JPS59227323A - Electric discharge machining controller - Google Patents
Electric discharge machining controllerInfo
- Publication number
- JPS59227323A JPS59227323A JP10308683A JP10308683A JPS59227323A JP S59227323 A JPS59227323 A JP S59227323A JP 10308683 A JP10308683 A JP 10308683A JP 10308683 A JP10308683 A JP 10308683A JP S59227323 A JPS59227323 A JP S59227323A
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- machining
- discharge machining
- gap
- workpiece
- 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.)
- Pending
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
- B23H1/00—Electrical discharge machining, i.e. removing metal with a series of rapidly recurring electrical discharges between an electrode and a workpiece in the presence of a fluid dielectric
- B23H1/02—Electric circuits specially adapted therefor, e.g. power supply, control, preventing short circuits or other abnormal discharges
- B23H1/022—Electric circuits specially adapted therefor, e.g. power supply, control, preventing short circuits or other abnormal discharges for shaping the discharge pulse train
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
Abstract
Description
【発明の詳細な説明】
この発明は、電極と被加工物とのあいだに形成された所
定寸法の加工間隙に、たとえば、直流Ｒｅ放電回路を用
いてパルス性アーク放電ヲ繰り返し発生させることによ
って生ずる導体抵抗による発熱、電子衝撃による発熱、
あるいは、蒸気発生による圧力などによシ被加工物を溶
融させて所定の加工を行なう放電加工制御装置に関する
ものである。DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for generating a pulsed arc discharge by repeatedly generating a pulsed arc discharge in a machining gap of a predetermined size formed between an electrode and a workpiece using, for example, a DC Re discharge circuit. Heat generation due to conductor resistance, heat generation due to electronic impact,
Alternatively, the present invention relates to an electric discharge machining control device that melts a workpiece using pressure generated by steam generation and performs a predetermined machining process.
一般にこの種の放電加工においては、電極と被加工物と
の加工間隙の状態がきわめて変化し易いため、平均加工
電流を常に一定にして加工すると、加工間隙の状態が著
しく悪化して異常放電状態が発生し、電極および被加工
物に思わぬ損傷を受けることが多い。したがって、従来
はこれに対処するため作業者が加工間隙の状態に応じ、
平均加工電流を手動的に調整するようにしているが、こ
の平均加工電流を適切に手ａ調整することはきわめて困
難で相当の熟練を要する欠点がある。In general, in this type of electrical discharge machining, the condition of the machining gap between the electrode and the workpiece changes very easily, so if the average machining current is always kept constant, the condition of the machining gap will deteriorate significantly and an abnormal discharge will occur. This often results in unexpected damage to the electrode and workpiece. Therefore, in the past, in order to deal with this, the operator had to
Although the average machining current is manually adjusted, it is extremely difficult to manually adjust the average machining current appropriately and has the drawback that it requires considerable skill.
すなわち、第１図は従来のこの種放電加工節１師装置を
示す回路口で、複数のスイッチングトランジスタ（１ａ
）（Ｉｂ）（１ｃ）−（１ｎ）のそれぞれのベースに、
制御装＠（２）から所定のベース電流７流し、この各ス
イッチングトランジスタを導通させることによシ、所定
の直流電源（３）から上記各スイッチングトランジスタ
（１ａ）（１ｂ）（１ｃ）甲（１ｎ）、およびこの各ス
イッチングトランジスタのコレクタ抵抗（４ａ）（４ｂ
）（４Ｃ）・・・（４ｎ）を経て、電極（５１と、被加
工物（６）との間に放電電流を流し、放電加工ケ行なｌ
）工うになされたものである。That is, FIG. 1 shows a circuit port showing a conventional electrical discharge machining device of this kind, and a plurality of switching transistors (1a
)(Ib)(1c)-(1n),
By flowing a predetermined base current 7 from the control device @ (2) and making each switching transistor conductive, each of the switching transistors (1a) (1b) (1c) A (1n) is connected to the predetermined DC power supply (3). ), and the collector resistances (4a) (4b
)(4C)...(4n), a discharge current is passed between the electrode (51) and the workpiece (6) to perform discharge machining.
