Abstract: A measuring apparatus includes a measuring unit for measuring an electrical characteristic of a measurement object by applying an electrical signal, and a discharge detection unit connected to the measuring unit, the discharge detection unit obtaining an electrical signal value that is the value of the electrical signal applied to the measurement object, wherein if the electrical signal value is smaller than a predetermined reference value, the discharge detection unit issues a discharge alarm to the outside when a difference value between the electrical signal value and the reference value becomes larger than a predetermined first comparison value after the difference value becomes smaller than the first comparison value, and wherein the reference value is set equal to or larger than the maximum of the electrical signal value when no electric discharge occurs.

Abstract: A machining pass generating apparatus for a wire electric discharge machine, which is configured to generate a machining pass for machining a key groove on a side surface of a round hole, includes a processor. The processor is configured to define a shape of the key groove to be machined, designate a diameter of the round hole, designate a position of the round hole, and generate a machining pass, the pass suppresses an opening of the key groove from being narrowed.

Abstract: When a Z axis is moved while interrupting or continuing taper machining, a wire electric discharge machining control apparatus controls position of a UV axis by re-creating a taper deviation vector, based on a distance between upper and lower guides, such that a wire tilt angle does not change.

Abstract: A wire machining method includes: a wire electrode set as cutting wires provided in parallel with a distance between the cutting wires of which a predetermined regional part faces a workpiece; a machining power source that generates a pulse-shaped machining voltage; and plural feeder units that are electrically connected to the plural cutting wires respectively of the wire electrode and supply the machining voltage between the cutting wires and the workpiece respectively. In the parallel cutting wires, the feeder units are arranged such that a direction of a current passed to at least a part of the cutting wires becomes a direction different from a direction of a current passed to other cutting wires.

Abstract: A mechanism in a wire electrical discharge machining apparatus for machining a workpiece by electrical discharge between a wire and the workpiece is disclosed. The mechanism includes a processing fluid bath configured to store processing fluid used for electrical discharge machining between the workpiece and the wire, a processing fluid supply port to communicate with the processing fluid bath and supply the processing fluid into the processing fluid bath from a processing fluid supply apparatus supplying the processing fluid, and a stream control mechanism to suppress a stream of the processing fluid supplied from the processing fluid supply port into the processing fluid bath in the direction of the water surface of the processing fluid in the processing fluid bath.

Abstract: A CAM apparatus includes: an input receiving unit that receives designation of a part where core fixing machining is performed in a machining shape forming a core and divides the machining shape into a first machining shape element for which the core fixing machining is performed and a second machining shape element, which is connected to the first machining element and for which the core fixing machining is not performed, a machining-condition setting unit that allocates a first electric condition for the core fixing machining to the first machining shape element and allocates a second electric condition to the second machining shape element, and a machining-program generating unit that generates a machining program for machining the second machining shape element under the second electric condition and continuously machining the first machining shape element under the first electric condition after the machining of the second machining shape element.

Abstract: A teaching system according to an embodiment includes an image generating unit, a start point specifying unit, a via point specifying unit, and a teaching data generating unit. The image generating unit generates a virtual image including a closed processing line set on a workpiece to be processed by a robot. The start point specifying unit specifies a start point at a position outside the processing line on the virtual image. The via point specifying unit specifies a via point on the processing line. The teaching data generating unit generates teaching data relative to the robot for a path that leaves the start point to follow the processing line by way of the via point and returns to the via point.

Abstract: A gap detection apparatus for determining in real time the gap required for electrochemical machining gap includes a tooling electrode, a plurality of tool adjusting electrodes, a feedback circuit, a processing feed mechanism for controlling the tooling electrode, a three-dimensional driving mechanism, and an automatic control and measurement system. The tooling electrode includes a plurality of through-holes for receiving tool adjusting electrodes. The three-dimensional driving mechanism is mounted upon the processing feed mechanism, which includes a Z-coordinate feeding portion having a thimble for the feeding of the tool adjusting electrodes. The automatic control and measurement system controls the feed of the processing feed mechanism and the three-dimensional driving mechanism, and establishes the required gap for electrochemical machining.

Abstract: A sear mechanism for a firearm includes a trigger element having one or more contact surfaces on which one or more movable or pivotable components of the sear mechanism selectively contacts or slides. In some embodiments, the trigger element is made by producing an intermediate workpiece of the trigger element by a manufacturing process, and electric discharge machining the intermediate workpiece of the trigger element to provide the contact surfaces.

