SU1433663A1 - Method of three-dimensional electromechanical machining - Google Patents

Abstract

The invention relates to electrophysical and electrochemical processing methods, in particular to dimensional electrochemical processing with a sectional electrode tool. The purpose of the invention is to increase the processing accuracy by eliminating the electrochemical dissolution of non-working sections. The supply and removal of technological voltage pulses from adjacent sections is performed with a relative time delay, the magnitude of which does not exceed the difference between the moments of voltage supply and the beginning of the electrochemical dissolution of the workpiece. 2 Il.

Description

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The invention relates to electrophoretic and electrochemical methods of processing and, in particular, to electrochemical dimensional processing with a sectional electrode tool.

: The aim of the invention is to improve processing accuracy by eliminating the H1H of the electrochemical dissolution of inactive sections.

The goal is achieved while the technological voltage pulses to adjacent sections are supplied with a relative time delay, the magnitude of which does not exceed the difference between the moments of applying voltage to the electrodes and the beginning of electrochemical dissolution, and The broken sections are produced at a time interval that does not exceed the equality of the voltage supply points it begins the electrochemical dissolution of the workpiece.

The essence of the method is as follows.

According to the process conditions, different amounts of electricity, for example, are supplied to the sections of the | pectrode instrument, for example, by applying pulses of technological voltage of various lengths. At the same time, in order to avoid the electrochemical dissolution of sections that are not currently connected to the source of the technological voltage, voltage pulses on the adjacent HJbie section are supplied with a temporary delay;

i It is known that during electrochemical processing, metal removal does not begin immediately after supplying an electrical voltage to an electrical | chemical cell, but with some delay called the induction period. At the time of this time, the cell passes through the electrical energy the amount of electricity that is spent on the charging of the double electrical C1o and the anodic activation of the passive metal. Thereafter, the spectrochemical dissolution of the anode begins. Duration of induction period Depends on current density, properties of Shektrolit and anode and cathode materials and some other factors.

Thus, due to the supply of im-Luls to the adjacent sections of the electrode-tool or their removal with a time delay, the value of which is not

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exceeds the duration of the induction period, it is possible to avoid the electrochemical dissolution of sections that are not currently connected to an is-. technological voltage point.

Fig. 1 is a block diagram of a process control system implementing the proposed method; in FIG. 2, timing diagrams.

Section 1, 2, 3 of the electrode-tool 4 through the switching device 5 is connected to the source 6 of the process pressure, to which the workpiece 7 is also connected (figure 1).

The treatment according to the proposed method is carried out as follows.

Suppose that at the initial moment the workpiece has an allowance that decreases in the direction from section 1 to section 3, Dp of the electrochemical removal, leveling out unevenness of the allowance, the quantity of electricity O, Q should be passed through the sections. Q, that Q 0 Q3 1, voltage U is applied at time t (FIG. 2). The process of electrochemical dissolution will begin with a delay of the induction period tind. Only after this period of time can the electrochemical dissolution of section 2, not connected to the source of technological voltage, begin. To avoid this, at time t, section 2 is supplied with technological voltage U. The moment t of supplying technological voltage to the second section is chosen from the condition t, j - t, and „d. At time t, - ;, voltage 11 is applied to section 3. It should be t

- t,

Ind,

at time t, the technological voltage is removed from all sections. Through each of the sections passed the amount of electricity

50

Q.

 G T "(t) dt,

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Where

p - section number;

I - technological current through

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nth section.

Regulation of the amount of electricity passed through the sections can be carried out by the process voltage supply moment t

on the section. At the same time, the depth of adjustment, i.e. the ratio of the maximum amount of electricity to the minimum (Q, / Q3K depends on the magnitude of the induction period t and on the duration of the pulses Г „.

In order to expand the range of adjustment, it is possible not to simultaneously sleep, let us say, at the moment of tension, you are t.

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t

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(figure 2), When

this must fulfill the conditions

t -1; t and t -1; t.

Obviously, the depth of adjustment can be changed by adjusting the pulse duration.

Thus, by adjusting the moments of supply and removal of technological voltage pulses on the sections of the electrode tool, it is possible. avoid the electrochemical dissolution of sections that are not currently connected to the source of technological voltage, and, consequently, increase the accuracy of processing.

Primer p. The approbation of the proposed technical solution was carried out by treating the die cavity with a depth of 10 mm and an area of 34 cm with a profiled electrode tool consisting of 6 sections. The tests were carried out on an EKU-150M electrochemical machine with a specially manufactured process current source with a total current of 1600 A, which provides for the possibility of adjusting the pulse duration and pulse supply to the section of the electrode tool with a time shift.

The electrolyte was a 15% sodium chloride solution. Workpiece material - steel 5HNV. The amplitude of technological voltage pulses is 18V, the nominal current density is 50 A / cm. The limits of the adjustment of the duration of the pulses of technological pressure

Nor 1 - 6 ms, the limits of regulation of the relative shift of pulses of 0.2 - 2 ms. The working interelectrode gap is 0.08 mm, the washing gap is 0.3 mm. Duration of the working period is 0.5 s. The control system of the electrochemical machine and the current source ensured that the electrodes touch and retract to the working gap in each processing cycle, as well as adjust the pulse duration so that each processing cycle ensures metal removal, reducing the initial unevenness of the allowance and gradually bringing the surface of the workpiece to equidistant cathode surface. The machining accuracy was 0.07 mm.

When machining with the same electrode tool according to the prototype method, the machining accuracy was 0.10 mm.

Thus, the application of the proposed method allowed to increase the processing accuracy by 0.03 mm or 30%.

Claims (1)

Invention Formula A method of dimensional electrochemical treatment with a sectional electrode tool, through each section of which a different amount of electricity is passed by varying the duration of the pulses, characterized in that, in order to improve processing accuracy by eliminating the electrochemical dissolution of the non-operating sections, the application of pulses to the voltage of adjacent sections or From these sections, they are produced with a relative time delay, the value of which does not exceed the difference in feed moments and beginning and electrochemical dissolution of the workpiece. (Rig.1