Electrical erosion is the destruction of metal surfaces under the influence of electrical charges. This technology is based on the work of Soviet scientists N. I. Lazarenko and B. R. Lazarenko. Using this method, you can easily change the dimensions of metal products and create holes of various shapes and depths in them. Excellent results are obtained by electrical discharge machining of profile grooves and grooves, shaped cavities in machine parts and mechanisms. Such equipment is especially in demand for the manufacture of parts made of hard alloys, where conventional machining is difficult.

Electroerosion machines have universal capabilities in processing materials with a dense surface structure. This type of material processing compares favorably with other methods of changing the shape and size of parts, since the labor intensity of operations thanks to electrical erosion technology is sharply reduced.

The operating principle of an electrical discharge machine is shown in the diagram below. Under the action of a pulsed electric generator, spark discharges or other electrical interaction are formed in the gap between the electrode and the surface of the part. The spark gap space is continuously washed by a flow of coolant, due to which the destroyed metal is removed from the treated surface. Under the control of the CNC unit, the process proceeds in given direction and in the required quantity. Brass wire is most often used as an electrode, which, as it is consumed, is fed into the electrical discharge processing zone. More modern consumables for electroerosion - molybdenum wire, the consumption of which for processing one part is negligible. However, these machines also have significant limitations compared to devices for machining parts. After all, they are suitable for processing only conductive metals and their alloys.

It is possible to influence metal by electroerosion different ways: supplying both electrical discharges and parametric pulses to the spark gap. Depending on the required processing result, a more suitable path for its implementation is selected. Very important elements This effect on metal surfaces is that with it it is possible to process the workpiece in different directions at the same time.

Among the methods of electrical discharge processing of products there are:

• electric pulse;
• electric spark;
• electrical contact;
• anodomechanical.

Technological operations that are performed by electroerosion include:

• structural strengthening;
• grinding;
• marking;
• cutting;
• finishing;
• volume copying;
• fine-tuning

Using electrical erosion on these machines, it is possible to make various blind openings, recesses and holes of non-geometric configuration. It is also possible to make threads of any profile on the surface of holes. The machines are capable of removing metal from the inner surface of products to a given depth, thereby performing operations that replace milling and turning. Electrical erosion technology is used in the processing of metals that are difficult to treat with classical mechanical machine tools. These include, in particular, titanium and its alloys.

To choose which EDM machine to buy, you need to accurately determine the tasks that will be assigned to this equipment at the enterprise and what operating parameters of the machine will be required to solve these problems. It is quite acceptable to buy a used machine to perform certain technological operations in a workshop, having first checked its performance. Practice shows that even with large quantities hours of operation, equipment for electrical discharge machining is almost not subject to wear.

Electroerosive type machines

The electrical discharge machining methods implemented in production can vary greatly depending on the design of the machines, but the very principle of operation of the equipment remains the same. Let's consider the main types of electrical discharge machines used for processing metal workpieces.

Wire cutting machine

This machine equipment is used for contour processing of products with high precision and low surface roughness. The workpiece is exposed to an electrode in the form of a molybdenum wire with a diameter of 0.18 mm. The operating costs of this equipment are quite low, since the wire itself is used many times. A traditional wire-cutting EDM machine, which cannot use wire repeatedly, significantly loses in the cost of similar work operations.

The role of the electrolyte in the working area of ​​the machine is played by the coolant, the flow of which washes away erosive products and which protects the processed surface of the part from oxidation by air. A water-soluble concentrate of a special composition is used as a cutting fluid.

Price of electroerosive copying machine is not very high compared to similar devices of the traditional type, but its maintenance is very convenient due to the use of a CNC unit. It will take no more than two days to train the operator in basic operating techniques.

Using this machine you can produce:

• various molds;
• stamps;
• gears;
• slotted holes;
• keyways;
• excavations of complex profile with a depth of up to 20 cm.

The picture above shows a high-speed CNC EDM cutting machine, which is a jet type machine that is used for contouring parts. Machines of this type can also be used in workshops small enterprise with piece production of products, and at large enterprises in mass production. The DK 7720 wire EDM machine can currently be purchased for 850 thousand rubles.

