RU72165U1 - DEVICE FOR ELECTROEROSION ALLOYING - Google Patents

Abstract

A device for electroerosive alloying containing a fixed housing with a magnetic circuit and a coil and a moving part consisting of an electrode holder with a coil connected to a voltage sensor at the spark gap through a control unit, characterized in that the opto-thyristor pair and relay element are additionally introduced into the device, the relay element at the input it is connected to a voltage sensor, and at the output it is connected via an optothyristor couple to the control unit.

Description

The utility model relates to electrophysical processing methods, in particular to electrospark alloying of cutting tools, die tools and machine parts.

A device is known for electroerosive alloying, in which an electromagnetic vibrator transmits vibration to an electrode fixed in a hinge. The mandrel, with the opposite permanent magnets mounted on it, is rotated by an electric motor using a pulley and a transmission element. In this case, the magnetic field shifts the free end of the electrode by an amount not exceeding the diameter of the electrode, which is ensured by the hinge design.

At the time of discharge, the magnetic field of the permanent magnets displaces the melt from the point of contact of the electrode and distributes it over the surface to be treated. Having come into contact with the treated surface, the electrode makes a reciprocating and rotational movement and under the influence of electric discharges, the process of applying electrode material to the hardened surface occurs [1].

The disadvantage of this device is the lack of continuity of the applied coating and low productivity of the installation.

A device for electrical discharge machining is known, in which a fixed housing with a magnetic circuit and a coil and a movable part consisting of an electrode holder with a coil connected to a current or voltage sensor on the spark gap through a control unit are used to automatically maintain the distance between the electrodes [2]. The disadvantage of this device is that the movable part is an electromagnetic damper, because the eddy currents arising in it during movement in a magnetic field create significant reactions that inhibit the sharp movements of the moving part. This affects the quality of the coating and reduces the performance of the installation.

A device is known that contains a power source, a vibrator and a generator, the electrical circuit of which contains a storage capacitance, an electric charging key, made on the basis of two transistors and a transistor module, control elements

a transistor switch, a discharge thyristor with its controls, a synchronization unit of a vibrator and a pulse generator [3]. The main disadvantages of the known device are the low reliability and stability, high specific energy consumption for the alloying process, low productivity of the device.

A device for spark hardening is known, comprising a transformer connected to the rectifier via a mode switch, the output of the rectifier is connected to resistor current limiters, which in turn are connected to storage capacitors and a processing electrode. The workpiece is connected with a working inductor and a rectifier, an electromagnetic vibrator coil is connected in parallel with the working inductor [4]. The disadvantage of this device is the low productivity due to overheating of the hardening electrode and the low frequency of spark discharges, which reduces the continuity and quality of the coating.

The closest technical solution to the claimed utility model is a device containing a fixed part - a body with a magnetic circuit and a coil and a moving part consisting of an electrode holder with a coil connected to a current and voltage sensor on the spark gap through the control unit [5]. The electrode fixed in the electrode holder interacts with the part, and the duration of the contact of the electrode with the part is controlled by the short circuit current flowing through the feedback solenoid. To prevent overheating, the electrode is constantly blown with compressed air.

However, this device has several disadvantages:

- low productivity of the device due to the use of rod electrodes of small diameter;

- the reinforcing layer is obtained with insufficient thickness;

- high energy consumption for the alloying process;

- low quality of the alloyed surface (coating continuity not higher than 80%) due to the impossibility of regulating the frequency and amplitude of vibration of the electrode-tool.

The technical result of the utility model is to improve the quality of electroerosive alloying by stabilizing the frequency and amplitude of the vibrations.

The technical result is achieved due to the device for electroerosive alloying, containing a stationary body with a magnetic circuit and a coil and a movable part, consisting of

an electrode holder with a coil connected to the current or voltage sensor at the spark gap through the control unit, an additional opto-thyristor pair and a relay element are introduced, the relay element at the input connected to the voltage sensor, and connected to the control unit through the opto-thyristor couple.

The proposed device is illustrated by drawings:

figure 1 - shows the mechanical components of the device,

figure 2 - shows the electrical functional diagram of the device.