Abstract: One arbitrary point on an upper surface of a workpiece and two points at arbitrary heights on a tapered section of the workpiece are measured using a contact detector disposed on an upper wire guide of a wire electric discharge machine to calculate the shape accuracy and tapered angle. Based on the calculated data, the upper and lower wire guide support positions of the upper and lower wire guides are calculated. Using the calculated upper and lower wire guide support positions, electric discharge machining is performed on the workpiece.

Abstract: A wire electric discharge machine includes: a wire electrode supporting device that holds one end portion of a wire electrode; and a wire electrode forwarding device that has a forwarding device supplying a fluid to forward the wire electrode from a wire electrode guiding section to a wire electrode collecting section, a rotating body positioned on a path between the forwarding device and the wire electrode collecting section and diverting the forwarding direction of the wire electrode, and a rotation restraining device restraining rotation of the rotating body rotated by the fluid supplied from the forwarding device.

Abstract: The present invention includes drive units 7a and 7b that change a relative position between a wire electrode 12 and a workpiece 14 by moving a position of wire guide 8a and 8b, drive control units 6a and 6b that drive the drive units 7a and 7b based on a machining shape on the workpiece 14, respectively, a correction-amount storage unit 3 that previously stores therein a position correction amount for the wire electrode 12 corresponding to a machining condition, a correction-amount reading unit 4 that reads the position correction amount corresponding to the machining condition from the correction-amount storage unit 3, and a wire-position correction unit 5 that causes the drive control units 6a and 6b to correct a relative distance between the wire electrode 12 and the workpiece 14 based on the read position correction amount.

Abstract: A control unit controls an on/off operation of a switching unit such that a first DC pulse voltage is applied across an electrode gap from a pulse-voltage generation unit adjusted to a first impedance, and when a detection unit detects a preliminary discharge, a second DC pulse voltage is applied across the electrode gap from the pulse-voltage generation unit adjusted to a second impedance, which is lower than the first impedance, so as to generate a main discharge in the electrode gap, and during an idle time since the main discharge is completed until the next preliminary discharge is started, a third DC pulse voltage that is equal to or higher than a discharge arc voltage is applied across the electrode gap from the pulse-voltage generation unit adjusted to a third impedance, which is higher than the first impedance.

Abstract: Polycrystalline compact tables for cutting elements include regions of grains of super hard material. One region of grains (“first grains”) and another region of grains (“second grains”) have different properties, such as different average grain sizes, different super hard material volume densities, or both. The region of first grains and the region of second grains adjoin one another at grain interfaces that may include a curved portion in a vertical cross-section of the table. In some embodiments, discrete regions of the first grains may be vertically disposed between discrete regions of the second grains. As such, the tables have ordered grain regions of different properties that may inhibit delamination and crack propagation through the table when used in conjunction with a cutting element. Methods of forming the tables include forming the regions and subjecting the grains to a high-pressure, high-temperature process to sinter the grains.

Abstract: Values of a current and a voltage from a heating power supply device that supplies a current to a wire electrode and that heats the wire electrode are measured, a load resistance value is calculated by dividing the voltage value by the current value, a resistance increment of the wire electrode is calculated from an increased amount in the load resistance value with reference to the load resistance value and an estimated resistance value, a temperature rise value of the wire electrode is estimated based on a specific resistance of the wire electrode and a temperature coefficient of the specific resistance, and a state of carrying a current to the wire electrode is controlled based on the temperature rise value.

Abstract: A wire electric discharge machining apparatus that machines a workpiece by using a wire supported between a lower arm and an upper arm. The apparatus includes a surface plate that has a vacant inner area in which the wire moves and supports part of the workpiece with an outer area thereof. The apparatus further includes a bellows that extends through a side surface of a casing of a machining bath, enclosing part of the lower arm, wherein a first end of the bellows that is on a side of the machining bath is attached to the lower arm so that the bellows does not get in under the inner area, at whatever position the wire machines the workpiece.

Abstract: The present invention includes a post-cooling temperature sensor that measures a temperature of the machining fluid immediately after being cooled by a cooling device as a post-cooling fluid temperature, and an intra-tank temperature sensor that measures a temperature of the machining fluid in a work tank as an intra-tank fluid temperature, for a cooling control device that controls a fluid temperature of the machining fluid in a wire electric discharge machining apparatus, and the cooling control device has a first temperature-feedback control unit that feeds back the post-cooling fluid temperature into a cooling instruction value as an instruction value for the cooling device, and a second temperature-feedback control unit adjusts the cooling instruction value by feeding back the intra-tank fluid temperature to cause the intra-tank fluid temperature to follow a target temperature.