Stitching machine

The electroerosive copying and piercing machine in a modern design is equipped with a CNC unit, which has built-in functions of automatic positioning, orbital movement of parts and the ability to burn side surfaces. The machine is also equipped with the functions of automatic edge search and search for the center point of the processing area. Along with this, the CNC block programs include determination of the cavity depth and automatic exit of the tool head to the zero point.

The EDM piercing machine is designed to process both internal and external spherical elements, working along a 3-dimensional linear path. Along with possible surface processing along a 2-dimensional arc, it can perform electrical discharge burning, using the original matrix of the product for processing as an original for copying.

Currently, the price of an electroerosive machine of this type fluctuates around 1 million 800 thousand rubles.

Electroerosive machine for cutting metals

Wire EDM cutting is used when the required cut can be made metal part or workpieces using classical traditional processing is impossible when both the milling cutter and the cutter are powerless against the strength of the workpiece lathe. Mechanical cutting is not profitable or even impossible when it is necessary to obtain sharp corners with ultra-small radii of curvature inside or outside the part. This situation occurs when processing hardened parts or carbide metal joints. Sometimes they also resort to electrical discharge cutting of metal if, due to the depth or complex structure cavities this can be performed by a simple mechanical operation on milling machine impossible. Wire-cutting machines complement the range of operations in the manufacture of complex parts of modern mechanical engineering.

Electroerosive cutting is intensive electrical erosion of metal in the desired section of a part. High-frequency pulses generated by the generator are applied to an electrode, which is a molybdenum wire. When the generator is operating, the part itself moves in the desired direction using an electric drive of the guides of the machine plate. The metal is burned out by electric sparks, and then the destroyed layer is washed off with a coolant of a special composition, continuously supplied to the cutting zone. Wire movement for EDM machines always occurs in a direction perpendicular to the axis of the winding drum.

We can single out those technological operations where the operation of electrical erosion cutting machines compares favorably with mechanical processing of metals:

• processing of superhard metals and alloys;
• making cuts in workpieces with angular sharp edges having ultra-small radii of curvature;
• processing of cylindrical and shaped surfaces of great depth;
• surface processing with very high precision.

To program the processing of a part with an electrical discharge machine, you need to have technical task and a layout of the product itself. The format of the presented data can be any; its translation into commands of the CNC block is carried out by the machine operator or programmer.

When performing electrical discharge cutting, there is no need to use tools that are harder than the material of the workpiece. For cutting carbide joints, non-ferrous alloy wire is used, which is obtained in the usual way. The cutting equipment is also not highly complex, as are the technological methods of working with it. The speed of the work process does not depend on the hardness and strength of the material being processed. When cutting, no mechanical effort is required, resulting in very high quality processing. The number of various operations and transitions per processing is reduced to a minimum even with a very complex part shape. Various by technical specifications cutting machines have different workflow performance, but they can all perform similar operations, just in different times.

Models of modern machines

A modern machine for electrical discharge machining of metals consists of the following components:

• electric motors operating independently of each other;
• device for feeding wire into the erosion zone;
• working bath with coolant;
• work table for positioning the workpiece during processing;
• machine control unit.

Manufacturers of machines of this type are both Asian and European states. Having the same purpose, machines from different manufacturers differ greatly in their functionality and price. If Chinese and South Korean equipment costs much less than European equipment, then the latter is performed by manufacturers at a higher level with a greater degree of automation of work processes.

ARTA

Russian manufacturers produce precision ARTA equipment for electrical discharge machining of metals.

Scientific and industrial corporation "Delta-Test" is today the leader in Russia in the manufacture of equipment of this type. While manufacturing new machines, the company is also modernizing equipment from earlier production periods.

Sodick

On the market modern equipment Sodick is a well-known company that produces wire-cut electrical discharge machines.

Possessing high technological parameters, the equipment of this company is used for processing refractory metals and single crystals. Using these machines, perforated plates and pipes, working elements of copying machines, dies with profiles of three coordinate dimensions, and metal-ceramic dies are produced. Specialists using such equipment can easily produce cams and their prototypes, electrodes-tools for machines of the copying-broaching group.

The Mitsubishi MV1200S wire-cutting machine, at a cost of about 7 million rubles, allows you to perform complex operations on electrical discharge machining of parts of any shape, made of a wide variety of conductive materials.

With intensive use of this machine equipment in modern production, the costs of its purchase pay off in a short time.

Agie

Agie EDM equipment is manufactured in Switzerland and successfully competes with other models of this machine group.

