JPS61219521A - Electric discharge machine - Google Patents

Electric discharge machine

Info

Publication number
JPS61219521A
JPS61219521A JP6013085A JP6013085A JPS61219521A JP S61219521 A JPS61219521 A JP S61219521A JP 6013085 A JP6013085 A JP 6013085A JP 6013085 A JP6013085 A JP 6013085A JP S61219521 A JPS61219521 A JP S61219521A
Authority
JP
Japan
Prior art keywords
discharge
current
resistor
electrodes
current detection
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
Application number
JP6013085A
Other languages
Japanese (ja)
Inventor
Takao Okabe
岡部 孝男
Akihiro Komori
小森 昭弘
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Brother Industries Ltd
Original Assignee
Brother Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Brother Industries Ltd filed Critical Brother Industries Ltd
Priority to JP6013085A priority Critical patent/JPS61219521A/en
Publication of JPS61219521A publication Critical patent/JPS61219521A/en
Pending legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23HWORKING 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
    • B23H1/00Electrical 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
    • B23H1/02Electric circuits specially adapted therefor, e.g. power supply, control, preventing short circuits or other abnormal discharges

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)

Abstract

PURPOSE:To securely detect the start of discharge in a machining gap by providing a DC power source, a charging capacitor, a switching element for applying voltage between electrodes, and a current detecting resistor, in the driving circuit of an electric discharge machine, and also providing a current detecting circuit. CONSTITUTION:One end of a DC power source 1 in a discharge driving circuit is connected to a workpiece 2 and also to the negative electrode of a charging capacitor 3, in an electric discharge machine. A wire electrode 4 which is opposite to a workpiece 2 across a machining gap G, is connected to the other end of the power source 1 via a field-effect transistor 5 as a switching element, a diode 6, a current detecting resistor 7, and a diode 8, while a current detecting circuit 9, which leads out the current of the resistor 7 as a discharge detecting signal is also provided. The voltage drop with respect to change in a current at the time of varying the specific resistance of water is slight, since the voltage drop which is proportionate to a current flowing in this resistor 7 is generated in the resistor 7. And, a charging current can be distinguished from a discharge current to securely detect the start of a discharge.

Description

【発明の詳細な説明】 「産業上の利用分野] 本発明は、被加工物電極と放電電極との間に電圧を印加
したと外の放電現象を利用して被加工物を加工するよう
にした放電加工機に関し、特にはその放電の検出に関す
る。
[Detailed Description of the Invention] "Industrial Application Field" The present invention is directed to a method for machining a workpiece by utilizing a discharge phenomenon caused by applying a voltage between a workpiece electrode and a discharge electrode. The present invention relates to electrical discharge machining machines, and particularly to detection of electrical discharge.

「従来の技術」 従来のワイヤーカット放電加工機においては、被加工物
電極と放電電極との間に生ずる放電を検出するためには
第3図に示されるように1、充電コ 。
``Prior Art'' In a conventional wire-cut electrical discharge machine, in order to detect the discharge occurring between the workpiece electrode and the discharge electrode, a charging unit is required as shown in FIG.

ンデンサ3から電界効果トランジスタ5を介して :被
・御工吻、2およびフ゛イコ!゛極4に到る放電経路の
゛ □外周に電流変成器13を絶縁して配設し、両電極
の放電による電流の時間的変化(微分)と、電流変成器
13の−のイン?クタンスとの積□による電圧によって
放電が検出されていた。しかしながら、従来においでは
このように電流を微分しているた  、。
From the capacitor 3 through the field effect transistor 5: the input signal, 2, and the input voltage. □A current transformer 13 is insulated and disposed on the outer periphery of the discharge path leading to the pole 4, and the time change (differentiation) of the current due to the discharge of both electrodes and the -in? Discharge was detected by the voltage obtained by the product □ of tactance. However, in the past, the current was differentiated in this way.

め、例えば加工間隙Gに供給される水の比抵、抗 :(
電一度)を変えた時の僅かな、!、早いi4F変化でさ
・でも放電が発生したものとして検出するので、検出ミ
ス、が発生し易くなるから正確な値をとるこ、とができ
ないという問題があ・うた。
For example, the specific resistance of water supplied to the machining gap G: (
A slight amount when changing the electric power (once)! However, even if the i4F changes quickly, it is detected as if a discharge has occurred, so there is a problem that detection errors are likely to occur, making it impossible to take accurate values.