Abstract: A contact element is provided. The contact element has a composite wire. The composite wire has a core made of steel or a steel alloy, a copper alloy layer surrounding the core and a metallic coating applied to the copper alloy layer. The contact element is configured as a connecting wire, a connection wire, a cable wire, a cable strand, a plug-in pin for plug connectors, a weaving wire, a woven wire mesh, a knitted wire mesh or a spring element.

Abstract: A wire electrical discharge machining apparatus includes a target-control-section calculating unit calculating a target control section, which is indicated by a start point and an end point of the corner control in a current electrical discharge machining during the finish machining, based on a machining parameter; an actual-control-section calculating unit correcting the start point and the end point of the corner control, which are indicated in the target control section calculated by the target-control-section calculating unit, and calculating an actual control section, based on a magnitude of a shape error of the corner portion in a previous electrical discharge machining during the finish machining; and a speed controlling unit controlling the feed speed of the wire such that an amount of machining per unit time in the actual control section becomes equal to that when a portion other than the corner portion is machined.

Abstract: In wire-cut electrical discharge machining apparatuses that simultaneously perform a plurality of cutting processes by engaging a wire between main guide rollers at a plurality of times, a wire-cut electrical discharge machining apparatus is provided that suppresses vibrations at cutting wire sections, to enable the cutting processes under steady-state accuracy. In addition to the main guide rollers, vibration-damping driven guide rollers or vibration-damping guides are included which form a plurality of cutting wire sections where the vibrations are suppressed by guiding the wire into place, and the positions of the cutting wire sections are thereby defined with respect to nozzles.

Abstract: A wire electric discharge machine for taper cutting includes a table on which a workpiece is mounted, at least two linear axes for moving the workpiece and a wire electrode relative to each other, a mount portion capable of being mounted on the table, and a control unit. The workpiece can be attached to the mount portion, and the mount portion has at least two rotary axes. The control unit synchronously moves the linear axes and the rotary axes in accordance with a machining program to perform machining while relatively changing the tilt of the workpiece with respect to the wire electrode.

Abstract: An ultra-hard material fixed to a cutting tool is formed into a cutting blade by electric discharge machining. The wire electric discharge machine has a rotating shaft to which the cutting tool is mounted, and has a touch sensor mounted to an upper wire guide. A measurement program is generated on the basis of a machining path instructed by the machining program. A machining program is regenerated from rotating shaft coordinate information and path coordinate position information obtained at measurement points, on the basis of the measurement program. As a result, a rake face position of the cutting tool can be accurately measured and a wire electrode can be positioned accurately with respect to that position during machining.

Abstract: A multi-wire electrical discharge machining system for slicing a workpiece into a thin leaf at intervals of a plurality of wires arranged together causes the wires arranged together to travel in the same direction and includes a power feed contact configured to collectively comes into contact with the traveling wires, a machining power supply portion configured to supply a machining power supply to the power feed contact, and an electrical discharge portion configured to electrically discharge a machining power supply in which the traveling wires comes into contact with the power feed contact to collectively supply power to the traveling wires to the workpiece, in which a resistance between the machining power supply portion and the power feed contact is smaller than a resistance between the power feed contact and the electrical discharge portion.

Abstract: A working fluid supply device of an electric discharge machine draws up a cleaned fluid from a cleaned-fluid tank by means of a pump and supplies it to a working tank. The pump is connected with a first fluid circuit configured to supply the drawn cleaned fluid to the working tank and a second fluid circuit configured to supply the drawn cleaned fluid to an ion-exchange resin and a refrigerator. In supplying the cleaned fluid to the working tank, the first and second fluid circuits are opened and closed, respectively. In supplying the cleaned fluid to the ion-exchange resin and the refrigerator, the first and second fluid circuits are closed and opened, respectively.

Abstract: In carrying out electric discharge machining of a graphite or carbon-composite workpiece by a wire electric discharge machine, a voltage lower than that used in machining a metal workpiece by the wire electric discharge machine is supplied to a machining gap. Further, the peak value and the pulse width of a total discharge current flowing from a power supply device for electric discharge machining to a wire electrode are adjusted within ranges of 30 to 150 amperes and 0.3 to 6.4 microseconds, respectively.

