Abstract: A machining-energy calculating unit accumulates a discharge current value for each discharge position to calculate a machining energy in a certain time period from the present time to the past time. An energy-distribution changing unit determines the presence or absence of imbalance in the energy by obtaining a machining energy distribution in an up-down direction of the machining gap based on the machining energy, and when there is imbalance, the energy-distribution changing unit produces a new open/close pattern in which a machining energy distribution that eliminates the imbalance. Power feeding is then performed based on the new open/close pattern.

Abstract: An electro discharge machining apparatus comprises an electrode configured to machine a desired feature in a workpiece, a pulse generator configured to energize the electrode and the workpiece to opposite electrical polarities, a machining solution source configured to pass a machining solution between the electrode and the workpiece, and a servomotor configured to drive the electrode to move relative to the workpiece. The electro discharge machining apparatus further comprises at least one detection element configured to detect machining signals, and a controller. The controller controls the pulse generator and the servomotor to machine the workpiece according to a plurality of first process parameters predetermined therein and analyzes the detected machining signals to generate a first response signal to activate a plurality of second process parameters predetermined therein and different from the first process parameters to machine the workpiece. An electro discharge machining method is also presented.

Abstract: A discharge voltage detecting unit of an electric discharge machine detects a discharge voltage and determines an average discharge voltage in a specified period of time. An optimum machining condition computing unit determines a discharge current that makes an average discharge voltage detected by a discharge voltage detecting unit equal to an average discharge voltage when a new machining liquid is used. The optimum machining condition computing unit determines an optimal discharging time, an optimal non-operating time, and an optimal servo reference voltage from relational equations depending on the determined discharge current. A machining condition data base storing unit stores the discharge current, the discharging time, the non-operating time, and the servo reference voltage. A servo control unit establishes the optimum machining conditions at the time of machining.

Abstract: A wire electrical discharge machining apparatus includes a unit capable of separately opening and closing each of a high impedance path and a low impedance path, a unit that sets an open/close pattern in which a combination of closing one of the feeding paths and opening another one of the feeding paths is designated for switching power feeding between the high impedance path and the low impedance path, a unit that changes pulse energy per feeding pulse in a present feeding path to reduce a difference in discharge pulse energy applied to an inter-electrode gap from a machining power supply between at a time of high-impedance-path feeding and at a time of low-impedance-path feeding, and a unit that controls opening and closing of the path open/close unit in accordance with the changed open/close pattern.

Abstract: In order to obtain an electric-discharge-machining power supply apparatus that can flow discharge current pulses through the machining gap uniformly and efficiently, and can realize reduction of the amount of electrode wear in machining in the alternate current pulse system, in an electric-discharge-machining power supply apparatus (2) for applying electric-discharge-machining pulse voltage to a machining gap between a machining electrode (8) and an object (9) to be machined, wherein a circuit (22) composed of a parallel connection of a rectifying element (24) and a resistive element (23) is inserted in series along a wiring path extending from an electric-discharge pulse generating unit (6) to the machining gap, and the rectifying element (23) is so connected as to cause machining pulse currents to flow in an intended direction during the electric discharge generation.

Abstract: A wire electric discharge machine includes a wire electrode; a machining power supply that supplies a machining current to between the wire electrode and a workpiece; a first power feed contact and a second power feed contact that respectively feed power to the wire electrode; a first machining-current loop that lets a first machining current to flow from the first power feed contact toward the workpiece; a second machining-current loop that lets a second machining current to flow from the second power feed contact toward the workpiece; an impedance switching circuit that is provided in at least any one of the first machining-current loop and the second machining-current loop; and a control unit that controls a flow ratio of the first machining current and the second machining current by changing an impedance of the impedance switching circuit.

