Types of metal cutting. Metal cutting purpose and purpose of metal cutting. What tools are used for manual chopping?

Chopping is an operation in which, using a chisel and plumber's hammer layers of metal are removed from the workpiece or the workpiece is cut.

The physical basis of cutting is the action of a wedge, the shape of which is the working (cutting) part of the chisel. Chopping is used in cases where machine processing of workpieces is difficult or irrational.

Chopping is used to remove (cut down) metal irregularities from the workpiece, remove hard crust, scale, sharp edges of the part, cut out grooves and grooves, and cut sheet metal into pieces.

Cutting is usually done in a vice. Chopping sheet material in parts - can be done on a stove.

The main working (cutting) tool for chopping is a chisel, and the striking tool is a hammer.

The bench chisel is made of tool carbon steel. It consists of three parts: shock, middle and working. The striking part is made tapering upward, and its top (the striker) is rounded; The middle part of the chisel is held during chopping; the working (cutting) part is wedge-shaped. The sharpening angle is selected depending on the hardness of the material being processed.

For the most common materials we recommend following angles sharpening: for hard materials (solid steel, cast iron) -- 70°; for materials of medium hardness (steel) ~ 60°; For soft materials(copper, brass) "-- 45°; for aluminum alloys-- 35°.

The working and impact parts of the chisel are subjected to heat treatment(hardening and tempering). The degree of hardening of a chisel can be determined by running a file along the hardened part of the chisel: if the file does not remove chips, but slides along the surface, the hardening is done well.

To cut out narrow grooves and grooves, use a chisel with a narrow cutting edge - a crosspiece. Such a chisel can also be used to remove wide layers of metal: first, grooves are cut with a narrow chisel, and the remaining protrusions are cut off with a wide chisel.

To cut out profile grooves (semicircular, dihedral, etc.), special crosscut tools are used - groovers that differ only in the shape of the cutting edge.

There are two types of metalworking hammers used for chopping metals: with a round head and with a square head. The main characteristic of a hammer is its mass. For chopping metals, hammers weighing from 400 to 600 g are used. Chopping metals is a very labor-intensive operation. To make work easier and increase productivity, mechanized tools are used. Among them greatest distribution has a pneumatic chipping hammer. It is put into action compressed air, which is supplied through a hose from a permanent pneumatic network or mobile compressor. When chopping metal, the trigger is pressed, pressing the spool. Air entering through the air-conducting channels moves the firing pin, which strikes the shank of the chisel inserted into the barrel. During chopping, the pneumatic chipping hammer is held with both hands: with the right - by the handle, with the left - by the end of the barrel, and the chisel is directed along the cutting line.

Chopping is a metalworking operation in which, with the help of a cutting tool (chisel, cross-cutter or groover) and a percussion tool (machinery hammer), workpieces or parts, excess layers of metal are removed or the workpiece is cut into pieces.

Felling is carried out in cases where it is not required high precision processing. The processing accuracy achieved when cutting is 0.4-0.7 mm.

Chopping is used to remove (cut down) large irregularities (roughness) from a workpiece, remove hard crust, scale, burrs, sharp corners of edges on cast and stamped parts, for cutting out keyways, lubrication grooves, for cutting cracks in parts for welding (cutting edges ), cutting off the heads of rivets when removing them, cutting holes in sheet material.

In addition, chopping is used when it is necessary to chop off some part of a rod, strip or sheet material.

The cutting is done in a vice, on a plate or on an anvil. Billets and castings small sizes When chopping, they are secured in a chair vice. Trimming defects welds and tides in large parts are carried out on site.

Cutting metal with a hand chisel is a very labor-intensive and difficult operation. Therefore, it is necessary to strive to mechanize it as much as possible.

The means of mechanizing metal cutting are: replacing the cutting with an abrasive tool, as well as replacing the manual chisel with a pneumatic or electric chipper.

When starting chopping, the mechanic must prepare his workplace. Taking the chisel and hammer out of the workbench box, he places the chisel on the workbench on the left side of the vice with the cutting edge facing him, and the hammer on the right side of the vice with the striker pointing towards the vice.

Of great importance for cutting is correct position locksmith body. When chopping, you must stand steadily at the vice, half-turning towards it; The worker’s body should be to the left of the vice axis. Place your left leg half a step forward so that the axis of the foot is located at an angle of 70-75° relative to the vice. Move your right leg back a little, turning your foot at an angle of 40-45° relative to the axis of the vice.

The hammer must be taken by the handle so that the hand is at a distance of 20-30 mm from the end of the handle (Fig. 32, a). The handle is grasped with four fingers and pressed against the palm; in this case, the thumb is placed on the index finger and all fingers are squeezed tightly. Hold the chisel with your left hand, without squeezing your fingers too tightly, at a distance of 20-30 mm from the head (Fig. 32, b).