).
次に、第２図（ａｌ （ｂｌおよび第６図（ＦＬＩ （
ｂｌは上記従来の放電加工制量装置による放電加工時の
被加工物と電極間の電圧波形と電流波形とを示す特性図
で、（７）はパルス幅、（８）は休止時間、（９）は無
負荷電圧印加時間、（１Ｄ）は放電持続時間、（１１）
は無負荷′α圧、（１２）は放電電圧、（１３）は放電
電流、（１４）は放電電・外、
泥波高値、（１５）は半）均加工電流ンそれぞれ示し、
放電加工が安定して行なわれているとぎは笛２図（ａｌ
に示すように無負荷電圧（１１）は、きわめて高い確率
で現われ、その平均的な無負荷電圧印加時間（９１は、
結果的に成る値に制御されていることになる。何故なれ
ば、加工間隙の平均加工電圧が一定になるように、サー
ボ機構（図示せず）によって制御されているからである
。この制（２）が安定して行なわれるのは、加工間隙の
状態が比較的良好な場合であって、たとえば、加工粉が
加工間隙内に堆積し几シして加工間隙の状態が悪化する
（、と、第３図ｔａ＋に示すように、無負荷電圧印加時
間〔第２図（ａｌにおいては（９Ｊ〕が短かくなるか、
あるいは殆んど消失してしまって放電が一点に集中し、
比較的太ぎなくばみを作る危険性があシ、この場合の電
流波形は第３図（ｂｌに示すようになり、放電加工が安
定して行なわれている場合の第２図（ｂＪと比較して、
必然的に平均加工電流（１５）が増加することはいうま
でもない。Next, Figure 2 (al (bl) and Figure 6 (FLI (
bl is a characteristic diagram showing the voltage waveform and current waveform between the workpiece and the electrode during electrical discharge machining using the conventional electrical discharge machining control device, (7) is the pulse width, (8) is the rest time, (9) ) is no-load voltage application time, (1D) is discharge duration, (11)
is the no-load 'α pressure, (12) is the discharge voltage, (13) is the discharge current, (14) is the discharge voltage, mud wave height, and (15) is the semi-uniform machining current, respectively.
Figure 2 (al.
As shown in , the no-load voltage (11) appears with extremely high probability, and the average no-load voltage application time (91) is
It is controlled by the resulting value. This is because it is controlled by a servo mechanism (not shown) so that the average machining voltage of the machining gap is constant. This control (2) is performed stably when the condition of the machining gap is relatively good. (, and as shown in Figure 3 ta+, the no-load voltage application time [Figure 2 ((9J) in al) becomes shorter,
Or, most of it disappears and the discharge concentrates in one point,
There is a risk of creating a relatively thick neck, and the current waveform in this case is as shown in Figure 3 (bl), and Figure 2 (bJ and Compared to,
It goes without saying that the average machining current (15) inevitably increases.
かかる状態が成る時間持続すると、消イオンが形成され
ないので、−崎罰亀が一点に集中し易くなシ、加工間隙
の状態は一層悪化して益々第３図（ａｌに示すような状
態に移行することになる。このような悪化した加工間隙
の状態を回復させるためには′平均加工電流を減少させ
る必要があるが、この平均加工電流を減少させる手段と
しては、たとえば、加工間隙の状態を平均的に検出し、
その検出結果に基づいて発振周波数に変化させる方法が
考えられるが、かかる手段においては時時刻刻変化する
加工間隙の状態に及ぼす効果がぎわめて小さい欠点があ
る。If such a state continues for a period of time, deionization is not formed, so that the -sakipengikame is not easily concentrated in one point, and the condition of the machining gap becomes even worse and gradually shifts to the state shown in Fig. 3 (al). In order to recover from such a deteriorated machining gap condition, it is necessary to reduce the average machining current, but as a means of reducing this average machining current, for example, Detected on average,
One possible method is to change the oscillation frequency based on the detection result, but such a method has the disadvantage that the effect on the state of the machining gap, which changes over time, is extremely small.
