JP2707019B2 - Electric discharge machine - Google Patents
Electric discharge machineInfo
- Publication number
- JP2707019B2 JP2707019B2 JP4133860A JP13386092A JP2707019B2 JP 2707019 B2 JP2707019 B2 JP 2707019B2 JP 4133860 A JP4133860 A JP 4133860A JP 13386092 A JP13386092 A JP 13386092A JP 2707019 B2 JP2707019 B2 JP 2707019B2
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- negative
- pulse width
- negative voltage
- 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 - Fee Related
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- Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は放電加工装置に関し、特
に加工間隙に正電源と負電源を並列に接続し正電圧と負
電圧を交互に印加しながら放電加工中の加工間隙に発生
する加工電圧の全電圧平均値を零に近づける制御をして
加工する放電加工装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge machining apparatus, and more particularly, to a machining apparatus in which a positive power supply and a negative power supply are connected in parallel to a machining gap, and a positive voltage and a negative voltage are alternately applied to the machining gap during electric discharge machining. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge machining apparatus that performs machining by controlling the average value of all voltages to be close to zero.
【０００２】[0002]
【従来の技術】図３は従来の放電加工装置を示す構成図
である。図において１ａは正電源、１ｂは負電源、２は
正電源１ａの正極と負電源１ｂの負極に接続する電極、
３は電極２により加工される被加工物で、電極２ととも
に加工間隙を構成する。４ａは正電源１ａの出力をオン
（ＯＮ）／オフ（ＯＦＦ）制御するスイッチ、４ｂは負
電源１ｂの出力をＯＮ／ＯＦＦ制御するスイッチ、５ａ
および５ｂは加工間隙の電流ピーク値を制限する抵抗
器、６ａおよび６ｂは加工間隙の電流が逆流するのを防
止する逆流阻止ダイオード、７ａおよび７ｂはスイッチ
４ａおよび４ｂがＯＦＦした後に加工間隙の電流を減少
させるフライホイールダイオードで正電源加工回路と負
電源加工回路を構成する。８は加工間隙に接続するダミ
ー抵抗器、９は発振回路で加工パルス信号を出力する。
１０は加工電圧検出器で加工間隙の電圧を検出し増幅す
る。全電圧平均値検出回路１１は加工電圧検出器１０の
出力電圧の全平均値を検出する。全電圧平均値検出回路
１１の出力電圧に基づいて負電圧のパルス幅を変調する
負電圧パルス幅変調回路１２は負電源１ｂのスイッチ４
ｂをＯＮ／ＯＦＦ制御する。2. Description of the Related Art FIG. 3 is a configuration diagram showing a conventional electric discharge machine. In the figure, 1a is a positive power supply, 1b is a negative power supply, 2 is an electrode connected to the positive electrode of the positive power supply 1a and the negative electrode of the negative power supply 1b,
Reference numeral 3 denotes a workpiece to be processed by the electrode 2, which forms a processing gap together with the electrode 2. 4a is a switch for controlling the output of the positive power supply 1a to ON (ON) / OFF (OFF), 4b is a switch for controlling the output of the negative power supply 1b to ON / OFF, 5a
And 5b are resistors for limiting the current peak value in the machining gap, 6a and 6b are backflow blocking diodes for preventing current in the machining gap from flowing back, and 7a and 7b are currents in the machining gap after switches 4a and 4b are turned off. A positive power supply processing circuit and a negative power supply processing circuit are configured with a flywheel diode that reduces the power consumption. 8 is a dummy resistor connected to the processing gap, and 9 is an oscillation circuit that outputs a processing pulse signal.
A machining voltage detector 10 detects and amplifies the voltage of the machining gap. The total voltage average value detection circuit 11 detects the total average value of the output voltage of the machining voltage detector 10. The negative voltage pulse width modulation circuit 12 that modulates the pulse width of the negative voltage based on the output voltage of the total voltage average value detection circuit 11 includes a switch 4 of the negative power supply 1b.
b is ON / OFF controlled.