The device has a fixed housing 1 with a magnetic circuit 2 and a coil 3, as well as a movable part 4, consisting of an electrode holder 5 and a coil 6. An electrode 15 mounted in an electrode holder 5 interacts with a part 16. As shown in FIG. 2, the movable coil 6 and Fixed 3 connected to power sources 7 and 8, and power amplifier 9. Power supplies and a power amplifier form a control unit. The input of the power amplifier 9 is connected to the voltage sensor 13 through the relay element 11 and the opto-thyristor pair 10. The spark gap 12 is included in the process current supply circuit 14.

The device operates as follows.

At the initial moment, the electrode 15 lies on the part 16 and the voltage at the input of the sensor is zero. At the same time, a current flows through the movable coil 6, included at the output of the power amplifier 9. As a result of the interaction of the magnetic fields of the movable coil 6 and the stationary coil 3, powered by power supply units 7 and 8, a force arises that pulls the movable coil 6 together with the electrode holder 5. This leads to the separation of the electrode 15 from the part 16.

The voltage at the input of the voltage sensor 13 increases and reaches the response voltage of the relay element 11. This causes a change in the direction of current flow in the movable coil 6, and the electrode holder 5 begins to move to the surface of the part and the electrode of the workpiece is touched, while the storage capacity is discharged and the mass transfer of the material electrode 15 on the workpiece 16.

In the future, the process is repeated. Self-oscillations occur, the frequency of which is determined by the mass of the moving parts and the characteristics of the power amplifier.

The proposed device allows you to automate electroerosive alloying of complex surfaces, which increases the processing performance and quality of hardening.

An example of a specific implementation of the device

The cutting knife of a woodworking machine, having the form of a narrow rectangular plate with a thickness of 4 mm and with dimensions of 50 × 400 mm, was subject to processing. The knife plate was made of ordinary carbon steel. A large surface of the knife was subjected to EDM, starting from the cutting edge over the entire length of the insert and with a width equal to half the width of the insert.

Electroerosive alloying was carried out by VK6 alloy with the following parameters:

- the speed of movement of the electric tool, mm / sec. - one - supply voltage, V (50 Hz) - 220 ± 20 - power consumption, kVA - 2.2 - short circuit current, amperes - 8.5 - capacitance of capacitors, microfarads. - 950 - open circuit voltage, volt - 90 - diameter of the hollow electrode, mm - 8 - electrode material - VK6 - processing speed, cm ² / min - up to 5.5 - pulse repetition rate, Hz - 60 - cooler - compressed air

The technical result is the quality of the coating:

- thickness, microns - 250 - continuity,% - 96 - wear rate, mg / km - 10.1 - surface roughness, Ra μm - 3.2

Using a microscope of the MPB -2 type with a 24x magnification, it was established that the entire surface had a uniform electroerosive coating, no gaps were observed between the individual sections. If necessary, alloying can be repeated by applying the 2nd reinforcing layer.

The operational stability of the processed woodworking knives depended on the material of the electrodes and increased by 1.8-3.0 times.

The use of the proposed device for electrospark alloying allows to increase the thickness of the alloyed layer, increase the continuity of the coating, its adhesion to the base metal and increase the productivity of the process. In addition, the device allows you to evenly cover the alloying layer of flat, cylindrical and complex surfaces.

Thus, the claimed technical solution fully fulfills the task.

The claimed technical solution is not known in the Russian Federation and abroad and meets the requirements of the criterion of "novelty."

The technical solution can be implemented industrially in mass production using well-known technical means, technologies and materials and meets the requirements of the criterion of "industrial applicability".

References

1. A.S. 1609564, V23H 9/00, publ. in bull. No. 44, 1990

2. A.S. 1627353, B23H 9/00, publ. in bull. No.6, 1991

3. Installation of Elitron-22, passport AIIZ. 299.157. PS, Chisinau, 1986.

4. P-2171162, B 23 H 7/04, publ. 07/27/2001

5 Sex Model No. 2529, V23H 7/18, publ. in bull. No. 8, 08.16.1996

Claims (1)

A device for electroerosive alloying containing a fixed housing with a magnetic circuit and a coil and a moving part consisting of an electrode holder with a coil connected to a voltage sensor at the spark gap through a control unit, characterized in that the opto-thyristor pair and relay element are additionally introduced into the device, the relay element at the input it is connected to a voltage sensor, and at the output it is connected via an optothyristor couple to the control unit.