JPH0360611B2 - - Google Patents
Info
- Publication number
- JPH0360611B2 JPH0360611B2 JP14033886A JP14033886A JPH0360611B2 JP H0360611 B2 JPH0360611 B2 JP H0360611B2 JP 14033886 A JP14033886 A JP 14033886A JP 14033886 A JP14033886 A JP 14033886A JP H0360611 B2 JPH0360611 B2 JP H0360611B2
- Authority
- JP
- Japan
- Prior art keywords
- wire electrode
- workpiece
- capacitor
- transistor
- power supply
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000003990 capacitor Substances 0.000 claims description 27
- 238000003754 machining Methods 0.000 claims description 16
- 238000005260 corrosion Methods 0.000 description 5
- 230000007797 corrosion Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- 238000005868 electrolysis reaction Methods 0.000 description 3
- 238000007599 discharging Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 238000009763 wire-cut EDM Methods 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000009760 electrical discharge machining Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
Landscapes
- Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、ワイヤカツト放電加工において、放
電加工時とは逆極性の電圧をワイヤ電極とワーク
間に印加し平均加工電圧をゼロにすることにより
電気分解作用を防止し、ワークの電食を防止する
放電加工源に関する。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention enables electrolysis in wire cut electrical discharge machining by applying a voltage of opposite polarity to that during electrical discharge machining between the wire electrode and the workpiece to reduce the average machining voltage to zero. The present invention relates to an electric discharge machining source that prevents electrolytic corrosion of workpieces.
従来の技術
加工液として水を用いる放電加工においては電
気分解作用が生じ、特に、超硬合金のような電食
性のワークを荒加工する場合等は電食が生じ、ワ
ークをもろくする等の欠点があつた。また、仕上
加工時においては、酸化被膜等が生じ安定した放
電が生じられなかつた。さらに、電気分解作用の
ために粒子の選択電食によりワークの表面が荒れ
て仕上面のあらさが悪くなる等の欠点があつた。
これを防止するために、非加工時に電極とワーク
間のギヤツプに加工時とは逆に逆電圧を印加する
ことによつて平均加工電圧をゼロにして電気分解
作用を防止することはすでに公知である。Conventional technology In electric discharge machining that uses water as a machining fluid, electrolytic action occurs, and especially when rough machining workpieces that are susceptible to electrolytic corrosion such as cemented carbide, electrolytic corrosion occurs, resulting in disadvantages such as making the workpieces brittle. It was hot. Further, during finishing processing, an oxide film etc. were formed and stable electric discharge could not be generated. Furthermore, there were other drawbacks, such as selective electrolytic corrosion of particles due to electrolysis, which roughened the surface of the workpiece, resulting in poor finished surface roughness.
In order to prevent this, it is already known to apply a reverse voltage to the gap between the electrode and the workpiece when not machining, in contrast to when machining, thereby reducing the average machining voltage to zero and preventing electrolysis. be.
この正逆電圧を簡単な構成で印加する方法とし
ては第３図に示すような方法がある。第３図にお
いて、１はワイヤ電極、２はワーク、３は直流電
源、Ｒは抵抗、Ｃはコンデンサ、Ｔはスイツチン
グ素子としてのトランジスタであり、該トランジ
スタＴのベースに周期的なパルス信号を入力し、
該トランジスタＴをオン、オフさせ、トランジス
タＴがオン中には、直流電源３からワーク２、ワ
イヤ電極１、コンデンサＣ、トランジスタＴを通
りコンデンサＣを充電させる。なお、このとき直
流電源３、抵抗Ｒ、トランジスタＴの回路にも電
流は流れる。 As a method of applying this forward and reverse voltage with a simple configuration, there is a method shown in FIG. 3. In Fig. 3, 1 is a wire electrode, 2 is a workpiece, 3 is a DC power supply, R is a resistor, C is a capacitor, and T is a transistor as a switching element. A periodic pulse signal is input to the base of the transistor T. death,
The transistor T is turned on and off, and while the transistor T is on, the capacitor C is charged from the DC power supply 3 through the workpiece 2, the wire electrode 1, the capacitor C, and the transistor T. Note that at this time, current also flows through the circuit including the DC power supply 3, the resistor R, and the transistor T.