Abstract: The electrical discharge machining device comprises a first voltage/current source (U1) for discharge initiation connected to the tool electrode (F) and a workpiece electrode (P) forming the poles of a machining gap (G) and a second voltage/current source (U2) that can be disconnected by way of two switches (SW1, SW2). Capacitive elements (C1, C5) are mounted in series in the lines (10, 11) connecting the first source to the poles of the machining gap (G). In addition, these poles can be connected by a self-induction coil (Lm) mounted in series with an adjustable DC source (Sm). Thanks to these features, the energy of the eroding discharges can be significantly reduced in order to obtain a superfine surface finishing process of high quality, while at the same time precisely controlling the mean voltage across the terminals of the machining gap.

Abstract: An electric discharge machining method of removing material having a dimension (d) and a removal surface area (S) from a workpiece. A removal volume (V) of the material to be removed is obtained based on the dimension (d) and the removal surface area (S). Machining conditions are set, and a removal volume rate (Vm) corresponding to the set machining conditions is obtained. Machining time (T) is determined based on the removal volume (V) and removal volume rate (Vm). The electric discharge machining is completed when the machining time (T) has elapsed from the start of electric discharge machining.

Abstract: A method of determining machining condition for a sinker electric discharge machining apparatus in which a tool electrode is advanced along a z-axis to machine the workpiece, comprises the steps of: (a) producing a cavity model (D) as a solid model of part of the tool electrode; (b) tessellating the cavity model into a mesh of triangle each of triangles having an ordered set of vertices and having an orientation defined by the ordering of the vertices; (c) projecting the triangles on an xy plane surface; (d) summing up areas (S) of the projected triangles having the same orientation to calculate a machining area; and (e) determining machining conditions based on the machining area.

Abstract: A power supply circuit for a wire electric discharge machining apparatus includes an auxiliary power supply (3) for generating an auxiliary discharge by applying a voltage between a workpiece (2) and a wire electrode (1); and a plurality of main power supplies (4 and 5), a first one of which electrically connected to an upper terminal block (9) for connecting to an upper electrical supply point (6) and a second one of which electrically connected to a lower terminal block (11) for connecting to a lower electrical supply point (7), in order to supply a main discharging current after the auxiliary discharge has occurred; wherein the power supply for the wire electric discharge machining apparatus controls the auxiliary power supply (3) and the plurality of main power supplies (4 and 5), to machine the workpiece (2), and a first end of the auxiliary power supply is connected to the upper terminal block (9) and a second end thereof to the lower terminal block (11).

Abstract: An apparatus and a method of generating machining pulses for electrical discharge machining by discharge of at least one line applying a voltage to a working gap formed between a machining electrode and a workpiece, including the steps of: charging the line via a first charging circuit by a voltage source, discharging the line after ignition of the spark gap directly via a diode, without impedance matching, at the working gap, and recharging the line after a predefined pulse-off time.

Abstract: In an electric-discharge machining apparatus for controlling a machining axis so that an average voltage Vg during a predetermined sampling time Ts agrees with a servo standard voltage SV, the apparatus includes: an electric power supplier 9 for supplying electric power between electrodes of a tool electrode 8 and a target W to be machined; an electric-discharge detector 13 for detecting the waveform of electric discharge generating between the electrodes based on the electric power supplied by the electric power supplier 9; an electric-discharge generation counter 14 for counting in response to the waveform an electric-discharge generation count Nd during the predetermined sampling time Ts; a calculator 12 for calculating an estimation average voltage Vgs between the electrodes based on the electric-discharge generation count Nd; and an electrode-position controller 10 for controlling the machining axis so that the estimation average voltage Vgs calculated by the calculator 12 agrees with the servo standard

Abstract: An electric discharge machining apparatus comprises a power supply (5) for applying a voltage to a work gap formed between a tool electrode (E) and the workpiece (W) and a motor (7) that moves the tool electrode relative to the workpiece. An electric discharges counter (45) counts a number of electric discharge occurrences within a specified period (Td1) and generating a first count. A gap controller (48) multiplies the first count by a gain to generate position command or speed command for motor drive. An inversion counter (42) counts a number of inversions of the gap voltage upwards or downwards within a second specified period (Td2) and generating a second count. An electric discharge discriminator (44) discriminates the occurrence of electric discharge when the second count reaches a set value.

