JPH0441121A - Electric discharge machining method and device - Google Patents

Abstract

PURPOSE:To perform electric discharge machining in any machining current waveforms corresponding to purposes by providing an addressing means for renewing addresses in a memory in sequence by one address for every setup time interval, when a first address in the memory is specified at the start of applying voltage and electric discharge is detected. CONSTITUTION:When the application of voltage between a work W and an electrode P is started, a current instruction value which is stored in a memory 38 at a first address is output to a machining power supply and voltage is applied so that a machining current can be of the current instruction value. When discharge occurs in between the electrode P and the work W, the machining current is of the instruction value, and after a setup time interval passes, the next address in the memory 38 is specified and the next current instruction value is output so that the machining current is of the instruction value. Then, every time a setup time interval passes, a current instruction value stored in the memory 38 at the address is output to the machining power supply and a machining current is controlled to be of the instruction value.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electric discharge machining method and apparatus, and more particularly to an electric discharge machining method and apparatus suitable for die-sinking electric discharge machining.

Conventional technology In conventional electric discharge machining, when electric discharge is started, the machining current waveform immediately rises to a set current value, and it is generally controlled to maintain that current value until the electric discharge is turned off. It is true. In addition, there is a method of controlling the slope of the rising edge of the machining current waveform to gradually increase the current to reach the set value when the discharge starts, and then controlling the current value to be maintained thereafter. When this happens, the machining current waveform is first immediately raised to an intermediate current value, then the slope of current increase is controlled to gradually increase the current to reach the set value, and the current value is maintained from then on. Methods and apparatuses for controlling this are also known.

Problems to be Solved by the Invention In electrical discharge machining, it is said that there is a close relationship between the machining current waveform and machining characteristics. For example, if the current rises quickly, the electrodes will wear out rapidly. However, if the current rises slowly, the machining speed decreases. The relationship between the current waveform and processing characteristics differs greatly between copper and graphite electrodes, and also varies depending on the area of the electrode.

Therefore, it may not be possible to obtain optimal machining characteristics by simply controlling the rise of the current, and it is desirable to be able to perform electrical discharge machining with an arbitrarily set current waveform.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electric discharge machining method and apparatus that can arbitrarily set the waveform of a machining current.

Means for Solving the Problems The present invention includes a discharge detection circuit that detects discharge between a workpiece and an electrode, a storage device that stores a plurality of set current specified values, and one of the storage devices when starting voltage application. address designation means for specifying the address of the storage device and sequentially updating the address of the storage device one by one at each set time interval when a discharge is detected; and when a voltage application signal is output, the address is stored in the specified address. Outputs the current command value to the processing power source,
Electric discharge machining is performed using a machining current waveform based on a commanded current value.

Alternatively, a discharge detection circuit that detects discharge between the workpiece and the electrode, a first storage device that sets and stores the switching time to the next stage, and a second storage device that sets and stores the current command value of each stage at each address. storage device, the elapsed time from the start of discharge, and the first
A comparison means is provided for comparing each switching time stored in the second storage device, and when starting voltage application between the workpiece and the electrode, the first stage current command value stored in the second storage device is applied to the machining power source. After the discharge starts, the address of the second storage device is updated based on the coincidence signals sequentially output from the comparison means, and the current command value of each stage is output to the machining power supply, and machining is performed using the specified current value. Perform electrical discharge machining using the current waveform.

Operation In the first method and device, when starting voltage application between the workpiece and the electrode, the current command value stored in the first address of the storage device is output to the machining power source, and the machining current is adjusted to the current. Apply voltage to reach the command value. When an electric discharge occurs between the electrode and the workpiece, the machining current reaches the command value, and when the set time interval has elapsed, the next address in the storage device is specified, the next current command value is output, and the machining current reaches the command value. The current becomes this command value. Thereafter, each time the set time interval elapses, the addresses of the storage device are sequentially changed, the current command value stored in each address is output to the machining power source, and the machining current is controlled so as to match the command value. becomes. Therefore, by setting the time interval for changing the address and/or the current command value stored in each address of the storage device to a desired value, any desired machining current waveform can be obtained.

