JPH01177922A - Retreat controlling device for electric discharge machine - Google Patents

Abstract

PURPOSE:To prevent decrease of electrode retreat efficiency by determining the shortest route of retreat of an electrode for at least either the distance or time based on a processing program and providing a shortest retreat means for letting the electrode retreat according to the route. CONSTITUTION:An NC input command 6 is analyzed by a command analyzing part 7, and when an electrode move command is included, it is sent to a shortest retreat route control part 8. The control part 8 analizes the move command, and the shortest route for retreat of an electrode is determined for at least either the distance or time and set in a retreat route memorizing part 9. A part 10 for detecting condition between electrodes detects the condition between electrodes, and an electrode retreat command 17 is given to an advance and retreat control part 11 based on the condition. The control part 11 gives an advance and retreat signal 15, 16 to an interpolation control part 14 based on the newest move command 12 outputted from the control part 8 when the detected condition between the electrode is normal (where a retreat command 17 is not included), or based on a retreat route command 13 at the time of abnormal processing (when a retreat command 17 is received) respectively, thereby motors 3-5 are driven.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、自動的に又は手動により与えられた後退指令
によって電極を後退させる放電加工機用後退制御装置に
関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a retraction control device for an electric discharge machine that retracts an electrode in response to a retraction command given automatically or manually.

〔従来の技術〕[Conventional technology]

放電加工中に、例えば極間短絡が生じた際、それ自体を
止めるため、及びその原因となる加工粉を除去するため
などの必要から、電極を後退させる後退制御装置が従来
から用いられている。During electric discharge machining, for example, when a short circuit occurs between electrodes, a retraction control device that retracts the electrode has been used to stop the short circuit itself and to remove the machining powder that causes it. .

ところで、従来のこの種の装置は、後退指令を受けると
、電極の加工経路の実行プログラムをそっくりそのまま
逆戻り実行していくというものであった。すなわち、第
５図において１図示電極１を用いて、被加工物２に図示
形状の加工を行う場合に、電極１の加工経路プログラム
が、第６図中ａ１点→ａ２点→ａ３点→ａ４点のように
なっているとする。そして、８４点直前の８５点で後退
指令を受けたとすると、従来装置では、ａＳ点→ａ３点
→ａ２点→ａ１点の経路で電極１が後退していくもので
、距離的にも時間的にも長くかかった。また、第７図に
おいて、図示電極１を用いて、被加工物２に図示形状の
加工を行う場合に、電極１の加工経路プログラムが、例
えば面粗さを小さく加工する必要から、第８図中のｂ１
点→ｂ２点→ｂ３点→ｂ４点→・・・・・・→ｂｎ点の
ように、ｂ２点からｂｎ点まで同一方向の微少線分が多
数続くものとする。そして、ｂｎ点で後退指令を受けた
とすると、従来装置では、ｂｎ点→ｂ（ｎ−＋）点→・
・・・・・ｂ４点→ｂ３点→ｂ２点→ｂ１点の経路で電
極１が後退していくもので、特に、ｂｎ点からｂ２点ま
での間について、時間的に長くかかった。By the way, in a conventional device of this kind, when a backward command is received, the execution program of the electrode machining path is executed backwards in its entirety. That is, when machining the workpiece 2 in the shape shown in FIG. 5 using one illustrated electrode 1, the machining path program for the electrode 1 is as follows: point a1→point a2→point a3→a4 in FIG. Suppose it looks like a dot. If a retreat command is received at the 85th point immediately before the 84th point, in the conventional device, the electrode 1 would retreat along the path of point aS → point a3 → point a2 → point a1, which would cause the electrode 1 to retreat in the path of point aS → point a3 → point a2 → point a1. It also took a long time. In addition, in FIG. 7, when the illustrated electrode 1 is used to process the workpiece 2 into the illustrated shape, the machining path program of the electrode 1 is changed, for example, because it is necessary to process the surface roughness to a small level, as shown in FIG. middle b1
Assume that many minute line segments continue in the same direction from point b2 to point bn, such as point → point b2 → point b3 → point b4 → ... → point bn. If a backward command is received at point bn, in the conventional device, point bn → point b(n-+) → ・
...The electrode 1 was retracted along the route of point b4 → point b3 → point b2 → point b1, and it took a particularly long time from point bn to point b2.