′・      □  、 [発明が解決しようとする間MAJ 本発明は、上記の問題を解決するためになされたもので
あり、加工間隙における放電開始を確実に検出すること
ができる放電加工機を提供することを目的とする。
′・ □ , [While the invention is intended to solve the problem MAJ The present invention has been made to solve the above problems, and provides an electrical discharge machine that can reliably detect the start of electrical discharge in the machining gap. The purpose is to

□゛ しかして、本発明によれば、放電電極と被加工、
物璽、極とめ両電極間に放電を発生させうる電圧を” 
 1jl−1−[1□、と。直流電源、ユよ、おわれ、
・充’ [コンデンサと、その充電コンデンサと前記両
電極間との放電経路に接続され、この放電経路を開閉し
て前記充電コン、デンサ、および直流電源より前、 記
、両電極間に電圧を印加するスイッチング素子と1、前
記直流電源からスイッチング素子を経て前記両電極間に
到る通電経路であって、かつ前記直流型、i源から充電
コンデンサに到る通電経路に界挿され、前記直流軍警か
ら両電極間に流れる電流を検出するための電流検出用抵
抗と、その電流検出用抵抗を備える放電加工機が提供さ
れる。
□゛ According to the present invention, the discharge electrode and the workpiece,
A voltage that can generate a discharge between the two electrodes of the seal and pole.
1jl-1-[1□, and. DC power supply, you, me.
・Charging [A capacitor is connected to a discharge path between the charging capacitor and the two electrodes, and opens and closes this discharge path to generate a voltage between the two electrodes before the charging capacitor, capacitor, and DC power supply. a switching element to apply voltage; The military and police provide a current detection resistor for detecting a current flowing between both electrodes, and an electric discharge machine equipped with the current detection resistor.

「作用」 上記fI11#、によれば、電流検出用抵抗には、この
対しては僅かな電圧降下しか発生しなく、な・す、・ま
た加工間隙に放電が発生した後p充電コンデンサへの充
電電流とも発生時点の差など眸、よって放電電流を区別
す・ることができるので、加工間隙における放電開始を
確実に検出することができる。
"Function" According to fI11# above, only a small voltage drop occurs in the current detection resistor, and after discharge occurs in the machining gap, there is no voltage drop in the p charging capacitor. Since the discharge current can be distinguished from the charging current by looking at the difference in the point of occurrence, it is possible to reliably detect the start of discharge in the machining gap.

「実施の態様」 本発明の実施の態様によれば、電流検出用抵抗は無誘導
抵抗よりなる。そして、、この態様によれば、加工間−
における放電の開始および終了、またはスイッチング素
子のオン、オフに基づく、電流変化によってもリアクタ
ンス電圧(ノイズパルス)が発生し難いため、放電電流
の検出が一層に容易になるという利点がある。
"Embodiment" According to an embodiment of the present invention, the current detection resistor is made of a non-inductive resistor. According to this aspect, during machining -
Since a reactance voltage (noise pulse) is less likely to be generated even by a current change based on the start and end of discharge or on/off of a switching element, there is an advantage that detection of the discharge current becomes easier.

「実施例」 次に、本発明を図面に示す一実施例について説明する。"Example" Next, an embodiment of the present invention shown in the drawings will be described.