【０００３】次に、従来の放電加工装置の動作につい
て、図３および図４を用いて説明する。上記加工回路の
加工間隙で発生する加工電圧を加工電圧検出器１０で検
出し増幅する。加工電圧検出器１０の出力電圧は全電圧
平均値検出回路１１においてその全平均値を検出して全
電圧平均値ＶGAを出力する。全電圧平均値ＶGAは負電圧
パルス幅変調回路１２においてパルス幅変調の信号とし
て用いられ、負電源１ｂのスイッチ４ｂをＯＮ／ＯＦＦ
制御するためパルス幅変調された負電圧パルス信号が作
られる。負電圧パルス信号のパルス幅ＴN は負電圧パル
ス幅変調回路１２の内部で作られる負電圧パルス幅変調
用基準三角波の定数Ｋにより全電圧平均値ＶGAを信号と
して式１により変換される。ＴR は休止時間である。 ＴN ＝Ｋ・ＶGA （ＴN ＜ＴR ） ………（式１） 図４は休止時間中に加工間隙に印加される負電源１ｂの
負電圧ＶN がパルス幅変調された加工電圧波形の例で、
図４（ａ）は図４（ｂ）より無負荷時間ＴL が長いので
負電圧パルス幅ＴN が長く変調されている。負電圧平均
値ＶNAは加工周期Ｔ0 と負電圧パルス幅ＴN および負電
圧ＶN により式２で、加工電圧の全平均値である全電圧
平均値ＶGAは正電圧平均値ＶPAと負電圧平均値ＶNAによ
り式３でそれぞれ表わされる。正電圧平均値ＶPAは式４
で表わされる波形平均である。ＶM は正電源１ａの正電
圧、ＶD は放電電圧、ＴP はパルス幅である。 ＶNA＝ＶN ・ＴN ／Ｔ0 ………（式２） ＶGA＝ＶPA−ＶNA ………（式３） ＶPA＝（ＶM ・ＴL ＋ＶD ・ＴP ）／Ｔ0 ………（式４） さらに、全電圧平均値ＶGAは式１と式２および式３によ
り式５で表わされる。 ＶGA＝ＶPA／（１＋Ｋ・ＶN ／Ｔ0 ） ………（式５） 以上のように、負電圧パルス幅変調用基準三角波の定数
Ｋまたは負電圧ＶN を充分大きな値に設定することによ
り全電圧平均値ＶGAが零に近づくように制御される。Next, the operation of the conventional electric discharge machine will be described with reference to FIGS. The machining voltage generated in the machining gap of the machining circuit is detected by the machining voltage detector 10 and amplified. The output voltage of the machining voltage detector 10 is detected by a total voltage average value detection circuit 11 to output a total voltage average value VGA . The total voltage average value VGA is used as a pulse width modulation signal in the negative voltage pulse width modulation circuit 12, and turns on / off the switch 4b of the negative power supply 1b.
A pulse width modulated negative voltage pulse signal is created for control. The pulse width T N of the negative voltage pulse signal is converted by the equation (1) using the total voltage average value VGA as a signal by the constant K of the reference triangular wave for negative voltage pulse width modulation generated inside the negative voltage pulse width modulation circuit 12. T R is the pause time. T N = K · V GA (T N <T R ) (Equation 1) FIG. 4 shows a machining voltage obtained by pulse width modulation of the negative voltage V N of the negative power supply 1b applied to the machining gap during the idle time. In the waveform example,
In FIG. 4A, since the no-load time T L is longer than that in FIG. 4B, the negative voltage pulse width T N is modulated to be longer. The negative voltage average value V NA is expressed by Expression 2 using the machining cycle T 0 , the negative voltage pulse width TN, and the negative voltage V N , and the total voltage average value V GA, which is the total average value of the machining voltage, is equal to the positive voltage average value V PA . The negative voltage average value V NA is represented by Expression 3. The average value of the positive voltage VPA is given by Equation 4.
Is the waveform average represented by V M is a positive voltage of the positive power source 1a, V D is the discharge voltage, T P is the pulse width. V NA = V N · T N / T 0 ......... ( Equation 2) V GA = V PA -V NA ......... ( Equation 3) V PA = (V M · T L + V D · T P) / T 0 (Equation 4) Further, the total voltage average value VGA is represented by Equation 5, Equation 2, Equation 3 and Equation 3. V GA = V PA / (1 + K · V N / T 0 ) (Equation 5) As described above, the constant K or the negative voltage V N of the negative voltage pulse width modulation reference triangular wave is set to a sufficiently large value. Thus, the control is performed so that the total voltage average value VGA approaches zero.