〔発明が解決しようとする課題〕[Problem to be solved by the invention]

以上のように従来装置では、後退指令を受けると、電極
１は、加工経路プログラムをそっくりそのまま逆戻り実
行していくため、距離的１時間的に長くかかり、電極後
退効率（加工中にあっては加工効率）が低下するという
問題点があった。As described above, in the conventional device, when receiving a retreat command, the electrode 1 goes back and executes the machining path program in its entirety. There was a problem that processing efficiency) decreased.

本発明の目的は、後退効率を低下させることなく電極を
後退させることができる放電加工機用後退制御装置を提
供することにある。An object of the present invention is to provide a retraction control device for an electric discharge machine that can retract an electrode without reducing retraction efficiency.

〔課題を解決するための手段〕[Means to solve the problem]

上記目的は、従来装置では加工経路が複雑であったり、
連続微少線分加工の場合にも、その加工プログラムをそ
っくりそのまま逆戻り後退することに、電極後退効率低
下の原因があることに着目し、本発明では最短後退手段
を設けることにより達成するものである。The above purpose is because the machining path is complicated with conventional equipment,
Even in the case of continuous minute line segment machining, we have focused on the fact that reversing the entire machining program and retracting it is the cause of the reduction in electrode retraction efficiency, and the present invention achieves this by providing the shortest retraction means. .

〔作　用〕[For production]

上記最短後退手段は、電極の加工経路プログラムを、あ
らかじめ、又は実行時に読み込み、距離及び時間のうち
の少なくとも一方について最短の電極後退順路を決定し
、後退指令を受けたとき。The shortest retreat means reads the electrode machining path program in advance or during execution, determines the shortest electrode retreat route in terms of at least one of distance and time, and receives a retreat command.

それに従って電極を後退させるもので、これにより電極
後退効率が向上する。The electrode is retracted accordingly, thereby improving the electrode retraction efficiency.

〔実施例〕〔Example〕

以下、図面を参照して本発明の詳細な説明する。第１図
は本発明による放電加工機用後退制御装置の一実施例を
示すブロック図で、図中１は電極、２は被加工物である
。３〜５は各々送りモータで、このうち３はＸ軸周、４
はＹ軸用、５はＺ軸周である。６はＮＣ入力指令で、こ
の指令６は指令解析部７で解析され、電極移動指令を含
むときは、それを最短後退順路制御部８に送る。この最
短後退順路制御部８は、後退順路記憶部９とで最短後退
手段の主構成をなすもので、前記移動指令を解析し、距
離及び時間のうちの少なくとも一方について最短の電極
後退順路を決定して、前記記憶部９にセットする。極間
状態検出部１０は例えば極間電圧検出器からなるもので
、極間状態を検出し、その状態に応じて（ここでは極間
短絡などの極間異常状態のとき）電極後退指令１７を前
進・後退制御部１１に与える。この前進・後退制御部１
１は、検出された極間状態が正常であるとき（後退指令
１７がないとき）には、前記最短後退順路制御部８から
出力される最新移動指令１２により、また異常加工１例
えば短絡状態であるとき（後退指令１７を受けたとき）
には、前記記憶部９からの後退順路指令１３により、各
々補間制御部１４に前進、後退信号１５．１６を与える
。補間制御部１４は、与えられた信号１５．１６に基づ
いて各送りモータ３〜５を駆動する。Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a retraction control device for an electric discharge machine according to the present invention, in which 1 is an electrode and 2 is a workpiece. 3 to 5 are feed motors, of which 3 is the X-axis circumference, and 4 is the feed motor.
is for the Y axis, and 5 is for the Z axis circumference. Reference numeral 6 denotes an NC input command. This command 6 is analyzed by a command analysis section 7, and when it includes an electrode movement command, it is sent to the shortest backward route control section 8. The shortest backward route control section 8, together with the backward route storage section 9, forms the main component of the shortest backward means, and analyzes the movement command and determines the shortest electrode backward route in terms of at least one of distance and time. and set it in the storage section 9. The gap condition detection unit 10 is composed of, for example, a gap voltage detector, and detects the gap condition, and issues an electrode retraction command 17 according to the condition (here, in the case of an abnormal condition between the electrodes such as a short circuit between the electrodes). It is applied to the forward/reverse control section 11. This forward/reverse control section 1
1, when the detected machining gap condition is normal (when there is no retreat command 17), the latest movement command 12 output from the shortest backward route control section 8 causes abnormal machining 1, for example, in a short circuit state. At some point (when receiving retreat command 17)
In response to the backward route command 13 from the storage section 9, forward and backward signals 15 and 16 are given to the interpolation control section 14, respectively. The interpolation control unit 14 drives each of the feed motors 3 to 5 based on the applied signals 15 and 16.

