SU1196184A1 - Device for controlling feed of electric discharge machine - Google Patents

Description

The invention relates to electrophysical and electrochemical methods of processing, and "in particular, relates to EDM machines with adaptive feed control systems.

The purpose of the invention is to improve processing performance by automatically adjusting for optimal feed, which allows you to select and maintain a feed rate that matches the erosion rate of the workpiece material.

In this case, the interelectrode gap has the greatest stability. The processing takes place at the highest rate for the set mode.

The drawing shows a block diagram of the proposed device.

The interelectrode gap 1, formed by the part and the electro-tool * which are connected to the generator 2 pulses of technological current, is controlled by the feed controller 3. To the EDM gap 1, an analyzer of 4 pulses with outputs 5-9 is connected.

The timer 10 contains a clock frequency generator 11 and a distributor on series-connected triggers 12-18, the outputs of which are combined at the inputs of the coincidence circuit 19. The generator 11 is connected to the input of the trigger 12, the other input of which is connected to the output of the coincidence circuit 19. Timer 10 has outputs 20-25.

Measurement unit 26 contains circuits 27 and 28 of coincidence, the output of circuit 27 is connected to the summing, and the output of circuit 28 with subtractive inputs of the counter 29 of operating pulses. The output 30 of the counter 29 is connected to the input of the memory unit 31 of the number of operating pulses, the output of which is connected to the input of the counter 29, and the output 32 of the counter 29 is connected to the input of the unit 33 for calculating the pulse utilization, the output of which is connected to the input 34 of the memory 35 of the value of the pulse utilization and input 36 is connected to the output 24 of timer 10. The output of memory block 35 is connected to input 37 of comparison unit 38, another input 39 of which is connected to output of block 33. The output of memory block 35 is also connected to display unit 40.

The output of block 38 comparison is connected to the input 41 of block 42 decision. The input 43 of the block 42 is connected to the output 44 of the block 45 of the memory of the increment sign of the control voltage of the supply regulator, with one input * of the block 45 of the memory connected to the output of the block 42 decision, and the other input of the block 45 receives a signal from the output 23 of the timer 10. The block 46 45 memory is connected to the bridge of the inputs of the reverse register 47 of the shift unit 48 forming the control voltage of the feed regulator.

The block 48 contains an actuator 49, the input of which is connected to the reversing shift register 47, and the output to the feed regulator 3.

The output 5 of the analyzer 4 pulses is connected to the input of the coincidence circuit 27, output 6 to the input of the reverse shift register 47, output 7 to the input of the counter 29, output 8 to the input of the coincidence circuit 28, output 9 to the input of the actuator 49.

The output 20 of the timer 10 is connected to the input of the coincidence circuit 27, the output _and 21 to the input of block 31, output 22 to the input of the coincidence circuit 28, output 23 to the input of block 45, output 24 to the inputs of memory block 35 and the reverse register 47, output 25 - to the inputs of the counter 29 and block 33.

The device automatically adjusts the supply controller for the EDM machine, taking into account the signs of the increments in the pulse utilization factor and the preceding change in the control voltage of the regulator during periodic measurement of the number of operating pulses and changes in the control voltage steps of the regulator. Such a regulation law is based on the extreme dependence of the percentage composition of the working pulses on the interelectrode gap size.

In this case, with the same signs of increments, the control voltage of the regulator changes in the direction of decreasing the interelectrode gap.

At opposite signs of increments, the control voltage of the regulator changes in the direction of increasing the interelectrode gap.

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If the previous approach of the electrodes leads to a decrease in the pulse utilization factor, this means that the maximum has been passed and the effect on the reduction of the electrode gap is produced.

If the previous dilution of the electrodes entails an increase in the pulse utilization factor, this means approaching the maximum and the interelectrode gap increases even more.

In the absence of a change in the control voltage of the feed regulator, the sign of its subsequent change coincides with the sign of the increment in the pulse utilization factor.

If there is no change in the pulse utilization factor, the control voltage of the feed regulator remains unchanged.

The device works as follows.

The analyzer 4 analyzes the pulses coming from the interelectrode gap 1. The pulses of the generator 2 technological current (output 5 ^ pass without conversion, the pulses of idling (output 6), short circuit (output 9) and work. by comparing the amplitude of the voltage pulses with the reference settings, the beginning of the processing pulses (output 7)

is obtained by measuring the voltage in the working area of the electrical wire.

