Mitsubishi Denki Kabushiki Kaisha

Mitsuyoshi Wada

Akihiro Goto

Yoshio Ozaki

Takashi Yuzawa

Hidehiko Tanaka

Yoshinori Asai

An electric-discharge machining apparatus for machining a workpiece by an electric discharge generated between a machining electrode and the workpiece, includes a correcting unit that corrects a machining amount input for machining the workpiece, based on a usage history of the machining electrode; and a control unit that controls a machining processing on the workpiece based on the machining amount corrected.

Electrical discharge machining apparatus

An electrical discharge machine for applying a pulsed voltage to a machining gap between an electrode and a workpiece disposed opposite thereto. An insulating dielectric fluid, such as oil or water mixed with a compound additive, is disposed in the gap. A positive polarity voltage and an opposite polarity voltage are applied via switches and respective impedances to the machining gap in order to generate a discharge for machining the workpiece. A pulse having a first polarity is applied to machine the workpiece and a pulse having a second polarity is applied when the first polarity pulse is not applied. A misfire pulse detector detects an undesired drop in the machining voltage by determining whether the first polarity voltage is in a range between two voltages, the first of which has a magnitude greater than the magnitude of the machining gap during discharge and the second of which has a magnitude greater than the magnitude of the first voltage.

Bipolar electrical discharge machine which detects misfire

An electrical discharge machine for applying a pulsed voltage to a machining gap between an electrode and a workpiece disposed opposite thereto. An insulating dielectric fluid, such as oil or water mixed with a compound additive, is disposed in the gap. A positive polarity voltage and an opposite polarity voltage are applied via switches and respective impedances to the machining gap in order to generate a discharge for machining the workpiece. A pulse having a first polarity is applied to machine the workpiece and a pulse having a second polarity is applied when the first polarity pulse is not applied. The time of application of the second polarity pulse is increased depending upon the number of short-circuits detected between the electrode and the workpiece.

Bipolar electrical discharge machine which adjusts voltage polarity

A machining operation end position detecting unit detects the end position for a machining operation at a (k-1)-th step. A machining operation starting position detecting unit detects the starting position for the machining operation at a k-th step. A machining position comparison unit compares them with each other. If the difference between them is less than a predetermined value, a signal is output to a machining condition changing unit and a control valve. As a result, the machining condition is changed, and a powdered substance is fed into a working fluid.

Electrical discharge apparatus and electrical discharge machining method

A method and apparatus for detecting the build up of tar on the electrode or workpiece in an electric discharge machine is achieved by determining the difference between a machining gap impedance found from dielectric fluid resistivity and an electrode area and a machining gap impedance actually measured.

Electrical discharge machine with tar build-up detector

An electrical discharge machine for applying a pulsed voltage to a machining gap between an electrode and a workpiece disposed opposite thereto. An insulating dielectric fluid, comprising an oil or water with compound additive, is disposed in the gap. A positive polarity voltage and an opposite polarity voltage are applied via switches and respective impedances to the machining gap in order to generate a discharge for machining the workpiece. The impedance values may be selectively set and the switching of the voltages controlled such as to apply a positive polarity voltage at the stop time of an opposite polarity pulsed voltage, whereby the average voltage approximates a predetermined value, preferably zero, during the stop time. Voltage control during the stop time will result in high speed and finish, especially for control in connection with a jump operation.

Electrical discharge machine with pulses of both polarities

An electrical discharge machine for applying a pulsed voltage to a machining gap between an electrode and a workpiece disposed opposite thereto. An insulating dielectric fluid, comprising an oil or water with compound additive, is disposed in the gap. A positive polarity voltage and an opposite polarity voltage are applied via switches and respective impedances to the machining gap in order to generate a discharge for machining the workpiece. A high frequency alternating current voltage is applied between the electrode and the workpiece when the first polarity and second polarity voltages are not being applied.

Electrical discharge machine

An electrical discharge machine for applying a pulsed voltage to a machining gap between an electrode and a workpiece disposed opposite thereto. An insulating dielectric fluid, including either oil or water with a compound additive, is disposed in the gap. A first voltage is applied to the machining gap. If a predetermined period of time passes and a discharge has not occurred at the machining gap, then a second voltage, opposite in polarity to the first voltage, is applied to the machining gap.

Electrical discharge machine which uses voltages of opposite polarity

A machining pulse control apparatus applies a first polarity pulse voltage during a machining operation and a second opposite polarity voltage in a machining stop period in which the electrode is moved away from and toward the workpiece during a jump operation. Preferably, the second opposite polarity is applied for a period of time sufficient to maintain the voltage across the machining gap at zero voltage. The amount of direct current voltage applied during the jump operation is adaptively controlled.

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Aichi, Japan

Mitsuyoshi Wada