次に、トランジスタＴがオフになるとコンデン
サＣの充電電圧が抵抗Ｒを介してワーク２、ワイ
ヤ電極１間に印加され、ワーク２、ワイヤ電極１
間に放電を生じせしめることとなる。 Next, when the transistor T is turned off, the charging voltage of the capacitor C is applied between the workpiece 2 and the wire electrode 1 via the resistor R, and
This will cause a discharge to occur between the two.
このように、トランジスタＴがコンデンサＣを
充電するときにはワーク２側がプラス、ワイヤ電
極１側がマイナスとなるが、トランジスタＴがオ
フでコンデンサＣの充電電圧がワーク２、ワイヤ
電極１間に印加されるときはワイヤ電極１側がプ
ラス、ワーク２側がマイナスに印加されることと
なり、ワイヤ電極１とワーク２間には交互に正、
逆の電圧が印加されうこととなる。 In this way, when transistor T charges capacitor C, the work 2 side becomes positive and the wire electrode 1 side becomes negative, but when transistor T is off and the charging voltage of capacitor C is applied between work 2 and wire electrode 1. is applied to the wire electrode 1 side with a positive voltage and the workpiece 2 side with a negative voltage, and between the wire electrode 1 and the workpiece 2, positive and negative voltages are applied alternately.
The opposite voltage will be applied.
発明が解決しようとする問題点
しかし、上記従来の方法では、抵抗Ｒにコンデ
ンサＣを充電するとき、また、コンデンサＣの電
荷を放電するとき、両方とも電流が流れ、この抵
抗Ｒによるエネルギーロスが大きいという欠点が
あつた。Problems to be Solved by the Invention However, in the conventional method described above, current flows both when charging the capacitor C to the resistor R and when discharging the charge from the capacitor C, and energy loss due to this resistor R is caused. It had the disadvantage of being large.
そこで、本発明の目的は、従来技術の欠点を改
善し、エネルギーロスが少なく、電源効率のよ
い、構成が簡単な両極性放電電源を得ることにあ
る。 SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve the drawbacks of the prior art and to obtain a bipolar discharge power supply that has a simple configuration, has little energy loss, and has good power supply efficiency.
問題点を解決するための手段
本発明はワイヤ電極、ワーク、コンデンサ及び
第１のスイツチング素子を直列に接続し直流電源
に接続された充電回路を設け、上記第１のスイツ
チング素子のオン−オフ動作と逆のタイミングで
オン−オフ動作を行う第２のスイツチング素子を
上記充電回路のワイヤ電極、ワーク、コンデンサ
の直列回路と並列に接続することによつて上記問
題点を解決した。Means for Solving the Problems The present invention provides a charging circuit that connects a wire electrode, a workpiece, a capacitor, and a first switching element in series and is connected to a DC power supply, and controls the on-off operation of the first switching element. The above problem was solved by connecting a second switching element, which performs on-off operations at opposite timings, in parallel with the series circuit of the wire electrode, workpiece, and capacitor of the charging circuit.
作 用
第１のスイツチング素子がオンなると直流電源
から該第１のスイツチング素子、コンデンサ、ワ
ーク、ワイヤ電極、直流電源へと電流が流れコン
デンサは充電され、第１のスイツチング素子がオ
フとなり第２のスイツチング素子がオンになる
と、コンデンサの充電電圧が第２のスイツチング
素子を介して、ワークとワイヤ電極間のギヤツプ
に印加される。その結果、ワークとワイヤ電極間
のギヤツプには、コンデンサの充電時と放電時で
は逆の極性の電圧が印加されることとなり、両極
性の放電電源を得ることとなる。Function When the first switching element is turned on, current flows from the DC power supply to the first switching element, the capacitor, the workpiece, the wire electrode, and the DC power supply, charging the capacitor, and the first switching element is turned off and the second switching element is turned off. When the switching element is turned on, the charging voltage of the capacitor is applied to the gap between the workpiece and the wire electrode via the second switching element. As a result, voltages of opposite polarity are applied to the gap between the workpiece and the wire electrode when charging and discharging the capacitor, resulting in a bipolar discharge power source.