【０００４】[0004]
【発明が解決しようとする課題】従来の放電加工装置は
以上のように構成されているので、全電圧平均値ＶGAを
零に近づける制御を行なうためには負電圧ＶN または負
電圧パルス幅変調用基準三角波の定数Ｋを充分大きな値
にしなければならない。従って負電源１ｂの負電圧ＶN
が高電圧となり装置が大掛かりで高価となったり、負電
圧パルス幅変調回路１２の負電圧パルス幅変調用基準三
角波の定数Ｋが非常に大きくなって負電圧パルス幅ＴN
の短い領域で、パルス幅変調の動作不良が発生したり応
答が遅くなるなどして加工が不安定となるという問題が
あった。Since the conventional electric discharge machining apparatus is configured as described above, in order to control the average value VGA of the entire voltage to be close to zero, the negative voltage VN or the negative voltage pulse width is required. The constant K of the reference triangular wave for modulation must be set to a sufficiently large value. Therefore, the negative voltage V N of the negative power supply 1b
Becomes high voltage, the device becomes large and expensive, or the constant K of the reference triangular wave for negative voltage pulse width modulation of the negative voltage pulse width modulation circuit 12 becomes very large, so that the negative voltage pulse width T N
In the short region, there is a problem that the processing becomes unstable due to an operation failure of pulse width modulation or a slow response.
【０００５】本発明は、かかる問題点を解決するために
なされたもので、安価でかつ応答の速い加工が安定に行
なえる放電加工装置を提供することを目的とする。The present invention has been made to solve such a problem, and an object of the present invention is to provide an electric discharge machine which is inexpensive and can perform machining with high response speed stably.
【０００６】[0006]
【課題を解決するための手段】本発明に係る放電加工装
置は、電極と被加工物とを対向させて移動させるととも
に電極と被加工物とで形成される加工間隙に正電源と負
電源とを並列に接続し加工パルスを印加してパルス電流
を通電し被加工物を放電加工する放電加工装置におい
て、前記加工間隙の加工電圧を検出する加工電圧検出器
と、前記加工電圧の正電圧の平均値を検出する正電圧平
均値検出回路と、負電圧パルス幅変調用の基準三角波を
生成し、前記基準三角波の定数と前記正電圧平均値検出
回路で検出された正電圧平均値に基づいて、前記負電源
の負電圧印加時間をパルス幅変調する負電圧パルス幅変
調回路と、前記基準三角波の定数と前記負電源の負電圧
との積が加工パルス周期に等しくなるように制御する制
御手段とを備えたものである。An electric discharge machining apparatus according to the present invention moves an electrode and a workpiece so as to face each other and places a positive power supply and a negative power supply in a machining gap formed between the electrode and the workpiece. A machining voltage detector for detecting a machining voltage of the machining gap, a machining voltage detector for detecting a machining voltage of the machining gap, and a positive voltage of the machining voltage. A positive voltage average value detecting circuit for detecting an average value, and a reference triangular wave for negative voltage pulse width modulation are generated, based on the constant of the reference triangular wave and the positive voltage average value detected by the positive voltage average value detecting circuit. A negative voltage pulse width modulation circuit that performs pulse width modulation on a negative voltage application time of the negative power supply, and control means that controls a product of a constant of the reference triangular wave and a negative voltage of the negative power supply to be equal to a processing pulse period. And with It is.
【０００７】また、制御手段は、負電圧パルス幅変調回
路の基準三角波の定数を固定値とし負電源の負電圧を変
化させるものである。The control means changes the negative voltage of the negative power supply by setting the constant of the reference triangular wave of the negative voltage pulse width modulation circuit to a fixed value.
【０００８】さらに、制御手段は、負電源の負電圧を固
定値とし負電圧パルス幅変調回路の基準三角波の定数を
変化させるものである。Further, the control means changes the constant of the reference triangular wave of the negative voltage pulse width modulation circuit by setting the negative voltage of the negative power supply to a fixed value.
