JPS60150910A - Electric discharge machine - Google Patents

Abstract

PURPOSE:To prevent the reduction of the efficiency of electric discharge machining by varying the cycle and stroke of the raising and lowering action of an electrode which is set at the beginning, according to the variation of the machining state. CONSTITUTION:A motor driving circuit 11 drives a motor 9 by the signal supplied from a comparison calculation controller 13. An electric-discharge detecting apparatus 15 detects the wave form of the voltage generated in an electrode gap 1 and outputs said wave form into the controller 13. A driving means is controlled on the basis of the comparison calculation between the detected voltage signal and the standard value of the voltage. Therefore, the cycle and stroke of the raising and lowering action of an electrode which is set in the early stage can be varied according to the variation of the working state, and the reduction of the machining efficiency can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to an h (heavy loading) device, and more particularly to an electric discharge machining device having a vertically movable electrode.

Electrical discharge machining equipment generally generates a discharge phenomenon in a gap formed by a pair of electrodes and performs a desired machining on a workpiece existing in the gap, and has a device that can freely adjust the gap between the electrodes. It is composed of a driving device, and a processing power supply for supplying power to the electrode.

Incidentally, in such an electric discharge machining apparatus, in order to stabilize machining, it is required to stably remove and cover machining chips generated during machining operations. Among electric discharge machining apparatuses, especially electric discharge machining apparatus J3 in which the electrode moves up and down (so-called reciprocating operation), machining chips have conventionally been removed by the method described below.

That is, by moving the electrodes up and down, processed chips accumulated in the gap between the electrodes are removed. The remaining machining chips are made of ions in the air generated due to the electrical discharge phenomenon, or oil used to maintain insulation between the machining chips and the electrodes, such as metals, by creating a forced liquid flow by the vertical movement of the electrodes. It is intended to exclude

However, in the conventional method of moving the electrode up and down, the A-pellator performs the above operation at a preset cycle and stroke, so the cycle of the up and down movement of the electrode is fixed regardless of the machining state of the workpiece. It was fixed.

Therefore, if the cycle of the vertical movement of the electrode and the stroke 1 to stroke periods are not properly set, it will result in unstable machining and a decrease in machining efficiency. In addition, even if the initial settings are appropriate, the machining conditions will change during the work, so the cycle and stroke of the vertical movement of the electrode should be changed in response to changes in the machining conditions. The drawback was that it could not be done.

Therefore, since the present invention improves the above-mentioned drawbacks of the prior art, its purpose is to adjust the period and stroke of the initially set electrode upper-F operation to changes in the machining state. An object of the present invention is to provide an electric discharge machining device that can be changed by changing the direction of the electric discharge machining device.

The features of the present invention for achieving the above object include a pair of electrodes that face each other in the vertical direction and at least one of which is vertically movable;
means for driving the vertically movable electrode, and for machining a workpiece by a discharge phenomenon occurring in the gap between the pair of electrodes, further comprising means for detecting a voltage generated in the gap between the electrodes. provided, and generated in the gap between the electrodes.
means for setting a reference value of the voltage, which compares and calculates the detection signal given from the detection means with the voltage reference value given from the voltage reference value setting means, and based on the result of the calculation, the drive means A comparison calculation control means is installed to control the
It is in the Tagotoki electrical discharge machining equipment.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a block circuit diagram of an electric discharge machining apparatus according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of an electric discharge machining apparatus according to an embodiment of the present invention and means for detecting the 11i electric voltage of the apparatus. FIG. 3 is a block diagram showing a comparison calculation control means according to an embodiment of the present invention, FIG. 4 is a voltage waveform diagram generated in the electric discharge machining apparatus according to an embodiment of the present invention, and FIGS. 5 and 6 shows a flowchart of the configuration of FIG. In Figures 1 and 2, the same reference numbers indicate the same parts.

In FIG. 1, the electrode gap 1 is the distance between the electrode 3 and the workpiece 7.
The distance between the electrode 5 and the electrode 5 on which the electrode 3 is placed can be adjusted by the movement of the electrode 3, which is vertically movable.

As described above, the electric current fli3 is an N-pole that can move up and down at high speed in response to the driving force of the motor 9 received from the drive shaft 8. The drive shaft 8 has one end connected to an output shaft (not shown) of the motor 9, and the other end connected to the electrode 3.
The motor drive circuit 11 receives the driving force from the motor 9 and moves up and down at a speed of △Z/,''. The motor 9 is driven in response to the drive command signal.

The discharge voltage detection device 15 detects the voltage waveform generated in the electrode gap 1 and outputs it to the comparison calculation control device 13. The processing power source 11 supplies necessary power to the electrode 3 and the motor drive circuit 11.

In FIG. 2, a resistor 18 is a machining current limiting resistor connected to limit the current flowing from the machining power source 17 to the electrode 3 when a discharge phenomenon occurs in the electrode gap 1. The pulse signal generator 20 is composed of an element such as a monostable multivibrator, and the switching element 1
Controls the opening/closing operation of 9.