Abstract: A measurement program for sequentially measuring measurement points, which are to be measured with a touch sensor, is created on the basis of a machining program, which is read in, for machining a turning tool. Then, the rake face height is measured on each of the measurement points and the measurement data is stored. Subsequently, a calculation method of a correction amount is selected so as to calculate the correction amount, and whether or not the calculated correction amount is smaller than a regulation value is determined. The machining program is modified on the basis of the correction amount when the correction amount is not smaller than the regulation value, while the machining program is modified on the basis of the correction amount in accordance with the selected method when the correction amount is smaller than the regulation value.

Abstract: A block in an electric discharge machining program is read out and analyzed, and when determined that a machining route correction command is issued to correct the machining route at a corner formed by consecutive first and second machining blocks, the machining route is corrected such that the end point of the first machining block, an extension point obtained by extending the first machining block from the end point thereof by a predetermined distance in the machining advancing direction, and a new start point obtained by partially removing the second machining block by a predetermined distance from the start point thereof are connected. Then, the wire electrode is moved with respect to the workpiece, following the corrected machining route.

Abstract: To provide a wire electrode removal device of a wire electric discharge machine, the wire electrode removal device including a wire-electrode guide unit that guides an end on a cut point side of a wire electrode cut by wire-electrode cut devices to outside of a running path, a rewind shaft that pressure-fixes the wire electrode on the cut point side guided by the wire-electrode guide unit with an end face thereof and rewinds the wire electrode on a columnar member having angular portions with subsequent rotational driving thereof, a rewind-shaft drive unit that drives the rewind shaft to perform pressure fixing or pressure releasing of the wire electrode with the rewind shaft, a scraper member that removes a wound wire electrode from the columnar member at a time of pressure releasing of the rewind shaft by the rewind-shaft drive unit, and a collection member that collects the removed wire electrode.

Abstract: The automatic wire-threading device includes a wire feed motor that drives a wire feed roller in a feeding direction, a wire-feed-motor control unit that outputs a feeding-direction rotation-speed reference to the wire feed motor at a time of a threading operation of a wire electrode and that reduces torque in a feeding direction when a detected rotation speed of the wire feed roller is larger than the feeding-direction rotation-speed reference, a wire collecting motor that drives a wire collecting roller in a collecting direction, and a wire-collecting-motor control unit that outputs a predetermined wire-collecting-roller speed reference to the wire collecting motor to collect a wire. The wire-feed-motor control unit limits torque so that an absolute value of motor torque in a winding-back direction of a wire feed roller is smaller than an absolute value of motor torque in a feeding direction.

Abstract: A numerical control device for a wire electric discharge machining apparatus generates a wire-breakage sign signal, outputs a machining-condition re-setting instruction and wire-breakage threshold re-setting instruction from the wire-breakage sign signal and wire-breakage threshold, sets the wire-breakage threshold according to the wire-breakage threshold re-setting instruction and a wire-breakage signal, calculates a machining energy from a discharge pulse count, measures a machining speed from position information, calculates a board thickness of the workpiece from the machining energy and machining speed, outputs, according to a predetermined algorithm, a machining-condition switching instruction from the board thickness, the machining-condition re-setting instruction, and the wire-breakage signal, sends an oscillation instruction to a oscillator and sends a shaft feed instruction to a servo amplifier so that the machining condition is set to one determined by the machining-condition switching instruction,

Abstract: A wire electric discharge machining apparatus is provided to equip with an automatic wire threader more reliably threading a wire electrode through an start hole. The wire electric discharge machining apparatus includes an automatic wire threader including: a feed roller disposed higher than the start hole and feeding a wire electrode toward the start hole; and a vertical drive device disposed between the feed roller and the start hole, and supplying compressed air in the upward and downward directions to vertically move the wire electrode slightly. The vertical drive device includes wire guides having guide holes through which the wire electrode is passed. The wire guides are constructed so that upward movement by the compressed air is possible.

Abstract: Upper and lower wire guides in a wire-cut electric discharge machine are moved until a wire electrode contacts with a workpiece, and after the contact, the upper and lower wire guides are moved backward to a position A which is away from the contact point at a fixed distance. Then, the upper wire guide is moved until the wire electrode contacts with the workpiece and the upper wire guide is returned to the position A. Subsequently, the lower wire guide is moved until the wire electrode contacts with the workpiece and the lower wide guide is returned to the position A. A coordinate value on the position where the wire electrode contacts with the workpiece is calculated by using position detection values which are obtained in the above respective steps, and board thickness is calculated from the coordinate value.

