RU2776570C1 - Method for electroerosive formation of a radius profile on a diamond grinding wheel - Google Patents

Abstract

FIELD: material processing.

SUBSTANCE: invention relates to the field of electrophysical processing and can be used for reprofiling diamond grinding wheels designed for processing the edges of glass and stone, as well as for performing a radius profile on new discs. The method includes electroerosive treatment of a rotating diamond grinding wheel with a profiling disk electrode on an electroerosive machine while maintaining a given value of the interelectrode gap. Before the start of processing, the C axis is installed on the electric erosion machine with equipment containing a rotation drive of the profiling disk electrode and made with the possibility of aligning the profiling disk electrode relative to the plane of the diamond grinding wheel being processed in two mutually perpendicular planes. When forming a radius profile, the axis of rotation of the profiling disk electrode is deflected from the plane passing through the axis of rotation of the diamond grinding wheel and the center of rotation of the profiling disk electrode, while the deviation of the axis of rotation of the profiling disk electrode is carried out at an angle of 2-7 degrees.

EFFECT: need to fit the disk profiling electrode during the electroerosive formation of the radius profile on the diamond grinding wheel is eliminated.

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Description

The invention relates to the field of electrophysical processing and can be used for reprofiling (dressing) diamond grinding wheels intended for processing glass and stone edges, as well as for making a radius profile on new disks.

In the process of electroerosive machining (dressing) of diamond grinding wheels with shaped profiling electrodes, the profile of the electrodes is worn out, and deformation of the electrode is also possible, associated with the transfer of erosion products of the diamond wheel bond to the surface of the electrode-tool and the formation of built-up on it. Accordingly, it becomes necessary to edit and/or clean the electrode.

There are many ways to solve this problem. For example, the electrode is periodically withdrawn and treated with a special tool. The type of special tool depends on the material of the electrode. A similar method is disclosed, for example, in the description of the patent RU 2014183 C1 (“Method of electroerosive dressing of diamond wheels on metal bonds”, IPC B23H 7/00, file 08/06/1990, op. 06/15/1994). Purpose of the method: dressing of diamond wheels on metal bonds. The essence of the invention: the electrode-tool and the diamond wheel are connected to the poles of the power source, they are given working movements and edited in two stages. At the first stage, the editing is carried out in the electric arc mode U=41-50 B; I=100-150 A. The process is accompanied by the formation of a build-up of erosion products on the surface of the electrode-tool. To maintain a constant gap in the dressing process, the electrode-tool is removed from the surface of the circle. The retraction speed is controlled by the magnitude of the operating current. At the second stage, the build-up from the erosion products is ground around at U-10 - 25 V and J-10 - 30 A. The technical result is a decrease in the wear of the tool electrode when performing high-quality high-quality straightening. Periodic editing of the electrode-tool is at least a large time expenditure for processing one product.

There are also known methods of continuous editing of the processing tool (electrode). For example, a device for EDM grinding with continuous wheel dressing, known from patent RU 133450 U1 (“Device for dressing wheels during EDM”, IPC B23H 5/00, B24B 53/00, file 26.12.2012, op. 20.10.2013 , Bull. No. 29), contains a grinding wheel (electrode) fixed on the spindle of the machine with a current collector, which is connected to a control unit containing an AC transformer, one output of the midpoint of which is connected to the circle through the current collector, and the other three outputs form electrical circuits, moreover, the first output through the thyristor, with the help of a device for continuous dressing of the circle, forms an electric circuit for straightening the wheel, the second output through the thyristor forms an electric circuit for anode dissolution of the workpiece, the third output through the thyristor forms an electric circuit for cathodic film deposition, while the thyristors are controlled by a thyristor control unit and have independent adjustment, and the circuits of all electrical circuits are closed through the current collector on the circle and work in different directions, while the circuits of the electrical circuits are interlocked with the main movements of the machine and operate independently of each other, and the gaps between the anode and cathode of the electrical circuits are supplied with electrolyte from a nozzle installed in the device for continuous dressing of the circle, characterized in that that it is configured to implement modes of ultrasonic vibrations when dressing the grinding wheel and additionally contains a plate that oscillates in the range of ultrasonic frequencies installed in the peripheral part of the grinding wheel, moreover, a plate vibrator is fixed at one of the ends of the plate, and the other end of the plate is pivotally fixed relative to of the machine and is spring-loaded relative to a fixed bracket for pressing the plate against the grinding wheel, and along the edges of the plate in the end planes of the grinding wheel, at least two hydraulic nozzles are installed, supplying a liquid-phase medium under pressure to the peripheral surface grinding wheel, and acting as hydrostatic supports, fixing the gap between the grinding wheel and the oscillating plate, into which the electrolyte is fed through the nozzle.