Abstract: A master mould is made by wire cutting a plate in two or more directions to provide a base with an array of master mould needles protruding therefrom. The size and shape of the master mould needles can readily be varied by varying the angles of upward and downward cuts in the two or more directions. The master mould is used to make a secondary mould by hot embossing a secondary mould plate onto the master mould. This forms through-holes in the secondary mould. The secondary mould is plated with a layer of metal, which forms a microneedle array.

Abstract: A wire electric discharge machining apparatus includes guide rollers, one electrode wire that is wrapped around each of the guide rollers to form cut wire portions spaced from one another between a pair of the guide rollers. A processing power supply feeds electric power to the individual cut wire portions through a power feed element, and a high frequency insulator has wound coils which are formed of the electrode wire and located between adjacent ones of the cut wire portions 2a, respectively, and cores which close magnetic circuits of the individual coils, respectively, and are magnetically insulated from one another. The power feed element is arranged between the individual cut wire portions and the individual coils, and the individual cut wire portions are insulated from one another by the individual coils at high frequencies. As a result, it becomes possible to impress voltages on the individual cut wire portions independently, so discharges can be generated in a simultaneous and parallel manner.

Abstract: A power supply apparatus for an electric discharge machine configured to perform melt-removal on a workpiece by supplying pulse-like power to a machining gap between an electrode (1) and a workpiece (2).

Abstract: A power-supply control device includes a high-frequency component detecting unit, a machining voltage level detecting device, and a pulse control device. The high-frequency component detecting unit detects a high-frequency component of discharge voltage at a machining gap. The machining voltage level detecting device detects a discharge voltage level at the machining gap. The high-frequency component is compared with a reference high-frequency component to obtain a first comparison result. The discharge voltage level is compared with a reference voltage level to obtain a second comparison result. The pulse control device controls pulse off time based on the first comparison result, and cuts off a discharge pulse based on the second comparison result.

Abstract: A voltage measurement circuit is connected between an electrode and a workpiece by a parallel cable through a resistor to measure a machining gap voltage. The parallel cable, like a television antenna feeder line, is formed such that two conductive wires are parallel fixed by an insulating and flexible material such as rubber or resin with a predetermined distance. The interline distance of the parallel cable is increased to decrease a stray capacitance of the cable, so that a high-frequency voltage in finish machining can be measured by the voltage measurement circuit without being attenuated. The resistor is connected to suppress oscillation of a voltage input to the voltage measurement circuit.

Abstract: An electric discharge machining method of removing material having a dimension (d) and a removal surface area (S) from a workpiece. A removal volume (V) of the material to be removed is obtained based on the dimension (d) and the removal surface area (S). Machining conditions are set, and a removal volume rate (Vm) corresponding to the set machining conditions is obtained. Machining time (T) is determined based on the removal volume (V) and removal volume rate (Vm). The electric discharge machining is completed when the machining time (T) has elapsed from the start of electric discharge machining.

Abstract: A power supply device for electric discharge machining includes a switching circuit that supplies a discharge pulse current to an inter-electrode portion that is a portion between an electrode and a workpiece serving as another electrode arranged to be opposed to the electrode at a predetermined interval; and a pulse-width control unit that generates a control pulse signal of a predetermined pulse width in response to a detection signal for starting a discharge at the inter-electrode portion. The switching circuit includes a switching circuit including a switching element suitable for a high-speed operation and a switching circuit including a switching element suitable for a low-speed operation, and receives the control pulse signal in parallel.

Abstract: A change in machining volume is calculated using a shape of the electrode and a shape of the workpiece expressed by three-dimensional models and machining condition data and the machining time is calculated according to actual machining status based on the calculated change in machining volume.

Abstract: An electrical discharge machining apparatus includes a work electrode adapted to support a work immersed in a working fluid, a tool electrode located opposing the work electrode with a predetermined gap therebetween, a capacitor that is connected between the work electrode and the tool electrode to provide a series of voltage pulses, a charging circuit having a power supply and a first switching element which are connected in series to the capacitor, a charge regulating circuit having a second switching element connected in series to the capacitor, and a control unit that controls the first and second switching elements, such that the first switching element turns on, and then the second switching element turns on before the first switching element turns off. Then, one voltage pulse, having a leading edge corresponding to the turning on of the first switching element and a trailing edge corresponding to the turning on of the second switching element, is generated.