Abstract: When contact between a wire electrode and a workpiece is detected while, after wire electric discharge machining is ended, the wire electrode is moved (retraced) in the direction opposite to the machining direction along the machining path, the movement of the wire electrode is stopped. The wire electrode is moved in the offset direction from the contact position. When the wire electrode and the workpiece are brought into a non-contact state, the non-contact state is detected, and the movement of the wire electrode is stopped. The wire electrode is returned from the non-contact position to the machining path, and the wire electrode is retraced along the machining path in the state where the detection of contact between the wire electrode and the workpiece is neglected. Then, an amount of distortion of the workpiece is calculated from the contact position and the non-contact position.

Abstract: In a wire electric discharge machine or an automatic programming device for a wire electric discharge machine, in which a core is held with a workpiece base material by attaching brass contained in a wire electrode to the machining groove during machining, an attachment/deposition region where machining chips containing brass produced during machining are attached and deposited to the workpiece is set based on a machining shape obtained from a machining program and the machining chips containing brass produced during machining are attached and deposited according to the set attachment/deposition region.

Abstract: A method for cutting by a traveling wire, wherein the wire traveling direction of the wire and/or the workpiece are/is inclined alternately in relation to one another into at least two different specific angular positions in the cutting direction, with the result that the effective cutting height (s) on the workpiece (2) becomes smaller than the entire workpiece height.

Abstract: An electrode wire for electro-discharge machining and a method for manufacturing the same. The method includes preparing a wire rod, which includes a first metal and has a first diameter, as a core wire, plating a second metal on the core wire, performing a fine wire process for the core wire plated with the second metal so that the core wire has a second diameter, while forming a corrugation having a predetermined pattern on a surface of the core wire having a second diameter, and performing a heat treatment process to form a first alloy layer at a boundary surface between the core wire and the second metal through a mutual diffusion between the core wire and the second metal, and to form a second alloy layer at an outer portion of the first alloy layer through diffusion of the first metal toward the second metal.

Abstract: A wire aspiration device includes a first member having a first curved surface with a projected portion that is in close contact with peripheral surfaces of first and second recovery rollers on one side, a second member having a second curved surface with a projected portion that is in close contact with the peripheral surfaces of the first and second recovery rollers on the other side, and a third member having a through hole formed in a central portion thereof to cause the ejected wire electrode to run in the wire-electrode recovering direction and coupling the first and second members to form two grooves between the first and second curved surfaces to be in contact with the through hole, wherein a fluid spout for spouting a fluid into the through hole in the recovering direction is formed in any of the first, second, and third members.

Abstract: The method of attaching a pulling head to two or more wires or cables for installation in a conduit, comprising providing a first area for attaching the pulling head, placing two or more wire or cable supply spools on a first side of the first area, placing a receiving spool on the opposite or second side of the first area, feeding a portion of the wires or cables from the wire or cable supply spools onto the receiving spool, placing a terminating table in the first area below the wires or cables, cutting the wires or cables at staggered length from the receiving spool, stripping a portion of the covering from the wires or cables from the outer diameter of the two or more wires or cables, installing a connection onto each of the two or more wires or cables.

Abstract: An extrusion press includes an end platen, a fixed platen arranged at the rear thereof, a tie rod configured to link the end platen and the fixed platen, a die, a container loaded with a billet, an extrusion stem configured to press the billet, a crosshead attached with the extrusion stem, and an extrusion drive configured to reciprocate the extrusion stem. The extrusion drive includes a rotatable wire drum driven by an electric extrusion main motor and drives the extrusion stem to perform extrusion molding by winding the wire by rotating the wire drum.

Abstract: A wire electric discharge machining apparatus includes a wire electrode, a guide roller that arranges wire electrodes in parallel by winding the wire electrode therearound, a plurality of slidable contact conductors that are in slidable contact with the wire electrodes arranged in parallel, respectively, and a power feeding jig that holds the slidable contact conductors individually and feeds power individually to the wire electrodes arranged in parallel via each of the slidable contact conductors, in which the power feeding jig includes a plurality of reference surfaces that determine a fixing interval between the slidable contact conductors.

Abstract: A wire electric discharge machine is provided with an automatic wire-connection pipe movable between an automatic wire connection position and a retracted position. A pickup unit configured to clamp a wire electrode to be cut is disposed below a wire cutting electrode on the outlet side of the automatic wire-connection pipe. The wire electric discharge machine is further provided with a stopper mechanism configured to regulate a movement of the automatic wire-connection pipe so that a distal end of a nozzle of the automatic wire-connection pipe is located between the wire cutting electrode and the pickup unit when the wire electrode is cut.