During the chopping process, the chisel should be directed at an angle of 30-35° relative to the surface being processed (Fig. 33, a). At a smaller angle of inclination, it will slide rather than cut (Fig. 33, b), and at a larger angle, it will unnecessarily go deeper into the metal and produce large processing unevenness (Fig. 33, d).

Essential to the process manual cutting in a vice also has correct installation chisels towards vertical plane fixed vise jaw. Normal installation The cutting edge of the chisel should be considered an angle of 40-45° (Fig. 34, a). At a smaller angle, the cutting area increases, the cutting becomes heavier, and the process slows down (Fig. 34, b). At a larger angle, the chips, curling,

Creates additional shear resistance, the cut surface is rough and torn; it is possible to shift the workpiece in the vice (Fig. 34, c).

The quality of the cut depends on the type of swing and hammer blow. There are blows of the hand, elbow and shoulder. In a wrist swing, hammer blows are made with the force of the hand. This blow is used for light work to remove thin chips or when removing small irregularities. With an elbow strike, the arm bends at the elbow, resulting in a more powerful blow. The elbow strike is used in ordinary cutting, when it is necessary to remove a layer of metal of medium thickness, or when cutting grooves and grooves. With a shoulder strike, the swing is greatest, and the blow is the strongest. The shoulder blow is used when chopping thick metal, when removing large layers in one pass, cutting metal and processing large planes.

When chopping using a wrist blow, the average is 40-50 blows per minute; with heavier work and shoulder impact, the cutting rate is reduced to 30-35 beats per minute.

The impact of the hammer on the chisel should be as precise as possible. It is necessary that the center of the hammer striker falls into the center of the chisel head, and that the hammer handle and chisel form a right angle. You can chop only with a sharply sharpened chisel; a blunt chisel slips from the surface, this quickly tires the hand and, as a result, the correctness of the blow is lost.

The size of the chips removed by a chisel depends on the physical strength of the worker, the size of the chisel, the weight of the hammer and the hardness of the metal being processed. The most productive is considered to be cutting, in which a layer of metal 1.5-2 mm thick is removed in one pass. When removing a layer of greater thickness, the mechanic quickly gets tired, and the cutting surface becomes unclean.

Chopping brittle metals (cast iron, bronze) should be done from the edge to the middle of the workpiece to avoid chipping off the edge of the part. When cutting tough metals ( mild steel, copper, brass) it is recommended to periodically wet the cutting edge of the chisel machine oil or soap emulsion.

Chopping in a vice can be done at the level of the jaws of the vice or above this level - at the marked marks. At the level of the vise jaws, thin metal is most often cut, and above the level - wide surfaces of the workpiece.

When chopping wide surfaces, you should use a cross-cutting tool and a chisel to reduce time. First, grooves are cut with a cross-section, and then the resulting protrusions are cut off with a chisel.

To perform chopping correctly, you need to have good command of the chisel and hammer, that is, hold the chisel and hammer correctly, without slipping, and correctly swing and hit the head of the chisel with the hammer.

Chopping is an operation in which layers of metal are removed from a workpiece using a chisel and a plumber's hammer or the workpiece is cut into pieces.

The physical basis of cutting is the action of a wedge, the shape of which is the working (cutting) part of the chisel. Chopping is used in cases where machine processing of workpieces is difficult or irrational.

Chopping is used to remove (cut down) metal irregularities from the workpiece, remove hard crust, scale, sharp edges of the part, cut out grooves and grooves, and cut sheet metal into pieces.

Cutting is usually done in a vice. Cutting sheet material into pieces can be done on a slab.

The main working (cutting) tool for chopping is a chisel, and the striking tool is a hammer.

Cold chisel (Figure 8) is made of tool carbon steel U7A or U8A. It consists of three parts: shock, middle and working. Impact part 1 it is made tapering upward, and its top (the striker) is rounded; for the middle part 2 the chisel is held during chopping; working (cutting) part 3 has a wedge shape.

Figure 8 Bench chisel

The sharpening angle is selected depending on the hardness of the material being processed. For the most common materials, the following sharpening angles are recommended:

For hard materials (hard steel, cast iron) - 70°;

For materials of medium hardness (steel) - 60°;

For soft materials (copper, brass) - 45°;

For aluminum alloys - 35°.

Kreutzmeisel - a chisel with a narrow cutting edge (Figure 10), designed for cutting out narrow grooves, low-precision keyways and cutting off rivet heads. Such a chisel can also be used to remove wide layers of metal: first, grooves are cut with a narrow chisel, and the remaining protrusions are cut off with a wide chisel.

Locksmith's hammers , used in cutting metals, there are two types: with round and with square briskly. The main characteristic of a hammer is its mass.