【０００９】[0009]
【作用】本発明においては、正電圧平均値検出回路が加
工電圧の正電圧の平均値を検出し、負電圧パルス幅変調
回路が、負電圧パルス幅変調用の基準三角波を生成し、
前記基準三角波の定数と前記正電圧平均値検出回路で検
出された正電圧平均値に基づいて、前記負電源の負電圧
印加時間をパルス幅変調する。そして、制御手段が負電
圧パルス幅変調回路の負電圧パルス幅変調用の基準三角
波の定数と負電源の負電圧との積が加工パルス周期に等
しくなるように制御し、加工間隙に発生する加工電圧の
全電圧平均値を零に近づけた加工を行なう。従って、負
電圧パルス幅変調用基準三角波の定数または負電圧を過
大な値に設定する必要が無い。In the present invention, the positive voltage average value detection circuit detects the average value of the positive voltage of the machining voltage, the negative voltage pulse width modulation circuit generates a reference triangular wave for negative voltage pulse width modulation,
The pulse width modulation of the negative voltage application time of the negative power supply is performed based on the constant of the reference triangular wave and the positive voltage average value detected by the positive voltage average value detection circuit. Then, the control means controls the product of the constant of the reference triangular wave for negative voltage pulse width modulation of the negative voltage pulse width modulation circuit and the negative voltage of the negative power supply to be equal to the processing pulse period, and the processing generated in the processing gap. Processing is performed so that the average value of all voltages is close to zero. Therefore, it is not necessary to set the constant of the reference triangular wave for negative voltage pulse width modulation or the negative voltage to an excessive value.
【００１０】また、制御手段は、負電圧パルス幅変調回
路の負電圧パルス幅変調用の基準三角波の定数を固定値
とし負電源の負電圧を変化させるから、加工パルス周期
が長くなれば負電圧が高くなり放電しやすくなる。結果
として周期を短くする方向に働く。In addition, the control means changes the negative voltage of the negative power supply by setting the constant of the reference triangular wave for negative voltage pulse width modulation of the negative voltage pulse width modulation circuit to a fixed value. And discharge becomes easy. As a result, it works in the direction of shortening the period.
【００１１】また、制御手段が、負電源の負電圧を固定
値とし負電圧パルス幅変調回路の負電圧パルス幅変調用
の基準三角波の定数を変化させるから、加工パルス周期
が長くなると負電圧パルス幅の変調ゲインが高くなり、
全電圧平均値を零に近づける応答が早くなる。Further, the control means changes the constant of the reference triangular wave for negative voltage pulse width modulation of the negative voltage pulse width modulation circuit using the negative voltage of the negative power supply as a fixed value. Width modulation gain is higher,
The response to make the average value of all voltages close to zero becomes faster.
【００１２】[0012]
実施例１．図１は本発明による放電加工装置の一実施例
を示す構成図である。図において１ａは正電源、１ｃは
負電源、２は正電源１ａの正極と負電源１ｃの負極に接
続する電極、３は電極２により加工される被加工物で電
極２とともに加工間隙を構成する。４ａは正電源１ａの
出力をＯＮ／ＯＦ制御するスイッチ、４ｂは負電源１ｃ
の出力をＯＮ／ＯＦＦ制御するスイッチ、５ａおよび５
ｂは加工間隙の電流ピーク値を制限する抵抗器、６ａお
よび６ｂは加工間隙の電流が逆流するのを防止する逆流
阻止ダイオード、７ａおよび７ｂはスイッチ４ａおよび
４ｂがＯＦＦした後に加工間隙の電流を減少させるフラ
イホイールダイオードで正電源加工回路と負電源加工回
路を構成する。８は加工間隙に接続するダミー抵抗器、
１３は発振回路で加工パルス信号と負電圧パルス幅変調
ゲイン信号及び負電圧信号を出力する。１０は加工電圧
検出器で加工間隙に発生する加工電圧を検出し増幅す
る。加工電圧検出器１０の出力電圧のうちの正電圧のみ
の平均値を検出する正電圧平均値検出回路１４の出力電
圧に基づいて負電圧のパルス幅を変調する負電圧パルス
幅変調回路１５は負電源１ｃのスイッチ４ｂをＯＮ／Ｏ
ＦＦ制御する。Embodiment 1 FIG. FIG. 1 is a block diagram showing one embodiment of the electric discharge machine according to the present invention. In the figure, 1a is a positive power supply, 1c is a negative power supply, 2 is an electrode connected to the positive electrode of the positive power supply 1a and the negative electrode of the negative power supply 1c, 3 is a workpiece processed by the electrode 2 and constitutes a processing gap together with the electrode 2. . 4a is a switch for ON / OF control of the output of the positive power supply 1a, 4b is a negative power supply 1c
Switches 5a and 5 for ON / OFF control of the output of
b is a resistor for limiting the current peak value of the machining gap, 6a and 6b are backflow prevention diodes for preventing the current of the machining gap from flowing backward, and 7a and 7b are currents of the machining gap after the switches 4a and 4b are turned off. The positive power supply processing circuit and the negative power supply processing circuit are configured by the flywheel diode to be reduced. 8 is a dummy resistor connected to the machining gap,
An oscillation circuit 13 outputs a processing pulse signal, a negative voltage pulse width modulation gain signal, and a negative voltage signal. A machining voltage detector 10 detects and amplifies a machining voltage generated in a machining gap. The negative voltage pulse width modulation circuit 15 that modulates the pulse width of the negative voltage based on the output voltage of the positive voltage average value detection circuit 14 that detects the average value of only the positive voltage among the output voltages of the machining voltage detector 10 is negative. Turn ON / O switch 4b of power supply 1c
FF control is performed.
