JP2010125541A - Electric discharge machining apparatus and electric discharge machining method - Google Patents

Electric discharge machining apparatus and electric discharge machining method Download PDF

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JP2010125541A
JP2010125541A JP2008301025A JP2008301025A JP2010125541A JP 2010125541 A JP2010125541 A JP 2010125541A JP 2008301025 A JP2008301025 A JP 2008301025A JP 2008301025 A JP2008301025 A JP 2008301025A JP 2010125541 A JP2010125541 A JP 2010125541A
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tool electrode
electric discharge
workpiece
electrode
hole
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Makoto Miyazaki
眞 宮崎
Hachiro Tsuchiya
八郎 土屋
Minoru Ota
稔 太田
Tamotsu Ohashi
保 大橋
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Kyoto Institute of Technology NUC
Nisshin Seisakusho KK
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Kyoto Institute of Technology NUC
Nisshin Seisakusho KK
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Abstract

<P>PROBLEM TO BE SOLVED: To attain deburring and chamfering for a difficult-to-machine part, such as an exit side of a hole formed in a workpiece, with a simple structure and control. <P>SOLUTION: A shaft-like tool electrode 11 extending along the center line Ct is inserted into a through-hole 15a formed in a workpiece 15 and a tip part 32 of the tool electrode 11 is disposed at an edge of the through-hole 15a on the exit side. With the center line Ct as the rotational center, the tool electrode 11 is rotated to be swung. A power supply voltage is applied between the workpiece 15 and the tool electrode 11. Since the tip part 32 of the tool electrode 11 is made to approach the edge of the through-hole 15a due to swing, a discharge clearance between the tip part 32 of the tool electrode 11 and the edge of the through-hole 15a is narrowed. As a result, discharge by a power supply voltage occurs between the tip part 32 of the tool electrode 11 and the edge of the through-hole 15a, thus the edge of the through-hole 15a is machined by electric discharge. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、放電加工装置及び放電加工方法に関する。詳細には、本発明は、工作物の穴の出口側のような加工が困難な部位のバリ取りや面取り加工を放電加工により行う方法及び装置に関する。   The present invention relates to an electric discharge machining apparatus and an electric discharge machining method. Specifically, the present invention relates to a method and an apparatus for performing deburring and chamfering of a difficult part such as an exit side of a hole of a workpiece by electric discharge machining.

従来、工作物の穴の出口側のバリ取りや面取り加工を行う方法としては、バリ取り工具を用いて手作業で行う方法、特殊形状の切削回転工具や研削回転工具を用いる方法、及び粘弾性流体砥粒等を用いる方法があった。手作業による方法では、加工能率が低く、自動化が困難である。また、回転工具を用いる方法では、穴径より小さな直径の工具を穴の入口側から挿入し、出口側近傍で工具切れ刃を拡大する特殊な機構が必要である。さらに、粘弾性流体砥粒等を用いる方法では,砥粒の研磨力が小さいため、加工能率が低い。   Conventional methods of deburring and chamfering on the exit side of a hole in a workpiece include a method of manually using a deburring tool, a method of using a special-shaped cutting rotary tool and a grinding rotary tool, and viscoelasticity. There was a method using fluid abrasive grains. The manual method has low processing efficiency and is difficult to automate. Further, the method using a rotating tool requires a special mechanism for inserting a tool having a diameter smaller than the hole diameter from the entrance side of the hole and enlarging the tool cutting edge in the vicinity of the exit side. Further, in the method using viscoelastic fluid abrasive grains and the like, the polishing efficiency of the abrasive grains is small, so that the processing efficiency is low.

これに対して、特許文献1には,バリを除去する方法及び装置が開示されている。すなわち、特許文献1には、長尺な棒状部材の先端に研削刃又は切削刃を有するバリ取り工具を被加工物の穴部に挿入し、その後バリ取り工具の先端側を偏心回転させて穴部内のバリを研削又は切削除去することが開示されている.   On the other hand, Patent Document 1 discloses a method and apparatus for removing burrs. That is, in Patent Document 1, a deburring tool having a grinding blade or a cutting blade at the tip of a long rod-shaped member is inserted into a hole portion of a workpiece, and then the tip side of the deburring tool is eccentrically rotated to make a hole. It is disclosed to grind or remove the burrs in the part.

また、特許文献2には,砥粒によりバリを除去する工具が開示されている。すなわち、特許文献2には、表面にダイヤモンド砥粒のような高硬度砥粒を被着させた三次元的多角形状の塊状体を一端又は両端に固着させた毛材を備え、この毛材を保持具に対して垂直、水平、直角、あるいは放射状に植毛した研磨用回転ブラシが開示されている。   Patent Document 2 discloses a tool for removing burrs with abrasive grains. That is, Patent Document 2 is provided with a hair material in which a three-dimensional polygonal lump with a high-hardness abrasive grain such as a diamond abrasive grain is attached to one end or both ends, and this hair material. A polishing rotating brush is disclosed which is flocked vertically, horizontally, perpendicularly or radially to the holder.

さらに特許文献3には,放電加工によりバリを除去する方法及び装置が開示されている。すなわち、特許文献3には、導電性を有する対象物に開設された加工穴のバリ取りを行う際に、バリに近接した位置に維持した電極と対象物との間に電圧を印加し、電極と対象物の間に放電を生じさせることでバリ取りを行うことが開示されている。   Further, Patent Document 3 discloses a method and apparatus for removing burrs by electric discharge machining. That is, in Patent Document 3, when deburring a processed hole opened in a conductive object, a voltage is applied between the electrode maintained at a position close to the burr and the object, And deburring by generating a discharge between the object and the object.

特開2003−117787号公報JP 2003-117787 A 特開2005−219130号公報JP-A-2005-219130 特開平9−295223号公報JP-A-9-295223

しかしながら、特許文献1の装置は、クラッチ手段等が組み込まれ複雑な構造で高価である。また、バリ取り工具は長尺な棒状部材の先端に切削刃等を設けたものであるので切削抵抗に対する強度が低くならざるを得ない。そのため、高能率の加工は困難であり、高硬度な被削材は加工できない。   However, the device of Patent Document 1 is expensive because it has a complicated structure incorporating a clutch means and the like. Further, since the deburring tool is provided with a cutting blade or the like at the tip of a long rod-shaped member, the strength against cutting resistance is inevitably lowered. Therefore, high-efficiency machining is difficult, and high-hardness work materials cannot be machined.

また、特許文献2の工具を使用するバリ取りは、砥粒を弾性支持体(毛材)により支持する砥粒加工であるため、単位時間当りの除去量が少なく加工能率が低く、高硬度な被削材に対しての加工能率も低い。   In addition, deburring using the tool of Patent Document 2 is abrasive grain processing in which abrasive grains are supported by an elastic support (hair material). Therefore, the removal amount per unit time is small, the processing efficiency is low, and the hardness is high. The machining efficiency for the work material is also low.

さらに、特許文献3の方法では,対象物に対する電極の位置をバリ取り加工の進行に追従させる制御が複雑であり、装置が高価になる。   Furthermore, in the method of Patent Document 3, the control for causing the position of the electrode relative to the object to follow the progress of the deburring process is complicated, and the apparatus becomes expensive.

本発明は、前記課題を解決するためになされたもので、簡易な構造・制御で工作物の穴の出口側のような加工が困難な部位のバリ取りや面取り加工を実現することを目的とする。また、本発明は、このようなバリ取りや面取り加工を高硬度な被削材についても容易とし、高い加工能率を実現することを目的とする。   The present invention has been made to solve the above-described problems, and aims to realize deburring and chamfering of a difficult part such as the exit side of a hole of a workpiece with a simple structure and control. To do. Another object of the present invention is to facilitate such deburring and chamfering even for a high-hardness work material, and to achieve high machining efficiency.

本発明の第1の態様は、中心線に沿って延びる軸状であって先端側が工作物の加工部位近傍に配置される工具電極と、前記工作物と前記工具電極との間に電源電圧を印加する放電加工電源と、前記工具電極の基端側を把持すると共に、前記中心線を回転中心として前記工具電極を回転させる回転駆動手段とを備え、前記回転駆動手段で回転された前記工具電極がふれまわりすることによって前記工具電極の先端側が前記加工部位に接近し、前記工具電極の先端側と前記加工部位との間の放電隙間が狭まり、それによって前記工具電極の前記先端側と前記加工部位との間に前記電源電圧による放電が生じる、放電加工装置を提供する。   According to a first aspect of the present invention, a power source voltage is applied between a tool electrode having a shaft shape extending along a center line and having a tip side disposed in the vicinity of a machining part of the workpiece, and the workpiece and the tool electrode. The tool electrode rotated by the rotation driving means, comprising: an electric discharge machining power source to be applied; and a rotation driving means for holding the proximal end side of the tool electrode and rotating the tool electrode around the center line. Makes the tip end of the tool electrode approach the machining site, and the discharge gap between the tip side of the tool electrode and the machining site is narrowed, whereby the tip side of the tool electrode and the machining site are reduced. Provided is an electric discharge machining apparatus in which a discharge is caused by the power supply voltage between parts.

