RU2585600C1 - Device for electric spark processing surfaces - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to electrophysical methods of processing materials, particularly, to spark alloying, and can be used in machine building and repair for obtaining wear-resistant coatings on parts of friction units and fixed joints. Device comprises encased electromagnet consisting of magnetic conductor with coil and armature in form of a plate made of material with low resistivity, at one end of which is fixed electrode holder, armature core is secured at end of magnetic conductor of electromagnet, and other end of armature is hinged on horizontal axis, fixed to housing of device. Device also has compressed air supply nozzle, which is rigidly fixed in device housing and installed above place of attachment of electrode holder to anchor, to nozzle is compressed air feed tube, other end connected with compressed air pressure regulator.

EFFECT: invention enables rapid change of characteristics of vibration to achieve optimal mode of processing.

4 cl, 1 dwg

Description

The invention relates to the field of electrophysical methods of processing materials, in particular to spark alloying, and can be used in engineering and repair production to obtain wear-resistant coatings on parts of friction units and fixed joints.

Known electromagnetic devices for electric spark surface treatment, in which the continuous oscillatory movement of the electrode in contact with the surface of the workpiece is carried out using a stationary electromagnet, to the magnetic circuit of which the movable armature with the electrode holder is periodically attracted. The return stroke of the anchor is carried out by a return spring [Burumkulov F.Kh., Lezin P.P., Senin P.V., Ivanov V.I., Velichko S.A., Ionov P.A. Electrospark technology for restoration and hardening of machine parts and tools (theory and practice). Saransk, "Red October", 2003, p. 49].

Studies of electrospark processing showed that an increase in the pulse repetition rate with a simultaneous increase in the electrode vibration frequency gives a significant increase in the process productivity [ibid, p. 47]. So, on installations for electric spark processing of the BIG series, the range of regulation of the frequency of vibration is from 100 to 400 Hz [Installations for electric spark processing of the BIG series. Specifications TU 3312-001 = 02069964-2012. Saransk, 2012. p. 1.3.4]. When studying the process of electrospark alloying, the vibration frequency of the electrode is changed from 10 to 2000 Hz (see Laboratory work N; 3. Electrospark alloying of metal materials. Electronic resource - Access mode: http://5fan.ru/wievjob.php.id=50242. Fig. 4a). The stiffness of the return spring cannot ensure the optimal operation of the device in such a frequency range, which leads to a decrease in the characteristics of the applied coating.

The closest analogue (prototype) is a device for electric spark alloying of metals, described in copyright certificate No. 248103 B23k, publ. 05. 08. 1970. The device contains an electromagnet enclosed in a housing, consisting of a magnetic circuit with a coil, and an armature made of three interconnected plates, the inner one on which the electrode holder is mounted, made of a material with low electrical resistivity, and the outer ones, one of which anchors core is fixed, made of spring steel.

The disadvantage of this device is:

- the impossibility of operational changes in the characteristics of vibration (amplitude, vibrational velocity) when changing the frequency of vibration;

- overheating of the electrode in medium and hard processing conditions due to lack of cooling, which leads to a decrease in the quality of the coating and annealing of the armature springs.

The aim of the invention is to provide a device for electric spark surface treatment with the ability to quickly change the characteristics of the vibration to achieve the optimal processing mode.

This goal is achieved in that a device for electric spark surface treatment, containing an electromagnet enclosed in a housing, consisting of a magnetic circuit with a coil, and a plate-shaped anchor made of a material with low electrical resistivity, at one end of which an electrode holder is fixed, as well as an anchor a core is attached under the end of the magnet core of the electromagnet, and the other end of the armature is pivotally mounted on a horizontal axis fixed to the device’s body, and into the device of the compressed air nozzle is rigidly fixed in the housing unit and installed over the place of fixing the electrode to the armature, is connected to the nozzle air supply tube, the other end connected to a compressed air pressure regulator. In the device, the gap between the end face of the magnetic core of the electromagnet and the core is 1.0-1.2 mm, the nozzle is mounted above the armature at a distance of 0.5-3.0 mm with an outlet diameter of the nozzle 0.2-2.5 mm, and air pressure regulated within 0.1-0.8 MPa.