実施例
第１図は本発明の一実施例の回路図であり、１
はワイヤ電極、２はワーク、３は直流電源、Ｃは
コンデンサ、Ｔ１，Ｔ２はスイツチング素子とし
てのトランジスタ、Ｄ１，Ｄ２はダイオードであ
る。ワイヤ電極１、ワーク２、コンデンサＣ、第
１のトランジスタＴ１、第１のダイオードＤ１は
直流電源に直列に接続され、第２のトランジスタ
Ｔ２と第２のダイオードＤ２は直列に接続され、
上記ワイヤ電極１、ワーク２、コンデンサＣの直
列回路と並列に接続されている。そして、本実施
例においては第１のトランジスタＴ１はPNP型
トランジスタで、第２のトランジスタＴ２は
NPN型トランジスタで構成し、両トランジスタ
Ｔ１，Ｔ２のベースには第２図ｂに示すようなパ
ルスが入力されるようになつており、一方のトラ
ンジスタがオンのときは他方のトランジスタはオ
フとなり、他方のトランジスタがオンのときは一
方のトランジスタはオフとなるようになつてい
る。なお、第１、第２のダイオードＤ１，Ｄ２は
第１、第２のトランジスタＴ１，Ｔ２を各々保護
するために入れられたものである。Embodiment FIG. 1 is a circuit diagram of an embodiment of the present invention.
2 is a wire electrode, 2 is a workpiece, 3 is a DC power supply, C is a capacitor, T1 and T2 are transistors as switching elements, and D1 and D2 are diodes. The wire electrode 1, the workpiece 2, the capacitor C, the first transistor T1, and the first diode D1 are connected in series to a DC power supply, and the second transistor T2 and the second diode D2 are connected in series,
It is connected in parallel with the series circuit of the wire electrode 1, work 2, and capacitor C. In this embodiment, the first transistor T1 is a PNP type transistor, and the second transistor T2 is a PNP type transistor.
It is composed of NPN type transistors, and a pulse as shown in FIG. 2b is input to the bases of both transistors T1 and T2. When one transistor is on, the other transistor is off. One transistor is turned off when the other transistor is turned on. Note that the first and second diodes D1 and D2 are inserted to protect the first and second transistors T1 and T2, respectively.
そこで、第１のトランジスタＴ１がオンのとき
には、直流電源３から第１のダイオードＤ１、第
１のトランジスタＴ１、コンデンサＣ、ワーク
２、ワイヤ電極１を通り直流電源３への回路が閉
となりコンデンサＣは充電されることとなる。次
に、第１のトランジスタＴ１をオフにし第２のト
ランジスタＴ２をオンとすると、コンデンサＣの
充電電圧は第２のトランジスタＴ２、第２のダイ
オードＤ２を介してワイヤ電極１、ワーク２間の
ギヤツプに印加され放電を生じせしめることとな
る。 Therefore, when the first transistor T1 is on, the circuit from the DC power supply 3 to the DC power supply 3 through the first diode D1, the first transistor T1, the capacitor C, the work 2, and the wire electrode 1 is closed, and the circuit is closed to the DC power supply 3. will be charged. Next, when the first transistor T1 is turned off and the second transistor T2 is turned on, the charging voltage of the capacitor C is applied to the gap between the wire electrode 1 and the workpiece 2 via the second transistor T2 and the second diode D2. is applied, causing a discharge.
