stages of processing cutting tools

According to the existing classification tools, all used cutting tools can be divided into three technological groups: the tail, shaft-mounted and flat, or prismatic.

the Characteristic feature of the rear group of tools (drills, core drills, reamers, cutters, tail cutters, etc.) is a cylindrical or conical shank. The latter serves as the most basic surface intended for attachment in the collet Chuck or in taper socket spindle. As a technological base during the mechanical machining of these tools are usually center holes or outer centers.

To the shell group include tools with cylindrical or tapered and threaded holes: shell core drills, reamers, cutters, round threading dies, round cutters, shaper cutters, etc. Holes in these tools are mostly basic and technological bases, respectively, of the orienting tool in the process of the PA machine and when it was manufactured.

Flat panel includes the following tools: rod and prismatic cutters, knives of assorted tools, gear cutting combs, flat broach, etc. the Characteristic feature of this group is the presence of a wide or narrow surfaces, in which the tool is installed as in the processing of it, and in his work on the machine.

the Specified classification of instruments technological group promotes a logical sequence in the development of technological process of manufacturing of tools. Due to the fact that the tools related to the tail and shell technology groups have to some extent the same sequence of operations, the following is the sequence of processes (with the inclusion of operations for the tail and shell tools):

1) stage of procurement operations, including cut blanks, forging to create the necessary metal structure and shape of the workpieces, welding, annealing, if necessary, the rolled shaped and Curling of the drills, etc.;

2) the stage of education forms, consisting mainly of turning operations, which turn out techno logical base surface and provides for the necessary instrument in appearance;

3) processing stage pulling and slotting of holes, keyways and other grooves in the shaft-mounted tools;

4) the stage of the marking tool by mechanical means;

5) the stage of education misovich chip grooves on the outer surfaces of the tool. This phase also includes the operations: setiloane of the teeth of the cutting tool, the milling of grooves and extending the corrugations in the grooves, milling squares and legs shanks, milling nests under the plate hard alloy, etc.;

6) stage metal processing deburring and surface conditioning;

7) the stage of formation of the additional surface (drilling and tapping holes for mounting screws, side sockets lerok, etc.);

8) stage heat treatment (surgery Kalki and vacations, and soldering carbide or high speed Nazarka records);

9) step solder removal and sanding, or Stripping of the underlying surfaces (pivot holes or core holes and ends);

10) the stage of Assembly of the composite tool;

11) the phase of finishing of holes and other surfaces, especially precise instruments;

12) stage grinding, sharpening and finishing;

13) stage of upgrading the working surfaces of the teeth of the tool.

the Flat band cutting tool based on the constructive and technological features, can be divided into PA two subgroups:

1) subgroup of integral and modular tool with knives of high speed steel and hard alloy;

2) subgroup brazed carbide tools.

For the first group of flat tools, the sequence processing is as follows:

1) the procurement phase, including the parting of the workpiece, welding, forging, stamping, annealing, etc.;

2) the stage of education of basic and technological base surfaces shape by planing, milling or grinding all surfaces of the workpiece for multiple tools and cutting it into individual dough pieces;

3) the stage of creating misovich bonded and profiled grooving;

4) the stage of education also includes additional surface drilling of mounting holes and threading in those holes;

5) stage Kalki and vacation;

6) the stage of grinding fundamental and technological base surfaces;

7) build-time for national instruments;

8) stage sharpening and finishing of cutting blades of the teeth.

When processing carbide, napijalo tool instead of the heat treatment is solder the plates, whereupon the operations are repeated almost in the same sequence.

the Technology of manufacture of any cutting tool can be attributed to one of the above groups. However, a strict sequence of operations within each stage is set in each case depending on the tool design. In addition, for some tools the individual stages may be missing altogether. Considering the processing steps of any group of cutting tools, we see that the production technology has some distinctive features compared with the technology of manufacturing of parts made of structural steel. This is associated with a specific form of the tools, and with the feature properties tool materials.

as a cost reduction tool, usually done composite. The working or cutting part made of a tool material, and the housing or the connecting part, made of construction steel grades 45 and 40S, and in some cases out of tool steel U8A, U10A, 9KHS etc. As tool materials for the manufacture of the working parts are mainly used high-speed steel and hard alloys, which includes such scarce elements as chromium, vanadium, tungsten and others that tell the tool the required toughness and wear resistance at relatively high cutting speeds. In addition, these elements composed of tool steel sharply reduce their machinability with cutting tools to Kalki. To reduce the hardness and create a structure with satisfactory machinability of high speed steel supplied in the form of forged, hot rolled, cold drawn normal bars and sheets, must be subjected to forging, and then isothermal annealing.

There are a variety of joining techniques of the working part, made of high speed steel or hard alloy to the tool body. Along with mechanical fastening widely used butt welding, welding, propeica and other methods.

it Should be noted that in connection with the extension of the scope of the new tool and design hard metals and alloys, and nonmetallic materials increasingly used in the Metalworking industry and in tool production methods get a new treatment in which the destruction of the removed surface layer is not due to large deformations, as is the case when cutting, as by electrical or chemical erosion, electron beam and other processing techniques.

