tools, which are divided into the following types:

1) for drawing and drawing depressions (scriber, compasses, center punches);

2) to measure and control linear and angular quantities (metal rulers, calipers, squares, micrometers, goniometers, etc.);

3) combined, allowing measurements and risks (marking calipers, calipers, etc.).

Scriberserve for drawing on the surface of the workpieces.

Marking compasses according to the device and purpose, they correspond to the drawing and serve to draw circles, transfer linear dimensions.

The steel legs of the inks and compasses are made of U7 and U8 steels, the working ends of the inks and compasses are sharpened sharply.

Punchit is used to apply recesses on the marking risks, so that during processing the marking risks, even when erased, are noticeable. Kerner - a steel round rod, made of alloyed (7ХФ, 8ХФ) or carbon steel (U7A, U8A) steel. Its working part is hardened and sharpened at an angle of 60 about.

Squaresused for drawing lines, angles and checking them .

Vernier Caliperserves for measuring the dimensions of the external and internal surfaces and for carrying out marking drawings. It differs from a conventional caliper in the presence of hard-alloy sharpened tips on its lips.

1.2. Cutting

Felling -method of metalworking workpieces using a chisel or crosshead. Excess metal is removed by cutting, the burrs on the parts are cut off, shells, non-metallic inclusions, lubricating and keyways are cut out, the welds are cleaned, etc.

Cutting is carried out in cases where special processing accuracy is not required and a small layer of metal needs to be removed from the part. This work is time-consuming and inefficient, requiring large expenditures of physical strength, is performed using a chisel, crosshead and hammer, used only in cases when it is impossible to use machine processing.

In the process of cutting, the cutting tool is held with the left hand in the middle part, and the hammer in the right and strike with the hammer with such force that the blade of the chisel cuts into the metal.

To increase the productivity (6-8 times) of the cutting process, pneumatic and electric chipping hammers are used. Due to air pressure P \u003d 5-6 atm. and the magnetic field is provided reciprocating motion of the striker.

Chisels are metalwork(GOST 7211-94) are used for metal cutting and are produced in length and width, respectively 100 (5), 125 (10), 150 (15), 175 (20) and 200 (25) mm. The angle of the tip is selected: for solid metal 70 about, for medium - 60 about and for soft - 45 about.

Kreutzmeisel -it is used for cutting narrow grooves and keyways and differs from the chisel in a narrower cutting part. Sharpening and hardening angles are similar to a chisel.

Chisels and crossheads are made of alloyed (7XF and 8XF) or carbon (U7A and U8A) steel.

Bench hammers (GOST 2310-94) are available with round and square strikers. They are made of steel U7 and U8, steel 50 and have numbers from 1 to 8 with a weight of 50 g. up to 1 kg. The length of the handle of hammers is 250 - 450 mm; they are made of hornbeam, maple, ash, birch, oak and other durable materials.

1.3. Metal cutting

Sharpthey call the process of dividing the workpiece into parts of a given size and shape, based on various methods of destroying the workpiece material at the cutting site. Cutting is used in cases where it is necessary to separate some part from a piece of metal, as well as when cutting corners, grooves, etc. in a metal.

The following cutting methods are distinguished.

1. Sawing with hacksaws, bandsaws or circular saws. Used for cutting long products.

2. Cutting with scissors. It is used for cutting sheet metal.

3. Cutting on metal-cutting machines (turning, milling, etc.).

4. Acetylene cutting used to cut carbon steel workpieces of considerable thickness. It does not provide high accuracy, but is widely distributed due to its simplicity, high performance and versatility.

5. Anode-mechanical, laser cutting, used for cutting high-strength materials, when other methods do not provide the necessary performance and quality.

Metal cutting can be done with wire cutters (wire cutting), scissors (sheets) with hacksaws (profile metal), pipe cutters (pipes).

Hacksaw machines (manual hacksaw)they are used for cutting pipes of small diameters, various profiles and are solid and extendable. Hacksaw blades are made of steel grades U10, U10A, U12 and U12A alloyed (X6VF, B2F) steels with small teeth in the form of wedges on one or two sides. Sizes of blades for hand hacksaws: distance between centers - 300 mm, width -15; thickness - 0.8 mm.

The number of teeth for every 25 mm of the working length of the blade is 16.19.22. Cloths with large teeth are used for cutting soft metals, with medium ones - for annealed steel, with small ones - for steel and cast iron.

During cutting, press the hacksaw only when moving forward (working stroke), when moving backward, metal cutting does not occur.

At large plants, special mechanical scissors, mechanized hacksaws, mechanical circular saws, gas cutters, abrasive wheels (grinders), etc. are used, which increase the productivity of cutting operations by 8 to 10 times and greatly facilitate labor.

The pipe cutter is used to cut pipes of various diameters, which greatly simplifies and speeds up the process of cutting pipes.

1.4. Editing and bending

Editing  they call the method of processing workpieces with bench hammers or using special devices in order to eliminate deviations from the form (warping, dents, bending, twisting) that occur when cutting and cutting material, during heat treatment, welding or as a result of improper storage and transportation.

Editing is done on the correct plates with hammer blows.