Round hammers are numbered : from 1st to 6th . The nominal weight of hammer No. 1 is 200 g; No. 2 - 400 g; No. 3 - 500 g; No. 4 - 600 g; No. 5 - 800 g; No. 6 - 1000 g. Square-faced hammers are numbered 1 to 8 and weigh from 50 to 1000 g.

Hammer material is steel 50 (not lower) or U7 steel.

The working ends of the hammers are heat treated to a hardness of HRC 49-56 over a length equal to 1/5 of the total length of the hammer at both ends.

For metalworking work, hammers with a round striker No. 2 and 3, and with a square striker No. 4 and 5 are used. The length of the hammer handle is approximately 300-350 mm.

3.4 Metal cutting

Cutting - metalworking operation for dividing a whole piece(blanks, parts) into parts. It is performed without removing chips: with nippers, scissors and pipe cutters, and with removing chips: with hacksaws, saws, cutters and special methods (gas cutting, anodic-mechanical and electric spark cutting, plasma cutting).

The wire is cut with needle-nose pliers (nippers), sheet material - with scissors; round, square, hexagonal and strip material of small sections - with hand hacksaws, and for large sections with cutting machines with hacksaw blades, circular saws, special methods.

The essence of the operation of cutting metal with needle-nose pliers (nippers) and scissors is to separate wire, sheet or strip metal into parts under the pressure of two wedges (cutting knives) moving towards each other.

Needle nose pliers cut (bite off) steel parts round section and wire. They are made in lengths of 125 and 150 mm (for biting off wires with a diameter of up to 2 mm) and lengths of 175 and 200 mm (for diameters up to 3 mm).

The cutting edges of the jaws are straight and sharply sharpened at an angle of 55-60°. Nippers are made from tool carbon steel U7, U8 or steel 60-70. The sponges are heat treated to a hardness of HRC 52-60.

Hand scissors Designed for cutting mild mild steel sheets, brass, aluminum and other metals. They are made in lengths of 200 and 250 mm for cutting metal up to 0.5 mm thick, 320 mm (for thickness up to 0.75 mm), 400 mm (for thickness up to 1 mm).

The material of the scissors is steel 65, 70. The blades of the scissors are heat-treated to a hardness of HRC 52-58. The cutting edges of the blades are sharply ground at an angle of 70°. The blades of the scissors overlap each other when closed, with the overlap at the ends not exceeding 2 mm.

Chair scissors cutting sheet metal up to 3-5 mm thick. One of the scissors' handles is bent at an angle of 90° and is rigidly attached to a table or other base. The length of the working handle of the scissors is 400-800 mm, the cutting part is 100-300 mm.

Lever shears used for cutting sheet metal up to 5 mm thick. The scissors are made from U8A tool steel and are thermally treated to a hardness of HRC 52-58. The sharpening angle of the cutting edges of the knives is 75-85°.

Pipe cutters Designed for manual cutting of thin-walled (gas) pipes made of mild steel, cutting is performed without removing chips. Available in two sizes: for cutting pipes from 1/2 to 2" and for pipes - from 1 to 3".

The main parts of the pipe cutter are rollers: one cutting (working) and two guides. The pipe is cut with a working roller; at the same time, it is fixed on guide rollers and tightened with a screw.

Hand saw (Figure 9, a) is used for cutting relatively thick sheets of metal and round or profile rolled products. A hacksaw can also be used to cut splines, grooves, trim and cut workpieces along the contour, and other work. They are made from steels U8-U12 or 9ХС with a cutting part hardness of HRC 58-61, core hardness HRC 40-45. It consists of a frame 1 , tension screw with wing nut 2, handles 6, hacksaw blade 4, which is inserted into the slots of the heads 3 and is secured with pins 5.

Metal cutting is one of the main processes of procurement and production the necessary details. With its help you can get a semi-finished product quite quickly and at a low cost. established size. The only limitation is the likelihood of making only straight pipes. Metal cutting is used in cases where it is necessary:

• divide the workpiece into parts;
• remove excess metal;
• cut out grooves and grooves in the parts.

Metal cutting tools

Metal cutting is performed using:

• hammer;
• kreuzmeisel. It is a narrow chisel for cutting out grooves and narrow grooves;
• chisels

The chisel is presented in the form of a steel rod, which has a wedge-shaped cutting edge. It must have a point angle for:

• steel blanks 60 degrees;
• non-ferrous metals – 35-45.

Our company provides services for various operations related to metal cutting.

The working principle of metal cutting

When chopping metal, you need to stand straight, hold the chisel so that its striking part protrudes from the hand by 15-30 millimeters. The force of hitting it with a hammer should depend on the thickness and hardness of the workpiece. A hand blow is used in cases where it is necessary to remove thin chips and minor irregularities.