Further, in the second method, since the time for switching to the current command value of each stage can be arbitrarily set in the first storage device, the switching time width of the current command value can be set to an arbitrary value. That is, when voltage application starts, the first stage current command value stored in the first address of the second storage device is output, discharge starts, and the first switching time stored in the first storage device elapses. Then, the second stage current command stored in the second address of the second storage device is output, and when the next switching time elapses, the third stage current command is output, and from now on, the set switching time is As time passes, the current command values set for each stage are sequentially output, and the commanded current flows as a machining current, so that an arbitrary machining current waveform can be obtained.

Embodiment FIG. 1 is an overall configuration diagram of an embodiment of the present invention, and is designated by reference numeral 1.
Reference numeral 2 indicates a current command generation circuit, and reference numeral 2 receives current control signals 81 to S6 output from the current command generation circuit 1, and
This is a current control circuit that controls the machining current flowing between the workpiece and the workpiece W.

FIG. 2 shows an embodiment of the current control circuit 2, in which reference numeral 10 is a DC power supply, R1-R6 are current limiting resistors, SW1 to SW6.
are switching elements such as transistors connected to the current limiting resistors R1 to R6, respectively. A switching element-current limiting resistance circuit (SWI) connected in parallel from the DC power supply 10.

R1-SW6. A voltage is applied between the electrode P and the workpiece W via R6). switching element S
W1 to SW6 are controlled on and off by current control signals 81 to S6 output from the current command generation circuit 1,
The current flowing between the workpiece W and the electrode P is controlled. In this embodiment, the current limiting resistor R
The resistance values of 1 to R6 are sequentially set to values that are in a multiple relationship.

For example, R1=80Ω, R2=40Ω, R3=20Ω,
R4 = 10Ω, R5 = 5Ω, R6 = 2°5Ω, the DC power supply is 100V, the gap voltage between the workpiece W and electrode 2 during electrical discharge machining is 20V1, and if the ON voltage of the switching element is ignored, each switching element SW1 to SW6 When turned on, the current that flows is as follows.

Switching current limiting resistance Electrical element SWI 80Ω IAS
W2 40Ω 2ASW3
20Ω 4ASW4
10Ω 8AW5 5Ω 16A W6 2, 5Ω 32. ~ Figure 3 shows a first embodiment of the current command generation circuit 1, in which the discharge detection circuit 20 detects the discharge state from the gap voltage Vg,
Outputs discharge raw signal ED. The on-time off-time control circuit 21 starts timing after the discharge raw signal ED becomes H level, and after the set on-time elapses, the voltage application signal VO is turned on.
N is turned off (L level), time measurement is started after the voltage application signal VON is turned off, and after the set off time has elapsed, it is turned on (H level). The voltage application signal VON is input to one terminal of each AND gate G1 to G6. Further, the discharge raw signal ED is inputted to the timing generator 23 and the pointing counter 24 via the inverter 22, and while the discharge raw signal ED is off, both elements are stored in a reset state by the H level signal from the inverter 22. However, when discharge starts, the discharge raw signal ED is turned on, and the output of the inverter 22 becomes L level, the operation starts. When the operation is started, the timing generator 23 outputs a timing pulse TP at each set time interval, using an arbitrarily set value as a cycle, and updates the pointing counter 24 by one. The output of the pointing counter 24 is input to the memory 25 and the upper limit detection circuit 26, and the output of the pointing counter 24 is input to the memory 25 and the upper limit detection circuit 26.
The address of the memory 25 is selected according to the count value of 4.