本発明の第2の態様は、中心線に沿って延びる軸状の工具電極の先端側を工作物の加工部位近傍に配置し、前記工具電極の基端側を把持すると共に、前記中心線を回転中心として前記工具電極を回転させて前記工具電極をふれまわりさせ、前記工作物と前記工具電極との間に電源電圧を印加し、前記ふれまわりにより前記工具電極の先端側を前記加工部位に接近させて前記工具電極の先端側と前記加工部位との間の放電隙間を狭め、それによって前記工具電極の前記先端側と前記加工部位との間に前記電源電圧による放電が生じさせる、放電加工方法を提供する。   According to a second aspect of the present invention, a distal end side of an axial tool electrode extending along a center line is disposed in the vicinity of a machining part of a workpiece, the proximal end side of the tool electrode is gripped, and the center line is The tool electrode is rotated as a center of rotation to swirl the tool electrode, a power supply voltage is applied between the workpiece and the tool electrode, and the tip end side of the tool electrode is moved to the machining site by the swirling. Electric discharge machining that causes a discharge gap between the tip side of the tool electrode and the machining site to be narrowed, thereby causing a discharge due to the power supply voltage between the tip side of the tool electrode and the machining site. Provide a method.

本発明の第3の態様は、部品に貫通穴を形成し、中心線に沿って延びる軸状の工具電極の先端側を前記部品の加工部位近傍に配置し、前記工具電極の基端側を把持すると共に、前記中心線を回転中心として前記工具電極を回転させて前記工具電極をふれまわりさせ、前記部品と前記工具電極との間に電源電圧を印加し、前記ふれまわりにより前記工具電極の先端側を前記加工部位に接近させて前記工具電極の先端側と前記加工部位との間の放電隙間を狭め、それによって前記工具電極の前記先端側と前記加工部位との間に前記電源電圧による放電が生じさせて放電加工する、部品の製造方法を提供する。   According to a third aspect of the present invention, a through hole is formed in the component, the distal end side of the axial tool electrode extending along the center line is disposed in the vicinity of the machining portion of the component, and the proximal end side of the tool electrode is The tool electrode is rotated about the center line as a center of rotation, the tool electrode is swung around, the power supply voltage is applied between the component and the tool electrode, and the tool electrode The tip side is brought closer to the machining site to narrow the discharge gap between the tip side of the tool electrode and the machining site, thereby causing the power supply voltage between the tip side of the tool electrode and the machining site. Disclosed is a method for manufacturing a component, in which electric discharge is generated and electric discharge machining is performed.

本発明の放電加工装置及びその方法は、工具電極のふれまわり現象を用いて放電加工を行い、放電隙間を工具電極の回転速度や工具電極の工作物に対する相対位置によって制御するものであるため、簡易な構造・制御で工作物の穴の出口側のような加工が困難な部位のバリ取りや面取り加工を実現できる。また、放電加工によるため、工作物に対する機械的な力の影響がほとんどなく、導電性材料であれば材料の硬さに関係なく容易に加工を行うことができ、加工能率も高い。   Since the electric discharge machining apparatus and the method of the present invention perform electric discharge machining using the whirling phenomenon of the tool electrode, and the discharge gap is controlled by the rotational speed of the tool electrode and the relative position of the tool electrode to the workpiece, Deburring and chamfering of difficult-to-machine parts such as the exit side of workpiece holes can be realized with a simple structure and control. Further, since it is based on electric discharge machining, there is almost no influence of mechanical force on the workpiece, and a conductive material can be easily machined regardless of the hardness of the material, and the machining efficiency is high.

以下、添付図面を参照して本発明の実施形態を詳細に説明する。   Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(第1実施形態)
図1は本発明の第1実施形態に係る放電加工装置1を示す。この放電加工装置1はベース2から上方に延びるフレーム3を備える。フレーム3には出力軸4aが鉛直方向下向きに延びる姿勢で直流モータ4が固定されている。直流モータ4の出力軸4aの下端には、鉛直方向に延びるストレートシャンク5の上端側が絶縁体6を含むカップリング7を介して連結されている。ストレートシャンク5はフレーム3に固定された軸受8A,8Bによって回転自在に支持されている。ストレートシャンク5の下端側にはコレットチャック等であるチャック9があり、このチャック9に工具電極11の上端側が着脱可能に把持される。直流モータ4の出力軸4a、ストレートシャンク5、及び後述する工具電極11の中心線Ctは同一鉛直線上に配置されている。ベース2上にはXYZテーブル12が搭載されており、このXYZテーブル12には絶縁板13を介して放電槽14が固定されている。放電槽14内には工作物(部品)15の保持機構16が配置されている。放電槽14内には加工液が蓄液される。
(First embodiment)
FIG. 1 shows an electric discharge machining apparatus 1 according to a first embodiment of the present invention. The electric discharge machining apparatus 1 includes a frame 3 that extends upward from a base 2. The DC motor 4 is fixed to the frame 3 such that the output shaft 4a extends downward in the vertical direction. The upper end side of the straight shank 5 extending in the vertical direction is connected to the lower end of the output shaft 4 a of the DC motor 4 via a coupling 7 including an insulator 6. The straight shank 5 is rotatably supported by bearings 8A and 8B fixed to the frame 3. A chuck 9 such as a collet chuck is provided at the lower end side of the straight shank 5, and the upper end side of the tool electrode 11 is detachably held by the chuck 9. The output shaft 4a of the DC motor 4, the straight shank 5, and the center line Ct of the tool electrode 11 described later are arranged on the same vertical line. An XYZ table 12 is mounted on the base 2, and a discharge tank 14 is fixed to the XYZ table 12 via an insulating plate 13. A holding mechanism 16 for a workpiece (part) 15 is disposed in the discharge tank 14. The machining fluid is stored in the discharge tank 14.

放電加工装置1は、工作物15と工具電極11との間に電源電圧を印加するための放電加工電源21を備える。また、放電加工時の工具電極11と工作物15との間の電圧である極間電圧Vgapを検出する極間電圧検出器22が設けられている。この極間電圧検出器22で検出された極間電圧Vgapは極間電圧波形演算処理器23に出力される。極間電圧波形演算処理器23は極間電圧Vgapに対して積分処理等の演算処理を行い、この演算処理の結果に基づいてモータON/OFF制御器24が直流モータ4に対して通電を指示する信号(オン信号)と通電停止を指示する信号(オフ信号)のいずれかを出力する。また、XYZテーブル12の動作を制御するXYZテーブル制御器25が設けられている。極間電圧検出器22、極間電圧波形演算処理器23、モータON/OFF制御器24、XYZテーブル制御器25の機能及び動作の詳細は後に詳述する。   The electric discharge machining apparatus 1 includes an electric discharge machining power source 21 for applying a power supply voltage between the workpiece 15 and the tool electrode 11. Further, an inter-electrode voltage detector 22 for detecting an inter-electrode voltage Vgap, which is a voltage between the tool electrode 11 and the workpiece 15 during electric discharge machining, is provided. The inter-electrode voltage Vgap detected by the inter-electrode voltage detector 22 is output to the inter-electrode voltage waveform calculator 23. The interelectrode voltage waveform arithmetic processing unit 23 performs arithmetic processing such as integration processing on the interelectrode voltage Vgap, and the motor ON / OFF controller 24 instructs the DC motor 4 to be energized based on the result of the arithmetic processing. Either a signal to turn on (ON signal) or a signal to turn off energization (OFF signal) is output. Further, an XYZ table controller 25 that controls the operation of the XYZ table 12 is provided. Details of the functions and operations of the interelectrode voltage detector 22, interelectrode voltage waveform processor 23, motor ON / OFF controller 24, and XYZ table controller 25 will be described later.