With small overall dimensions on the Agie machine it is possible to automatic mode perform the most complex work on processing carbide products for a wide range of purposes.

As can be seen from the article, equipment for electrical discharge machining of parts at modern market plenty. It is produced by almost all the leading industrial countries of the world under different brands and at different prices. It is not easy to choose from this offer exactly what our domestic manufacturer needs. However, by weighing your financial capabilities and conducting substantive negotiations with managers of companies represented on Internet sites on this topic, you can draw the right conclusions and then make the purchase itself.

Advantages of jet type EDM machines:

• Precision machining of any conductive materials
• Low processing cost
• Fast payback equipment
• No need for additional equipment
• Processing of large workpieces

What is it used to make:

• Matrices
• Punches
• Stamps
• Injection molds
• Gears
• Impeller
• Keyway
• Tooth cutting
• Trims along the contour of the product

What should you pay attention to when choosing?

It’s no secret that accuracy indicators directly depend on the quality of the frame and ball screw when choosing an electroerosive machine Special attention it is necessary to pay attention to the maximum load on the work table, the maximum height of the workpiece, the diameter of the ball screw and rail guides. The differences in the maximum load on the work table are explained by the use of the bed of a younger model of an electroerosive machine - this certainly reduces the cost of the machine, but entails the use of a smaller diameter ball screw and rail guides, which undoubtedly affects the durability of the equipment. Eg: maximum load on the working table of the Tosun DK7732 machine is 500 kg, and the load of the DK7725 machine is 300 kg, which corresponds to the standard indicators of Chinese manufacturers.

All our equipment is used for own production, so we are always ready to demonstrate distinctive features, carry out electrical discharge machining and measure the machining results.

Features of installations

The main tool is a stretched wire, which acts as one of the electrodes; the second is the workpiece itself. High frequency pulses supplied from a special generator are regulated according to the conditions of the task being performed and the established processing parameters. capable of working with workpieces of various thicknesses. The movement of the part, controlled by automation, occurs according to the program laid down by the operator. Polarity allows parts to be processed with minimal waste. The presented equipment is efficient, reliable and economical.

All our machines are multi-pass.

Demonstration of the operation of a wire machine

Metal processing on our machines

Although many methods and principles of metal processing have now appeared, not all of them are universal. Even fewer methods are available for widespread use due to the high cost of specialized units and tools. The wire cutting machine is a type that can guarantee high accuracy and efficiency, regardless of the hardness of the material, because even the most resistant alloys are subject to EDM processes.

Features of the impact allow you to vary the speed and accuracy, thereby determining the productivity and quality of processing. The widest possible settings, combined with a carefully tuned and well-proven impact scheme, have already made the corresponding installations extremely popular in the segment of manufacturing complex volumetric components with curved surfaces. The product is not only affordable, but also inexpensive to operate. This significantly increases the profitability of its use. Electronic inspection systems enable even the smallest and most complex parts to be produced consistently.

Wire cutting machine device

The flexibility of equipment use is based on modern systems positioning of the conductive wire. The working tool is tensioned between the base lower and upper guides. Uniform rewinding is ensured by a drive shaft with a connected electric motor. The guides are made of materials with increased wear resistance, in particular, diamond or sapphire. The reusable working tool is looped and is changed only in case of rupture or before a large amount of work. The path elements are insulated and protected from breakdown to the housing. The flushing circulation system directs a specialized electrolyte with specified electrical conductivity characteristics into the gap between the wire and the workpiece. The products of combustion and melting of the workpiece are separated by coolant filters, after which the composition is again sent to work by pumping components. The key element is the process current generator, which ensures the formation of voltage with the specified power and frequency characteristics. Modern machines are controlled by electronic components under program numerical control, and information screens form the basis of the display system.

The process of electrical discharge machining (EDM) of conductive materials is based on the principle of directed destruction of the anode (workpiece), which is located in a liquid dielectric medium, as a result of the passage of a high-power electric discharge between it and the cathode (working tool). Due to the significant technological capabilities of the method, it is implemented on electrical discharge machines of various designs.

Structure and types of equipment for EEE

A typical EDM machine includes:

1. several electric motors operating autonomously from each other;
2. electrode-tool supply unit;
3. bath with working environment;
4. table for placing the workpiece being processed;
5. control scheme.