Abstract: 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.

Abstract: An electric-discharge-machining power supply device in which energy loss is hardly produced and a charge voltage of a capacitor is easily controlled. When a switching element SW1 is turned on, a capacitor C is charged via an inductor L. When the voltage Vc of the charged capacitor exceeds the voltage of a direct-current power source E, a current is returned to the power source E via a diode D2. When the switching element SW1 is turned off, energy stored in the inductor L flows from the inductor L through the diode D2, the power source E and the diode D1, so that the voltage Vc of the capacitor C is kept at the power source voltage. When a switching element SW2 is turned on, the voltage of the capacitor is applied between an electrode and a workpiece.

Abstract: An electric discharge machine has a main power supply and a sub-power supply connected in parallel across a gap formed by an electrode and a workpiece. A voltage is first applied to the gap from the sub-power supply, and then machining energy is supplied to the gap from the main power supply when detected that the gap voltage has fallen to or below a certain detection level. Stable machining is achieved by changing the detection level according to the machining state.

Abstract: The electric power unit for machining of a wire electric discharge machine includes an electric discharge state discriminate or (1a) for discriminating a state of electric discharge generated between the electrodes and an impression voltage selecting means (1b) for inverting the polarity of the electric discharge inductive pulse voltage from the previous electric discharge inductive pulse voltage when an electric discharge state between the electrodes is discriminated to be abnormal (Y1) or open (Y3) and for making the polarity of the electric discharge inductive pulse voltage to be the same as the polarity of the previous electric discharge inductive pulse voltage when the electric discharge state between the electrodes is discriminated to be normal (Y2).

Abstract: Machining electrical power supply device for wire electrical discharge machining. Includes an electrical discharge state distinguishing circuit (6) for distinguishing at least two inter-electrode states, including electrical shorting and normal electrical discharge, between a wire electrode (E) and a workpiece (W), and an inter-electrode current waveform control means for supplying, and for switching between supply of, a triangular wave and a trapezoidal wave current to the electrodes. According to the inter-electrode state distinguished by the electrical discharge state distinguishing circuit (6), in cases where the inter-electrode state is that of electrical shorting (Y1), the inter-electrode current waveform control means supplies a triangular wave current (I) to the electrodes, and in cases where the inter-electrode state is that of normal electrical discharge (Y3), it supplies a trapezoidal wave current (I) to the electrodes.

Abstract: A wire cutting electric discharge machine has a high frequency voltage applying unit that applies a high frequency voltage and a direct current voltage applying unit applies a direct current voltage to the gap between the wire electrode and the workpiece. A detecting unit detects a low frequency component of a voltage occurring in the gap as a result of the electric discharge. The apparatus controls a feed rate based upon the state of the gap determined by the detecting unit.

Abstract: A carbon nanotube apparatus for surface discharge polishing using a transistor discharge circuit includes a signal generator having a integrated circuit for generating square wave; a photo coupler for isolating a cathode of the apparatus and an anode for processing; a discharge machining area comprising the anode for placing a target and the cathode having more than one multi-wall carbon nanotubes (MWCNT) grown on it. The apparatus uses the signal generator to control a waveform of square wave for electrical discharge machining and to control a current value for nanotube tips for electrical discharge machining, thus to enable the cathode of MWCNT apparatus for nanometer-level micro machining.

Abstract: The device for machining by electroerosion comprises an electrode-tool (EO) and an electrode-workpiece (EP) constituting the opposite poles of a working gap (GA) and an electrical circuit with a double voltage source (UD) connected to a supply network (A) arranged so as to produce erosive discharges between the electrode-tool (EO) and the electrode-workpiece (EP). This double voltage source (UD) comprises a first (U1) and a second (U2) voltage source connected galvanically to each other by their poles. This double source (UD) is connected to the working gap by at least four separate branches (B1 to B4) of which at least one comprises a self-induction element (LL, LL). Switching elements (SW1, SW2) permit producing by selective connection of the branches at least two increasing current slopes and at least two decreasing current slopes.