工作物15は金属材料等の導電性材料からなり、予めドリル加工によって貫通穴15a(図2(A)等参照)が形成されている。図2(A)は工作物15の具体的な一例を示す。図2(A)の工作物15では貫通穴15aは他の大径貫通穴15bと交差するように形成された断面円形の交差穴であり、工作物15の表面から大径貫通穴15bまでドリル等(図示せず)を送って形成している。貫通穴(交差穴)15aの大径貫通穴15bの開口している部分の縁部にはバリ15cが生じている。本実施形態では放電加工装置1によって、このバリ15cを除去するバリ取り加工を実行する共に、バリ15cが除去された後も貫通穴15aの縁部をさらに除去してテーパ状に面取する面取加工を実行する。以下の説明では、貫通穴15aのドリル加工時に最初にドリルが工作物15と接触する側を入口側15dと呼び、ドリルが工作物15を貫通する側を出口側15eと呼ぶ。バリ15cは貫通穴15aの出口側15eに発生している。図2(B)及び図2(C)に示すように、貫通穴15aが段付穴あるいはテーパ穴等の入口側15dより出口側15eで穴径が大きいものであっても、本実施形態の放電加工装置1による加工が可能である。図2(A)〜(C)以外の図面では、理解を容易にするために工作物15は単なる板状体として模式的に示している。   The workpiece 15 is made of a conductive material such as a metal material, and a through hole 15a (see FIG. 2A and the like) is formed in advance by drilling. FIG. 2A shows a specific example of the workpiece 15. In the workpiece 15 of FIG. 2A, the through hole 15a is a cross hole with a circular cross section formed so as to intersect with the other large diameter through hole 15b, and drills from the surface of the workpiece 15 to the large diameter through hole 15b. Etc. (not shown). A burr 15c is formed at the edge of the through hole (intersection hole) 15a where the large diameter through hole 15b is open. In this embodiment, the electric discharge machining apparatus 1 performs the deburring process for removing the burr 15c, and after the burr 15c is removed, the edge of the through hole 15a is further removed to chamfer the taper shape. Perform machining. In the following description, the side where the drill first comes into contact with the workpiece 15 when drilling the through hole 15a is referred to as an inlet side 15d, and the side where the drill penetrates the workpiece 15 is referred to as an outlet side 15e. The burr 15c is generated on the outlet side 15e of the through hole 15a. As shown in FIGS. 2B and 2C, even if the through hole 15a has a larger diameter on the outlet side 15e than the inlet side 15d such as a stepped hole or a tapered hole, Processing by the electric discharge machining apparatus 1 is possible. In drawings other than FIGS. 2A to 2C, the workpiece 15 is schematically shown as a simple plate-like body for easy understanding.

図3を併せて参照すると、工具電極11は全体として細長く長尺な軸状であり、軸部31と先端部32を備える。軸部31は、真直な中心線Ctに沿って延びる細長い円柱であり、例えばベリリウム銅のような導電性を有するばね材からなる。軸部31の上端側がチャック9に把持される。軸部31の下端側には先端部32が設けられている。先端部32は頂端側が軸部31の下端に接続した円錐部33と、この円錐部33の下側の円柱部34とを備える。軸部31と先端部32及び円錐部33とは別の材料を接合して形成してもよい。例えば、先端部32及び円錐部33の材料として銅タングステンを採用できる。さらに、円錐部33の材料として、ダイヤモンド焼結体などの硬質材料又は導電性を有する焼結材料を円錐部33の全体部あるいは表面等の一部に採用できる。   Referring also to FIG. 3, the tool electrode 11 is a slender and long shaft as a whole, and includes a shaft portion 31 and a tip portion 32. The shaft portion 31 is an elongated cylinder extending along the straight center line Ct, and is made of a spring material having conductivity such as beryllium copper. The upper end side of the shaft portion 31 is gripped by the chuck 9. A tip end portion 32 is provided on the lower end side of the shaft portion 31. The tip portion 32 includes a conical portion 33 whose top end side is connected to the lower end of the shaft portion 31, and a cylindrical portion 34 below the conical portion 33. The shaft portion 31, the tip portion 32, and the conical portion 33 may be formed by joining different materials. For example, copper tungsten can be adopted as the material of the tip portion 32 and the conical portion 33. Furthermore, a hard material such as a diamond sintered body or a conductive sintered material can be used as the material of the conical portion 33 as the entire portion of the conical portion 33 or a part of the surface.

工具電極11は貫通穴15aに挿入される(図4(A))。より具体的には、後述する先端部32の円錐部33が貫通穴15aの出口側15eのバリ15cと対向する位置まで、工具電極11が貫通穴15aに挿入される。この状態で、直流モータ4によって回転駆動された工具電極11が中心線Ctを回転中心として回転する。回転速度が上昇してある速度(危険速度)付近となる大きく工具電極11がふれまわり現象を起こす(図4(B))。ふれまわりの振幅Aの増大に伴って工具電極11の先端部32がバリ15cに接近し、先端部32とバリ15cとの間の放電隙間Gが狭まる。その結果、工具電極11と工作物15との間に放電加工電源21からの電源電圧により放電が生じ、放電加工によってバリ15cの部分の工作物材料が除去される。   The tool electrode 11 is inserted into the through hole 15a (FIG. 4A). More specifically, the tool electrode 11 is inserted into the through hole 15a until a conical portion 33 of the distal end portion 32 described later faces a burr 15c on the outlet side 15e of the through hole 15a. In this state, the tool electrode 11 that is rotationally driven by the DC motor 4 rotates about the center line Ct. The tool electrode 11 greatly swirls around the speed (dangerous speed) where the rotational speed is increased (FIG. 4B). As the amplitude A of the whirling increases, the tip 32 of the tool electrode 11 approaches the burr 15c, and the discharge gap G between the tip 32 and the burr 15c is narrowed. As a result, electric discharge is generated between the tool electrode 11 and the workpiece 15 by the power supply voltage from the electric discharge machining power source 21, and the workpiece material in the burr 15c portion is removed by electric discharge machining.

再度図3を参照すると、工具電極11の軸部31の長さ(チャック9で把持された部分から先端部32の上端)L1は所望の危険速度に応じて設定される。軸部31の長さL1が長い程危険速度は低くなる。先端部32の直径D2は軸部31の直径D1よりも大きい。また、先端部32を貫通穴15aに挿入可能とするために直径D2は貫通穴15aの直径Dbよりも小さく設定される。例えば、貫通穴15aの直径Dbが3.0mmの場合、先端部32の直径D2は2.8mm程度に設定される。円錐部33のテーパ角θtは先端部32におけるふれまわりのたわみ角α(図4(B))と共に放電加工によって貫通穴15aの出口側15eに形成されるテーパ面15fのテーパ角θw(図5(D))を決める要因となる。具体的には、テーパ面15fのテーパ角θwは、概ねテーパ角θtとたわみ角αの和に相当する角度となる。円柱部34は先端部32の質量調整により危険速度を任意に決定するために設けられている。先端部32の質量が大きいほど危険速度は低速となる。例えば、先端部32の全長L2は3〜6mm程度で、円錐部33の長さL3は1〜3mm程度、円柱部34の長さL4は2〜3mm程度に設定される。工具電極11の構造については種々の態様があるが、それらについては後に詳述する。   Referring to FIG. 3 again, the length L1 of the shaft portion 31 of the tool electrode 11 (from the portion gripped by the chuck 9 to the upper end of the tip portion 32) L1 is set according to a desired critical speed. The danger speed decreases as the length L1 of the shaft portion 31 increases. A diameter D2 of the tip portion 32 is larger than a diameter D1 of the shaft portion 31. Further, the diameter D2 is set smaller than the diameter Db of the through hole 15a so that the tip end portion 32 can be inserted into the through hole 15a. For example, when the diameter Db of the through hole 15a is 3.0 mm, the diameter D2 of the distal end portion 32 is set to about 2.8 mm. The taper angle θt of the conical portion 33 is the taper angle θw (FIG. 5) of the tapered surface 15f formed on the outlet side 15e of the through hole 15a by electric discharge machining together with the deflection angle α (FIG. 4B) around the tip portion 32. (D)) is a factor to determine. Specifically, the taper angle θw of the taper surface 15f is an angle substantially corresponding to the sum of the taper angle θt and the deflection angle α. The cylindrical portion 34 is provided to arbitrarily determine the critical speed by adjusting the mass of the tip portion 32. The dangerous speed becomes lower as the mass of the tip 32 is larger. For example, the total length L2 of the tip portion 32 is about 3 to 6 mm, the length L3 of the conical portion 33 is set to about 1 to 3 mm, and the length L4 of the cylindrical portion 34 is set to about 2 to 3 mm. There are various modes for the structure of the tool electrode 11, which will be described in detail later.

次に、図1、図4(A),(B)、及び図5(A)〜(D)を参照して、本実施形態の放電加工装置1により実行される放電加工方法を説明する。放電加工の前工程として、工作物15にはドリル加工により貫通穴15a(本実施形態では断面円形の穴)が形成される。   Next, with reference to FIG. 1, FIG. 4 (A), (B), and FIG. 5 (A)-(D), the electric discharge machining method performed by the electric discharge machining apparatus 1 of this embodiment is demonstrated. As a pre-process of electric discharge machining, a through hole 15a (a hole having a circular cross section in the present embodiment) is formed in the workpiece 15 by drilling.