次に、第２図〜第４図を併用して、後退指令１７を受け
たときの最短の電極後退順路決定例について述べる。ま
ず第２図は、８１点において２軸下降後、８２点におい
てＸ軸一方向に移動し、８３点においてＸ軸＋方向への
移動があり、そこでの加工中において後退指令１７を受
けた場合を示す、この場合は、実行加工点が８２点より
右方に達していればＸ軸一方向端（８３点）まで戻る必
要がなく、実線矢印イに示すような順路で後退するのが
、距離的にも時間的にも最短である。また第３図は、６
１点でＺ軸下降後、ｂ２点からＸＹＺａ軸にて左斜め下
方のｂｎ点まで、同一方向の微少線分ｂ２〜ｂａ、ｂ３
〜ｂ４−ｂ（ｎ−１）　〜ｂｎが多数続き、ｂｎ点加工
中に後退指令１７を受けた場合を示す。この場合は、個
々の微少線分は考慮せず、これらをｂｎ”ｂ２までの１
本の線分にまとめ、実線矢印口に示すような順路で後退
するのが時間的に最短である。第４図は、第２図、第３
図とは異なり、加工中において、加工プログラムの実行
点より先の部分を読み込んでいき、最短後退順路を決定
する例を示す、すなわち第４図において、Ｃ１点から０
２点へのＸ軸子方向加工途中０３点からの後退順路につ
いては、加工プログラムの先読み込み結果から１次線分
０２〜Ｃ４が戻り、すなわち非加工線分で、かつ次々線
分０４〜ｃ５も被加工線分（共に破線で示す）であると
き、実線矢印ハに示す順路で後退するのが、時間的にも
距離的にも最短である。Next, an example of determining the shortest electrode retreat route when the retreat command 17 is received will be described with reference to FIGS. 2 to 4. First, in Figure 2, after descending on the two axes at point 81, there is movement in one direction of the X-axis at point 82, movement in the + direction of the X-axis at point 83, and a backward command 17 is received during machining at that point. In this case, if the execution machining point has reached the right side of point 82, there is no need to return to the end in one direction of the X axis (point 83), and it is better to retreat along the route shown by the solid arrow A. It is the shortest in terms of distance and time. Also, Figure 3 shows 6
After descending on the Z axis at one point, from point b2 to point bn diagonally downward to the left on the XYZa axis, minute line segments b2 to ba, b3 in the same direction
~b4-b(n-1) This shows a case where a large number of ~bn continue and a retreat command 17 is received during bn point machining. In this case, individual minute line segments are not considered, and these are 1 up to bn''b2.
The shortest time is to group them into line segments and retreat along the route shown by the solid arrow. Figure 4 is similar to Figures 2 and 3.
Unlike the figure, an example is shown in which during machining, the part beyond the execution point of the machining program is read and the shortest backward route is determined.
Regarding the backward route from point 03 during machining in the X-axis direction to point 2, primary line segments 02 to C4 are returned from the pre-read results of the machining program, that is, non-machined line segments, and line segments 04 to c5 are returned one after another. When both are line segments to be processed (both shown by broken lines), retreating along the route shown by the solid arrow C is the shortest in terms of time and distance.

上述したように、加工を進めつつ、電極１の最短後退順
路を決定することにより、後退指令１７を受けたとき（
上述実施例では極間短絡検出時）、無駄な順路を経るこ
となく後退制御できることになる。As described above, by determining the shortest retreat route for the electrode 1 while proceeding with machining, when the retreat command 17 is received (
In the above-described embodiment, when a short circuit between poles is detected), backward control can be performed without going through a wasteful forward route.