The upper limit detection circuit 26 is configured to set an arbitrary pointer upper limit setting value, and when the count value of the pointing counter 24 reaches the set upper limit setting value, the output I
H is output and input to the count enable terminal of the pointing counter 24, and the operation of the counter 24 is stopped. The memory 25 is made up of a rewritable non-volatile memory, and in this embodiment, it is made up of a plurality of words with 6 bits from the least significant bit D1 to the most significant bit D6 as one word. The stage current command value is set and stored.

As a result, the count value of the pointing counter 24 is 0.
．． 1.2..., the data at addresses θ, 1, 2, 3, etc. of the memory 25, that is, the current command values, are read out, and each bit D1 to D1 is read out. D
6 to rlJ, (H level) or "0" (L level)
signals are output to AND gates D1 to D6, respectively, and current control signals 81 to S6 are output from AND gates G1 to G6 where the AND condition is satisfied, and switching elements SW1 to
SW6 is turned on to flow a machining current between the electrode P and the workpiece W.

Therefore, the on time of the on time off time control circuit 21 and the timing setting value of the timing generator 23.

Pointer upper limit setting value of upper limit detection circuit 26, memory 25
For example, when each data (current command value) at θ address, 1 address, 2 address, and 3 address is set as shown below, the 4th
The operation of this embodiment will be explained with reference to the operation timing chart shown in the figure.

On time 50μs Timing setting value 5μs Pointer upper limit setting value 3 Memory 0 address data 3 (Dl・D2・I D3~D
6=0)〃1〃5(Dl・D3・ID2.D4~D6=
0)” 2 ” 7(Di~D3=I D
4~D6=00)〃3〃10(D2・D4・I Dl,
D6. D5. D6.0) When the off time of the previous cycle ends, the voltage application signal YON is output from the on time off time control circuit 21 (see FIG. 4(a)). On the other hand, the timing generator 23. Pointing counter 24
Since the discharge raw signal ED is off, the count value of the pointing counter 24 is rOJ, and the memory 2
Since address 0 is selected for 5, data 3 at address 0 is sent from memory 25 (D1=1.D
2=2. The output of D3~D6=0) is output and the game is played.)
Output SL of Gl and G2.

5l (rlJ (HL/bell) 63~G4 output s3
~S4 becomes rOJ (L level), switching elements SWI and SW2 are turned on, and a voltage is applied between the electrode P and the workpiece W.

Then, when a discharge occurs between the electrode P and the work W and the gap voltage Vg decreases, the discharge detection circuit 20 detects this and turns on the discharge raw signal ED (see FIG. 4(b)).

The current I at this time is the current limiting resistor R1 (=80Ω),
It is limited to 1+2=3A by R2=(40) (see FIG. 4(k)).

When the discharge raw signal ED turns on, the timing generator 23
．． Since the reset state of the bointing counter 24 is released, the timing generator 23 outputs the timing pulse TP after the set time (5 μs) after the discharge raw signal ED turns on, and the bointing counter 24 is 1” (see Figure 4 c and d). The pointing counter 24 becomes "1", and data 5 (Di, D3=L D2.
D4 to D6=O) are output (see FIG. 4e), switching elements SWI and SW3 are turned on, and the machining current 1 is set to 5A (1+4=5A) (see FIG. 4). Then, when further time elapses, the next timing pulse T
P is output from the timing generator 23, the pointing counter 24 is set to "2", the address of the memory 25 is set to "2", and data 7 at address 2 (=D1.D2.
D3=1. D4゜D5. D6=O) to memory 25
output from switching elements SWI, SW2 . SW3
Turn on.

The machining current ■ is 7A (1+2+
4=7A). When the set time further passes and the next timing pulse TP is output from the timing generator 23, the count value becomes "3" and the upper limit detection circuit 26
Since it matches the value set in , the upper limit detection circuit 26
Output signal IH is output from pointing counter 2.
Stop the count operation of 4. After that result, the pointing counter 24 holds the count value "3",
Since the memory 25 address "3" is kept selected, the third data 10 is stored from the memory 25.
(D2.D4=1.DI.

