Abstract: A method and apparatus for wire cutting electric discharge machining to achieve precise surfaces with Ra<0.1 microns. An intermittent operation is used with erosion pulses for primarily machining and erosion pulses for measuring any excursion of the wire electrode from the rest position. An evaluation unit is used to determine any excursions of the wire electrode from the rest position that might have been present during the preceding machining time, and a controller controls the machining process so that the wire electrode is practically straight during electroerosion.

Abstract: Disclosed is a wire electric discharge machining apparatus comprising a wire-driving system for feeding a wire electrode while opposing it to a workpiece, and a power supply unit for supplying electric power to the wire electrode, wherein electric discharge is effected between the wire electrode and the workpiece to machine the workpiece to have an arbitrary shape. The wire electrode is allowed to approach the workpiece to effect the electric discharge between the wire electrode and the workpiece so that the workpiece is machined to have an arbitrary shape, while a suction mechanism is used to remove undesirable matters including sludge together with a working fluid via cylindrical members from holes formed in the workpiece.

Abstract: The present invention relates to a porous electrode wire for use in electrical discharge machining and the method of manufacturing the same. The wire improves the machining speed at least 15% compared with a conventional zinc coated wire, which results from an increased cooling ability of the wire with a cooling liquid because of the increase in the surface area of the wire having porous surface morphology. Since the surface of the porous wire presents uniform profile of outer periphery rather than surface protrusions, it does not affect machining accuracy. Further, the porous nature of the wire is expected to improve flushability during the electrical discharge machining, providing spaces to eliminate particles of the machining. Therefore, in accordance with the method of the present invention, a zinc coated wire having improved performance of machining speed and flushability compared with a conventional coated wire can be provided without additional processes.

Abstract: A wire electrode for wire electro-discharge machining comprises a core, and a coating layer formed on an outer periphery of the core at least a surface layer of which contains copper. The coating layer comprises an alloy of copper and at least one element selected from the group consisting of Zn, Cs, Se, Te and Mg, with the copper content being about 55.5 wt % to about 75 wt %. The coating layer does not have an oxide film thereon other than a natural oxide film.

Abstract: A wire cut electric discharge machine according to the invention includes a machining tank storing a machining fluid, an upper arm disposed at an upper portion of the machining tank, a lower arm inserted into the machining tank, a wire electrode extending between the upper arm and the lower arm for performing electric discharge machining on a workpiece placed fixedly in the machining tank, a support member mounted to the machining tank for supporting the lower arm such that the lower arm is slidable relative to the machining tank and sealed from the machining tank, and an O-ring interposed between the lower arm and the support member. The support member has a groove formed all around its inner circumference, and the O-ring makes contact with sidewalls of the groove. Accordingly, even when the outside diameter of the O-ring varies depending on an error in diameter of the lower arm, contact between the sidewalls and the O-ring remains unchanged and fluid-tightness can be reliably ensured.

Abstract: A wire electrical discharge machine including a wire electrode for processing a workpiece while causing electrical discharge to take place with a working fluid interposed between the wire electrode and the workpiece, and an upper wire guide and a lower wire guide through which the wire electrode is passed and which have therein channels for the working fluid to flow therethrough, including: a working fluid nozzle fixed to a guide body portion and adapted to jet and supply the working fluid toward the workpiece; an electric supply die provided in the working fluid nozzle to energize the wire electrode by coming into contact therewith; a recessed portion for engagement with the wire electrode being provided in a surface of the electric supply die along a moving direction of the wire electrode; and a plurality of jetting ports for jetting the working fluid toward the wire electrode so as to press the wire electrode against the electric supply die.