【００１３】次に、動作について、図１および図２を用
いて説明する。上記加工回路の加工間隙で発生する加工
電圧を加工電圧検出器１０で検出し増幅する。加工電圧
検出器１０の出力電圧は正電圧平均値検出回路１４にお
いてその内の正電圧のみを整流した後正電圧の平均値を
検出して正電圧平均値ＶPAを出力する。正電圧平均値Ｖ
PAは負電圧パルス幅変調回路１５においてパルス幅変調
の信号として用いられ、負電源１ｃのスイッチ４ｂをＯ
Ｎ／ＯＦＦ制御するためパルス幅変調された負電圧パル
ス信号が作られる。負電圧パルス信号のパルス幅ＴN は
負電圧パルス幅変調回路１５の内部で作られる負電圧パ
ルス幅変調用基準三角波の定数Ｋにより正電圧平均値Ｖ
PAを信号として式６により変換される。 ＴN ＝Ｋ・ＶPA （ＴN ＜ＴR ） ………（式６） 図２は休止時間中の負電源１ｃの負電圧印加時間をパル
ス幅変調した例で、図２（ａ）の加工電圧の内図２
（ｂ）の正電圧のみを平均化した正電圧平均値信号とパ
ルス幅変調用基準三角波とを図２（ｃ）に示すように比
較して、負電圧ＶNのパルス幅信号である図２（ｄ）を
作っている。全電圧平均値ＶGAは式６と式２および式３
により式７で表わされる。 ＶGA＝（１−Ｋ・ＶN ／Ｔ0 ）・ＶPA ………（式７） 全電圧平均値ＶGAが零となる条件は式７より導かれる式
８で表わされる。 Ｋ・ＶN ／Ｔ0 ＝１ ………（式８） 以上のように、負電圧パルス幅変調用基準三角波の定数
Ｋと負電圧ＶN との積を加工周期Ｔ0 に等しくなるよう
に制御することにより全電圧平均値ＶGAを零に近づけた
加工を行なうことができる。このため負電圧パルス幅変
調用基準三角波の定数Ｋまたは負電圧ＶN を過大な値に
設定する必要が無くなる。Next, the operation will be described with reference to FIGS. The machining voltage generated in the machining gap of the machining circuit is detected by the machining voltage detector 10 and amplified. The output voltage of the machining voltage detector 10 rectifies only the positive voltage in the positive voltage average value detection circuit 14 and then detects the average value of the positive voltage to output the positive voltage average value VPA . Positive voltage average value V
PA is used as a pulse width modulation signal in the negative voltage pulse width modulation circuit 15, and the switch 4b of the negative power supply 1c is
A pulse width modulated negative voltage pulse signal is generated for N / OFF control. The pulse width T N of the negative voltage pulse signal is determined by the constant K of the reference triangular wave for negative voltage pulse width modulation generated inside the negative voltage pulse width modulation circuit 15 and the average positive voltage V
It is converted by Equation 6 using PA as a signal. T N = K · V PA (T N <T R ) (Equation 6) FIG. 2 is an example in which the negative voltage application time of the negative power supply 1c during the idle time is pulse width modulated, and FIG. Figure 2 of machining voltage
A positive voltage average value signal and the pulse width modulation reference triangle wave positive voltage only averaged in (b) in comparison as shown in FIG. 2 (c), FIG. 2 is a pulse width signal having a negative voltage V N (D) is being made. The total voltage average value VGA is calculated by Equations 6, 2 and 3.
Is represented by equation (7). V GA = (1−K · V N / T 0 ) · V PA (Expression 7) The condition that the total voltage average value V GA becomes zero is expressed by Expression 8 derived from Expression 7. K · V N / T 0 = 1 (Equation 8) As described above, the product of the constant K of the reference triangular wave for negative voltage pulse width modulation and the negative voltage V N is set to be equal to the machining period T 0. By performing the control, it is possible to perform processing in which the total voltage average value VGA approaches zero. Therefore it is not necessary to set a negative voltage pulse width constant K or negative voltage V N of the modulating reference triangular wave to an excessive value.