The equipment in question is classified according to the following criteria:

• According to technological purpose. It is possible to distinguish universal, specialized and special machines for EEE;
• Based on the principle of arrangement of the main components. It can be made horizontal and inclined, but a vertical layout is more often used;
• By type of table: fixed or coordinate;
• By type of bath – removable or rising;
• According to the degree of accuracy - equipment for work of ordinary precision and precision;
• Based on the principle of excitation and subsequent regulation of electrical discharge parameters.

Size range of types of electrical erosion equipment domestic production determined by the requirements of GOST 15954.

Methods for producing an electrical discharge in the working circuits of machine tools

Dimensional processing can be carried out by spark, pulse and arc discharges. In the first case, a spark discharge of low duty cycle is formed between the cathode and anode, but with precisely specified characteristics of the interelectrode gap. Such machines are compact, distinguished by high accuracy of operation and surface quality after electroerosion, ease of regulation by technological parameters, but at the same time they have low power, and, therefore, productivity. Areas of expedient use of such machines are precise cutting of difficult-to-cut materials (in particular, hard alloys), and production of parts with complex contours. They can also be used to remove broken tools, etc.

An increase in the energy of the electric discharge is achieved by introducing a pulse generator into the circuit, which increases the interval between adjacent discharges and at the same time increases the thermal power during a single electrical erosion event. As a result, work productivity increases, but accuracy decreases, and the surface of the machined part may have a fairly extended heat-affected zone, which is not always acceptable. Electric pulse machines are used where more significant metal removal per unit of time is required.

If it is necessary to ensure even higher metal removal (and not only to change the shape of the original workpiece, but also to strengthen it), electric arc machines are used. The productivity of such equipment increases several tens of times, since the arc, unlike other types of electrical discharge, burns continuously. To control the technological parameters of an arc discharge, it is compressed by a transverse flow of a dielectric medium, which is constantly pumped under high pressure through the arc combustion zone pumping unit provided in the machine diagram. Electric arc machines can be used to produce large blanks for rolls, hot hammer dies, etc.

Application of different types of electrical discharge machines

Among the electric spark type equipment, the MA4720 copying and piercing machine is considered one of the most accurate. It is designed to work with difficult-to-process workpieces of complex configuration, for example, for carbide die equipment, molds, and molds. The productivity of the machine does not exceed 70 mm 3 /min, but it is possible to achieve an accuracy of 0.03...0.04 mm, with a fairly low roughness of the final surface (not higher than Rz 0.32...0.4 μm in finishing processing modes). The work table is moved by a CNC system. The dimensions of the work table and the permissible range of values ​​of the interelectrode gap between the anode and the cathode do not allow the production of products with overall dimensions of more than 120×180×75 mm on this machine.

An example of an electric pulse machine is the widespread model 4E723, also equipped with a CNC. Higher specific power values ​​make it possible to achieve EDM productivity of up to 1200 m 3 /min, with a processing error in finishing modes within 0.25...0.1 mm. Higher accuracy is achieved with EDM of shaped surfaces. The machine is also used primarily in tool production, but the surface roughness increases noticeably - up to Ra 2.5 μm, so grinding will be required after processing in most cases. The machine can perform EDM of parts with overall dimensions of 620×380×380 mm, as well as cutting shaped grooves.

These types belong to universal electroerosive machines. An example of specialized equipment is the Model 4531 electrical discharge machine, which produces profile cutting of complex contours using a non-profiled electrode. The 4531 uses a brass wire that is continuously rewound across the electrode gap, generating a discharge between the cathode and anode. With relatively low productivity (no more than 16...18 mm 3 /min for steel; for hard alloy productivity is even lower), the 4531 machine, in principle, allows for an error of ±0.01 mm, so the equipment in question is effective in the production of die-cutting dies matrices of particularly complex configurations and templates. The maximum dimensions of the cut contour are 100×60 mm.

Principles of optimal choice of technology and machine size for EDM

The initial data are the accuracy of the contour, the dimensions (depth) of the thermally modified zone, as well as the desired removal rate per unit time. For machines working with non-profiled electrodes, it is important to have devices for automatic threading of wire, and for pulse machines - generators that allow the use of bimetallic wire, which increases the productivity of EDM.