Abstract: An electric discharge machine for machining a workpiece (2a) made of insulating material or other materials comprises: a first comparison member (17) for comparing voltage (V) between the electrodes of the electrode (1) and the workpiece (2a) with the first reference voltage (V1) which is set at a value close to electric power source voltage (V0) not higher than electric power source voltage (V0); a second comparison member (18) for comparing voltage (V) between the electrodes with the second reference voltage (V2) which is set at a value lower than the first reference voltage (V1); and a control member (19) for setting a short electric discharge pulse width (TP1) in the case where voltage (V) between the electrodes is lower than the second reference voltage (V2) according to the result of comparison conducted by the second comparison member (18) at a point of time when a predetermined period of time (T0) has passed from the time when voltage (V) between the electrodes becomes lower than the first reference v

Abstract: A method and apparatus for electrical discharge machining of a workpiece wherein an erosion pulse is applied on the tool electrode. During the time of the erosion pulse the voltage (Ue) set on the electrode is acquired, and the erosion pulse is interrupted, after an asymptotic behavior of the acquired voltage (Ue) or a value derived therefrom has been acquired. Before the interruption of the erosion pulse an increase of current may occur.

Abstract: A power supply unit for wire electrical discharge machining using an ac high-frequency power supply for applying an ac high-frequency voltage between a wire electrode (1a) and a workpiece (2) includes a high-frequency oscillation and amplification circuit (4) and a pulse power supply (5) which is an ac-high-frequency-voltage intermittently supplying unit for effecting the application of the ac high-frequency voltage between the electrode and the workpiece and a pause thereof. In wire electrical discharge machining using this power supply unit for wire electrical discharge machining, it is possible to suppress the vibration of the wire electrode (1a) due tog the electrostatic force acting between the wire electrode (1a) and the workpiece (2), making it possible to improve the straightness accuracy of a machined surface of the workpiece (2) and make surface roughness small.

Abstract: An electric sparking drill and a method for using the same to drill a hole in a workpiece where at least one of a voltage applied to an electrode, the conductivity of a liquid applied between the electrode and the workpiece during drilling, and a gap between the electrode and the workpiece are controlled to create the desired hole in the workpiece. The electric sparking drill and a method for using the same to drill a hole in a workpiece also improve the hole operation and/or the quality of the hole made by operating at the arcing voltage, including a touch stop function, including a sacrificial electrode, and/or including a guide member function.

Abstract: A power supplying device for an electric discharge machine prevents electric discharge by a voltage from a subsidiary power supply circuit during a delay time from generation of the electric discharge to a rise of a voltage from a main power supply circuit. A parallel circuit, of a current reducing resistor and a capacitor, is provided in series in the subsidiary power supply circuit. A controller turns on the subsidiary power supply circuit to apply a voltage between a first electrode and a workpiece, as a second electrode, to generate an electric discharge therebetween, electricity charging the capacitor flowing between the electrodes to maintain the electric discharge even if an electric discharge current oscillates. The controller further turns on a main power supply circuit to supply a machining current in response to detection of the electric discharge and the current reducing resistor suppresses any leakage current during the application of the voltage from the subsidiary power supply circuit.

Abstract: An electric discharge machining apparatus for supplying machining electric power to a gap between an electrode (1) and a workpiece (2). The apparatus includes a gap dimension detection device (8) for detecting a dimension of the gap, a gap average voltage detection device (11) for detecting an average voltage of the gap, a gap dimension correction device (13) for correcting the dimension of the gap, and a gap dimension correction starting device (12) for starting the gap dimension correction device (13) when a first comparison between a detected gap dimension and a predetermined allowable value and a second comparison between a detected gap average voltage and a predetermined reference average voltage are made and the gap dimension detected by the first comparison is larger than the predetermined allowable value and the gap average voltage detected by the second comparison is smaller than the predetermined reference average voltage.