D3. D5. D6=0) is output, and the switching elements SW2. Turn on SW4 and set the machining current I to 10A (2
+8=10A) (see FIG. 4(k)). and,
Since the count value of the pointing counter 24 does not advance, a machining current of 10 A flows until the voltage application signal VON is turned off.

When 50 μs elapses from the start of discharge and the voltage application signal VON from the on-time off-time control circuit 21 turns off, AND gates G1 to G6 close and all switching elements SW
Since I to SW6 are turned off, the machining current I becomes "0" and the raw discharge signal ED is turned off, so the timing generator 23. Pointing counter 24 is reset.

Then, the on-time off-time control circuit 21 starts measuring the off-time. After the off time has elapsed, the voltage application signal VON is turned on and the above-described operation is started again.

In this way, by adjusting the data (current command value), timing setting value, and pointer upper limit setting value set in each address of the memory 25, it is possible to obtain an arbitrary machining current waveform.

In the first embodiment, the on-time off-time control circuit 21. Although the upper limit detection circuit 26 is used, these circuits are not necessarily necessary. A second embodiment of the current command generation circuit 1 that does not use these circuits is shown in FIG. The memory 27 has a memory capacity corresponding to the on time minus the off time.

For example, if the on time and off time are each 50 μs,
If the timing setting value set in the timing generator 23 is 5 μs, addresses 0 to 19 ((50+50)÷5=
20) or more memory capacity. Further, the pointing counter 28 is composed of a ring counter, and is set to count cyclically from 0 to 19. When the pointing counter 24 is set to "0", the flip-flop 29 is reset at the rising edge of the output, and the flip-flop 29 is set by the discharge raw signal ED of the discharge detection circuit 20. The timing generator 23 is held in a reset state when the reset output q of the flip-flop 29 is at the H level, and outputs the timing pulse TP when the output σ becomes the L level. Note that the same elements as in the first embodiment are given the same reference numerals.

Therefore, the current command value of the desired machining current waveform is set and stored in addresses 0 to 9 of the memory 27.
A current command value of "0" is set and stored from the address to the 19th address.

It is now assumed that the pointing counter 28 is "0", the flip-flop 29 is reset, and the timing generator 23 is in a reset state. At this time, the address 0 of the memory 27 is selected, the data set at address 0 is output, and the switching elements SWI-SW6 are turned on or off by each of the output signals 81-S6. If it is the same as the previous example, D1=D2=1. D3-D6=0 is output as current control signals 81-S6, turning on SWI and SW2.

Therefore, when a discharge occurs and the raw discharge signal ED is output from the discharge detection circuit 20, the flip-flop 29 is set, and the timing generator 23 is released from the reset state, so it starts operating and sets the timing pulse TP to the set value. The pointing counter 28 starts outputting with a period of .times. As a result, the current command value set at each address in the memory 27 is outputted from the memory 27, turning each switching element on and off, and setting the machining current I to the command value.

Then, the count value of the pointing counter 28 becomes “
10", the current command value output from the memory 27 becomes "0", so all switching elements SW1 to SW
6 is off. That is, the on time is 5μ5×10=50μs. Then, from address 10 of memory 27 to 19
Since the current command value is set as "0" up to the address, the off time is 50 μs (5×10=50 μs). Pointing counter 28 changes from "19" to "
When the pointing counter 28 changes to “0”, the pointing counter 28 changes to “0”.
''The flip-flop 29 is reset at the rising edge of the output. As a result, the timing generator 23 is reset, and the pointing counter 28 has a count value of "0".
is held, the current command value stored in address 0 of the memory 2 is output, a voltage is applied between the electrode P and the workpiece W, and discharge is started, the discharge raw signal ED is output from the discharge detection circuit 20. is output and the flip-flop wrap 29 is set again, so the above-described operation is restarted.