A machining gap voltage detection resistor 24 is connected in parallel with the electrode 3.5, and a voltage equal to the voltage generated in the electrode gap 1 is generated across the resistor 24. Machining gap voltage detection resistor 2
The voltage generated at 4 is applied to one input terminal of the -C comparator 22 as a detection signal. As will be explained in detail in the section of explanation regarding FIG. 4, the detection signals are generally classified into four types: those due to normal discharge, those due to abnormal discharge, those due to contamination of the electrode gap, and those due to no discharge.

The reference voltage setting circuit E021 is a circuit for setting the reference value of the voltage generated in the electrode gap 1, as shown in FIG.
o is applied to the other input terminal of comparator 22.

The comparator 22 takes in the voltage signal generated in the machining gap voltage detection resistors 21 and 4, and compares it with the reference voltage J]-set value Eo output from the reference voltage setting circuit E021, and calculates the voltage signal based on the comparison. [<A signal is output to the reflex 1~ side terminal of the S control flop 23.

The comparator 22 outputs a pulse signal when the voltage waveform corresponds to the waveform shown in FIG. Do not let the flip knob into the corresponding position. The RS flip-flop 23 is set by the output signal given from the calibrator 22 as described above,
from the pulse signal generator 20 to the switching element 1
Reset 1 to 1 is performed by inputting an output signal that opens 9, that is, an L level signal, to the reset terminal. Therefore, the RS flip 70 knob 23 is connected to the pulse signal generator 2.
Each time a level signal of 0 or 61 is output, the resistor 2
It is to be distinguished whether the voltage waveform generated in step 4 corresponds to either the waveform (■) or the waveform (■) shown in FIG. 4, or the waveform (■ or ■) shown in FIG.

The AND element 25 performs a logical product of the inverted output signal from the RS flip-flop 23 and the sampling pulse TI. The AND element 25 calculates the logical product as described above so that the voltage waveform generated in the electrode gap 1 is equal to the voltage E set by the reference voltage setting circuit E021.
Outputs a 1" level signal only when it does not exceed o.
do.

In FIG. 3, a programmable counter 27 converts the pulse signal output from the AND element 25 into a counter #
Increment in φ.

Counter #1 of the programmable counter 27 outputs an interrupt request signal every time the total value of the incremented pulse signals of the counter #φ reaches a certain number.

The CPU 29 performs arithmetic and logical operations and comparison operations. C
The PU 29 takes in the interrupt request signal output from counter #1 of the programmable counter 27 and starts an interrupt response program as shown in FIGS. 5 and 6.

The CPU 29 takes in the total value of the count output from the counter #φ of the programmable counter 27. The CPU 29 calculates the statistics of the total value outputted from the counter #φ every predetermined period, and determines whether or not it is necessary to move the electrode 3 up and down.

The CPU 29 calculates the movement ■ΔZ and the moving speed of the drive shaft 8 based on the above judgment, and outputs a drive command signal to the motor drive circuit 11 based on the calculation results.

The control operation of the above configuration will be mainly explained using the flowcharts of FIGS. 5 and 6.

In the flowchart of FIG. 5, the CI U 29 checks whether an interrupt request signal is output from counter #1 of the programmable counter 27 (step 31). When the CPU 29 recognizes that the signal has been applied from the counter #1, it proceeds to the next step 33. When the CPU 29 determines that the interrupt request signal is not output from the counter #1, the CPU 29 does not consider the operations from step 31 onward. CI) U 29
At step 31, iJ'3 indicates that the signal has been applied from counter #1, and then clears the data held so far that has been applied from counter #φ (step 33).

The CPU 29 accumulates the data given from the counter #φ in the newly set period (step 35).
. The data that the CPU 29 processes in step 35 is the number of times a voltage waveform similar to ■ or ■ in FIG. 4 appears within a predetermined period. The reason why the data that the CPU 29 processes in step 35 is limited to the voltage waveforms of ■ or ■ is as follows. That is, the voltage waveform (■) indicates an abnormal discharge due to an unknown cause, (2) indicates an impedance drop due to contamination of the electrode gap 1, etc., and the voltage waveform (2) indicates a normal tIl voltage, and (2) indicates an excessively wide electrode gap 1. This is a waveform in which no discharge occurs.

If the voltage waveforms (1) or (2) occur more than a certain number of times within a predetermined period, it is necessary to move the electrode 3 up and down according to an embodiment of the present invention. However, since the vertical movement of the electrode 3 is not necessary for the voltage waveforms (1) and (2), the CPU 29 does not perform calculation processing for the voltage waveforms (2) and (2) -C.

As a result of the arithmetic processing in step 35, the CPU 29 determines whether or not the electrode 3 should be moved up and down.
- (step 37). When the CPU 29 recognizes that the vertical movement of the electric motor (~3) is necessary in step 37, the CPU 29 activates the motor drive circuit 11 to move the drive shaft 8 vertically.
A command signal is output to (step 39), and the process shifts to the normal machining process. CPU29 is d5C on Stella/37
1. Once you realize that the vertical movement of the drive shaft 8 is unnecessary,
The normal machining process immediately begins.