まず、XYZテーブル12が放電槽14をXY方向に移動させることにより、工具電極11が工作物15に対してXY方向に相対移動し、この相対移動により工具電極11は貫通穴15aに対して位置合わせされる。本実施形態では、工具電極11の中心線Ctが貫通穴15aの穴中心線Cbと一致するように位置合わせされる(図4(A))。位置合わせ完了後、XYZテーブル12が放電槽14をZ方向(鉛直方向上向き)に移動させることにより、工具電極11が工作物15に対して相対的に降下する。この降下により工具電極11の下端側は入口側15dから出口側15eに向かって下向きに貫通穴15aへ挿入される(図4(A),図5(A))。先端部32が備える円錐部33が加工部位であるバリ15cと対向する位置まで、工具電極11が降下する。次に、モータON/OFF制御器24が直流モータ4にオン信号出力して工具電極11を回転させる(図5(B))。また、放電加工電源21が工作物15と工具電極11に対する電源電圧の印加を開始する。工具電極11がふれまわりすることにより先端部32とバリ15cとの間の放電隙間Gが狭まり(図4(B),図5(C))、工具電極11の先端部32との間に放電加工電源21からの電源電圧により放電が生じる。本実施形態では、放電中の工具電極11の工作物15の対する水平方向(XY方向)及び鉛直方向(Z方向)の位置は一定に保持される。本実施形態では、バリ15cが除去されて貫通穴15aの出口側15eにテーパ面15fが形成されるまで放電加工が継続される。なお、バリ15cの除去が完了した時点で放電加工を終了してもよいし、バリ15cが生じていない貫通穴15aの縁部にテーパ面15fを形成してもよい。   First, the XYZ table 12 moves the discharge tank 14 in the XY direction, so that the tool electrode 11 moves relative to the workpiece 15 in the XY direction. By this relative movement, the tool electrode 11 is positioned relative to the through hole 15a. To be combined. In this embodiment, the center line Ct of the tool electrode 11 is aligned so as to coincide with the hole center line Cb of the through hole 15a (FIG. 4A). After the alignment is completed, the XYZ table 12 moves the discharge tank 14 in the Z direction (vertically upward), so that the tool electrode 11 is lowered relative to the workpiece 15. By this lowering, the lower end side of the tool electrode 11 is inserted downward into the through hole 15a from the inlet side 15d toward the outlet side 15e (FIGS. 4A and 5A). The tool electrode 11 is lowered to a position where the conical portion 33 provided in the tip end portion 32 is opposed to the burr 15c which is a processing site. Next, the motor ON / OFF controller 24 outputs an ON signal to the DC motor 4 to rotate the tool electrode 11 (FIG. 5B). Further, the electric discharge machining power source 21 starts to apply the power source voltage to the workpiece 15 and the tool electrode 11. When the tool electrode 11 is swung around, the discharge gap G between the tip 32 and the burr 15c is narrowed (FIGS. 4B and 5C), and the discharge is generated between the tip 32 of the tool electrode 11. Discharge occurs due to the power supply voltage from the machining power supply 21. In the present embodiment, the positions of the tool electrode 11 being discharged with respect to the workpiece 15 in the horizontal direction (XY direction) and the vertical direction (Z direction) are kept constant. In the present embodiment, electric discharge machining is continued until the burr 15c is removed and the tapered surface 15f is formed on the outlet side 15e of the through hole 15a. The electrical discharge machining may be terminated when the removal of the burr 15c is completed, or the tapered surface 15f may be formed at the edge of the through hole 15a where the burr 15c is not generated.

以下、本実施形態における放電加工中の放電隙間Gの制御について説明する。本実施形態では、モータON/OFF制御器24から直流モータ4に対して出力するオン信号とオフ信号の切り換えにより工具電極11の回転速度を制御することでふれまわりの振幅A(図4(B)参照)を制御し、振幅Aを制御することにより放電隙間Gを制御する。モータON/OFF制御器24から直流モータ4に対してオフ信号が出力されると直流モータ4に対する通電が停止されるが、慣性により直流モータ4の出力軸4aは回転を継続する。そのため、オフ信号とオン信号の切り換えによって直流モータ4の回転速度、つまり工具電極11の回転速度を制御できる。   Hereinafter, control of the discharge gap G during electric discharge machining in the present embodiment will be described. In this embodiment, the amplitude A of the whirling is controlled by controlling the rotational speed of the tool electrode 11 by switching between an ON signal and an OFF signal output from the motor ON / OFF controller 24 to the DC motor 4 (FIG. 4B). )) And the discharge gap G is controlled by controlling the amplitude A. When an off signal is output from the motor ON / OFF controller 24 to the DC motor 4, the energization to the DC motor 4 is stopped, but the output shaft 4a of the DC motor 4 continues to rotate due to inertia. Therefore, the rotational speed of the DC motor 4, that is, the rotational speed of the tool electrode 11 can be controlled by switching between the off signal and the on signal.

図1及び図6を参照して放電隙間Gの制御をより詳細に説明する。放電加工電源21が工具電極11と工作物15に印加する電源電圧は矩形パルス波状である。例えば、極間電圧検出器22で検出される極間電圧Vgapは放電隙間Gが広いために放電が生じていない状態(極間状態が開放状態(図6の符号(1)))では電源電圧となり、放電隙間Gが適切に設定されて放電が発生している状態(正常放電状態(図6の符号(2))では放電電圧となり、放電隙間Gがなく工具電極11と工作物15が短絡状態(図6の符号(3))ではほぼ0Vとなる。極間電圧波形演算処理器23は極間電圧検出器22が検出した極間電圧Vgapを積分処理し、積分処理した電圧を閾値THと比較する。この閾値THは放電隙間Gが狭くなり工具電極11が工作物15に接触しつつある状態(短絡が生じつつある状態)に相当する値(0Vに近い値)である。極間電圧波形演算処理器23が積分処理後の極間電圧Vgapが閾値TH以上であることを検出している間は、モータON/OFF制御器24はオン信号を直流モータ4に出力する。オン信号が入力されているときには、直流モータ4の回転速度は上昇し、工具電極11のふれまわりの振幅Aが増大して放電隙間Gは狭まる。一方、極間電圧波形演算処理器23が積分処理後の極間電圧Vgapが閾値THを下回ることを検出している間は、モータON/OFF制御器24はオフ信号を直流モータ4に出力する。オフ信号が入力されているときには、直流モータ4の回転速度が降下し、工具電極11のふれまわりの振幅Aが減少して放電隙間Gが拡がる。以上のように、極間電圧Vgapに応じたオン信号とオフ信号の切り換えによって直流モータ4の回転速度を制御することで、放電隙間Gは適切な距離で維持され、最適な条件で放電加工が進行する。   The control of the discharge gap G will be described in more detail with reference to FIGS. The power supply voltage applied to the tool electrode 11 and the workpiece 15 by the electric discharge machining power supply 21 is a rectangular pulse wave. For example, the inter-electrode voltage Vgap detected by the inter-electrode voltage detector 22 is a power supply voltage in a state in which no discharge occurs because the discharge gap G is wide (the inter-electrode state is an open state (reference numeral (1) in FIG. 6)). Thus, in the state where the discharge gap G is appropriately set and discharge is occurring (normal discharge state (reference numeral (2) in FIG. 6)), the discharge voltage is obtained, and there is no discharge gap G and the tool electrode 11 and the workpiece 15 are short-circuited. In the state (symbol (3) in FIG. 6), the voltage is approximately 0 V. The inter-electrode voltage waveform processor 23 integrates the inter-electrode voltage Vgap detected by the inter-electrode voltage detector 22, and sets the integrated voltage to the threshold value TH. This threshold value TH is a value (a value close to 0 V) corresponding to a state where the discharge gap G is narrowed and the tool electrode 11 is in contact with the workpiece 15 (a state where a short circuit is occurring). The voltage Vgap after the integration processing by the voltage waveform processor 23 is While detecting the value TH or more, the motor ON / OFF controller 24 outputs an ON signal to the DC motor 4. When the ON signal is input, the rotational speed of the DC motor 4 increases. Then, the amplitude A around the contact of the tool electrode 11 is increased and the discharge gap G is narrowed, while the inter-electrode voltage waveform calculation processor 23 detects that the inter-electrode voltage Vgap after the integration processing is below the threshold value TH. In the meantime, the motor ON / OFF controller 24 outputs an OFF signal to the DC motor 4. When the OFF signal is input, the rotational speed of the DC motor 4 decreases, and the amplitude A of the whirling of the tool electrode 11 is reduced. As a result, the discharge gap G is expanded and the discharge gap G is maintained at an appropriate distance by controlling the rotational speed of the DC motor 4 by switching between the on signal and the off signal in accordance with the interelectrode voltage Vgap. In optimal conditions Electrostatic processing progresses.