The elbow strike is used for:

• cutting off excess metal;
• dividing the workpiece into parts.

Shoulder Punch for:

• cutting thick strips and rods;
• cutting thick chips.

Our company serves clients in Moscow. Contact us, we are always happy to help you. Metal blanks are chopped on a plate and in a vice.

Metal cutting in teaks and on a slab

When cutting a workpiece in a vice, it is necessary that the marking mark be 1.5 - 2 millimeters below the level of the jaws. Then, after processing, there will be an allowance left on the workpiece for filing the edges. The cutting edge of the chisel is placed on the surface of the jaws at an angle of 30-40 degrees to the cutting plane. In relation to the edges of the jaws, the angle of inclination should be 45-60 degrees.

When cutting metal on a slab, the chisel is placed vertically on the marking line and strikes are applied. Having delivered the first blow, the chisel is placed in such a position that one half of the cutting edge is in the hole already cut, the other is on the marking line, and a second blow is performed. This movement of the chisel facilitates its correct installation and produces a continuous cut.

When the thickness of the workpiece does not exceed 2 millimeters, the metal is cut on one side and a soft steel plate is placed on the other. This will prevent the chisel from getting dull on the slab. If the workpiece is more than 2 millimeters, then the mark is applied on both sides. First, the sheet is cut through on one side, approximately half the thickness, then it is turned over and cut completely.

Safety regulations:

1. Operate only when specified protective screen and glasses.
2. Securely secure the workpiece in a vice.
3. Use a defect-free tool.
4. It is prohibited to stand behind the worker.
5. When finishing work, reduce the impact force.

Execution of metal cutting

At enterprises, metal cutting is performed by metalworkers using electric and pneumatic hammers. Our company carries out custom cutting of metal blanks. Blanks are cut out of sheet metal using special dies and presses by stampers. Processing of semi-finished products from high-strength steels is carried out using laser and plasma cutting.

The following is cut in a vice:

• strip;
• sheet metal;
• processing of wide surfaces.

The durability of the cutting part of the chisel is increased by wetting it soapy water or wiping with an oily rag when cutting non-ferrous metal alloys, aluminum - with turpentine. When cutting a sheet with a guillotine, its edge is not:

• deformed;
• crumples;
• is damaged.

The price for metal cutting services in our company is low.

Chopping is a metalworking operation in which cutting and percussion instrument a layer of metal is removed from the part. Cutting tool when chopping, a chisel or cross-cutting tool is used, and the hammer is used for impact.

The chisel and crosspiece are made of tool carbon steel, then the working and striking parts are hardened and subjected to low tempering.

A chisel is used to chop metal and cut off burrs. Its cutting part has the shape of a wedge, which, depending on the hardness of the metal being processed, is sharpened at different angles: for cast iron and bronze 70°, for steel 60°, for copper and brass 45°. The impact part of the chisel (head) is tapered and rounded to center the impact. Keyholes and narrow grooves are cut out with a Kreutzmeisel.

Bench hammers have a round or square striking part - a striker. A hammer with a square-shaped striker, when struck at an angle, leaves dents on the surface being processed with sharp corners.

The end of the hammer opposite the striker, which has the shape of a rounded wedge, is called the toe. The hammer is selected by weight; for each millimeter of the length of the cutting edge of the chisel, 40 g of hammer weight is required.

Hammers are made from steel grades 50, 40X, U7 and U8. The working parts of the hammer - the head and the toe - are subjected to hardening and tempering.

Chopping is done in a vice, on a plate or on an anvil; large parts are processed on the floor. It is recommended to carry out chopping in a chair vice, installed in accordance with the height of the worker. When chopping, you must stand straight and stable at the vice so that the body is to the left of the axis of the vice. The left leg is placed on the floor, stepping forward, and the right leg, which serves as a support, is moved slightly back. The chisel is held in the left hand without excessive clamping; the distance from the hand to its striking part should be 20-25 mm.

Depending on the thickness of the metal, cutting is done with a wrist, elbow or shoulder swing. The wrist swing is made by moving the hand, the elbow swing is made by the elbow movement of the arm, and the shoulder swing is a swing with the whole arm. Usually chopping is done with an elbow swing; with such a blow you can chop for quite a long time without getting tired.

While working, look at the cutting area. Chopping in a vice is carried out according to the level of the jaws of the vice or according to the intended risks. Thin strip or sheet metal is cut according to the level of the jaws of the vice, and wide surfaces of the workpieces are cut according to the intended marks. Metal (sheet, strip and round) of considerable thickness is cut on a slab or on an anvil with a strong vertical blow. To facilitate the cutting process and increase labor productivity, this process is currently being mechanized using pneumatic hammers.