   、・ 第1図はこの一実施例の電流検出構成による放電加工機
の放電駆動回路の回路図1.第2図(a)、(b)はそ
の電流検出用抵抗により検出される電流の波形、および
加工間隙間の電圧波形を示す特性図である。1゛’  
、、:    ・ 電源としての直流電源1の一端は、被加工物2多こ接続
されるとともに、同じく電源をなす充電コンデンサ3の
一極にも接続されている。また讐被加工物2と加工間隙
Gを介1.て対向し、相対的に移動可能なワイヤ電極4
は、スイッチング素子としての電界効果トランジスタ(
以下単にFETという)5、ノイズパルスを除、去する
ためのダイオード6゜無誘導抵抗よりなる電流検出用抵
抗7、およびノイズパルス(リアクタンス電圧)を除去
するためのダイオード8を介して直流電源1の他端に接
続されており、かつ前記ワイヤ電極4はFET5を介し
て充電コンデンサ3Q他極に接続されている。また、電
流検出用抵抗7の両端には、前記ダイオード8を介して
、周知構成による分圧用抵抗14゜15、発光ダイオー
ド16.その発光ダイオード16を補償するためのツェ
ナーダイオード17゜光ファイバ18.およびホトトラ
ンジスタ19によるアイソレータを包含した電流検出回
路9が接続されており、その電流検出回路9の出力は放
電制御回路10に導入されており、放電制御回路10の
出力信号路は、FET 5のデート端子に導入されてい
る。なお、被加工物2およびワイヤ電極4の両端と並列
に、ダイオード11と抵抗12との直列回路が接続され
ており、このダイオード11および抵抗12は、FET
 5のスイッチング動作によって生ずるリアクタンス電
圧を消去するものである。また、直流電源1は加工間隙
Gに放電を発生させうる電圧を有する。
,・ FIG. 1 is a circuit diagram of a discharge drive circuit of an electric discharge machine using the current detection configuration of this embodiment. FIGS. 2(a) and 2(b) are characteristic diagrams showing the waveform of the current detected by the current detection resistor and the voltage waveform of the machining gap. 1゛'
,,: - One end of a DC power source 1 serving as a power source is connected to the workpiece 2 and also to one pole of a charging capacitor 3, which also serves as a power source. Also, there is a machining gap G between the workpiece 2 and the workpiece 1. Wire electrodes 4 facing each other and movable relatively
is a field effect transistor (
(hereinafter simply referred to as FET) 5, a diode 6 for removing noise pulses, a current detection resistor 7 made of a non-inductive resistor, and a diode 8 for removing noise pulses (reactance voltage) to a DC power supply 1. The wire electrode 4 is connected to the other terminal of the charging capacitor 3Q via the FET 5. Furthermore, voltage dividing resistors 14, 15 and light emitting diodes 16, 16, 16, 16, 15, 14, 15, etc., each having a well-known configuration, are connected to both ends of the current detecting resistor 7 via the diode 8. Zener diode 17° optical fiber 18 for compensating the light emitting diode 16. A current detection circuit 9 including an isolator using a phototransistor 19 is connected to the current detection circuit 9, and the output of the current detection circuit 9 is introduced to a discharge control circuit 10. It has been introduced to the date terminal. Note that a series circuit of a diode 11 and a resistor 12 is connected in parallel with both ends of the workpiece 2 and the wire electrode 4, and this diode 11 and resistor 12 are connected to the FET.
This eliminates the reactance voltage generated by the switching operation of step 5. Further, the DC power supply 1 has a voltage capable of generating electric discharge in the machining gap G.

「作動」 上記構成においては、充電コンデンサ3は直流電源1に
よって、その直流電源1の電圧に充電されている。放電
加工の開始に際して、放電制御回路10から出力信号パ
ルスが発生されると、このパルスがFET 5のデート
端子に加えられることにより、FET 5はターンオン
し、被加工物2とワイヤ電極4の開にコンデンサ3の電
圧が印加される。
"Operation" In the above configuration, the charging capacitor 3 is charged by the DC power supply 1 to the voltage of the DC power supply 1. At the start of electrical discharge machining, when an output signal pulse is generated from the electrical discharge control circuit 10, this pulse is applied to the date terminal of the FET 5, thereby turning on the FET 5 and opening the workpiece 2 and the wire electrode 4. The voltage of capacitor 3 is applied to .

そして、若干の無負荷時間taの後に加工間隙Gに放電
が発生すると、FET 5を介して充電コンデンサ3か
ら加工間隙Gに放電電流が流れ、また同時に直流電流1
からもFET 5、ダイオード6.8 および電流検出
用抵抗7を介して加−に間隙Gに放電電流が流れる。周
知の過渡現象8!論によるごとく、抵抗が小さい導通状
態のFET 5のみを介して力L[間隙Gと接続される
コンデンサ3の放電電流は、極めて短時間の間に最大値
から零(三())に17.下り、直流電源1から加工間
隙Gに流れる放電電流は火花放電現象と合致した比較的
に緩やかな変化を辿り、第2図に示1ような放電電流;
5が若干の負荷時間to の開扉に間隙Gに流れる。放
電駆動回路1()の出力に号パルスが消滅し、FET 
5が夕・−ンオ7すると極のζ微小な時間、7)Itに
加−1−間隙(iにおける放電は消滅する。
When a discharge occurs in the machining gap G after a certain no-load time ta, a discharge current flows from the charging capacitor 3 to the machining gap G via the FET 5, and at the same time, a DC current 1
A discharge current also flows into the gap G through the FET 5, the diode 6.8, and the current detection resistor 7. Well-known transient phenomenon 8! As per the theory, the discharge current of the capacitor 3 connected to the force L [gap G] decreases from the maximum value to zero (17. The discharge current flowing downward from the DC power supply 1 to the machining gap G follows a relatively gradual change consistent with the spark discharge phenomenon, and the discharge current as shown in FIG.
5 flows into the gap G when the door opens for a certain load time to. The signal pulse disappears in the output of the discharge drive circuit 1 (), and the FET
When 5 is evening - 7, the pole's ζ minute time, 7) It is added to -1 - gap (i) and the discharge at i disappears.