本実施形態の放電加工装置1には、特に以下の利点がある。まず、工具電極11のふれまわり現象を用いて放電加工を行い、放電隙間Gを工具電極11の回転速度によって制御するものであるため、簡易な構造・制御で加工が困難な工作物15の貫通穴15aの出口側15eのバリ取りや面取り加工を実現できる。具体的には、工具電極11を回転させるための直流モータ4等の比較的簡単な機構と、極間電圧Vgapに基づいて直流モータ4の回転速度を制御する機構とによりバリ取りや面取り加工を実現でき、工具電極11を偏心回転させる必要も、高速制御を行う必要もない。また、放電加工によるため、工作物15に対する機械的な力の影響がほとんどなく、導電性材料であれば材料の硬さに関係なく容易に加工を行うことができ、加工能率も高い。   The electric discharge machining apparatus 1 of the present embodiment has the following advantages in particular. First, since electric discharge machining is performed using the whirling phenomenon of the tool electrode 11 and the electric discharge gap G is controlled by the rotation speed of the tool electrode 11, the penetration of the workpiece 15 that is difficult to machine with a simple structure and control is performed. Deburring and chamfering of the outlet side 15e of the hole 15a can be realized. Specifically, deburring and chamfering are performed by a relatively simple mechanism such as a DC motor 4 for rotating the tool electrode 11 and a mechanism for controlling the rotational speed of the DC motor 4 based on the interelectrode voltage Vgap. This can be realized, and there is no need to rotate the tool electrode 11 eccentrically or to perform high-speed control. Moreover, since it is based on electric discharge machining, there is almost no influence of mechanical force on the workpiece 15, and a conductive material can be easily machined regardless of the hardness of the material, and the machining efficiency is high.

(第2実施形態)
図7に示す本発明の第2実施形態に係る放電加工装置1は、第1実施形態のモータON/OFF制御器24(図1)に代えて、モータ回転数制御器35を備える。また、極間電圧波形演算処理器23の機能が第1実施形態と異なる。図8を参照すると、極間電圧波形演算処理器23は極間電圧検出器22が検出した極間電圧Vgapを積分処理し、モータ回転数制御器35は積分処理された極間電圧Vgapに対応して回転数を指示する電圧信号を直流モータ4に出力する。積分処理された極間電圧Vgapが0V(短絡状態)に向けて降下すると、それに対応して電圧信号の電圧も0Vに向けて降下する。電圧信号の電圧が降下すると直流モータ4の回転数が低下し、その結果工具電極11のふれまわりの振幅Aが減少して放電隙間Gが拡がる。逆に、積分処理された極間電圧Vgapが上昇すると、それに対応して電圧信号の電圧も上昇する。電圧信号の電圧が上昇すると直流モータ4の回転数が上昇し、その結果工具電極11のふれまわりの振幅Aが増加して放電隙間Gが狭まる。
(Second Embodiment)
The electric discharge machining apparatus 1 according to the second embodiment of the present invention shown in FIG. 7 includes a motor rotation speed controller 35 instead of the motor ON / OFF controller 24 (FIG. 1) of the first embodiment. Further, the function of the inter-electrode voltage waveform calculation processor 23 is different from that of the first embodiment. Referring to FIG. 8, the inter-electrode voltage waveform calculation processor 23 integrates the inter-electrode voltage Vgap detected by the inter-electrode voltage detector 22, and the motor speed controller 35 corresponds to the integrated inter-electrode voltage Vgap. Then, a voltage signal indicating the rotation speed is output to the DC motor 4. When the inter-electrode voltage Vgap subjected to the integration process decreases toward 0V (short circuit state), the voltage signal voltage also decreases correspondingly toward 0V. When the voltage of the voltage signal decreases, the rotational speed of the DC motor 4 decreases, and as a result, the amplitude A around the contact of the tool electrode 11 decreases and the discharge gap G increases. On the contrary, when the inter-electrode voltage Vgap subjected to the integration process increases, the voltage of the voltage signal also increases correspondingly. When the voltage of the voltage signal rises, the rotational speed of the DC motor 4 rises. As a result, the amplitude A around the contact of the tool electrode 11 increases and the discharge gap G narrows.

本実施形態の放電加工装置1は、工具電極11のふれまわり現象を用いて放電加工を行い、放電隙間Gを工具電極11の回転速度によって制御するものであるため、簡易な構造・制御で加工が困難な工作物15の貫通穴15aの出口側15eのバリ取りや面取り加工を実現できる。特に、極間電圧Vgapに対応して直流モータ4に回転数を指示するので、ふれまわりによって生じる放電隙間Gをより適切に制御できる。また、放電加工によるため、工作物15に対する機械的な力の影響がほとんどなく、導電性材料であれば材料の硬さに関係なく容易に加工を行うことができ、加工能率も高い。   The electric discharge machining apparatus 1 of the present embodiment performs electric discharge machining using the whirling phenomenon of the tool electrode 11 and controls the electric discharge gap G according to the rotation speed of the tool electrode 11, so that machining is performed with a simple structure and control. Deburring or chamfering of the exit side 15e of the through hole 15a of the workpiece 15 that is difficult to achieve can be realized. In particular, since the rotational speed is instructed to the DC motor 4 corresponding to the inter-electrode voltage Vgap, the discharge gap G caused by the whirling can be controlled more appropriately. Moreover, since it is based on electric discharge machining, there is almost no influence of mechanical force on the workpiece 15, and a conductive material can be easily machined regardless of the hardness of the material, and the machining efficiency is high.

第2実施形態のその他の構成及び作用は第1実施形態と同様であるので、同一の要素には同一の符号を付して説明を省略する。   Since other configurations and operations of the second embodiment are the same as those of the first embodiment, the same elements are denoted by the same reference numerals and description thereof is omitted.

(第3実施形態)
第1及び第2実施形態では、モータON/OFF制御器24(図1)やモータ回転数制御器35(図7)により直流モータ4による工具電極11の回転速度を制御してふれまわりの振幅Aを制御することで、放電隙間Gを制御している。これに対して、図9に示す本発明の第3実施形態に係る放電加工装置1では、直流モータ4の回転速度は一定速度(危険速度付近の速度)に保持し、工具電極11のふれまわりの振幅Aを一定値に保持している。そして、放電隙間Gの制御は工具電極11を工作物15に対して鉛直方向(Z方向)に昇降させることにより昇降している。具体的には、放電加工中にXYZテーブル制御器25がXYZテーブル12を鉛直方向(Z方向)に昇降させることにより、工具電極11を工作物15に対して相対的に昇降させている。図11を参照すると、工具電極11が工作物15に対して上昇すると放電隙間Gが狭まる一方、工具電極11が工作物15に対して降下する放電隙間Gが拡がる。
(Third embodiment)
In the first and second embodiments, the rotation speed of the tool electrode 11 by the DC motor 4 is controlled by the motor ON / OFF controller 24 (FIG. 1) or the motor rotation speed controller 35 (FIG. 7), and the amplitude of the whirling is detected. By controlling A, the discharge gap G is controlled. In contrast, in the electric discharge machining apparatus 1 according to the third embodiment of the present invention shown in FIG. 9, the rotational speed of the DC motor 4 is maintained at a constant speed (speed near the critical speed), and the tool electrode 11 is swung around. Is maintained at a constant value. The discharge gap G is controlled by moving the tool electrode 11 up and down in the vertical direction (Z direction) with respect to the workpiece 15. Specifically, the XYZ table controller 25 raises and lowers the tool electrode 11 relative to the workpiece 15 by raising and lowering the XYZ table 12 in the vertical direction (Z direction) during electric discharge machining. Referring to FIG. 11, when the tool electrode 11 is raised with respect to the workpiece 15, the discharge gap G is narrowed, while the discharge gap G where the tool electrode 11 is lowered with respect to the workpiece 15 is widened.

図10を併せて参照すると、極間電圧波形演算処理器23は極間電圧検出器22が検出した極間電圧Vgapを積分処理し、積分処理した電圧を閾値THと比較する。この閾値THは放電隙間Gが狭くなり工具電極11が工作物15に接触しつつある状態(短絡が生じつつある状態)に相当する値(0Vに近い値)である。極間電圧波形演算処理器23が積分処理後の電圧が閾値TH以上であることを検出している間は、XYZテーブル制御器25は降下を指示する信号をXYZテーブル12に出力する。XYZテーブル12により放電槽14と共に工作物15が降下すると、工具電極11は工作物15に対して上昇することになるので、放電隙間Gは狭まる。一方、極間電圧波形演算処理器23が積分処理後の極間電圧Vgapが閾値THを下回ることを検出している間は、XYZテーブル制御器25は上昇を指示する信号をXYZテーブル12に出力する。XYZテーブル12により加工槽14と共に工作物15が上昇すると、工具電極11は工作物15に対して降下することになるので、放電隙間Gは拡がる。以上のように、極間電圧Vgapに応じて工具電極11の工作物15に対する昇降を制御することで、放電隙間Gは適切な距離で維持され、最適な条件で放電加工が進行する。本実施形態では、工具電極11と工作物15のZ方向の相対位置制御をXYZテーブル制御器25により行っているが,Z方向制御を工具電極側、例えばフレーム3にZ方向の制御軸を設ける等によっても行うことができる。   Referring also to FIG. 10, the inter-electrode voltage waveform calculation processor 23 integrates the inter-electrode voltage Vgap detected by the inter-electrode voltage detector 22, and compares the integrated voltage with the threshold value TH. This threshold value TH is a value (a value close to 0 V) corresponding to a state where the discharge gap G is narrowed and the tool electrode 11 is in contact with the workpiece 15 (a state where a short circuit is occurring). While the inter-electrode voltage waveform calculation processor 23 detects that the voltage after the integration processing is equal to or higher than the threshold value TH, the XYZ table controller 25 outputs a signal for instructing a drop to the XYZ table 12. When the workpiece 15 is lowered together with the discharge tank 14 by the XYZ table 12, the tool electrode 11 is raised with respect to the workpiece 15, so that the discharge gap G is narrowed. On the other hand, while the inter-electrode voltage waveform calculation processor 23 detects that the inter-electrode voltage Vgap after the integration processing is below the threshold value TH, the XYZ table controller 25 outputs a signal for instructing an increase to the XYZ table 12. To do. When the workpiece 15 is lifted together with the machining tank 14 by the XYZ table 12, the tool electrode 11 is lowered with respect to the workpiece 15, so that the discharge gap G is expanded. As described above, by controlling the elevation of the tool electrode 11 with respect to the workpiece 15 according to the interelectrode voltage Vgap, the discharge gap G is maintained at an appropriate distance, and the electric discharge machining proceeds under optimum conditions. In the present embodiment, the relative position control of the tool electrode 11 and the workpiece 15 in the Z direction is performed by the XYZ table controller 25. However, the Z direction control is performed on the tool electrode side, for example, the frame 3, by providing a Z direction control axis. Etc. can also be performed.