今、直流電源３の電圧をＥ、ワイヤ電極１とワ
ーク２間のギヤツプ電圧をVGとして、第２図の
波形図を参照しながら、ワイヤ電極１とワーク２
間のギヤツプに加わる電圧VGについて詳説する
と、第２図ｂは第１、第２のトランジスタＴ１，
Ｔ２のベースに印加されるパルスで第２図ａはワ
イヤ電極１とワーク２内のギヤツプ電圧VGを表
すもので、第２図ｂに示す正のパルスが第１、第
２のトランジスタＴ１，Ｔ２のベースに印加され
ると、第１のトランジスタＴ１はオンとなる。こ
の瞬間はワイヤ電極１とワーク２間のギヤツプに
直流電源３の電圧Ｅがワーク２側をプラスにして
すべて印加されるが、その後、ワイヤ電極１とワ
ーク２間のギヤツプ抵抗とコンデンサＣの容量で
決まる時定数によりコンデンサＣは徐々に充電さ
れ、その結果ギヤツプ電圧VGは徐々に低下する。
次に、負のパルスが両ベースに印加されると、第
２のトランジスタＴ２がオンとなり、コンデンサ
Ｃの充電電圧がワイヤ電極１とワーク２間にワイ
ヤ電極１側をプラスに印加される。 Now, assuming that the voltage of the DC power source 3 is E and the gap voltage between the wire electrode 1 and the workpiece 2 is VG , the wire electrode 1 and the workpiece 2 are
To explain in detail the voltage V G applied to the gap between the first and second transistors T1, FIG.
The pulse applied to the base of T2 in FIG. 2a represents the gap voltage V G between the wire electrode 1 and the workpiece 2, and the positive pulse shown in FIG. 2b is applied to the first and second transistors T1, When applied to the base of T2, the first transistor T1 is turned on. At this moment, the voltage E of the DC power supply 3 is applied to the gap between the wire electrode 1 and the workpiece 2, with the workpiece 2 side being positive, but after that, the gap resistance between the wire electrode 1 and the workpiece 2 and the capacitance of the capacitor C are applied. The capacitor C is gradually charged by a time constant determined by , and as a result, the gap voltage V G gradually decreases.
Next, when a negative pulse is applied to both bases, the second transistor T2 is turned on, and the charging voltage of the capacitor C is applied between the wire electrode 1 and the workpiece 2 with the wire electrode 1 side being positive.
即ち、第２図ａに示すように、ギヤツプ電圧
VGの立上り、立下りは直流電源３の電圧Ｅだけ
ジヤンプしてワイヤ電極１とワーク２間に正逆極
性の電圧を印加することとなり、この動作が繰り
返されると、第２図ａに示すように0vラインよ
り上部の面積Ａ１と下部の面積Ａ２は等しくな
り、ワイヤ電極１とワーク２間には平均加工電圧
が０となるように印加されることとなる。 That is, as shown in Figure 2a, the gap voltage
The rise and fall of V G jumps by the voltage E of the DC power supply 3, applying a voltage of positive and negative polarity between the wire electrode 1 and the workpiece 2. When this operation is repeated, the voltage shown in Figure 2a is shown. As such, the area A1 above the 0v line and the area A2 below the 0v line are equal, and the average machining voltage is applied between the wire electrode 1 and the workpiece 2 to be 0.
そして、第２図に示すように両トランジスタＴ
１，Ｔ２をオン、オフさせるパルスのデユーテイ
ー比を１／２とすると（プラス幅、マイナス幅を
同一）、ワーク２とワイヤ電極１間には極性の異
なる同一電圧が交互に印加されることとなり、パ
ルス幅を（デユーテイー比１／２で）変えること
によりこの電圧±Ｅ／２〜±Ｅまで変えることが
でき、放電パルスの強さをパルス幅によつて調整
することができる。また、このパルスのデユーテ
イー比を変えることによつてワイヤ電極１とワー
ク２間のギヤツプに印加される正、逆の電圧の大
きさを変えることもできる。 Then, as shown in Fig. 2, both transistors T
1. If the duty ratio of the pulse that turns T2 on and off is 1/2 (the plus width and minus width are the same), the same voltage with different polarity will be applied alternately between the workpiece 2 and the wire electrode 1. By changing the pulse width (with a duty ratio of 1/2), this voltage can be varied from ±E/2 to ±E, and the intensity of the discharge pulse can be adjusted by changing the pulse width. Further, by changing the duty ratio of this pulse, the magnitude of the positive and reverse voltages applied to the gap between the wire electrode 1 and the workpiece 2 can be changed.