また、これ以外の手段としては、無負荷゛庖圧印加時間
（９）が短くなったときに、放電持続時間（１０）を短
くして平均加工電流（１５）’ｆ減少さぜる方法もある
が、この場合には、敏速な応答性に富む効果はあるが、
このように放電持続時間（１０）を短くすると電極（５
３の消耗がはげしくなる欠点がある。Another method is to reduce the average machining current (15)'f by shortening the discharge duration (10) when the no-load pressure application time (9) becomes shorter. However, in this case, although it has the effect of being quick and responsive,
When the discharge duration (10) is shortened in this way, the electrode (5
The disadvantage is that 3 is rapidly consumed.
この発明は、かかる点に着目してなされたもので、電極
と被加工物との加工ｒｌ−１ｌ隙の状態が悪化して無負
荷電圧印加時間が殆んど消失してしまうような場合には
、各パル斃こおける無負荷電圧印加時間の長さにしたが
って、個々のパルスについて。This invention has been made with attention to this point, and is effective in cases where the condition of the machining gap rl-1l between the electrode and the workpiece deteriorates and the no-load voltage application time almost disappears. is for each individual pulse according to the length of the no-load voltage application time during each pulse.
電流波形のパルス幅と、電流波高値とを一定電極消耗率
となるように制御することによって平均加工電流を制御
するようにしたもので、敏速な応答性に優れ、加工間隙
の状態が悪化しても、すぐに正常状態にり帰して再び安
定した放電加工を行なうことができる放電加工制御装＠
、？提供しようとするものである。The average machining current is controlled by controlling the pulse width of the current waveform and the current peak value to maintain a constant electrode wear rate.It has excellent quick response and does not deteriorate the machining gap condition. Electrical discharge machining control system that can quickly return to normal state and perform stable electrical discharge machining again.
,? This is what we are trying to provide.
すなわち、第４図はこの発明の一実施ｆ１１ Ｙ示すも
のであるが、上述した従来のもの（簗１図）と同一符号
は同一構成部材につきその説明を省略する。That is, although FIG. 4 shows one embodiment f11Y of the present invention, the same reference numerals as in the above-mentioned conventional system (Fig. 1) refer to the same constituent members, and the explanation thereof will be omitted.
（２２）は上記電極（５）と、被加工物１６＋とに並列
接続された極間状態検出装置、（２３）ｌまこの極間状
態検出装置（２２）と、上記制御装置＋２１との間に挿
入された波形制御装置で、上記極間状態検出装置（２２
）によって無負荷電圧印加時間を検出すると、この無負
荷電圧印加時間の長さに応じて、上記波形制御装置（２
６）は、一定の電極消耗率であるところの最適な電流波
形を選択し、その波高値は上記スイツチングトランジス
タ（１ａＨ１ｂ）（１ｃ）・・・（１ｎ）の選択信号を
、またはパルス幅の信号をそれぞれ制御装置（２１に入
力する。次に、この制御装置（２）からの出力信号は、
上記スイッチングトランジスタ（１ａＨ１ｂ）（１ｃ）
・・・（１ｎ）のベースに流れ込み、この各スイッチン
グトランジスタをそれぞれ導通させるため、直流電源（
６）から上記各スイッチングトランジスタ（１ａ）（１
ｂ）（１ｃ）・（ｉｎ） 、およびコレクタ抵抗（４ａ
）（４ｔ））（４ｃ）・・・（４ｎ）を経て所定形状の
パルス電流を電極向と被加工物（６１との間の極間に流
すことによって放電加工を行なうものである。(22) is a gap condition detection device connected in parallel to the electrode (5) and the workpiece 16+; (23) is a gap between the gap condition detection device (22) and the control device +21; A waveform control device inserted in the electrode gap state detection device (22
) detects the no-load voltage application time, the waveform control device (2) detects the no-load voltage application time according to the length of the no-load voltage application time.