When editing  a leaf with local bulges; blows should be applied from the periphery to the center of the bulge; when editing a sheet having a waviness at the edges, hammer blows are applied in the middle.

Mechanized metal dressing is achieved using various devices, straightening rolls, multi-roll sheet straightening and angle straightening machines. Sheets are passed between the rolls several times until bulging or hollows disappear on them.

Flexible -they call the method of metalwork, in which the geometric shape of the workpiece changes as a result of plastic deformation in the cold or hot state. Flexible parts of complex spatial form are obtained (clamps, staples, pipe elements, etc.). They are used to give the necessary shape to sheet, as well as round, square and rectangular material. Bending is done manually by hammer blows in a vice, in clamps, using special devices (universal bending machines). Pipe bending is usually done with fillers in order to avoid wrinkling and flattening of the walls (sand, lead, rosin are used).

For pipe bending, manual pipe benders (up to d \u003d 20 mm) and mechanical (up to d \u003d 100 mm) with wall thicknesses up to 4 mm are used.

1.5. Filing

Sawing -they call the method of processing workpieces with a file to obtain the necessary shape, size, surface roughness.

Filingmetal is made by file, in a vice and is based on the destruction of the surface layer of the workpiece material by the cutting elements of the tool (file).

Files(GOST 1465-93) are a multi-blade cutting tool, in which the teeth are located on the surface of hardened steel bars having a different cross-sectional profile and length. Files are divided by the shape of the cross section into flat, square, trihedral, hacksaw, rhombic, semicircular and round, and by the number of notches per unit length - into drachts having from 4 to 12 notches, personal - 13 - 24 notches and velvet, having 30 -80 notches per 10 mm length.

File lengths from 100 to 450 mm (after 50 mm).

Bastard files are used to remove from the part a metal layer up to 0.7-1 mm, personal files are used after bastard files.

Files are made of steel grades U12, U12A, U13, U13A, 14HF and 13X, as well as high-speed steel.

The mechanization of the sawing operation is achieved by the use of filing machines, grinders, special devices.

1.6. Hole machining

Holes in the metal body for fasteners (bolts, studs, screws), as well as for subsequent processing (drilling, countersinking, reaming, threading and boring) are achieved by drilling. As a tool for drilling, standard drills made of high-speed steel with a diameter of 0.3 - 80 mm are used. According to the design and nature of the work performed, the drills are divided into feather, spiral, centering drills for deep holes, etc.

Feather- (flat) easy to manufacture, durable, but do not provide high accuracy and cleanliness of the hole. Used for drilling shallow holes.

Spiral -perfect in design, easily remove chips through screw channels, low friction against the wall of the hole, do not require additional processing of the hole, allow a large number of regrinds.

Drills are made with cylindrical (up to d \u003d 12 mm), conical (6 - 60 mm) shanks. Drills are made of high-speed steel of grades P18, P9, U10-U12 (small drills) and with hard-facing hard-alloy plates.

Drillingit is designed to increase the diameter of the hole of the workpieces and is used when processing holes with a diameter of more than 30 mm. First, drill a hole with a diameter of (0.2 - 0.3) D, and then drill this hole to a predetermined diameter D.

Countersink -used for chamfering holes, producing cylindrical and conical recesses for screw heads and rivets.

Countersinking -used for boring holes and preparing it for deployment. Standard drills made of high-speed steel process holes with a diameter of 3 - 100 mm. The core drill has a larger number of cutting teeth than the drill, therefore processing it is more productive than drilling, and the quality of the core drilling is higher than when drilling.

Deployment -used for the final processing of pre-drilled holes and obtain accurate geometric shape, size and high purity

surfaces using cylindrical or conical reamers. Standard reamers are used for processing holes with a diameter of 1 - 300 mm in workpieces made of various materials.

For mechanical processing of holes by drilling, countersinking, pneumatic and electric machines and machine tools are used.

Types of marriage. The main types of rejects when dressing metal are nicks on machined surfaces from the edge of the hammer, dents are traces from the hammer head having an irregular and non-smooth surface. These defects are usually the result of the inability to strike with a hammer correctly or as a result of the use of a hammer on the sides of which there are chinks and nicks.

When bending metal, marriage results from improper dimensions of bent blanks, oblique bending, and damage to machined surfaces. The causes of these types of defects are: incorrect time - marking of bending places, careless clamping of the workpiece in a vise (above or below the marking risks), inflicting too strong blows, the use of mandrels of the wrong size.

When winding springs, marriage can result from improper selection of wire diameter, mandrel of the inner or outer diameter of the spring, spring length and number of turns. With careful and serious attitude to work, avoiding marriage is not difficult.

Safety precautions. In order to ensure safety when editing workpieces on sheet straightening machines, it is first necessary to check the state of grounding and the condition of the enclosing devices. Starting and turning off devices are checked by repeatedly starting the machine idle and turning it off.

When editing workpieces having cutouts (windows), the workpiece must be fed over the edge, and not for cutouts, as hands can be pulled together with the part on the rolls. In order not to injure your hands during dressing, you need to use canvas gloves.

When editing and bending, you need to work with a hammer, well mounted on the handle. Hammers must not have cracks, nicks or burrs. It is necessary to systematically check the hammer head on the handle.

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