Abstract: A wire electrical discharge machine includes an approach control unit. The approach control unit relatively moves a wire electrode with respect to a workpiece while inclining the wire electrode within a plane parallel to the machining surface to which the wire electrode approaches, in an approach section where the wire electrode performs cutting machining on the machining surface of the workpiece.

Abstract: Disclosed is a method of manufacturing a composite ball for electronic parts by preparing a core ball with spherical shape, forming a solder-plated layer encompassing the core ball to obtain a composite ball, and then conducting a smoothing work on the surface of the solder-plated layer, therein the smoothing work is preferably conducted by bringing a medium into contact with the surface of the solder-plated layer.

Abstract: A wire electric discharge machine configured to perform machining while swinging a wire electrode and comprising a swing frequency counting unit configured to count a swing frequency of the wire electrode, a machining stop unit configured to stop machining by the wire electrode when the swing frequency reaches a predetermined value, and a machining resuming unit configured to drive an axis drive unit to move the wire electrode by a predetermined distance relative to a workpiece after the machining is stopped by the machining stop unit and thereafter to return the wire electrode to a position where the machining is stopped and resume the machining.

Abstract: A wire electric discharge machining apparatus that machines a workpiece by using a wire supported between a lower arm and an upper arm. The apparatus includes a surface plate that has a vacant inner area in which the wire moves and supports part of the workpiece with an outer area thereof. The apparatus further includes a bellows that extends through a side surface of a casing of a machining bath, enclosing part of the lower arm, wherein a first end of the bellows that is on a side of the machining bath is attached to the lower arm so that the bellows does not get in under the inner area, at whatever position the wire machines the workpiece.

Abstract: In a wire electric discharge machine, one end of a tube filled with a pressure transmission medium is connected to a nozzle and a pressure sensor is attached to the other end of the tube by a joint outside a working fluid tank. The pressure sensor is used to detect the pressure of a working fluid ejected from the nozzle.

Abstract: A photon collimator, suitable for use in medical imaging equipment, is constructed from a block of photon-attenuating material, such as solid tungsten or molybdenum alloy that defines a plurality of integrally formed septa slats. Each slat has an elongated length dimension greater than thickness and depth dimensions, and is oriented in an opposed pattern array that is laterally spaced relative to its respective thickness dimension. An aperture channel is defined between each pair of opposed slats. Rows of integrally formed slats in one block or separately affixed blocks may be stacked on each other at skewed angles to form two-dimensional grids of apertures having polygonal cross sections. The slats may be formed by electric discharge or laser thermal ablation machining, such as by a sequential passing of an EDM wire cutting head along the pattern array, repeating sequential cutting of respective channel depth and width.

Abstract: A voltage is applied to a machining gap between a wire electrode and a workpiece for a period of one microsecond or less with a quiescent time longer than the duration of voltage application between each two adjacent cycles of voltage application provided, and the number of duty cycles and a machining-gap voltage are detected. An open-circuit state in which electric discharge does not occur after the voltage is applied is identified by the detected machining-gap voltage, and the number of open-circuits is counted. An average machining-gap voltage is obtained based on the numbers of duty cycles and open-circuits and the supply voltage or an average voltage for each duty cycle.

Abstract: A workpiece mounting table (20) for an electric discharge machine, which machines a workpiece (12) by discharging electricity between an electrode and the workpiece (12) in an interior of a work tank (6) and removing a surface of the workpiece (12), includes a surface-plate mounting table (3) made of a conductive material and arranged at the bottom of the work tank (6), a plurality of insulating materials (2), each of which has a flat shape and is arranged and fixed on the surface-plate mounting table (3) with a gap (4) between the insulating materials (2) to constitute an insulating flat plate (30), and a surface plate (1) made of a metal material, fixed on the insulating flat plate (30) and insulated from the surface-plate mounting table (3) by the insulating flat plate (30), for fixing thereon the workpiece (12).

Abstract: A plurality of plate-like workpieces held by a workpiece holder are subjected to discharge machining by a wire electric discharge machine. The workpiece holder includes a cylindrical member in which the plurality of plate-like workpieces are housed in a stacked state, lid members placed on upper and lower ends of the plate-like workpieces housed in the cylindrical member so as to press the plate-like workpieces, and a workpiece stage mount member having an insertion hole in which the cylindrical member is inserted and housed. Concave sections are formed in positions corresponding to a machining start point and a machining end point on an inner circumference surface of the cylindrical member.