そ17て、この放電の;17減の時点から、充電コンデ
ンサ3は直流電源1により、ダイオード6.8および電
流検出用抵抗7を介して充電を開始され、この電流検出
用抵抗°7の抵抗値およびコンデンサ3の静電容量によ
って定まるタイムコンスタントをもった緩やかな電流変
化による充電電流ieが、第2図(、)に示すように電
流検出用抵抗7に流れる。
Then, from the point in time when this discharge decreases by 17, the charging capacitor 3 starts to be charged by the DC power supply 1 via the diode 6.8 and the current detection resistor 7, and the current detection resistor 7 starts to charge. A charging current ie due to a gradual current change with a time constant determined by the value and the capacitance of the capacitor 3 flows through the current detection resistor 7 as shown in FIG.

電流検出用抵抗7の両端に発生する電圧降下は、第2図
(a)に示された放電電流isおよび充電電流ieに比
例した波形を持つ。電流検出用抵抗7の両端に発生した
電圧降下は抵抗14.15  によって適切な値−二分
圧されて発光ダイオード16に加えられるため、発光ダ
イオード16は発光し、光ファイバ18を介してホトト
ランジスタ19に受光され、検出信号SGが発生される
。この検出信号SGは、放電電流isおよび充電電流i
cに対応するものであるが、放電電流isに対応した検
出信号SGが適宜のワンショットマルチバイブレーク−
(図示せず)に入力され、所定時間幅の信号に変換され
るため、放電電流isと放電電流icとの間の立下りに
よる影=8− 響けない。
The voltage drop generated across the current detection resistor 7 has a waveform proportional to the discharging current is and the charging current ie shown in FIG. 2(a). The voltage drop generated across the current detection resistor 7 is divided by an appropriate value by a resistor 14.15 and applied to the light emitting diode 16, so that the light emitting diode 16 emits light and is connected to the phototransistor 19 via the optical fiber 18. The light is received and a detection signal SG is generated. This detection signal SG is a discharge current is and a charge current i
c, the detection signal SG corresponding to the discharge current is is an appropriate one-shot multi-by-break.
(not shown) and is converted into a signal with a predetermined time width. Therefore, the influence of the fall between the discharge current is and the discharge current ic = 8- is not affected.

ここで、電流検出用抵抗7は、直流電源1からFET 
5を経て加工間隙Gに到る通電経路であって、かつ直流
電源1から充電コンデンサ3に到る通電経路に介挿され
ているため、充電コンデンサ3の放電電流はダイオード
6.8 によっても阻止されて電流検出用抵抗7には流
れないので、この電流検出用抵抗7によって電源1の放
電電流isに対応した検出(i号SGを確実に検出する
ことができる(実施例の利点) 上記実施例によれば、放電駆動回路におけるインダクタ
ンスが非常に少ないから、充電コンデンサ3の充放電、
および加]二間隙Gにおける放電が極めて円滑に行なわ
れるという利点がある。
Here, the current detection resistor 7 is connected to the FET from the DC power supply 1.
5 to the machining gap G, and is inserted in the current-carrying path from the DC power supply 1 to the charging capacitor 3, so the discharge current of the charging capacitor 3 is also blocked by the diode 6.8. Therefore, the current detecting resistor 7 detects the discharge current is of the power source 1 (the i SG can be reliably detected (advantages of the embodiment)). According to the example, since the inductance in the discharge drive circuit is very small, charging and discharging the charging capacitor 3,
There is an advantage that the discharge in the two gaps G is carried out extremely smoothly.