なお上述実施例では、後退指令１７が、極間短絡などの
異常加工時に自動的に制御部１１に与えられる場合につ
いて説明したが、これのみに限られることはない。例え
ば、（１）正常加工中ではあるが、加工粉が極間に多く
滞留し、極間短絡の恐れが出てきたときに自動的に、（
２）加工粉による極間短絡が現在発生しているか、ある
いはその恐れがあるか、に拘わらず定期的に後退させる
ため、一定時間間隔で自動的に、（３）加工中途の所望
時１手動で、各々後退指令１７が制御部１１に与えられ
るようにしてもよい、上記（１）によれば極間短絡の予
防が、（２）によれば極間短絡の「十分」な予防が。In the above-mentioned embodiment, a case has been described in which the retreat command 17 is automatically given to the control unit 11 at the time of abnormal machining such as a short circuit between machining parts, but the present invention is not limited to this. For example, (1) during normal machining, if a large amount of machining powder accumulates between the machining holes and there is a risk of a short circuit between the machining holes, then (
2) Automatically at fixed time intervals to periodically retract regardless of whether or not a short circuit between machining machining particles is currently occurring or there is a risk of such occurrence; (3) Manually at a desired time during machining. Then, the retreat command 17 may be given to the control unit 11. According to (1) above, short circuit between poles can be prevented, and according to (2), short circuit between poles can be "sufficiently" prevented.

（３）によれば加工中止など何らかの理由による任意的
な電極後退が、各々可能となる。According to (3), it is possible to arbitrarily retract the electrode for any reason such as stopping processing.

〔発明の効果〕〔Effect of the invention〕

以上述べたように本発明によれば、後退指令を受けたと
き、最短の電極後退順路に従って電極を後退させるので
、電極後退効率が高いという効果がある。また、これに
より加工粉除去効率も高くなり、加工時においては、そ
の加工効率が大幅に向上するという効果もある。As described above, according to the present invention, when a retraction command is received, the electrode is retracted along the shortest electrode retraction route, so that the electrode retraction efficiency is high. Moreover, this also increases processing powder removal efficiency, and has the effect of significantly improving processing efficiency during processing.

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

第１図は本発明装置の一実施例を示すブロック図、第２
図〜第４図は同上装置における最短電極後退順路決定例
の説明図、第５図〜第８図は各々従来装置の問題点を説
明するための図である。 １・・・電極、２・・・被加工物、３〜５・・・送りモ
ータ、８・・・最短後退順路制御部、９・・・後退順路
記憶部。 １０・・・極間状態検出部、１１・・・前進・後退制御
部、１４・・・補間制御部、１７・・・電極後退指令。 特　許　出　願　人　　日立精工株式会社代理人　　弁
理士　　秋　本　　正　実（外１名） 第２図 ｎイ 第３図 第　４図 Ｃ５、 ｂａ５図 第７図 ４ｓ　６　図 ｔ 第８図FIG. 1 is a block diagram showing one embodiment of the device of the present invention, and FIG.
4 to 4 are explanatory diagrams of an example of determining the shortest electrode retreat route in the same device as above, and FIGS. 5 to 8 are diagrams for explaining the problems of the conventional device, respectively. DESCRIPTION OF SYMBOLS 1... Electrode, 2... Workpiece, 3-5... Feed motor, 8... Shortest backward route control part, 9... Backward route memory part. DESCRIPTION OF SYMBOLS 10... Electrode gap state detection part, 11... Advance/backward control part, 14... Interpolation control part, 17... Electrode retreat command. Patent applicant Hitachi Seiko Co., Ltd. Agent Patent attorney Masami Akimoto (1 other person) Figure 2 n a Figure 3 Figure 4 C5, ba5 Figure 7 4s 6 Figure t Figure 8

Claims (1)

【特許請求の範囲】[Claims] １、後退指令により電極を後退させる放電加工機用後退
制御装置において、距離及び時間のうちの少なくとも一
方について最短の電極後退順路を加工プログラムに基づ
いて決定し、後退指令を受けたとき、その決定された順
路に従って電極を後退させる最短後退手段を具備するこ
とを特徴とする放電加工機用後退制御装置。1. In a retraction control device for an electric discharge machine that retracts the electrode in response to a retraction command, the shortest electrode retraction route in terms of at least one of distance and time is determined based on the machining program, and when the retraction command is received, the determination is made. 1. A retraction control device for an electrical discharge machine, comprising a shortest retraction means for retracting an electrode according to a determined route.