なお、仕上加工時には放電電流を小さくするの
で、第１、第２のトランジスタＴ１，Ｔ２や電源
の持つ浮遊容量の悪影響が出るので、放電回路
中、即ち、例えばワイヤ電極１と第２のダイオー
ドＤ２間に抵抗、またはインダクター等を挿入す
るようにしてその影響を小さくすればよい。即
ち、ワイヤ電極１と第２のダイオードＤ２間に抵
抗とスイツチの並列回路を挿入し、荒加工時には
スイツチをオンにし、仕上加工時にはスイツチを
オフとすればよい。そして、この場合抵抗は小さ
な値のものでよいからエネルギーロスは少なくて
すむ。 In addition, since the discharge current is made small during finishing machining, the stray capacitance of the first and second transistors T1 and T2 and the power supply will have an adverse effect. The effect can be reduced by inserting a resistor, inductor, etc. between the two. That is, a parallel circuit of a resistor and a switch may be inserted between the wire electrode 1 and the second diode D2, and the switch may be turned on during rough machining and turned off during finishing machining. In this case, the resistance only needs to have a small value, so energy loss can be reduced.
発明の効果
以上述べたように、本発明は簡単な構成によつ
てワークとワイヤ電極間に両極性の電圧を印加で
きる両極性放電電源を提供でき、かつエネルギー
ロスが少ないので電源効率の良い放電加工電源を
得ることができる。そして、ワークとワイヤ電極
間に両極性の電圧が印加されるから、加工液に水
を使用する場合でも電食及びさびを防止すること
ができ、超硬合金のワイヤカツト放電加工に適
し、また、仕上加工時には酸化被膜等が生じ難い
から加工が安定し、特に有用である。Effects of the Invention As described above, the present invention can provide a bipolar discharge power source that can apply bipolar voltages between a workpiece and a wire electrode with a simple configuration, and has low energy loss, resulting in high power supply efficiency. You can obtain processing power. Since a bipolar voltage is applied between the workpiece and the wire electrode, electrical corrosion and rust can be prevented even when water is used as the machining fluid, making it suitable for wire cut electrical discharge machining of cemented carbide. It is particularly useful because it is difficult to form an oxide film during finishing, resulting in stable processing.
第１図は本発明の一実施例の回路図、第２図
ａ，ｂは同実施例におけるギヤツプ電圧とトラン
ジスタのベースに印加するパルスの波形を示す
図、第３図は従来の両極性放電加工電源の回路図
である。
１……ワイヤ電極、２……ワーク、３……直流
電源、Ｔ１，Ｔ２……トランジスタ、Ｃ……コン
デンサ、Ｄ１，Ｄ２……ダイオード、VG……ギ
ヤツプ電圧。
Figure 1 is a circuit diagram of an embodiment of the present invention, Figures 2a and b are diagrams showing the gap voltage and pulse waveforms applied to the base of the transistor in the same embodiment, and Figure 3 is a diagram of a conventional bipolar discharge. It is a circuit diagram of a processing power supply. 1...Wire electrode, 2...Work, 3...DC power supply, T1, T2...Transistor, C...Capacitor, D1, D2...Diode, V G ...Gap voltage.