本実施形態の放電加工装置1は、工具電極11のふれまわり現象を用いて放電加工を行い、工具電極11の工作物15に対する相対高さの昇降制御によって放電隙間Gをするものであるため、簡易な構造・制御で加工が困難な工作物15の貫通穴15aの出口側15eのバリ取りや面取り加工を実現できる。また、放電加工によるため、工作物15に対する機械的な力の影響がほとんどなく、導電性材料であれば材料の硬さに関係なく容易に加工を行うことができ、加工能率も高い。   Since the electric discharge machining apparatus 1 of the present embodiment performs electric discharge machining using the whirling phenomenon of the tool electrode 11 and forms the electric discharge gap G by the elevation control of the relative height of the tool electrode 11 with respect to the workpiece 15. Deburring and chamfering of the exit side 15e of the through hole 15a of the workpiece 15 which is difficult to machine with a simple structure and control can be realized. Moreover, since it is based on electric discharge machining, there is almost no influence of mechanical force on the workpiece 15, and a conductive material can be easily machined regardless of the hardness of the material, and the machining efficiency is high.

第3実施形態のその他の構成及び作用は第1実施形態と同様であるので、同一の要素には同一の符号を付して説明を省略する。   Since other configurations and operations of the third embodiment are the same as those of the first embodiment, the same elements are denoted by the same reference numerals and description thereof is omitted.

図12(A)〜(D)は、工具電極11の種々の態様を示す。図12(A)の工具電極11は軸部31と先端部32が一体構造である。図12(B)の工具電極11では先端部32は軸部31と別体であり先端部32に形成した穴32aに軸部31の挿通した状態で両者を固定している。図12(C)の工具電極11の先端部32は、円錐部33のみを備えており円柱部34は備えていない。前述のように円柱部34は質量調整により危険速度の設定のために設けられているので、適切な危険速度が得られる場合には円柱部34を設ける必要はない。加工対象となる貫通穴15aの直径が小さい場合、円錐部33の加工が容易でない場合もある。この場合には、図12(D)の工具電極11のように、軸部31の先端側を屈曲してすることで先端部32を形成してもよい。この場合、軸部31の先端の屈曲角度θbは円錐部33のテーパ角θtに相当する。   12A to 12D show various modes of the tool electrode 11. In the tool electrode 11 of FIG. 12A, the shaft portion 31 and the tip portion 32 have an integral structure. In the tool electrode 11 of FIG. 12 (B), the tip portion 32 is separate from the shaft portion 31, and both are fixed in a state where the shaft portion 31 is inserted into a hole 32 a formed in the tip portion 32. The tip portion 32 of the tool electrode 11 in FIG. 12C includes only the conical portion 33 and does not include the cylindrical portion 34. As described above, since the cylindrical portion 34 is provided for setting the critical speed by adjusting the mass, it is not necessary to provide the cylindrical portion 34 when an appropriate dangerous speed can be obtained. When the diameter of the through hole 15a to be processed is small, the processing of the conical portion 33 may not be easy. In this case, the distal end portion 32 may be formed by bending the distal end side of the shaft portion 31 as in the tool electrode 11 of FIG. In this case, the bending angle θb at the tip of the shaft portion 31 corresponds to the taper angle θt of the conical portion 33.

図13に示す貫通穴15aが穴中心線Ctが出口側15eの工作物15の表面に対して傾斜している穴(傾斜穴)である場合にも、第1から第3実施形態の放電加工装置1によりバリ取りや放電加工を施すことができる。この場合、貫通穴(傾斜穴)15aの穴中心線Cbが鉛直方向に延びる姿勢となるように工作物15傾けて保持し、中心線Ctが穴中心線Cbに対して水平方向にずれ量δだけずれた状態となるように工具電極11を貫通穴15aに挿入する。仮に、貫通穴(傾斜穴)15aの穴中心線Cbに対して中心線Ctが一致する状態で工具電極11を貫通穴15aに挿入した場合、貫通穴15aの縁部の位置毎の放電隙間Gが不均一となる(縁部の位置によって放電隙間Gが狭い個所と広い個所が生じる)。ずれ量δを適切に設定することで貫通穴15aの縁部全周で放電隙間Gを均一化でき(図13において放電隙間G1,G2が同じなる。)。その結果、貫通穴15aの縁部全周に対して均一に放電加工を施すことができる。   Also when the through hole 15a shown in FIG. 13 is a hole (inclined hole) in which the hole center line Ct is inclined with respect to the surface of the workpiece 15 on the outlet side 15e, the electric discharge machining of the first to third embodiments. The apparatus 1 can perform deburring and electric discharge machining. In this case, the workpiece 15 is tilted and held so that the hole center line Cb of the through hole (inclined hole) 15a extends in the vertical direction, and the center line Ct is displaced in the horizontal direction δ with respect to the hole center line Cb. The tool electrode 11 is inserted into the through-hole 15a so as to be shifted by a distance. If the tool electrode 11 is inserted into the through hole 15a in a state where the center line Ct coincides with the hole center line Cb of the through hole (inclined hole) 15a, the discharge gap G for each position of the edge of the through hole 15a. Becomes non-uniform (where the discharge gap G is narrow and wide depending on the position of the edge). By appropriately setting the deviation amount δ, the discharge gap G can be made uniform over the entire periphery of the edge of the through hole 15a (the discharge gaps G1 and G2 are the same in FIG. 13). As a result, electric discharge machining can be performed uniformly on the entire periphery of the edge of the through hole 15a.

第1から第3実施形態では、放電加工中には工具電極11を工作物15に対する水平面(XY平面)上の位置を固定しているが、貫通穴15aの形状に応じて放電加工中には工具電極11を工作物15に対して水平面上で移動させてもよい。例えば、図14に示すように貫通穴15aが断面円形ではなく工具電極11の先端部32の直径D2(図3)に近い狭い溝幅を有する長溝穴である場合、工具電極11をふれまわりさせつつ水平方向に直線状の移動経路で移動させることにより、貫通穴15aの縁部全周に対してバリ取りや放電加工を施すことができる。また、図15に示すように貫通穴15aが断面円形ではなく工具電極11の先端部32の直径D2よりも大幅に広い溝幅を有する長溝穴である場合、工具電極11をふれまわりさせつつ貫通穴(長溝穴)の縁部に沿った無端状の移動経路で移動させることにより、貫通穴15aの縁部全周に対してバリ取りや放電加工を施すことができる。   In the first to third embodiments, the position of the tool electrode 11 on the horizontal plane (XY plane) with respect to the workpiece 15 is fixed during electric discharge machining, but during electric discharge machining according to the shape of the through hole 15a. The tool electrode 11 may be moved on the horizontal plane with respect to the workpiece 15. For example, as shown in FIG. 14, when the through-hole 15a is not a circular cross section but a long slot having a narrow groove width close to the diameter D2 (FIG. 3) of the tip 32 of the tool electrode 11, the tool electrode 11 is swung around. However, deburring and electric discharge machining can be performed on the entire periphery of the edge of the through hole 15a by moving the straight line along the horizontal movement path. Further, as shown in FIG. 15, when the through hole 15a is not a circular cross section but is a long slot having a groove width that is significantly wider than the diameter D2 of the tip 32 of the tool electrode 11, the tool electrode 11 is passed through while being swung around. By moving along an endless movement path along the edge of the hole (long slot hole), deburring or electric discharge machining can be performed on the entire periphery of the edge of the through hole 15a.