Abstract: A wire electrical discharge machine having an upper wire guide and a lower wire guide through which a wire electrode is passed and which have therein channels for the working fluid to flow therethrough, including: ajet nozzle which is engaged with and fixed to an outer peripheral surface of a distal end portion of the upper wire guide, and is adapted to guide the wire electrode to a hole in the lower wire guide through use of the fluid; a working fluid nozzle for covering the jet nozzle and having a through hole in a central portion thereof and a collar portion in a periphery thereof; a retaining plate for fixing an outer peripheral portion of the working fluid nozzle including the collar portion, and the retaining plate having a channel for supplying and discharging the fluid; and a sealed space portion which is disposed between the collar portion of the working fluid nozzle and the retaining plate and expands and contracts due to the fluid which flows in or out through the channel.

Abstract: A wire electrical discharge machine includes a wire electrode for causing electrical discharge to take place between the wire electrode and a workpiece; a first roller and a second roller for feeding the wire electrode while nipping the wire electrode; wire conveyor for inserting the wire electrode into a portion between the first roller and the second roller by causing a fluid to flow to opposing portions of the first roller and the second roller; and driver for moving a distal end of the wire conveyor to a vicinity of the opposing portions, and for moving the distal end of the wire conveyor away from the opposing portions a predetermined distance upon completion of the insertion of the wire electrode into the nip between the first roller and the second roller.

Abstract: The present wire electrode for wire electro-discharge machining includes a core and a plurality of coating layers covering the outer peripheral surface of the core. The core and the plurality of coating layers are formed of different materials, and each of coating layers is made of a metal or a metal alloy including the metal selected from the group consisting of Cu, Sn, Ag, Al, Zn, Cs, Se, Te, Mg, Bi, Ti, P, In, Cr, and Fe.

Abstract: A controller of a wire electric discharge machine monitoring a change in thickness of a workpiece and a current density in real time, promoting a machining speed by preventing occurrence of disconnection of a wire electrode even when the change in the thickness is caused in the workpiece and improving a dispersion in a machining enlargement amount. A machining distance calculating device outputs a signal at each progress of machining by a predetermined distance &Dgr;x. A main pulse number storing device counts a main pulse number for discharge machining outputted from a main pulse generator during a time period of the signal. A thickness calculating device calculates the thickness from a reference main pulse number in machining a reference thickness, the main pulse number stored to the main pulse number storing device and the reference thickness at each reception of the signal. The calculated thickness, further, a machining current, the machining speed and a machining current density are displayed.

Abstract: A wire cut electric discharge machine which has a first wire guide movable relative to a workpiece in a first axial direction, and a second wire guide movable relative to a workpiece in a second axial direction which is parallel to the first axial direction, for machining the workpiece by generating an electrical discharge between a wire electrode traveling between the first and second wire guide, and the workpiece, where the sum of the degree of movement in the first axial direction and the degree of movement in the second axial direction is limited in order to prevent component parts of the device from striking one another.

Abstract: The present invention relates to a porous electrode wire for use in electrical discharge machining and the method of manufacturing the same. The wire improves the machining speed at least 15% compared with a conventional zinc coated wire, which results from an increased cooling ability of the wire with a cooling liquid because of the increase in the surface area of the wire having porous surface morphology. Since the surface of the porous wire presents uniform profile of outer periphery rather than surface protrusions, it does not affect machining accuracy. Further, the porous nature of the wire is expected to improve flushability during the electrical discharge machining, providing spaces to eliminate particles of the machining. Therefore, in accordance with the method of the present invention, a zinc coated wire having improved performance of machining speed and flushability compared with a conventional coated wire can be provided without additional processes.

Abstract: The shape of each electrical supply die for contact-supplying electricity to a wire electrode is changed to a cylindrical shape, and grooves are provided in its outer surface in parallel to the traveling direction of the wire, wherein upper electric supply is effected by contact-supplying of electricity at a projecting surface formed between adjacent ones of the grooves, while lower electric supply is effected by pressure contact-supplying of electricity by causing a concave surface to contact the groove.

Abstract: EDM according to the present invention involves an intermttent type of operation between erosion pulses and measurement pulses in order to circumvent an interfering self-control effect of an electrode during fine machining. To achieve shorter processing times, higher precision and better reproducibility, the method and apparatus determine with an electrical measurement the amount that an electrode is in contact with a workpiece during a measurement time that erosion has been interrupted. A pulse duty factor is then obtained from the contact amount to control further processing via, for example, the duration of the erosion pulses.