「効果」 以上述べたように、本発明の放電加工磯は上記の構成を
有するから、電流検出用抵抗によって加工間隙における
放電開始を確実に検出することかでと、検出ミスを発生
し歎くなるという優れた効来がある。
"Effects" As described above, since the electrical discharge machining plate of the present invention has the above configuration, detection errors may occur due to the fact that the start of electrical discharge in the machining gap is reliably detected by the current detection resistor. It has an excellent effect.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は本発明の一実施例の電流検出構成による放電加
工機の放電駆動回路の回路図、第2図(a)*(b)は
その電流検出用抵抗により検出される電流の波形、およ
び加工間隙間の電圧波形を示す特性図、第3図は従来の
電流検出構成による放電駆動回路を示す回路図である。 1・・・直流電源、2・・・被加工物、3・・・充電コ
ンデンサ、4・・・ワイヤ電極、5・・・電界効果トラ
ンジスタ、 7・・・電流検出用抵抗、9・・・電流検
出回路、10・・・放電制御回路、13・・・電流変成
器。
Fig. 1 is a circuit diagram of a discharge drive circuit of an electric discharge machine using a current detection configuration according to an embodiment of the present invention, and Fig. 2 (a) * (b) shows the waveform of the current detected by the current detection resistor. FIG. 3 is a circuit diagram showing a discharge drive circuit using a conventional current detection configuration. DESCRIPTION OF SYMBOLS 1... DC power supply, 2... Workpiece, 3... Charging capacitor, 4... Wire electrode, 5... Field effect transistor, 7... Current detection resistor, 9... Current detection circuit, 10...Discharge control circuit, 13...Current transformer.

Claims (1)

【特許請求の範囲】 1、放電電極と被加工物電極とを相対的に移動させると
ともに、それらの電極間に電圧を印加してそれらの加工
間隙に放電を発生させ、その放電エネルギーにより被加
工物を加工する放電加工機において、 前記両電極間に放電を発生させうる電圧を有する直流電
源と、 その直流電源と並列な通電経路に接続され、この直流電
源により充電される充電コンデンサと、その充電コンデ
ンサと前記両電極間との放電経路に接続され、この放電
経路を開閉して前記充電コンデンサおよび直流電源より
前記両電極間に電圧を印加するスイッチング素子と、 前記直流電源からスイッチング素子を経て前記両電極間
に到る通電経路であって、かつ前記直流電源から充電コ
ンデンサに到る通電経路に介挿され、前記直流電源から
両電極間に流れる電流を検出するための電流検出用抵抗
と、 その電流検出用抵抗に並列に接続され、この電流検出用
抵抗に流れる電流を放電検出信号として導出する電流検
出回路とを備える放電加工機。 2、前記電流検出用抵抗は無誘導抵抗であることを特徴
とする特許請求の範囲第1項に記載の放電加工機。
[Claims] 1. While moving the discharge electrode and the workpiece electrode relatively, a voltage is applied between these electrodes to generate a discharge in the machining gap between them, and the workpiece is machined by the discharge energy. An electric discharge machine for machining objects includes: a DC power supply having a voltage capable of generating a discharge between the two electrodes; a charging capacitor connected to a current carrying path parallel to the DC power supply and charged by the DC power supply; a switching element connected to a discharge path between the charging capacitor and the two electrodes, opening and closing the discharge path to apply a voltage between the charging capacitor and the DC power source between the electrodes; a current detection resistor that is inserted in a current-carrying path leading between the two electrodes and from the DC power source to the charging capacitor, and for detecting a current flowing from the DC power source between the two electrodes; , a current detection circuit that is connected in parallel to the current detection resistor and derives the current flowing through the current detection resistor as a discharge detection signal. 2. The electrical discharge machine according to claim 1, wherein the current detection resistor is a non-inductive resistor.
JP6013085A 1985-03-25 1985-03-25 Electric discharge machine Pending JPS61219521A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6013085A JPS61219521A (en) 1985-03-25 1985-03-25 Electric discharge machine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6013085A JPS61219521A (en) 1985-03-25 1985-03-25 Electric discharge machine

Publications (1)

Publication Number Publication Date
JPS61219521A true JPS61219521A (en) 1986-09-29

Family

ID=13133241

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6013085A Pending JPS61219521A (en) 1985-03-25 1985-03-25 Electric discharge machine

Country Status (1)

Country Link
JP (1) JPS61219521A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE112010005586T5 (en) 2010-05-21 2013-03-28 Mitsubishi Electric Corp. The wire erosion

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE112010005586T5 (en) 2010-05-21 2013-03-28 Mitsubishi Electric Corp. The wire erosion

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