6) selects the optimal current waveform with a constant electrode consumption rate, and its peak value is determined by the selection signal of the switching transistors (1aH1b) (1c)...(1n) or the pulse width. Each signal is input to the control device (21). Next, the output signal from this control device (2) is as follows.
The above switching transistor (1aH1b) (1c)
...(1n), and in order to make each switching transistor conductive, the DC power supply (
6) to each of the above switching transistors (1a) (1
b) (1c)・(in), and collector resistance (4a
)(4t))(4c)...(4n), electric discharge machining is performed by passing a pulse current of a predetermined shape between the poles between the electrode and the workpiece (61).
なお、第５図ｔａｌ （ｂｌは上記一実施例の放電加工
制御装置による放電加工時の被加工物と電極間の電圧波
形と電流波形とを示す特性図で、第５図（＆）において
、（１６）（１７）（１Ｂ）の極間電圧波形のうち、（
１６）は安定して放電加工している状態の極間電圧波形
、また、第５図（ｂ）において、 （１９）（２０）
（２１）の極間電流波形のうち、（１９）は安定して放
電加工している状態の極間電流波形を示すもので、上記
＄５図（ａｌにおける極間電圧’閏島（１７）は、極間
電圧波形（１６）と比較して無負荷電圧印加時間（１１
）が若干短かく、極間が若干不安定な電圧波形ケ示し、
また、極間′ｒ！Ｌ！Ｅ波形（１８）は上述した無負荷
電圧印加電圧（１１）がなく、極間状態が著しく不安定
な場合の電圧波形をそれぞれ示している。そして、上述
した極間電圧波形（１６）のように極間状態が安定して
いる場合は、第５図（ｂｌに示す極間電流波形（１９）
のように設定された矩形状パルス電流で加工を行ない、
また上記無負荷電圧印加時間（１１）が成る値以下にな
ると、この無負荷電圧印加時間（１１）に応じてパルス
電流を、第５図（ｂＪに示す極間電流波形（２０）（２
１）のように変化させるようになされており、以上述べ
たように、極間状態が不安定になると、平均加工電流を
減少させることによって、極間状態を迅速に安定させる
ことができるものである。In addition, FIG. 5 tal (bl is a characteristic diagram showing the voltage waveform and current waveform between the workpiece and the electrode during electrical discharge machining by the electrical discharge machining control device of the above-mentioned embodiment, and in FIG. 5 (&), (16) (17) (1B) Among the electrode voltage waveforms, (
16) is the gap voltage waveform during stable electrical discharge machining, and in Figure 5 (b), (19) (20)
Among the machining current waveforms in (21), (19) shows the machining current waveform during stable electrical discharge machining. is the no-load voltage application time (11) compared with the electrode-to-electrode voltage waveform (16).
) is slightly short and the voltage waveform is slightly unstable between poles.
Also, Gokuma'r! L! The E waveform (18) shows a voltage waveform when the above-mentioned no-load voltage is not applied (11) and the inter-electrode state is extremely unstable. When the inter-electrode condition is stable as shown in the inter-electrode voltage waveform (16) mentioned above, the inter-electrode current waveform (19) shown in FIG.
Machining is performed using a rectangular pulse current set as follows.
Further, when the no-load voltage application time (11) becomes less than the value, the pulse current is changed according to the no-load voltage application time (11) to the inter-electrode current waveform (20) (2) shown in Figure 5 (bJ).
1), and as mentioned above, when the machining gap condition becomes unstable, the machining gap condition can be quickly stabilized by reducing the average machining current. be.
以上述べたように、この発明によれば極間の電流波形形
状を、無負荷電圧印加時間の長さに応じて一定電極消耗
率となるように制御するようにしたので、電極消耗の増
加を防止することかできるばかりでなく、放１〉工の安
定化が計り得られ、しかも時時刻刻と変化する加工間隙
に応じて最適な加工速度が得られる優れた効果を有する
ものである。As described above, according to the present invention, the current waveform shape between the electrodes is controlled so that the electrode wear rate is constant according to the length of the no-load voltage application time, so that increase in electrode wear can be prevented. Not only can this be prevented, but it also has the excellent effect of stabilizing the free machining process and obtaining the optimum machining speed depending on the machining gap that changes with time.