Abstract: A wire cut electric discharge machining apparatus for machining a workpiece using a wire electrode traveling vertically between upper and lower wire guide devices includes a work tank in which the lower wire guide device and the workpiece are disposed, a lower wire guide drive unit disposed outside the work tank for driving the lower wire guide device horizontally in a direction of a first axis, a connecting shaft for connecting the lower wire guide device and the lower wire guide drive unit, a guide rail extending from the outside to the inside of the work tank in the direction of the first axis and being movable relative to the work tank in the direction of a second axis perpendicular to the first axis, and a support provided on the first guide rail for movably supporting the lower wire guide device.

Abstract: A method for manufacturing thin-plate sintered compacts according to the present invention includes the steps of: forming a conductive sintered compact to have such a thickness as to cause a warp to a negligible degree; and slicing the conductive sintered compact, thereby cutting and dividing the conductive sintered compact into at least two wafers.

Abstract: A flushing device having therein a chamber into which dielectric fluid is supplied for injecting dielectric fluid into a machining gap formed between a workpiece being machined and a wire electrode in a wire-cut electric discharge machine, a nozzle movable between a first position and a second position that is nearer the workpiece than the first position, for directing the dielectric fluid in the chamber toward the machining gap; and a spring or other bias apparatus for holding the nozzle in the first position.

Abstract: An intermediate electrode guide is disposed between an electrode guide and an electrode holder. An intermediate electrode chuck of rubber elastic body is provided on the intermediate electrode guide. The intermediate electrode chuck has an insertion hole. The hole is enlarged when a fine hole machining electrode is inserted therein so as to facilitate such insertion. On the other hand, a diameter of the hole is lessened by driving a piston when feeding the electrode or machining the workpiece. Thus, the electrode is grasped by the intermediate chuck. The chuck and the electrode are rotated via bearings 13 and 19 so as to prevent shift of the electrode.

Abstract: A wire-cut discharge machine includes an extendable pipe which is provided in between a frame and a first wire guide to guide a wire electrode therein. To allow the first wire guide to move horizontally, a pair of spherical bearing mechanisms is provided; one is used for connecting a top end of a first pipe to a guide; and the other one is for connecting a bottom of a second pipe to the first wire guide. Therefore, due to the extendable pipe, broken wire electrodes can be connected automatically without fail and a workpiece can be electric discharge machined so that it can be tapered.

Abstract: A method for solving the problem that the machining accuracy in a corner part or in a circular arc is reduced by the line flexure during the wire-cut electric discharge machining. In the method, the controller of the wire-cut electric discharge machine with a built-in function of measuring error of wire flexure, after the machining, a detection voltage of the machine detects the machined groove. If the wire electrode comes into contact with the workpiece, the short-circuit caused by the wire flexure in the corner part or in a circular arc is detected, and then the compensation value of the wire flexure is gradually changed to continue the groove detection until the wire electrode and the workpiece are not short-circuited and the groove detection stops. Then the wire flexure value in the corner part or in the circular arc is obtained to establish the machining parameter data of the machine to automatically compensate the wire flexure value in the following machining.

Abstract: A method of forming a metal seal ring of separable semicircular segments of a predetermined diameter by providing an annular metal ring workpiece, wire EDM cutting transversely through the ring workpiece at a first circumferential location to form a first set of two adjacent ends, cutting a circumferentially extending shoulder on the radially inner portion of one of the adjacent ends and an opposite circumferentially extending shoulder on the radially outer portion of the other adjacent end, wire EDM cutting transversely through the ring workpiece at a second circumferential location diametrically opposite the first circumferential location, to separate the ring and thereby form a second set of two adjacent ends, forming by said cutting at the second location a circumferentially extending shoulder on the radially inner portion of one of the second set of adjacent ends and an opposite circumferentially extending shoulder on the radially outer portion of the other of the second set of adjacent ends, the cutting