The measurement cycle of the percentage of working impulses is carried out over two time intervals. During the first interval, the number of all generator pulses is calculated and stored, and the calculated number of working pulses is repeatedly subtracted from this number during the second interval, and the multiplicity of these subtractions is calculated as the current value of the pulse utilization factor. The duration of the second interval is set longer than the duration of the first.

Through the coincidence circuit 27, the summing input of the counter 29 receives pulses with a frequency equal to the generated oscillator frequency 2 for a time equal to the time of the signal at the output 20 of the timer 10. Timer 10 is configured so that I exclude.4

There is a simultaneous appearance of signals at two or more outputs. When a signal appears at output 21, the flow of signals to counter 29 stops (at the output 20 there is no signal), and block 31 records the number of pulses that arrived at the counter during the presence of the signal at output 20.

Then, when a signal appears on; output 22 of timer 10, through circuit 28 from analyzer 4, only operating pulses of generator 2 are fed to the subtracting input of counter 29. The signal output time 22 is many times longer than output 20.

At the moment when on the counter 29 the number of recorded pulses becomes 0, the output and the contents of block 31 are formed at the output 32. memory is again recorded in the counter

29. This happens every time when the counter 20 as it is subtracting the working pulses from the memorized number is reset. The ratio of the measurement times of working pulses and generator pulses determines the measured share of working pulses. When setting the time of the signal at the output 22 of the timer 10 is 100 times longer than the time of the signal at the output 20, the measurement result corresponds to the percentage ratio of operating pulses and generator pulses.

The counter is included in the work on the signal of the beginning of processing at the output 7 of the analyzer 4.

The number of pulses from output 32 of counter 29 is calculated in block 33 as a direct value of the pulse utilization factor, is stored in block 35 by a signal from output 24 of timer 10, fed to input 36, and displayed on display unit 40.

The preceding signal from the output 23 of the timer 10 allows storing in the block 45 of the increment sign of the previous change in the control voltage of the regulator.

Block 38 receives the current value of the pulse utilization factor from the output of block 33 and the previous value of the utilization factor from the output of block 35 recorded in the previous cycle. The signal sign of the increment of the utilization of pulses at the output

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block 38 comparison is fed to the input 41 of the block 42 decision, input 43 of which receives a signal from output 44 of block 45. The output signal of block 42 depends on a combination of increment signs and controls block 45, the output 46 of which is generated, the shift signal of the reverse register 47

The shift register 47 in the block 48 of the control voltage of the feed regulator controls the actuator 49, acting on the feed regulator 3 of the EDM machine. The shift register 47 is also controlled by a signal of idling (output 6 of the analyzer 4 pulses) so that at idle the control voltage of the regulator has the maximum value. The change in the state of the shift register and, consequently, the change in the step of the control voltage of the regulator are carried out on the permissive signal at the output!

24 timers 10.

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The subsequent time signal at the output 25 of the timer 10 resets the counter 29 and the block 33,

measurement unit 26, preparing _{5 the} next cycle of measurement and change of the control voltage of the regulator. The end of the cycle is the resetting of the trigger 12 of the timer 10 by the output signal of the trigger 18, at 10 this a signal appears at the output of the coincidence circuit 19 allowing the start of the next cycle according to the signals of the clock generator 11.

Thus, the device by the method of step-by-step extremum search 15 performs automatic adjustment of the feed controller to the optimum interelectrode gap. The technical effect of using the invention is to improve the performance of EDM equipment, reduce the number of operators serving EDM machines, and decrease.

25 share of the influence of significant factors manual adjustment of the machine on performance.

Claims (2)

DEVICE OF REGULATION OF SUPPLY OF ELECTROUSING MACHINE, containing a timer with a clock frequency generator, a pulse analyzer having a measuring unit, with a counter of operating pulses and a utilization factor calculation unit, a display unit, a comparison and decision making unit, and a control voltage generating unit of the feed regulator characterized by that, in order to improve processing performance by automatically adjusting for optimal flow, a block of the number of impo- The output is connected to the output of the operating pulse counter, and the output to the input of the specified counter, the timer is equipped with a clock frequency divider, the low-end output of which is connected to the memory block of the number of working pulses, and the high-level output is connected to the subtracting input of the counter of working pulses. one 1196184 2