As described above, in this second embodiment, the number of counts in one counting cycle of the pointing counter 28 constituted by a ring counter is determined by the timing pulse period and the total value of the on time and off time, and is set and stored in the memory 27. The current command value at each address determines the machining current value during the on time and the off time.

FIG. 6 shows a third embodiment of the current command generation circuit 1.
The differences from the embodiment include a first memory 30 that stores data for each stage instead of a timing generator, and a first memory 30 that stores data for each stage in place of a timing generator, and a clocked time of an on timer of an on time off time control circuit 21 and a memory 30 for storing data for each stage stored in the memory 30. Two points are provided: a time discrimination circuit 32 for comparing time data, and a second memory 31 for storing current command values for each stage. Further, since other elements are the same as those in the first embodiment, they are given the same reference numerals.

The first memory 30 stores the time of the first stage when the first stage current command is output from the start of discharge and switching to the second stage, and the time when the second stage current command is output after the first stage ends and the second stage current command is switched to the third stage. The time of the second stage to be switched and the times of each stage required thereafter are stored in sequence.

The time discrimination circuit 32 compares the time of each stage detected from the first memory 30 with the time measured by the on-timer, and when they match, outputs a match signal TEQ, increments the pointing counter 24, and controls the pointing counter 24. The addresses of the first and second memories 30 and 31 are specified according to the output value. Also, the second memory 3
1, current command values for each stage are set and stored at each address.

Therefore, the counting unit of the on-timer is set to 1 μs, and the 1st. For example, if the second memory is set as follows:
The operation will be explained with reference to the timing chart of FIG.

1st 2nd memory 30 Memory 31 0 address data 51 1 address data 10 52 address data 20 83 address data 40
104 address data 60 1
5. In the above example, the data at address 4 of the first memory 30 may be any data as long as it is greater than the on time.

First, during the off time, the voltage application signal YON output from the on time off time control circuit 21 is turned off. In this case, since no discharge has occurred, the pointing counter 24
is reset, and when the count value is "0", the address of address 0 of the first and second memories 30.31 is specified, and from each memory 30.31, the switching time from the first stage to the second stage ( 5) and the first stage current command value (1) are output.

Therefore, when the off time elapses, the voltage application signal vON turns on and opens the AND gates G1 to G6 (see FIG. 7). In the above example, the data at address 0 of the second memory 31 is "1". Therefore, only the signal S1 from the AND gate G1
is output (see Fig. 7g-), and the switching element S
Turn on WI and apply voltage to electrode P and work W.

Then, when the discharge is started and the discharge signal ED is turned on, the machining current (2) of IA flows as shown in FIG. 7(1). Further, the pointing counter 24 is released from the reset state. Then, when the discharging signal ED turns on,
The on timer of the on time off time control circuit 21 starts operating, and the output of the on timer and the data (5) output at address 0 of the first memory 30 are compared in the time discrimination circuit 32, and when 5 μs has passed after the start of discharge, , when the coincidence signal TEQ is output from the time discrimination circuit 32, the pointing counter 2
4 is advanced by one step, and the 1st. 2nd memory 30°31:1
Specify the street address. As a result, the first memory 30 outputs the data at address 1 (10), the second memory 31 outputs the data at address 1, that is, "5", and the AND gates G1 to G6 control the current. signal, S
l, 83 is output (see Figure 7 (g) and (i))
, the switching elements SWI and SW3 are turned on, and the machining current I becomes 5A (see FIG. 7(1)). Then, when the counted time of the on-timer reaches 10, a coincidence signal TEQ is output from the time discrimination circuit 32, and the pointing counter 2
4 to "2" and the first. Specify the address of the second address of the second memory 30.31. As a result, "8", which is the data at address 2 of the second memory 31, is output, only the current control signal S4 is output, and the machining current I becomes 8A.