The essence of the invention lies in the fact that in the device the action of the spring on the armature is replaced by the effect of the pressure of compressed air flowing from the nozzle onto the surface of the armature. Air pressure can be regulated over a wide range by a pressure regulator (see, for example, Compressed air pressure regulators. Electronic resource - Access mode: http://www.pnevmo-i.ru/regulators-pressure.htm), which makes it possible to adjust the vibration to any processing frequencies. The gap between the end face of the electromagnet magnetic core and the core is selected from the conditions that during hard processing conditions it takes a long time (several hundred microseconds) to charge the storage capacitors (600 μF or more) of the pulse generators, and therefore the processing is carried out at low frequencies (100-150 Hz) with an amplitude of vibration of an electrode to 1 mm. The installation of the nozzle above the anchor at a distance of 0.5-3.0 mm with an output diameter of the nozzle of 0.2-2.5 mm is theoretically justified (see Technical Dictionary. Volume 1. Diameter - exit port - nozzle. Electronic resource - Access mode: http://www.ai08.org/index.php/index) and verified practically. The air pressure is adjustable and can be 0.1-0.8 MPa at the nozzle inlet.

The invention is illustrated in the drawing (Fig.).

In the housing 1 of the device, using the bracket 2, the magnetic circuit 3 is fixedly mounted with the coil 4 of the electromagnet. Anchor 5, with an electrode holder 6 and a core 7 attached to it, is pivotally attached at one end to an axis 8 fixed to the housing 1. Above the point of attachment of the electrode holder 6 to the anchor 5, a nozzle 10 for supplying compressed air is installed using the bracket 9. The nozzle 10 by a flexible tube 11 is connected to a pressure regulator 12 of compressed air. To the armature 5, using cable 13, voltage is supplied from the pulse generator of the technological current (not shown in Fig.). An electrode 14 is clamped in the electrode holder 6.

The device operates as follows.

The device is turned on by supplying compressed air to the regulator 12, air enters the nozzle 10, and a pulse voltage is supplied to the coil 4. In this case, the air coming from the nozzle 10 to the surface of the armature 5 creates a pressure that moves the armature 5, and accordingly the electrode 14, to the surface of the workpiece (not shown in Fig.). When a voltage pulse arrives at the coil 4 of the electromagnet, the core 7 is attracted to the end of the magnetic circuit 3 and the armature 5, and accordingly the electrode 14, are moved away from the surface of the part. Upon termination of the voltage pulse on the coil 4, due to air pressure, the electrode 14 begins to approach the surface of the part and the cycle of vibrational movement of the electrode 14 is repeated. With the help of the regulator 12, the vibration of the electrode is adjusted and electric spark surface treatment of the part is carried out. Compressed air creates excess pressure in the housing 1 of the device and is used to cool the electrode holder 6 and the electrode 14 through the gap between the electrode holder 6 and the housing 1.

Tests of a test sample of a device for electric spark surface treatment showed that with an increase in the frequency of vibration of the electrode, it is necessary to increase the pressure of compressed air.

The invention makes it possible to change the characteristics of the vibration of the electrode to obtain the optimal mode of electrospark processing and obtain coatings of the required parameters.

Claims (4)

1. Device for electric spark surface treatment, comprising an electromagnet enclosed in a housing, consisting of a magnetic circuit with a coil, and a plate-shaped anchor made of a material with low electrical resistivity, at one end of which an electrode holder is fixed, characterized in that it is provided with a feed nozzle compressed air, rigidly fixed in the housing and installed above the place of attachment of the electrode holder to the anchor, and the core is attached to the anchor under the end face of the electromagnet magnetic core And the other end of the armature is pivotally mounted on a horizontal axis fixed on the chassis, wherein the nozzle is connected to a compressed air supply pipe which other end is connected to a compressed air pressure regulator. 2. The device according to p. 1, characterized in that the gap between the end face of the magnetic core of the electromagnet and the core is 1.0 ÷ 1.2 mm. 3. The device according to p. 1, characterized in that the nozzle is mounted above the armature at a distance of 0.5 ÷ 3.0 mm with an output diameter of the nozzle of 0.2 ÷ 2.5 mm. 4. The device according to p. 1, characterized in that it is made with the possibility of regulating the air pressure within 0.1 ÷ 0.8 MPa.

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