本発明の第1実施形態に係る放電加工装置を示す模式図。The schematic diagram which shows the electric discharge machining apparatus which concerns on 1st Embodiment of this invention. (A)、(B)、及び(C)は工作物の一例を示す断面図。(A), (B), and (C) are sectional views showing an example of a workpiece. 工具電極を示す模式図。The schematic diagram which shows a tool electrode. (A)は工具電極が穴に挿入される状態を示す模式図、(B)は工具電極のふれまわり状態を示す模式図。(A) is a schematic diagram which shows the state in which a tool electrode is inserted in a hole, (B) is a schematic diagram which shows the whirling state of a tool electrode. (A)は工具電極が穴に挿入される状態を示す模式図、(B)は工具電極の回転開始時を示す模式図、(C)はふれまわり状態を示す模式図、(D)はバリ取り完了時を示す模式図。(A) is a schematic diagram showing a state in which the tool electrode is inserted into the hole, (B) is a schematic diagram showing the start of rotation of the tool electrode, (C) is a schematic diagram showing a swirling state, and (D) is a varistor. FIG. 第1実施形態における放電加工電源の出力波形、極間電圧検出器の検出波形、極間電圧波形演算処理器の出力波形、及びモータON/OFF制御器の出力波形を示す線図。The diagram which shows the output waveform of the electrical discharge machining power supply in 1st Embodiment, the detection waveform of an interelectrode voltage detector, the output waveform of an interelectrode voltage waveform arithmetic processing unit, and the output waveform of a motor ON / OFF controller. 本発明の第2実施形態に係る放電加工装置を示す模式図。The schematic diagram which shows the electric discharge machining apparatus which concerns on 2nd Embodiment of this invention. 第2実施形態における放電加工電源の出力波形、極間電圧検出器の検出波形、極間電圧波形演算処理器の出力波形、及びモータ回転数制御器の出力波形を示す線図。The diagram which shows the output waveform of the electrical discharge machining power supply in 2nd Embodiment, the detection waveform of an interelectrode voltage detector, the output waveform of an interelectrode voltage waveform arithmetic processing unit, and the output waveform of a motor rotation speed controller. 本発明の第3実施形態に係る放電加工装置を示す模式図。The schematic diagram which shows the electric discharge machining apparatus which concerns on 3rd Embodiment of this invention. 第3実施形態における放電加工電源の出力波形、極間電圧検出器の検出波形、極間電圧波形演算処理器の出力波形、及びXYZテーブル制御器の出力波形を示す線図。The diagram which shows the output waveform of the electrical discharge machining power supply in 3rd Embodiment, the detection waveform of an interelectrode voltage detector, the output waveform of an interelectrode voltage waveform arithmetic processor, and the output waveform of an XYZ table controller. 工具電極の昇降による放電隙間の調整を説明するための概念図。The conceptual diagram for demonstrating adjustment of the discharge gap by raising / lowering of a tool electrode. (A)は軸部と先端部が一体の工具電極を示す模式図、(B)は軸部と先端部が別体の工具電極を示す模式図、(C)は先端部が円錐部のみを備え円柱部を備えない工具電極を示す模式図、(D)は軸部の下端を屈曲して形成した先端部を備える工具電極を示す模式図。(A) is a schematic diagram showing a tool electrode with an integral shaft and tip, (B) is a schematic diagram showing a separate tool electrode with a shaft and tip, and (C) is a tip with only a conical portion. The schematic diagram which shows the tool electrode which is not provided with a provided cylindrical part, (D) is a schematic diagram which shows the tool electrode provided with the front-end | tip part formed by bending the lower end of a shaft part. 傾斜穴の場合の工具電極の挿入位置を示す模式図。The schematic diagram which shows the insertion position of the tool electrode in the case of an inclined hole. 狭幅の長溝穴の場合の工具電極の水平面上の移動経路を示す模式的な平面図。The typical top view which shows the movement path | route on the horizontal surface of the tool electrode in the case of a narrow slot hole. 広幅の長溝穴の場合の工具電極の水平面上の移動経路を示す模式的な平面図。The typical top view which shows the movement path | route on the horizontal surface of the tool electrode in the case of a wide slot hole.

符号の説明Explanation of symbols

1 放電加工装置
2 ベース
3 フレーム
4 直流モータ
4a 出力軸
5 ストレートシャンク
6 絶縁体
7 カップリング
8A,8B 軸受
9 チャック
11 工具電極
12 XYZテーブル
13 絶縁板
14 放電槽
15 工作物
15a 貫通穴
15b 大径貫通穴
15c バリ
15d 入口側
15e 出口側
15f テーパ面
16 保持機構
21 放電加工電源
22 極間電圧検出器
23 極間電圧波形演算処理器
24 モータON/OFF制御器
25 XYZテーブル制御器
31 軸部
32 先端部
33 円錐部
34 円柱部
35 モータ回転数制御器
DESCRIPTION OF SYMBOLS 1 Electrical discharge machining apparatus 2 Base 3 Frame 4 DC motor 4a Output shaft 5 Straight shank 6 Insulator 7 Coupling 8A, 8B Bearing 9 Chuck 11 Tool electrode 12 XYZ table 13 Insulating plate 14 Discharge tank 15 Workpiece 15a Through hole 15b Large diameter Through hole 15c Burr 15d Inlet side 15e Outlet side 15f Tapered surface 16 Holding mechanism 21 Electric discharge machining power source 22 Electrode voltage detector 23 Electrode voltage waveform processor 24 Motor ON / OFF controller 25 XYZ table controller 31 Shaft part 32 Tip portion 33 Cone portion 34 Column portion 35 Motor rotation speed controller

Claims (17)