When the EDM method the destruction of the removed layer of conductive material is due to the thermal effects of pulsed electrical discharges between the tool and the workpiece. Depending on the type and magnitude of discharge there are four varieties, PLI method, electric discharge method of dimensional processing of metals.

Electrocontact processing can be successfully used for cutting billets, roughing ingots and forgings from special hard alloys. It looks like andnumerical processing and is characterized in that the electrolyte is not applied and the process is carried out on the air. This eliminates the electrochemical dissolution of the workpiece material. The workpiece and the tool in the form of a disk connected to the AC power source. The speed of movement of the tool relative to the workpiece is 30-80 m/s. To improve the performance of the process, the treatment area is cooled with compressed air, oil or emulsion.

Electrochemical methods based on the phenomenon of anodic dissolution by passing electric current through the electrolyte from the cathode to the anode. The latter is the workpiece-tool. Along with the electrolytic polishing in the tooling industry electrolyze grinding of hard alloys and chemical etching of tools from high speed steels. The intensity of this process is significantly increased due to the increase in current density (up to 100-300 A/cm2) passing through the electrolyte, and due to the flow of electrolyte near the surfaces. In the latter case more intensively removes the oxide film and increased to 3-4 times the performance of the surface treatment of complex profile grooves and holes in products made of hard materials.

Energy of ultrasonic fluctuations is increasingly used in mechanical dimensional processing of hard alloys, and nonmetallic materials, machining of small parts by a loose abrasive for facilitating cutting processes viscous materials, clean circles in the process of grinding, etc. Especially promising is the application of ultrasonic vibrations in the processing of hard alloys, semiconductor materials, glass, diamond, silicon, fluorine and other materials, as many of them are not conductive and are processed very difficult even abrasive tool.

Ultrasonic treatment has two versions: free directed and oriented abrasives. In the first case, a workpiece is placed in a suspension consisting of grains of abrasive suspended in the liquid. In the suspension oscillations is happening decorative grinding and deburring. On the contrary, in the second case, the grains receive energy from a special tool, which makes longitudinal oscillations with ultrasonic frequency (16-20 kHz) and small amplitude (A =0,02—0,06 mm). Thus in the working area between the vibrating tool and the workpiece is fed suspended in water, the abrasive grain of boron carbide from a shock implementation of which is the puncturing of the material particles of the workpiece. Used ultrasound machine 4772А consists of two main components: vacuum-tube oscillator and the mechanical part of the machine. Besides, heads acoustic electric oscillations of the generator is converted into mechanical. The main motion under ultrasonic treatment are longitudinal oscillations of the tool at an ultrasonic frequency, and auxiliary movement, or flow, can be times of personal direction. Depending on its species and combinations, and forms of instrument of ultrasonic processing to perform various operations. However, the performance can be improved by intensive abrasive material under pressure into the treatment area. The advantage of ultrasonic method before EDM is the possibility of processing of dielectrics, as well as obtaining in the processing of various materials surfaces, higher grades of purity.

Method of electron beam treatment the most promising in the processing of small holes (diameter 1 mm>D>10 µm), the recess grooves and cutting of products from ruby, tantalum, molybdenum, uranium, and other elements, for example, holes in jewels for bearings with a diameter from 0.02 to 0.5 mm with a tolerance of ±0.01 are processed in 3 s.

based on electron beam processing method is the ability of an electron beam with great efficiency to convert kinetic energy into heat. From physics it is known that when heated, the metal electrons can gain speed enough to overcome the potential barrier. The necessary energy density depends on the properties of the processed material and the desired treatment area. It can reach high values, therefore, material under the action of an electron beam melts and evaporates. It is established that the electron beam can affect the surface layer of metal and therefore can be used to reflow the surface layer and healing of cracks formed during quenching, to repair the defective hardened surface after grinding and polishing, and also for implementation into the surface layer of more durable and wear resistant material. Installation for electron beam treatment consists of the following main components: electron gun, which is formed by a powerful electron beam; a vacuum, or the working chamber in which the processing components; the vacuum pumping system creates a vacuum to 10~5 cm RT. article; control systems,managing the size of the electron beam and its trajectory; a high-voltage source of energy; devices for control and monitoring of the process.

Drilling, cutting, welding and other microrobot can successfully produce the light beam of lasers, sometimes called laser. The basis of this treatment (focused light beam) allowed the use of the internal energy of the atoms and molecules of certain substances. Although the energy of the light pulse is small, however, when its concentration in the beam with a diameter of about 0.01 mm for the millionth fraction of a second provides heating of the processed material to many hundred degrees and it evaporates. Optical maser, or laser, works as follows. Capacitor discharge is the excitation of optical oscillations and there is a flash of light with a duration of about 0.001 s. the Light with the reflector is focused on a rod of synthetic ruby, with the result that the chromium atoms come in an excited state, the equilibrium is disturbed and stored in the crystal, energy is released and simultaneously the crystal emits bright red light. The advantages of processing the light beam before the electron beam treatment include the fact that processing is performed directly on the air and not need the protection of personnel from x-ray irradiation. However, quantum generators have low efficiency and insufficient accuracy.

In General for tool production characteristic is the use of tool materials with special properties, as well as additional kind of transactions.
According to: Gigalo N. I., Kiselev V. V. design and manufacture of cutting tools.

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