Claims (1)
スイツチング素子を直列に接続し直流電源に接続
された充電回路と、上記第１のスイツチング素子
のオン−オフ動作と逆のタイミングでオン−オフ
動作を行う第２のスイツチング素子を上記充電回
路のワイヤ電極、ワーク、コンデンサの直列回路
と並列に接続したことを特徴とする放電加工電
源。 ２ 上記第２のスイツチング素子と並列に接続さ
れたワイヤ電極、ワーク、コンデンサの直列回路
に抵抗が直列に挿入接続された特許請求の範囲第
１項記載の放電加工電源。 ３ 上記第２のスイツチング素子と並列に接続さ
れたワイヤ電極、ワーク、コンデンサの直列回路
にインダクターが直列に挿入接続された特許請求
の範囲第１項記載の放電加工電源。[Claims] 1. A charging circuit in which a wire electrode, a workpiece, a capacitor, and a first switching element are connected in series and connected to a DC power supply, and a charging circuit that is connected in series to a DC power source and turns on and off at a timing opposite to the on-off operation of the first switching element. An electric discharge machining power supply characterized in that a second switching element that performs an on-off operation is connected in parallel with a series circuit of a wire electrode, a workpiece, and a capacitor of the charging circuit. 2. The electric discharge machining power supply according to claim 1, wherein a resistor is inserted and connected in series to a series circuit of a wire electrode, a workpiece, and a capacitor connected in parallel with the second switching element. 3. The electric discharge machining power supply according to claim 1, wherein an inductor is inserted and connected in series to a series circuit of a wire electrode, a workpiece, and a capacitor connected in parallel with the second switching element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14033886A JPS632611A (en) | 1986-06-18 | 1986-06-18 | Electric discharge machining power source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14033886A JPS632611A (en) | 1986-06-18 | 1986-06-18 | Electric discharge machining power source |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS632611A JPS632611A (en) | 1988-01-07 |
| JPH0360611B2 true JPH0360611B2 (en) | 1991-09-17 |
Family
ID=15266504
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14033886A Granted JPS632611A (en) | 1986-06-18 | 1986-06-18 | Electric discharge machining power source |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS632611A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01310818A (en) * | 1988-06-08 | 1989-12-14 | Seibu Electric & Mach Co Ltd | Power supply device for electric discharge machining |
| DE102004060290A1 (en) * | 2004-12-15 | 2006-06-22 | Robert Bosch Gmbh | Method for processing a workpiece |
| JP5887378B2 (en) | 2014-04-30 | 2016-03-16 | ファナック株式会社 | Machining power supply device for electrical discharge machine |
| CN108672858B (en) * | 2018-06-30 | 2020-05-22 | 南京理工大学 | Full-bridge staggered parallel bipolar wire cut electrical discharge machining pulse power supply and machining method |
-
1986
- 1986-06-18 JP JP14033886A patent/JPS632611A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS632611A (en) | 1988-01-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH0355251B2 (en) | ||
| JPS60201826A (en) | Power source for wire electric discharge machining | |
| JPH0360611B2 (en) | ||
| JPH0120013B2 (en) | ||
| NL8204685A (en) | INVERTOR CIRCUIT WITH SYMMETRY CONTROL. | |
| US4864092A (en) | Electric discharge machining power source | |
| US4492881A (en) | Stored charge inverter circuit | |
| JPS61274812A (en) | Rust preventive machining method of machined surface in electric discharge machining under water | |
| JPS632612A (en) | Electric discharge machining controller | |
| JPS60180720A (en) | Discharge machining power supply | |
| JPS61274811A (en) | Electric discharge machining method | |
| JPH0355253B2 (en) | ||
| SU1517121A1 (en) | Pulser | |
| JPS60180721A (en) | Discharge machining power supply | |
| JPS5973226A (en) | Machining power supply of electric discharge machining device | |
| JPS60118423A (en) | Electric discharge machining power source | |
| JPS5943846B2 (en) | flip-flop circuit | |
| JPH0355252B2 (en) | ||
| JPH0351064Y2 (en) | ||
| JPS6343793Y2 (en) | ||
| JPS59134621A (en) | Electric discharge machine | |
| JPH06276724A (en) | Gate drive circuit | |
| SU1262696A1 (en) | Generator of geteropolar pulses | |
| JPH073828Y2 (en) | On-gate circuit | |
| JPH04105774A (en) | Capacitor type spot welding machine |