【００１４】実施例２．全電圧平均値ＶGAを零に近づけ
る条件は式８で表わされるが、その内の負電圧パルス幅
変調用基準三角波の定数Ｋを一定値に固定して、負電圧
ＶN を発振回路１３からの負電圧信号により式８から導
かれる式９の値に制御することにより全電圧平均値ＶGA
を零に近づけることができる。 ＶN ＝Ｔ0 ／Ｋ ………（式９） ＶN は加工電圧で、電極間には放電前の無負荷時間中に
印加されるので、放電の発生のしやすさを変える効果が
ある。Ｔ0 が長くなればＶN が高くなり放電しやすくな
るので、結果としてＴ0 を短くする方向に働き加工が安
定する。Embodiment 2 FIG. The condition for bringing the total voltage average value VGA close to zero is expressed by Expression 8, in which the constant K of the reference triangular wave for negative voltage pulse width modulation is fixed to a constant value, and the negative voltage VN is All average voltage V GA by controlling the value of the expression 9 derived from equation 8 by a negative voltage signal
Can approach zero. V N = T 0 / K (Equation 9) V N is a machining voltage, which is applied between the electrodes during the no-load time before the discharge, and has an effect of changing the easiness of the discharge. . As T 0 becomes longer, V N becomes higher and electric discharge becomes easier. As a result, T 0 becomes shorter and machining becomes stable.
【００１５】実施例３．また、式８の内の負電圧ＶN を
一定値に固定して、負電圧パルス幅変調用基準三角波の
定数Ｋを発振回路１３からの負電圧パルス幅変調ゲイン
信号により式８から導かれる式１０の値に制御すること
により全電圧平均値ＶGAを零に近づけることができる。 Ｋ＝Ｔ0 ／ＶN ………（式１０） Ｋは変調定数で、負電圧パルス幅の変調ゲインを変え
る。Ｔ0 が長くなると負電圧パルス幅の変調ゲインが高
くなり、全電圧平均値を零に近づける応答が早くなる。
従って、放電周波数が下った時の応答遅れを補う効果が
ある。Embodiment 3 FIG. Further, the negative voltage V N in Equation 8 is fixed to a constant value, and the constant K of the reference triangle wave for negative voltage pulse width modulation is derived from Equation 8 by the negative voltage pulse width modulation gain signal from the oscillation circuit 13. By controlling the value to 10, the total voltage average value VGA can be made close to zero. K = T 0 / V N (Equation 10) K is a modulation constant, which changes the modulation gain of the negative voltage pulse width. As T 0 becomes longer, the modulation gain of the negative voltage pulse width becomes higher, and the response for bringing the total voltage average value close to zero becomes faster.
Therefore, there is an effect of compensating for a response delay when the discharge frequency decreases.
【００１６】上記実施例１〜３において、発振回路１３
はマイクロコンピュータ等のコンピュータを備えてお
り、制御回路としての機能を有する制御手段である。式
８で表わされるＫ・ＶN ／Ｔ0 ＝１となるように、負電
圧信号により負電圧を変更する制御をしたり、変調ゲイ
ン信号により定数Ｋを変更する制御を行なう機能は、予
めメモリに格納されたプログラムによって達成される。
２０は電極間電圧の内加工電圧の周期Ｔ0 を読み込む信
号線である。なお、図１において、鎖線で示す部分は、
いわゆる電線ではなく、制御で結ばれていることを示し
ている。また、２１で示す回路は、負電圧パルス幅をパ
ルス幅変調するための三角波を作る積分器をリセットす
るものである。加工パルス信号（正電圧）の出ている間
は積分器をリセットし、休止時間中に負電圧を印加する
様に積分を行ない三角波を出力している。つまり、結果
として休止時間中を信号とする方形波を積分しているこ
とになる。In the first to third embodiments, the oscillation circuit 13
Is a control means having a computer such as a microcomputer and having a function as a control circuit. The function of controlling to change the negative voltage by the negative voltage signal and changing the constant K by the modulation gain signal so that K · VN / T0 = 1 represented by the equation 8 is stored in the memory in advance. Achieved by the program.
Reference numeral 20 denotes a signal line for reading the period T0 of the inner working voltage of the inter-electrode voltage. Note that, in FIG.