中心線に沿って延びる軸状であって先端側が工作物の加工部位近傍に配置される工具電極と、
前記工作物と前記工具電極との間に電源電圧を印加する放電加工電源と、
前記工具電極の基端側を把持すると共に、前記中心線を回転中心として前記工具電極を回転させる回転駆動手段と
を備え、
前記回転駆動手段で回転された前記工具電極がふれまわりすることによって前記工具電極の先端側が前記加工部位に接近し、前記工具電極の先端側と前記加工部位との間の放電隙間が狭まり、それによって前記工具電極の前記先端側と前記加工部位との間に前記電源電圧による放電が生じる、放電加工装置。
A tool electrode that is axially extending along the center line and whose tip side is disposed in the vicinity of the machining site of the workpiece;
An electric discharge machining power supply for applying a power supply voltage between the workpiece and the tool electrode;
A rotation driving means for holding the base end side of the tool electrode and rotating the tool electrode around the center line as a rotation center;
When the tool electrode rotated by the rotation driving means is swung around, the tip side of the tool electrode approaches the machining site, and a discharge gap between the tip side of the tool electrode and the machining site is narrowed. An electric discharge machining apparatus in which discharge due to the power supply voltage is generated between the tip side of the tool electrode and the machining site.
前記加工部位は前記工作物に形成された貫通穴の出口側の縁部であり、
前記工具電極の前記先端側は貫通穴に入口側から挿入されて前記貫通穴の前記縁部近傍に配置される、請求項1に記載の放電加工装置。
The machining site is an edge on the exit side of a through hole formed in the workpiece,
The electric discharge machining apparatus according to claim 1, wherein the tip end side of the tool electrode is inserted into a through hole from an entrance side and is disposed in the vicinity of the edge of the through hole.
前記回転駆動手段による前記工具電極の回転の回転速度で前記ふれまわりの振幅を制御することにより前記放電隙間を制御する放電隙間制御手段を備える、請求項1又は請求項2に記載の放電加工装置。   3. The electric discharge machining apparatus according to claim 1, further comprising: a discharge gap control unit configured to control the discharge gap by controlling an amplitude of the swivel at a rotation speed of rotation of the tool electrode by the rotation driving unit. . 前記工具電極と前記工作物との間の電圧である極間電圧を検出する極間電圧検出手段と、
前記極間電圧検出手段によって検出される前記極間電圧を積分処理し、積分処理した前記極間電圧と閾値との比較に基づいて前記工具電極の前記先端側と前記工作物の加工部位の接触を検出する演算手段と
をさらに備え、
前記放電隙間制御手段は、前記演算手段が工具電極の前記先端側と前記工作物の加工部位の接触を検出していなければ前記回転駆動手段にオン信号を出力し、前記演算手段が工具電極の前記先端側と前記工作物の加工部位の接触を検出すると前記回転駆動手段にオフ信号を出力する、請求項3に記載の放電加工装置。
An inter-electrode voltage detection means for detecting an inter-electrode voltage that is a voltage between the tool electrode and the workpiece;
The interpolar voltage detected by the interpolar voltage detection means is integrated, and the contact between the tip side of the tool electrode and the machining part of the workpiece is based on a comparison between the integrated interpolar voltage and a threshold value. And a calculation means for detecting
The discharge gap control means outputs an ON signal to the rotation drive means if the calculation means has not detected contact between the tip side of the tool electrode and a machining part of the workpiece, and the calculation means The electric discharge machining apparatus according to claim 3, wherein an off signal is output to the rotation driving unit when contact between the tip side and a machining part of the workpiece is detected.
前記工具電極と前記工作物との間の電圧である極間電圧を検出する極間電圧検出手段と、
前記極間電圧検出手段によって検出される前記極間電圧を積分処理する演算手段と
をさらに備え、
前記放電隙間制御手段は、前記演算手段が積分処理した前記極間電圧に応じた回転数の信号を前記回転手段に出力する、請求項3に記載の放電加工装置。
An inter-electrode voltage detection means for detecting an inter-electrode voltage that is a voltage between the tool electrode and the workpiece;
And an arithmetic means for integrating the inter-electrode voltage detected by the inter-electrode voltage detection means,
The electric discharge machining apparatus according to claim 3, wherein the discharge gap control means outputs a signal of the number of rotations according to the inter-electrode voltage integrated by the calculation means to the rotation means.
前記工具電極の前記先端側の前記加工物に対する前記中心線方向の位置を制御することにより前記放電隙間を制御する放電隙間制御手段を備える、請求項1又は請求項2に記載の放電加工装置。   The electric discharge machining apparatus according to claim 1, further comprising: a discharge gap control unit that controls the discharge gap by controlling a position of the tool electrode on the tip side with respect to the workpiece in the center line direction. 前記工具電極を前記加工部位に沿って前記中心線に対して直交する面内で移動するように前記工作物に対して相対移動させる工具電極移動手段をさらに備える、請求項1から請求項6のいずれか1項に記載の放電加工装置。   The tool electrode moving means for moving the tool electrode relative to the workpiece so as to move in a plane perpendicular to the center line along the machining site is further provided. The electric discharge machining apparatus according to any one of claims. 前記工具電極は前記基端側から前記先端側に向けて延びる軸部と、この軸部の先端側に設けられて少なくとも円錐部を有する先端部とを備える、請求項1から請求項7のいずれか1項に記載の放電加工装置。   The said tool electrode is provided with the axial part extended toward the said front end side from the said base end side, and the front-end | tip part which is provided in the front end side of this axial part, and has a cone part at least. The electric discharge machining apparatus according to claim 1. 前記工具電極の前記先端部が、軸部と別の材料からなる、あるいは導電性を有する硬質材料又は導電性を有する焼結材料からなる、請求項8項に記載の放電加工装置。   The electric discharge machining apparatus according to claim 8, wherein the tip portion of the tool electrode is made of a material different from that of the shaft portion, or is made of a hard material having conductivity or a sintered material having conductivity. 前記工具電極は前記基端側から前記先端側に向けて延びる軸部と、この軸部の先端側を屈曲して形成した先端部とを備える、請求項1から請求項7のいずれか1項に記載の放電加工装置。     The said tool electrode is provided with the axial part extended toward the said front end side from the said base end side, and the front-end | tip part formed by bending the front end side of this axial part, The any one of Claims 1-7. The electric discharge machining apparatus according to 1. 中心線に沿って延びる軸状の工具電極の先端側を工作物の加工部位近傍に配置し、
前記工具電極の基端側を把持すると共に、前記中心線を回転中心として前記工具電極を回転させて前記工具電極をふれまわりさせ、
前記工作物と前記工具電極との間に電源電圧を印加し、
前記ふれまわりにより前記工具電極の先端側を前記加工部位に接近させて前記工具電極の先端側と前記加工部位との間の放電隙間を狭め、それによって前記工具電極の前記先端側と前記加工部位との間に前記電源電圧による放電が生じさせる、放電加工方法。
The tip side of the axial tool electrode extending along the center line is arranged near the machining part of the workpiece,
While gripping the base end side of the tool electrode, the tool electrode is rotated around the center line as a center of rotation, the tool electrode is swung around,
Applying a power supply voltage between the workpiece and the tool electrode;
The tip end side of the tool electrode is brought close to the machining site by the swirling, thereby narrowing a discharge gap between the tip side of the tool electrode and the machining site, and thereby the tip side of the tool electrode and the machining site. An electric discharge machining method in which a discharge due to the power supply voltage is generated between the two.
前記加工部位は前記工作物に形成された貫通穴の出口側の縁部であり、
前記工具電極の前記先端側を前記貫通穴に入口側から挿入して前記貫通穴の前記縁部近傍に配置する、請求項11に記載の放電加工方法。
The machining site is an edge on the exit side of a through hole formed in the workpiece,
The electric discharge machining method according to claim 11, wherein the tip end side of the tool electrode is inserted into the through hole from the entrance side and disposed near the edge of the through hole.
前記貫通穴は傾斜穴であり、前記工具電極を前記中心線が前記傾斜穴の穴中心線に対して前記中心線と直交する方向のずれを有するように前記傾斜穴に挿入する、請求項12に記載の放電加工方法。   The through hole is an inclined hole, and the tool electrode is inserted into the inclined hole so that the center line has a deviation in a direction perpendicular to the center line with respect to the hole center line of the inclined hole. The electric discharge machining method described in 1. 前記工具電極の回転の回転速度で前記ふれまわりの振幅を制御することにより前記放電隙間を制御する、請求項11から請求項13のいずれか1項に記載の放電加工方法。   The electric discharge machining method according to any one of claims 11 to 13, wherein the electric discharge gap is controlled by controlling an amplitude of the whirling around at a rotation speed of the tool electrode. 前記工具電極の前記先端側の前記加工物に対する前記中心線方向の位置を制御することにより前記放電隙間を制御する、請求項11から請求項13のいずれか1項に記載の放電加工方法。   The electric discharge machining method according to claim 11, wherein the discharge gap is controlled by controlling a position of the tool electrode in the center line direction with respect to the workpiece on the tip side. 前記工具電極を前記加工部位に沿って前記中心線に対して直交する面内で移動するように前記工作物に対して相対移動させる、請求項11から請求項15のいずれか1項に記載の放電加工方法。     The tool electrode according to any one of claims 11 to 15, wherein the tool electrode is moved relative to the workpiece so as to move in a plane orthogonal to the center line along the machining site. Electric discharge machining method. 部品に貫通穴を形成し、
中心線に沿って延びる軸状の工具電極の先端側を前記部品の加工部位近傍に配置し、
前記工具電極の基端側を把持すると共に、前記中心線を回転中心として前記工具電極を回転させて前記工具電極をふれまわりさせ、
前記部品と前記工具電極との間に電源電圧を印加し、
前記ふれまわりにより前記工具電極の先端側を前記加工部位に接近させて前記工具電極の先端側と前記加工部位との間の放電隙間を狭め、それによって前記工具電極の前記先端側と前記加工部位との間に前記電源電圧による放電を生じさせて放電加工する、部品の製造方法。
Form a through hole in the part,
The tip side of the axial tool electrode extending along the center line is arranged in the vicinity of the processing site of the part,
While gripping the base end side of the tool electrode, the tool electrode is rotated around the center line as a center of rotation, the tool electrode is swung around,
A power supply voltage is applied between the component and the tool electrode;
The tip end side of the tool electrode is brought close to the machining site by the swirling, thereby narrowing a discharge gap between the tip side of the tool electrode and the machining site, and thereby the tip side of the tool electrode and the machining site. A method of manufacturing a component, in which electric discharge machining is performed by generating electric discharge due to the power supply voltage.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012028830A1 (en) * 2010-09-02 2012-03-08 Snecma Electrode and facility for chamfering the corners of a metal workpiece
WO2018016158A1 (en) * 2016-07-22 2018-01-25 株式会社放電精密加工研究所 Method for manufacturing integrated impeller
JP2018518374A (en) * 2015-06-26 2018-07-12 ゼネラル・エレクトリック・カンパニイ Electromachining apparatus and method

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012028830A1 (en) * 2010-09-02 2012-03-08 Snecma Electrode and facility for chamfering the corners of a metal workpiece
FR2964335A1 (en) * 2010-09-02 2012-03-09 Snecma INSTALLATION OF ANGLE BREAKING ON A METAL PIECE
CN103079738A (en) * 2010-09-02 2013-05-01 斯奈克玛 Electrode and facility for chamfering the corners of a metal workpiece
CN103079738B (en) * 2010-09-02 2016-02-10 斯奈克玛 The device on the limit on the metal parts that fractures
JP2018518374A (en) * 2015-06-26 2018-07-12 ゼネラル・エレクトリック・カンパニイ Electromachining apparatus and method
US10843283B2 (en) 2015-06-26 2020-11-24 General Electric Company Apparatus and method for electrically machining
WO2018016158A1 (en) * 2016-07-22 2018-01-25 株式会社放電精密加工研究所 Method for manufacturing integrated impeller
EP3489524A4 (en) * 2016-07-22 2020-03-25 Hoden Seimitsu Kako Kenkyusho Co., Ltd. Method for manufacturing integrated impeller
US11103945B2 (en) 2016-07-22 2021-08-31 Hoden Seimitsu Kako Kenkyusho Co., Ltd. Integrated impeller manufacturing method

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