SU1426714A1 - Method of dimensional electrochemical machining - Google Patents

Description

: The invention relates to electrophysical and electrochemical machining, in particular, to methods of dimensional electrochemical machining with a sectional electrode tool.

The aim of the invention is to improve the accuracy and productivity of processing;

During the processing according to the proposed method, the sectional electrode tool is brought to contact with the workpiece; the discharge current is diverted to the working gap $ m at the same time. A current pulse is applied to all sections (the amplitude of which may be less than the amplitude of the process current).

The value of the amplitude of the current pulse through each section is memorized. Then, technological current pulses are supplied to the sections of the electrode tool, with the amount of electricity transmitted through each section proportional to the ratios of the amplitudes of the first current pulses stored in the memory device to the maximum amplitude of the first current pulse Electricity supplied to the electrochemical cell, can be adjusted by changing the amplitude, duration or number of pulses. After that, the electrode inst. The coping is diverted to the backlash and the electrolyte is pumped for a time sufficient to completely renew the electrolyte in the air. Then the whole cycle is repeated. Since the electrical conductivity of the electrolyte is the same at all points of the workpiece surface during the supply of the first current pulse, the ratios of the interelectrode gap values fairly reliably characterize the ratios of the amplitudes of the first current pulse through the nth section to the maximum amplitude of the first current pulse. The use of this operational information about the size of the interelectrode gap under each section for metering the amount of electricity across the section increases the accuracy of processing.

In order to increase the processing capacity, the technological current pulses are fed to those sections of the electrode tool for which the ratio of the amplitudes of the currents of the first pulse is maximum and through the nth section to the amplitude of the currents of the first pulse through the nth section the value of the working interelectrode gap. The drawing shows a block diagram of a process control system according to the invention. Output source 1 technological

current is connected to the input of the switch. 2, and the switch output is the 2nd block of 3 shunts. The exit of the unit 3 shunts is connected to the sections of the electrode tool 4 and to the input of the measuring unit

5. The output of the measuring unit 5 is connected to the inputs of the storage and calculation unit 6 and the integrator unit 7. The output of the storage and calculation unit 6 is connected to the second input of the latter.

The output of the integrator unit 7 is connected to the input of the control unit 8, and its output is connected to the input of the switch 2. The sections of the electrode tool 4 are connected to the workpiece 9 through the electrolyte 10.

The control system works as follows.

The voltage from the process current source is supplied through the switch 2 and the shunt unit 3 to the section of the electrode tool 4 by the control unit 8 so that at the beginning of each working period a current pulse is simultaneously applied to the sections

the total value of which is determined by the energy characteristics

mi current source v

   with - max)

 g 1

where Ij, is the total current through the sections;

1 „- current through the n-th section, mlk maximum source current

technological current-. The signals from the shunt block 3, proportional to the current values through section 1, are fed through measuring unit 5 to storage and calculation unit 6 and integrator unit 7 and then to control unit 8. Control unit 8 connects sections of tool electrode 4 to the source 1 process current and adjusts the source voltage so that the total current through the sections does not

For example, for the case of simultaneous connection of all sections, the technological current values through each section at the beginning of the processing cycle are determined by the formula

 I

The integrator unit 7 integrates the values of the current technological current through the sections. The result of the integration is the amount of electricity carried by the current through the section. As soon as the section passes the amount of electricity

one"

Q. 1, -t: max

 - -max - - n

Denoting i S S - Brdr and U I and substituting it in (1) after transformations we get

AJ I.

lz

Since S cannot be greater than Q above the processing tolerance S, the inequality must be satisfied

L1

S

(2)

where K, is the coefficient having the dimension of the quantity of electric-. properties.

t is the current processing time; the control unit 8 will receive a signal to disconnect the pth section from the process current source. The ratio I / Ij gi p is calculated in block 6 of memorization and calculation.

The value of K ,, is determined from the condition of providing the necessary removal of metal in one working cycle under a section with a working gap. At 1 - Tdlax equality is true

K, Q.

After that, the interelectrode gap is flushed, and the processing cycle is repeated.

When processing by the proposed method, it is allowed to feed the process current only to those sections of the tool electrode for which the ratio of the difference of the maximum of all measured amplitudes of the current of the first pulse and the amplitude of the current of the first pulse through. The nth Section to the amplitude of the current of the first pulse through the n-section does not exceed the ratio of the tolerance for processing to the size of the working interelectrode gap, i.e.

In SpaS IMOKC S

f I.

Max

 ooE 3 „

the amplitude of the current of the first pulse through the p-section; the maximum amplitude of the current of the first pulse through the section with the working (minimum) gap; the size of the working gap, the size of the gap under the n-th section.

 o / yin

from which it follows that the supply of technological current only to those sections for which inequality (2) is satisfied.

Claims (2)

1. A method of dimensional electrochemical treatment with a sectional electrode tool, through sections of which various amounts of electricity are passed by varying the duration and number of pulses of the process current, characterized in that, in order to improve the processing accuracy, all sections of the tool electrode at the beginning of each processing cycle are simultaneously a current pulse is supplied, its amplitude is memorized through each section, and technological current pulses are supplied to the sections, with the amount of electricity through each This section is chosen in proportion to the ratios of the amplitudes of the first current pulses through each section to the maximum value of the first current impulse. 2. A method according to claim 1, distinguished by the fact that, in order to increase the processing performance, the technological current pulses serve only those sections of the electrode-instrument for which the ratio of the difference of the maximum of all measured current amplitudes of the first of the pulse and the amplitude of the current of the first pulse through the nth section to the amplitude of the current of the first pulse through the nth sec "ration does not exceed the ratio of tolerance 55 processing to the size of the working interelectrode gap.