The known solution is characterized by high technical complexity and is hardly suitable for use in conjunction with a disk profiling electrode for forming a radius profile.

As a prototype, a method was chosen in which there is no stage (stages) of editing the profiling electrode (patent RU2553779C2 "Method of electroerosive profiling of a grinding wheel on a conductive bond", IPC B23H 1/02, B23H 9/00, file 07.10.2013, op. 20.06 .2015, Bull. No. 17). The invention is aimed at improving the productivity and accuracy of processing by increasing the speed of regulation and stabilizing the size of the interelectrode gap at the optimal level by automatically controlling the electrode feed.

The task in the prototype solution is achieved by the fact that the electroerosive profiling of the grinding wheel on a conductive bond includes electroerosive processing of the rotating grinding wheel with a shaped electrode while maintaining a given value of the interelectrode gap by automatically adjusting the electrode feed, while setting the value of the interelectrode gap from the condition for ensuring equality of the magnitude of the amplitude ratio current pulses to the value of the short circuit current and the value of the ratio of the amplitude of the voltage pulses to the value of the open circuit voltage, and then maintain it by regulating the electrode supply by means of a proportional-integral controller of the electrode supply drive.

The essence of the known method lies in the fact that the automatic regulation of the electrode feed during electroerosive profiling of grinding wheels is carried out according to the observed electrical parameters, as a result of which the stabilization of the gap between the grinding wheel and the electrode is achieved at an optimal level corresponding to the maximum productivity and accuracy of profiling. According to the invention, the amplitudes of voltage pulses and current pulses of the process pulse generator, which are released in the interelectrode gap, are selected as the observed electrical parameters. This method allows you to maintain a given value of the interelectrode gap, but does not eliminate the need for straightening the electrode, albeit with a greater frequency.

The objective of the present invention was to develop such a method for electroerosive machining of diamond grinding wheels with a radius profile, in which the need for dressing the disk profiling electrode would be minimized or completely eliminated.

The specified problem is solved by the method of electroerosive formation of a radius profile on a diamond grinding wheel on a conductive bond, including electroerosive processing of a rotating diamond grinding wheel with a profiling disk electrode while maintaining a given value of the interelectrode gap, in which, according to the proposal, before starting processing, the C axis is installed on the electroerosive machine with equipment that includes a rotation drive of the profiling disk electrode and allows you to align the profiling disk electrode relative to the plane of the diamond-grinding wheel being processed and tilt the profiling disk electrode relative to the plane of the diamond-grinding wheel (that is, set the electrode in two mutually perpendicular planes, tilting it back and forth or right-left), and when forming a radius profile, the axis of rotation of the profiling disk electrode is deflected from the plane passing through the axis of rotation of the diamond-grinding wheel and the center of rotation of the profiling disk electrode.

The simplest implementation of the method is that the axis of rotation of the profiling disk electrode is deflected in a plane perpendicular to the plane passing through the axis of rotation of the diamond grinding wheel and the center of rotation of the profiling disk electrode (back and forth).

In the most common cases, the deviation of the axis of rotation of the profiling disk electrode is 2 - 7 degrees. By selecting a combination of the thickness of the profiling disk electrode (taking into account the interelectrode gap, which depends, for example, on the bond of the diamond grinding wheel) and the angle of inclination within the indicated limits, it is possible to achieve high quality (accuracy) of the given radius profile of the diamond grinding wheel. Unexpectedly, it turned out that under the specified conditions, the profiling disc electrode retains its shape throughout the entire operation time and does not require editing at all. In this case, it should be taken into account that when the slope is less than 2 degrees, the detected effect is lost, and when the angle of inclination is more than 7 degrees, the radius profile is distorted, which begins to acquire a V-shape.