It is not a so-called electric wire, but indicates that it is connected by control. The circuit denoted by 21 resets an integrator for generating a triangular wave for pulse width modulation of a negative voltage pulse width. While the processing pulse signal (positive voltage) is being output, the integrator is reset, and integration is performed so that a negative voltage is applied during the pause time to output a triangular wave. That is, as a result, a square wave having a signal during the pause time is integrated.
【００１７】[0017]
【発明の効果】本発明は以上説明したとおり、電極と被
加工物とを対向させて移動させるとともに電極と被加工
物とで形成される加工間隙に正電源と負電源とを並列に
接続し加工パルスを印加してパルス電流を通電し被加工
物を放電加工する放電加工装置において、前記加工間隙
の加工電圧を検出する加工電圧検出器と、前記加工電圧
の正電圧の平均値を検出する正電圧平均値検出回路と、
負電圧パルス幅変調用の基準三角波を生成し、前記基準
三角波の定数と前記正電圧平均値検出回路で検出された
正電圧平均値に基づいて、前記負電源の負電圧印加時間
をパルス幅変調する負電圧パルス幅変調回路と、前記基
準三角波の定数と前記負電源の負電圧との積が加工パル
ス周期に等しくなるように制御する制御手段とを備えた
ので、安価でかつ応答の速い加工が安定に行なえる効果
がある。As described above, according to the present invention, an electrode and a workpiece are moved to face each other, and a positive power supply and a negative power supply are connected in parallel to a processing gap formed between the electrode and the workpiece. In an electric discharge machining apparatus for applying a machining pulse and applying a pulse current to discharge machining a workpiece, a machining voltage detector for detecting a machining voltage of the machining gap and an average value of a positive voltage of the machining voltage are detected. A positive voltage average value detection circuit,
A reference triangular wave for negative voltage pulse width modulation is generated, and a negative voltage application time of the negative power supply is pulse width modulated based on a constant of the reference triangular wave and a positive voltage average value detected by the positive voltage average value detection circuit. And a control means for controlling the product of the constant of the reference triangular wave and the negative voltage of the negative power supply to be equal to the processing pulse period. Has the effect that it can be performed stably.
【００１８】また、制御手段は、負電圧パルス幅変調回
路の基準三角波の定数を固定値とし負電源の負電圧を変
化させるので、加工パルス周期が長くなれば負電圧が高
くなり放電しやすくなる。結果として周期を短くする方
向に働き加工が安定する効果がある。Further, the control means changes the negative voltage of the negative power supply with the constant value of the reference triangular wave of the negative voltage pulse width modulation circuit fixed, so that the longer the machining pulse period, the higher the negative voltage and the easier the discharge. . As a result, it works in the direction of shortening the cycle, and has the effect of stabilizing the processing.
【００１９】さらに、制御手段は、負電源の負電圧を固
定値とし負電圧パルス幅変調回路の基準三角波の定数を
変化させるので、加工パルス周期が長くなると負電圧パ
ルス幅の変調ゲインが高くなる。従って、全電圧平均値
を零に近づける応答が早くなり、放電周波数が下った時
の応答遅れを補う効果がある。Further, since the control means changes the constant of the reference triangular wave of the negative voltage pulse width modulation circuit with the negative voltage of the negative power supply fixed, the modulation gain of the negative voltage pulse width increases as the processing pulse period becomes longer. . Therefore, the response for bringing the average value of all the voltages close to zero becomes faster, and there is an effect of compensating for a response delay when the discharge frequency is lowered.
【図１】本発明による放電加工装置の一実施例を示す構
成図である。FIG. 1 is a configuration diagram showing one embodiment of an electric discharge machine according to the present invention.
【図２】負電圧パルス幅変調の例を示す波形図である。FIG. 2 is a waveform chart showing an example of negative voltage pulse width modulation.
【図３】従来の放電加工装置を示す構成図である。FIG. 3 is a configuration diagram showing a conventional electric discharge machine.
【図４】負電圧を印加した加工電圧波形の例を示す波形
図である。FIG. 4 is a waveform diagram showing an example of a machining voltage waveform to which a negative voltage is applied.