Flowcharts 1 to 6 in FIG. 6 are used when it is desired to have a longer time period than the command determination period for the electrode up and down movement of flowcharts A and 5 shown in FIG. In FIG. 6, step 41 and step 43 are the same as step 31 and step 33 in FIG. Recite the given data step 45).CPU2
9 decrements the count of counter #1 (step 47). Here, the counter #1 is set as an initial value to a count value N indicating a period for determining whether or not the electrode vertical movement is necessary. The CPU 29 has a counter #
Each time #φ data is given from φ, the counter #1
Step 47)
.

The CPU 29 determines whether or not the count of counter #1 has reached O (step 49).

The CPU 29 sets the counter #1 in step 49.
When the content of is recognized as N≠0, the operations from step 41 to step 47 are repeated until N=O. CPU
29, upon recognizing that N=O in step 49, proceeds to step 51.

The CPU 29 calculates the total value of #φ data for one cycle indicated by the count value N (step 51). The CPU 29 determines whether or not it is necessary to move the electrode 3 up and down based on the data processed in step 51 (step 53).
).

CPU U 29 c, step 53 k: a5 iT
When it is recognized that it is necessary to move the electric motor 8i3 up and down, a command signal is output to the motor drive circuit 11 to move the drive shaft 8 up and down (step 55). CI) U 29 returns the contents of a counter D and a counter N (not shown) to their initial states (step 57), and shifts to a normal machining process. C
When the PU 29 recognizes that the above operation is not necessary in the step J3, it immediately moves to step 57.

The content explained above is just one embodiment according to the present invention. For example, the command signal given by the CPU 29 is limited to the amount of movement of the drive shaft 8, and the movement speed is set as high as possible within a reasonable range for the mechanical system. There is no problem even if it is a fixed speed. Therefore, it goes without saying that the present invention is not limited to the one embodiment described above.

As explained above, according to the present invention, the driving means is controlled based on a comparison calculation between the detection signal given from the voltage detection means and the voltage reference value given from the voltage reference value setting means. It is possible to provide an electric discharge machining apparatus that can change the initially set cycle and stroke of the vertical movement of the electrode in response to changes in the machining state.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram of an electric discharge machining apparatus according to an embodiment of the present invention, FIG. 2 is a circuit diagram of an electric discharge machining apparatus according to an embodiment of the present invention and means for detecting a discharge voltage of the apparatus, and FIG.
FIG. 4 is a block diagram showing a comparison calculation control means according to an embodiment of the present invention, FIG. 4 is a voltage waveform diagram generated in the electrical discharge machining apparatus according to an embodiment of the present invention, and FIGS. 5 and 6 are Third
A flowchart of the configuration of the figure is shown. 1... Electrode gap 3... Electrode 5... Electrode 7... Workpiece 9... Motor 11... Motor drive circuit 13...
Comparison calculation control means 15...Discharge voltage detection device 21...Reference voltage setting circuit E. 4 - GF Application No. 2651 2, Title of Invention /19. Relationship between electrical processing equipment 3 and amendments made by Ministry of Education 9 Patent applicant address (residence) Kanayo Prefecture (J' 200 Ishida, Sehara City Name) Amada Co., Ltd. Representative Ten 1) Uzu 4, Agent address: 5th floor, Toranomon Building 1, 1-2-3 Toranomon, Minato-ku, Tokyo 105 Telephone: Tokyo (504) 3075-3016-3017
No. (1) Specification (2) Drawing 7, contents of amendment (1) Delete "[and the motor drive circuit 11"] from page 5, line 16 of the specification. (2) In the 12th line of page 5 of the specification, the words ``that is, L level signal'' are deleted. (3) On page 8, line 10 to line 11 of the same page of the specification, “
The statement that the sum S1 value of the incremented pulse signals of the counter #φ is ``is corrected to ``[fixed cycle clock pulses] are J-runted, and the count value is''. (4) On the 19th line of page 9 of the specification to the 4th line of page 10, the following information is written: [The data given is accumulated from the counter #φ held up to that point (step 35). "After reading the data held by the counter #φ, the counter #φ is initialized, and the counter #φ counts to the new IC."~The operation starts. ” he corrected. (5) On page 11, line 20 of the book, page 12, line 5, page 12, line 7, page 12, line 9 to line 10, “Counter #1 "Count contents" should be corrected to "Sequence counter N." (6) In the third line of page 12 of the specification, the text "rNJ" is corrected to "NO". (7) In the third line of page 13 of the specification, "contents of counter D and counter N, not shown" is corrected to "internal memory D and sequence counter N". (8) Figures 5 and 6 will be corrected as shown in the attached sheet. Figure 5 Figure 6

Claims (1)

[Claims] ``A pair of electrodes facing each other in the vertical direction, at least one of which is vertically movable, and means for driving the vertically movable electrode; In an electric discharge machining device that processes a workpiece by an electric discharge phenomenon occurring in a gap, a means for detecting a voltage generated in the electrode gap is installed, and a reference value of the voltage generated in the electrode gap is set. A comparison operation is provided, wherein the detection signal given from the detection means is compared with the voltage reference value received from the voltage reference value setting means, and the driving means is controlled based on the result of the operation. Electrical discharge machining equipment equipped with main control means.