When reprofiling or processing new diamond grinding wheels, the angle of inclination can reach 30 degrees with an appropriate thickness of the profiling disk electrode (the necessary ratios can be obtained empirically) and, possibly, with a decrease in the quality of the resulting radius profile while gaining, for example, in processing time one diamond grinding wheel, in the time of uninterrupted operation of the disk electrode, etc.

The invention is illustrated by graphic materials.

In FIG. 1 shows a general view of the equipment of the EDM machine (axis C) for implementing the method.

In FIG. 2 shows a frontal view of the EDM assembly.

In FIG. 3 shows a side view (right) of the EDM assembly.

In FIG. 4 shows a large-scale contact between the profiling disk electrode and the diamond grinding wheel being machined during operation (the gap (interelectrode gap) between the profiling electrode and the diamond grinding wheel being machined is visible).

In FIG. 5 (photo) shows the equipment (axis C) for implementing the method, installed on an electroerosive machine.

The method of electroerosive formation of a radius profile on a diamond grinding wheel on a conductive bond can be implemented using equipment that includes a rotation drive of the profiling disk electrode 1 from an electric motor 2. The structure 3 of the C axis with the equipment is attached to the machine 4 using a clamp (EROWA mount). The equipment also includes a rod 5 that allows to align the profiling disc electrode 1 relative to the plane of the diamond grinding wheel 7 being processed and a rod 6 that allows the profiling disk electrode 1 to be tilted relative to the plane of the diamond grinding wheel 7.

The method is carried out as follows.

The C-axis rig is attached to the machine 4 with a clamp (not shown). The profiling disk electrode 1 is installed on the seat. The disk electrode 1 is aligned with respect to the plane of the diamond grinding wheel 7 being processed using the adjusting rod 5.

Adjusting rod 6 axis of rotation of the profiling disk electrode 1 is deflected from the plane passing through the axis of rotation of the diamond grinding wheel 7 and the center of rotation of the profiling disk electrode 1 by an angle α. After that, the EDM machine 4 is put into operation. The drive of the profiling disk electrode 1 (rotation) is carried out using an electric motor 2.

The implementation of the method is characterized by examples.

Processing of disks was carried out on a Mitsubishi EA8 electroerosive copy-piercing machine.

Example 1

A steel electrode 3.2 mm thick burns through a diamond-grinding wheel on a tungsten-cobalt bond with an electrode approach (tilt) angle of 2 degrees, forming a radius of 1.8 mm. Bundle processing time 17 minutes.

Example 2

A steel electrode 2.1 mm thick burns through a diamond grinding wheel on a copper-brass bond with an approach angle of 5 degrees, forming a radius of 1.3 mm. Bundle processing time 15 minutes.

Example 3

A steel electrode 3.6 mm thick burns through a diamond grinding wheel on a metal bond (M2-00) with an approach angle of 7 degrees, forming a radius of 3.5 mm. Processing time 18 min.

During operation, editing of the electrode 1 is not required, the specified radius of the profile of the diamond grinding wheel remains constant.

Claims (2)

1. The method of electroerosive formation of a radius profile on a diamond grinding wheel on a conductive bond, including electroerosive processing of a rotating diamond grinding wheel with a profiling disk electrode on an electroerosive machine while maintaining a given value of the interelectrode gap, characterized in that before starting processing, an axis C is installed on the electroerosive machine with equipment containing a rotation drive of the profiling disk electrode and made with the possibility of aligning the profiling disk electrode relative to the plane of the processed diamond grinding wheel in two mutually perpendicular planes, and when forming a radius profile, the axis of rotation of the profiling disk electrode is deflected from the plane passing through the axis of rotation of the diamond-grinding wheel grinding wheel and the center of rotation of the profiling disk electrode, while the deviation of the axis of rotation of the profiling disk electrode is carried out at an angle of 2-7 degrees. 2. The method according to claim 1, characterized in that the axis of rotation of the profiling disk electrode is deflected in a plane perpendicular to the plane passing through the axis of rotation of the diamond grinding wheel and the center of rotation of the profiling disk electrode.

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