１ａ 正電源 １ｂ，１ｃ 負電源 ２ 電極 ３ 被加工物 ９，１３ 発振回路 １０ 加工電圧検出器 １１ 全電圧平均値検出回路 １２，１５ 負電圧パルス幅変調回路 １４ 正電圧平均値検出回路 Ｔ0 加工周期 ＴL 無負荷時間 ＴP パルス幅 ＴR 休止時間 ＴN 負電圧パルス幅 ＶM 正電圧 ＶD 放電電圧 ＶN 負電圧1a positive power supply 1b, 1c negative power supply 2 electrode 3 workpiece 9,13 oscillation circuit 10 machining voltage detector 11 the total voltage mean value detecting circuit 12 and 15 a negative voltage pulse width modulation circuit 14 the positive voltage mean value detecting circuit T 0 machining period T L unloading time T P pulse width T R downtime T N negative voltage pulse width V M positive voltage V D discharge voltage V N negative voltage
Claims (3)
るとともに電極と被加工物とで形成される加工間隙に正
電源と負電源とを並列に接続し加工パルスを印加してパ
ルス電流を通電し被加工物を放電加工する放電加工装置
において、 前記加工間隙の加工電圧を検出する加工電圧検出器と、 前記加工電圧の正電圧の平均値を検出する正電圧平均値
検出回路と、負電圧パルス幅変調用の基準三角波を生成し、前記基準
三角波の定数と前記 正電圧平均値検出回路で検出された
正電圧平均値に基づいて、前記負電源の負電圧印加時間
をパルス幅変調する負電圧パルス幅変調回路と、前 記基準三角波の定数と前記負電源の負電圧との積が加
工パルス周期に等しくなるように制御する制御手段とを
備えたことを特徴とする放電加工装置。An electrode and a workpiece are moved to face each other, and a positive power supply and a negative power supply are connected in parallel to a processing gap formed between the electrode and the workpiece, and a processing pulse is applied to apply a pulse current. A machining voltage detector that detects a machining voltage of the machining gap, a positive voltage average value detection circuit that detects an average value of the positive voltage of the machining voltage, Generate a reference triangular wave for negative voltage pulse width modulation, and
The constant of the triangular wave was detected by the positive voltage average value detection circuit .
Based on the positive voltage average value, a negative voltage pulse width modulation circuit for negative voltage application time of the pulse width modulation of the negative power supply, the product is processed pulse period of the negative voltage of the constant before Symbol reference triangular wave and the negative power supply An electric discharge machining apparatus comprising: control means for performing control so as to be equal.
基準三角波の定数を固定値とし負電源の負電圧を変化さ
せることを特徴とする請求項１記載の放電加工装置。Wherein the control means of the negative voltage pulse width modulation circuit
Electric discharge machining apparatus according to claim 1, wherein the the constants of criteria triangular wave and the fixed value to change the negative voltage of the negative power supply.
し負電圧パルス幅変調回路の基準三角波の定数を変化さ
せることを特徴とする請求項１記載の放電加工装置。Wherein the control means, electrical discharge machining apparatus according to claim 1, wherein varying the negative voltage a fixed value criteria triangular wave constant of the negative voltage pulse width modulation circuit of the negative power supply.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4133860A JP2707019B2 (en) | 1992-05-26 | 1992-05-26 | Electric discharge machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4133860A JP2707019B2 (en) | 1992-05-26 | 1992-05-26 | Electric discharge machine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05329710A JPH05329710A (en) | 1993-12-14 |
| JP2707019B2 true JP2707019B2 (en) | 1998-01-28 |
Family
ID=15114743
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4133860A Expired - Fee Related JP2707019B2 (en) | 1992-05-26 | 1992-05-26 | Electric discharge machine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2707019B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4819091A (en) * | 1987-04-30 | 1989-04-04 | International Business Machines Corporation | High speed magnetic disk contact recording system |
| US6727455B1 (en) * | 2000-06-06 | 2004-04-27 | Mitsubishi Denki Kabushiki Kaisha | Power supply system for applying a voltage of both positive and negative polarities in electric discharge machining |
| US8309876B2 (en) | 2008-01-31 | 2012-11-13 | Mitsubishi Electric Corporation | Electric discharge machining apparatus and electric discarge machining method |
| JP5137711B2 (en) * | 2008-06-24 | 2013-02-06 | 三菱電機株式会社 | Power supply device for wire electric discharge machine |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63102825A (en) * | 1986-10-20 | 1988-05-07 | Fanuc Ltd | Power source for electric discharge machining |
-
1992
- 1992-05-26 JP JP4133860A patent/JP2707019B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05329710A (en) | 1993-12-14 |
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