To improve the quality of the process and reduce erosive wear of the electrode-tool, it is better to use oil as a working medium (the most common is a mixture of industrial-20 oil with kerosene). In principle, for products with increased tolerances, it is possible to use water.

The technological capabilities of electroerosive machines are significantly expanded by the presence of additional devices (for example, for producing conical surfaces).

To remove metal from 20,000 mm 3 /min and above, only electric arc machines should be used. The smallest operating error of such equipment is achieved with reverse polarity when using graphite electrodes. At the same time, the relatively high surface roughness - not lower than Rz 0.8...1.6 μm - forces, after EDM with an arc discharge, to provide for finishing grinding of the resulting contour. The pumping pressure of the working medium must be at least 50...60 kPa.

• Electroerosive wire-cutting machines with CNC Balt-System (Russia) jet type DK77-MS series
• Electroerosive wire-cutting machines of jet type DK77 series available in warehouse in Moscow
• Electroerosive copying and piercing machines ZNC with a controlled Z axis, D71 series, available in warehouse in Moscow
• Electroerosive wire cutting machines ACCUTEX, Taiwan
• Electroerosive wire-cutting machines of submersible type (CW series) Aristech, Taiwan
• Electroerosive wire-cutting machines of submersible type with automatic wire filling (СW-S series) Aristech, Taiwan
• EDM copying and broaching machine (LS series) Aristech, Taiwan
• CNC electroerosive piercing machines (CNC series) Aristech, Taiwan
• Electroerosive Super Drills
• EDM copying and broaching machines with CNC lifting bath MAXSEE, Taiwan
• Precision copying and broaching machines NEU-AR
• Electroerosive extractor. Removal of drills and taps from NPP "MEATEC". Available in warehouse in Moscow.

Electroerosive wire-cutting machines of jet type DK77 series available in warehouse in Moscow

Price: from $11,500 including VAT

Installation of servo drives on a DK77 series machine.

Electroerosive wire cutting machines are designed for the production of parts of various shapes and sizes, such as tools, machine parts, jewelry, stamps, processing of teeth, splines, etc. These machines allow you to process parts made of various grades of steel, high-strength composite alloys, titanium, graphite and much more. Models differ in the amount of movement along the axes, the dimensions of the work table, and the type of processing - “single-pass” or “multi-pass”. All machine models are designed for processing any conductive materials with high precision and excellent surface quality.

Application area:

When designing the machines of LLC NPP "MEATEK", processing accuracy, ease of operation, labor savings and long service life were taken as a basis, which undoubtedly affected the popularity of this equipment and its widespread use in enterprises of various levels. These machines are mainly used in the production of stamps and molds, because Accuracy is the main advantage of these models. With just one tool to get the job done, this machine is your affordable alternative to milling, turning and grinding equipment.

Processing scheme.

Advantages of our equipment:

• Processing of any conductive materials of any hardness.
• No chips (metal melts and evaporates).
• Lack of thermal and mechanical influence on the structure (the surface is not deformed).
• The minimum cutting thickness of 0.2 mm allows you to effectively save the processed material.
• The ability to obtain parts of complex shapes and very small sizes, the production of which is difficult by other methods.
• Processing of holes of small diameters and roundings of small internal and external radii.
• Possibility of batch processing.
• Due to the low cost of the processing process and eliminating the problems of manufacturing expensive punching dies, the machine is the best replacement for stamping production.
• Possibility of short-term payback of equipment in the presence of problematic parts due to the overall low cost of processing, quick changeover of equipmentfrom one product to another.
• The simplicity of the machine design increases its reliability.
• The presence of a wire drum, which rotates in different directions and at different speeds, thereby ensuring rough and finishing cuts.
• Repeated use of a wire electrode reduces the cost of the processing process.
• Rational use of consumables.
• Simplicity and clarity of creating complex contours and surfaces using the popular CAM/CAD programs Compass and AutoCAD.

Made in Russia LLC NPP "MEATEK".

Jet-type wire-cut electroerosive machines of the DK77 series operate on molybdenum wire. Unlike wire electroerosive machines of submersible type SV series, jet-type machines of the DK77 series are equipped with an open work table on which the workpiece is placed for processing without immersing it directly in the working fluid.

Coolant fluid is supplied to the molybdenum wire through a nozzle, directly into the zone electrical discharge machining, which leads to cooling in the area electrical discharge cutting and leaching of erosion products.