When the time measured by the on-timer matches the output "20" at address 2 of the first memory 30, the time discrimination circuit 32 outputs the match signal TEQ again and the pointing counter 24 outputs the match signal TEQ.
is "3". As a result, the first memory 30 outputs data "40" from address 3, the second memory 31 outputs data "10" from address 3, and switching element SW4. SW2 is turned on and the machining current of IOA flows. When further time passes and the count time of the on-timer reaches "40", the coincidence signal TEQ is outputted again, the pointing counter 24 becomes "4", and the first
The memory 30 outputs the data "60" at address 4, the second memory 31 outputs the data "15" at address 4, and the machining electrician outputs 15A (31, S2, 83
．． S4 on). On the other hand, the on time expires before the count time of the on timer reaches the output "60" from the first memory 30, and the voltage application signal VON turns off, so in this case, the time discrimination circuit 32 outputs the coincidence signal TEQ. Not done. Further, since the voltage application signal VON is turned off, the discharge is stopped, the discharging signal ED is turned off, and the pointing counter 24 is reset and the count value becomes "0".
Therefore, address 0 of memory 30.31 is specified and the OFF time is waited for. After the off time has elapsed, the above-described operation is restarted.

FIG. 8 is a block diagram of a fourth embodiment of the current command generation circuit 1. This embodiment is different from the third embodiment in that a timer 35 is provided in place of the on-time and off-time control circuit 21. The pointing counter 36 is composed of a ring counter, and the number of counts per cycle of the ring counter can be changed. Also, 1st. This embodiment differs from the third embodiment in the contents set and stored at each address of the second memory 37 and 38.

That is, the first memory 37 also stores the time (on time + off time) at which voltage is to be applied again after the on time and off time have elapsed since the start of discharge, and the second memory 38 stores the time when the voltage is applied again after the on time and off time have elapsed, and the second memory 38 stores the off time. Current command value (OA) is also stored.

For example, if the on time is 50 μs and the off time is 50 μs,
When performing machining current waveform control similar to the third embodiment,
1st. The following data is set and stored in the second memory 37 and 38.

1st 2nd memory 37 Memory 38 0 address data 51 1 address data 10 52 address data
20 83rd address data 40
104 address data 50 155 address data 100 0 Furthermore, the pointing counter 36 is composed of a ring counter that cycles from count value 0 to 5. Therefore, the count value of the pointing counter 36 is "0" at the stage where the discharge has not started. The second memory 37.38 is at address 0
A street address has been specified. As a result, the data "1" detected from the second memory 38 is output and the switching element SW
1 is on (only the current control signal S1 is on), and a voltage is applied between the electrode P and the workpiece W. When discharge occurs, the discharge detection circuit 20 detects it and outputs a discharging signal ED, resets the timer 35, and starts timing. When discharge starts, a machining current of IA flows as shown in FIG. When 5 μs has passed and the data matches the data "5" stored at address 0 of the first memory 37, the time discrimination circuit 32 outputs a match signal TEQ, sets the pointing counter 36 to "1", and the first... The data at address 1 of the second memory is output and the machining current becomes 5A. When the time further passes and reaches 10 μs, the time discrimination circuit 32
The coincidence signal TEQ is output from the pointer 36, the pointing counter 36 becomes "2", and the machining current becomes 8A. 3rd below
As in the example above, time elapses, 20 μs, 40 μs
A coincidence signal TEQ is output every time s, and the count value of the pointing counter 36 advances to r3J and r4J, and the machining currents become rlOAJ and r15AJ, respectively.

Then, when the count value of the pointing counter 36 becomes "5" after 50 μs has passed from the start of discharge, rl 001 is output from the first memory 37 and "0" is output from the second memory 38. Switching elements SWI to SW6 are all turned off, and the machining current I is "0".
”. Then, after 100 μs has passed, the coincidence signal TEQ is output again and the pointing counter 36 becomes “0”.
becomes. That is, during the period from 50 μs to 100 μs after the start of discharge, the switching elements SW1 to SW6 are all turned off.
It's off time.