なお、上述した一実施例においては、加工間隙の状態を
判別する手段として、無負荷電圧印加時間を検出するよ
うにした場合について述べたが、電極と被加工物間の振
動、あるいは電極と被加工物との対向距離を検出するよ
うにしても同様の効果が得られることはいうまでもない
。In the above embodiment, a case was described in which the no-load voltage application time was detected as a means for determining the state of the machining gap, but vibration between the electrode and the workpiece, or between the electrode and the workpiece. It goes without saying that similar effects can be obtained by detecting the facing distance to the workpiece.
第１図は従来のこの種放電加工制量装置を示す回路図、
第２図および第６図は従来の放電加工制御装置による放
電加工時の被加工物と′４電極の電圧波形と電流波形を
示す特性図、！４図はこの発明の一実施例を示す回路図
、第５図はこの発明の放電加工制御装置による放電加工
時の電圧波形と電流波形を示す特性図である。
図面中−（１ふ）（Ｉｂ）（Ｉｃ）・・・（１ｎ）はス
イッチングトランジスタ、＜２１は制御装置、（６）は
直流電源、（４ａ）（４ｂ）（４ｃ）＝（４ｎ） １耘
コレクタ抵抗、（５）は電極、（６）は被加工物、（２
２）は極間状態検出装置−（２３）は波形制御装置であ
る。なお、図中同一符号４１同一または相当部分を示す
。
代理人大岩増雄
第１図
第２図
第３図
第４図Figure 1 is a circuit diagram showing a conventional electric discharge machining control device of this type.
Figures 2 and 6 are characteristic diagrams showing the voltage and current waveforms of the workpiece and the '4 electrode during electrical discharge machining using a conventional electrical discharge machining control device. FIG. 4 is a circuit diagram showing an embodiment of the present invention, and FIG. 5 is a characteristic diagram showing voltage waveforms and current waveforms during electrical discharge machining by the electrical discharge machining control device of the present invention. In the drawings - (1F) (Ib) (Ic)... (1n) is a switching transistor, <21 is a control device, (6) is a DC power supply, (4a) (4b) (4c) = (4n) 1还Collector resistance, (5) electrode, (6) workpiece, (2
2) is a gap state detection device; and (23) is a waveform control device. Note that the same reference numeral 41 in the drawings indicates the same or equivalent parts. Agent Masuo Oiwa Figure 1 Figure 2 Figure 3 Figure 4
Claims (4)
流を流すことによって放電加工を行なうようにしたもの
において、上記加工間隙の状態を判別する極間状態検出
装置と、該極間状態検出装置の検出出力に基づいて加工
間隙の状態に応じ常に一定１！極消耗率となるように電
流波形を制御する波形制御装置とｔ備えたことを特徴と
する放電加工制御装置。(1) In an apparatus in which electrical discharge machining is performed by intermittently passing a pulse current through a machining gap between an electrode and a workpiece, a machining gap state detection device for determining the state of the machining gap; Always constant 1 depending on the state of the machining gap based on the detection output of the state detection device! An electrical discharge machining control device comprising: a waveform control device that controls a current waveform to achieve an extreme wear rate.
負荷電圧印加時間を検出するものを備えたことを特徴と
する特許請求の範囲第１項記載の放電加工制御装置。(2) The electrical discharge machining control device according to claim 1, further comprising a gap state detection device that detects the no-load voltage application time between the electrode and the workpiece.
動を検出するものを備えたことを特徴とする特許１Ｎ求
の範囲第１項記載の放電加工制御装置。(3) The electrical discharge machining control device according to item 1 of the scope of Patent No. 1N, characterized in that the gap state detection device includes a device that detects vibration between the electrode and the workpiece.
