Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Denki K.k.

Shigeo Yamada

Toshimitsu Sakakibara

Toshiro Oizumi

Tamio Takawashi

Tetsuro Ito

Yoshio Ozaki

Testuro Itoh

A method for electrochemical machining a work piece using an electrochemical machining device including a tool electrode opposing the workpiece across a predetermined machining gap and a device for supplying a pulse current to the machining gap via electrolyte provided in the machining gap includes the steps of determining a predetermined pulse current having a predetermined pulse width, selecting a plurality of partial pulse currents each having a predetermined partial pulse period, calculating a plurality of rest periods based on said partial pulse widths and applying the partial pulse currents, each of the partial pulse periods separated by at least one of the rest periods. According to the method of the present invention, the predetermined pulse width is in the range of about 10-50 msec. An electrochemical machining device, which includes a control unit, a tool electrode, a machining tank and circuitry for supplying a predetermined amount of the electrolyte to the machining gap during a dwell time between two sequential pulse currents to remove residual electrolytic products from the machining gap and the tool electrode is also disclosed.

Electrochemical machining process and equipment

A control apparatus for an EDM machining device includes electrode a position control servo system provided with a zero order hold circuit. This circuit issues a position control instruction which is preset in an error counter which outputs an electrode difference signal used to drive the electrode. The difference signal is also applied to a processor or the like wherein it is added to the position control instruction and applied to the zero order hold circuit.

Electrospark machining control device

An EDM machining apparatus is provided with means for automatic shut off upon completion of a machining process, including a voltage variation pattern detector capable of discriminating electrode penetration of the workpiece. Several other machining parameters, such as machining solution flow and pressure, machining depth, and electrode speed and direction may be used is secondary or confirmation detection factors, so as to positively detect the time of electrode penetration, and halt the machining process.

Breakthrough detection means for electric discharge machining apparatus

Herein disclosed is an electric discharge machine, by which, after the machining operation of a workpiece by an electrode has reached a predetermined position, the machining operation is further accomplished while rocking the electrode in a plane generally normal to the feeding direction of the workpiece for the machining operation. The workpiece has its respective portion uniformly machined by effecting the machining operation accompanied by the rocking motions for a preset period, e.g., either for a predetermined time period or a predetermined number of the rocking motions so that the precision of the finishing operation can be improved.

EDM controller for providing a rocking motion to the electrode for

In an electric discharge machine in which the machining gap between an electrode and a workpiece is maintained suitably by a control device having sampling, logic operation and holding functions, an up-down counter is provided for integration, over a predetermined period corresponding to the sampling period, servo signals from a discrimination circuit adapted to discriminate the conditions of the machining gap, so that sampling for all periods of time within the sampling period can be achieved.

Electric discharge machining control device

Electric discharge machine including rocking motion fine machining and

An electric discharge machining device is provided with detecting means operable to determine when a particular machining operation, e.g. the formation of a through-hole in a workpiece, has been completed. In all cases, the position of the electrode is monitored to determine the present machining depth, and whether this depth is the largest depth thus far achieved. The detection of an increasing machining depth is coupled with at least one other detection factor, such as electrode speed, machining fluid flow or machining fluid pressure, such that the penetration of the electrode through the workpiece can be positively sensed. In response to such an indication, a stop signal is output to the power supply unit, to end the machining operation.

A discharge machining apparatus wherein the workpiece is supported over an aperture in the work support plate on top of a tank at the machining station for cooperation with an electrode movable toward and away from the workpiece in alignment with the aperture. A machining solution recirculation device injects the solution into the tank and removes the solution from the tank at a greater rate than it is injected into the tank. Additional fluid is directed into the tank through the aperture between the workpiece and electrode. An additional conduit having a solenoid controlled valve is provided for supplying an excess of solution to the tank upon raising of the electrode to overflow the tank and remove all sludge and combustible gases. The exhaust pipe for the solution is also adjustably mounted within the tank to more effectively position the inlet of the exhaust pipe for the optimum removal of combustible gases. A pressure release valve is provided in the side wall of the tank to vent explosive gases and prevent damage to the workpiece and electrode.

Discharge machining apparatus

A discharge machining method for machining a workpiece by causing electric discharge between the workpiece and the machining electrode and an apparatus for practicing the method wherein, with the electrode confronting the workpiece in a primary machining direction and in the direction of a plane substantially perpendicular to the primary machining direction, the relative displacement of the electrode and workpiece is controlled in such a manner that a space is maintained between the electrode and the workpiece so that electric discharge occurs therein. The electrode is moved towards the intersections of straight lines which are parallel to and equally spaced from the contour of the electrode whereby the electrode is uniformly consumed. Very little abnormal arcing can occur. The machined workpiece has an excellent final configuration.

Method and apparatus for discharge machining polygonal contours

Electric discharge machine

An electrical discharge machine control device which controls the displacement of the relative positions of a machining electrode and a workpiece so that the relative positions of the electrode and workpiece are changed not only in the main direction in which the workpiece is machined with the electrode but also in a plane perpendicular to the Z-axis without rotating the electrode while a predetermined machining discharge gap is maintained between the electrode and the workpiece. The relative displacement in the perpendicular plane is displayed at an enlarged scale on an X-Y display device which may be a cathode-ray tube with the center of the displacement maintained at a predetermined origin point. An optical encoder detects the movement in the X-Y plane to provide a detection signal. The detection signal is applied through reversible counters to the horizontal and vertical deflection amplifiers of the display device.

Growing community of inventors

Aichi, Japan

Shigeo Yamada