When the pointing counter 36 reaches "0", the first
Since data "1" is output from address 0 of the memory 38 and the switching element SWI is turned on, a voltage is applied between the electrode P and the workpiece W. Then, when the discharge is started, the above-described operation is started again.

In this way, in this fourth embodiment, the first and second
By arbitrarily changing the data set in the memories 37 and 38 and the number of counts circulated in the pointing counter 36, a desired machining current waveform can be obtained.

Effects of the Invention Since the present invention can control the machining current waveform into any shape, electrical discharge machining can be performed with any machining current waveform depending on the purpose such as the electrode used, machining characteristics, and machining time.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of one embodiment of the present invention, FIG. 2 is a block diagram of a current control circuit in the same embodiment, and FIG. 3 is a first embodiment of a current command generation circuit in the same embodiment. 4 is an operation timing chart of the current command generation circuit of the first embodiment, FIG. 5 is a block diagram of the second embodiment of the current command generation circuit, and FIG. 6 is a diagram of the operation timing of the current command generation circuit of the first embodiment. 7 is a timing chart of the operation of the third embodiment, and FIG. 8 is a block diagram of the current command generation circuit of the embodiment of FIG. 4. 1... Current command generation circuit, 2... Current control circuit 10
... DC power supply, SW1 to SW6... Switching element, P... Electrode, W... Work, 20... Discharge detection circuit, 21... On time off time control circuit, 23.
...Timing generator, 24.28.36...Bointing counter, 25.37...Memory, 26...
- Upper limit detection circuit, 30.37... first memory, 31
．． 38... second memory, 32-... time discrimination circuit,
35...Timer. 31~S6 Current control signal No.

Claims (4)

[Claims] (1) In an electric discharge machining method using an electric discharge machining device that has a machining power source that can control electric discharge machining current to a commanded current value, a plurality of current command values are set and stored in a storage device, and the voltage between the workpiece and the electrode is At the time of application, the current command value stored in the first address of the storage device is output to the machining power supply, and when discharge starts, the address is sequentially updated at set time intervals and the current command value stored in each address is updated. An electric discharge machining method that outputs a value to the machining power source and controls the machining current waveform to match the commanded current value. (2) In an electric discharge machining device that has a machining power source that can control electric discharge machining current to a commanded current value, there is a discharge detection circuit that detects discharge between the workpiece and the electrode, and a memory that stores multiple set current command values. and an addressing means that specifies the first address of the storage device at the start of voltage application and sequentially updates the address of the storage device by one address at each set time interval when discharge is detected. An electric discharge machining device that outputs a current command value stored at a specified address to a machining power source when a signal is output. (3) In an electric discharge machining method using an electric discharge machining device having a machining power source that can control electric discharge machining current to a commanded current value, a switching time to the next stage is set and stored in a first storage device, and a second The current command value for each stage is set and stored sequentially from the first address in the second memory device, and when it is time to apply voltage between the workpiece and the electrode, the second memory device 1
The current command value to be stored in the first address is output to the machining power source, and when discharge is started, the current command value stored in the first storage device is stored in the second storage device every time the switching time to the next stage is reached. An electrical discharge machining method that updates the address of the device by 1, outputs the current command value stored in each address to the machining power source, and controls the machining current waveform to the commanded current value. (4) In an electric discharge machining device that has a machining power supply that can control electric discharge machining current to a commanded current value, a discharge detection circuit that detects discharge between the workpiece and the electrode and a set switching time to the next stage are memorized. A first storage device, a second storage device that stores the set current command value of each stage in each address, and a second storage device that stores the elapsed time from the start of discharge and each switching time that is stored in the first storage device. The first stage current command value stored in the second storage device is output to the machining power source when voltage application between the workpiece and the electrode starts, and after the start of discharge, the comparison means outputs the first stage current command value stored in the second storage device to the machining power source. An electrical discharge machining apparatus that updates the address of a second storage device based on matching signals that are sequentially output, and outputs current command values for each stage to a machining power source.