向圧′Ｍ１ｗ検出するものを備えたことを特徴とする特
許請求の範囲第１項記載の放電加工制御装置。(4) The electric discharge machining control device according to claim 1, further comprising a machining gap state detecting device that detects the opposing pressure 'M1w between the electrode and the workpiece.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10308683A JPS59227323A (en) | 1983-06-09 | 1983-06-09 | Electric discharge machining controller |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10308683A JPS59227323A (en) | 1983-06-09 | 1983-06-09 | Electric discharge machining controller |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS59227323A true JPS59227323A (en) | 1984-12-20 |
Family
ID=14344819
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10308683A Pending JPS59227323A (en) | 1983-06-09 | 1983-06-09 | Electric discharge machining controller |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59227323A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0899222A (en) * | 1994-09-15 | 1996-04-16 | Ind Elektronik Agie Losone Locarno:Ag | Method and pulse generator for electric erosion of workpiece |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55157431A (en) * | 1979-05-21 | 1980-12-08 | Hitachi Seiko Ltd | Device for automatically setting discharge pulse energy |
| JPS5712648A (en) * | 1980-06-27 | 1982-01-22 | Nitto Electric Ind Co | Bubble-less vacuum pasting mechanism |
| JPS5754257A (en) * | 1980-09-18 | 1982-03-31 | Shigekado Sakakibara | Heat treatment of aluminum alloy cast |
-
1983
- 1983-06-09 JP JP10308683A patent/JPS59227323A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55157431A (en) * | 1979-05-21 | 1980-12-08 | Hitachi Seiko Ltd | Device for automatically setting discharge pulse energy |
| JPS5712648A (en) * | 1980-06-27 | 1982-01-22 | Nitto Electric Ind Co | Bubble-less vacuum pasting mechanism |
| JPS5754257A (en) * | 1980-09-18 | 1982-03-31 | Shigekado Sakakibara | Heat treatment of aluminum alloy cast |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0899222A (en) * | 1994-09-15 | 1996-04-16 | Ind Elektronik Agie Losone Locarno:Ag | Method and pulse generator for electric erosion of workpiece |
| US5874703A (en) * | 1994-09-15 | 1999-02-23 | Agie Sa | Method and apparatus for impulse generator for electroerosive machining of workpieces |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4553018A (en) | Short circuiting transfer arc welding machine | |
| US3999028A (en) | Method and apparatus for electrical discharge machining | |
| JP3347277B2 (en) | EDM power supply for EDM | |
| US4695696A (en) | Electric discharge machine with control of the machining pulse's current value in accordance with the delay time | |
| JPS614620A (en) | Electric discharge machining power supply device | |
| JP2024099058A (en) | Arc welding method and arc welding device | |
| KR890700059A (en) | Electric discharge processing method and device | |
| JPS58206312A (en) | Wire cut discharge machining power supply | |
| JPS59227323A (en) | Electric discharge machining controller | |
| JP2000288836A (en) | Power supply device for electric discharge machine | |
| JP3323457B2 (en) | Electric discharge machining method and power supply device for electric discharge machining | |
| JP3574503B2 (en) | Electric discharge machining method and apparatus | |
| JPS6052891B2 (en) | Power supply device for wire cut electrical discharge machining | |
| JP2801280B2 (en) | Wire cut EDM power supply | |
| KR880001517B1 (en) | Dc arc welding apparatus | |
| JPH0230810B2 (en) | ||
| JPS63318210A (en) | Control device for electric discharge machine | |
| JPS63130276A (en) | Tig welding method | |
| JPS6059098B2 (en) | Power supply device for electrical discharge machining | |
| JPS5820732B2 (en) | Houden Kakoseigiyohouhou | |
| JPS61146419A (en) | Electric discharge machine | |
| JPH11333632A (en) | Electrical discharging device | |
| EP0696488B1 (en) | A power supply apparatus for electrical discharge machining and an electrical discharge interval control method using the power supply apparatus | |
| JPH07112325A (en) | Power unit for electric discharge machine | |
| JPH05329710A (en) | Electric discharge machining device |