Abstract: A method and apparatus for electrical discharge machining of a workpiece wherein an erosion pulse is applied on the tool electrode. During the time of the erosion pulse the voltage (Ue) set on the electrode is acquired, and the erosion pulse is interrupted, after an asymptotic behavior of the acquired voltage (Ue) or a value derived therefrom has been acquired. Before the interruption of the erosion pulse an increase of current may occur.

Abstract: WC powder (11) and W powder (12) are mixed and entered in a press mold and compressed and molded, thereby forming a discharge surface treatment electrode (10). Discharge is caused to occur between the discharge surface treatment electrode (10) and a workpiece (16) by a discharge surface treatment power unit (17), whereby a component of the discharge surface treatment electrode (10) melted by discharge heat is deposited on the workpiece (16). W, a component of the discharge surface treatment electrode (10), reacts with C, a component of work liquid (4), to produce WC and together with the WC which is a component of the discharge surface treatment electrode (10) a hard film (20) made of WC is formed on the workpiece (16). The hardness and strength of the hard film formed on the workpiece (16) by the discharge surface treatment can be enhanced.

Abstract: An electric discharge machine in which electric power for working is supplied between an electrode and workpiece by an electric power unit so as to generate electric discharge between the electrode and workpiece and conduct machining on the workpiece, the electric discharge machine having a voltage detector for detecting output voltage V of a DC electric power source of the electric power unit; a current detector for detecting output current I of the DC electric power source of the electric power unit; a calculator for calculating product V·I of V and I; and a controller for controlling output electric power of the electric power unit to be constant on the basis of a difference between a working command signal for giving a predetermined electric power command and V·I. Even when load impedance fluctuates, it is possible to suppress the fluctuation of electric discharge power, so that surface roughness on a machined face of the workpiece can be made uniform.

Abstract: An electric discharge machining apparatus having: a machining condition storage device (13) including a machining condition database in which machining condition data are stored; an input-output device (14) for reading either of shape data of a tool electrode (9) and machining shape data of a subject (W) for machining; a shape computing device (15) for extracting a plurality of sections from the shape data, mesh-dividing the sections into split elements, giving mesh data of solidness or hollowness and extracting machining shape characteristic from the mesh data; and a machining condition setting device (12) for selecting a machining condition while making the machining shape characteristic correspond to machining condition data in the machining condition database of the machining condition storage device (13). Even when the machining shape is complex, more efficient machining can be performed because an appropriate machining condition can be set.

Abstract: A wire-electrical discharge machine infuses a processing liquid in a gap between a wire and a workpiece and processes the workpiece using predetermined processing parameters. The machine includes a processing parameter memory that stores processing parameters, a second memory that stores a relationship between nozzle height and processing energy, a processing energy determining unit that determines the processing energy, for example, during rough processing, based on the relationship, and a processing parameter changing unit that changes the processing parameters based on the processing energy. The workpiece is processed using the changed processing parameters. According to this construction, wire breakage can be prevented and the accuracy of the processed surface can be improved.

Abstract: A wire electric discharge machine includes storage means for storing threshold value data found from a relation between the normal electric discharge pulse energy and the electric discharge machining energy setting value corresponding to various electric discharge machining conditions; and a controller for controlling the electric discharge machining energy setting value so that the threshold value data can approach an operation point at which wire breakage occurs.

Abstract: A method and a device are for controlling multiple machining processes in a die-sink erosion machine with several identical or different electrodes (R1, R2, R3, R4), whereby the machining sequence of the machining processes and the electrode used for each machining process are determined by providing the following criteria: a) predefining priorities of workpieces to be machined, of a group of machining procedures, of individual machining jobs (ARB), of work cycles (AZ) and/or work steps (AS) of a machining job; and/or (b) predefining the life span or wear limit of the electrodes used for the individual machining jobs, work cycles or work steps. The overall machining on the die-sink erosion machine is performed with consideration of the determined machining sequence.

Abstract: In a power source apparatus for wire electric discharge machining capable of applying voltages of both of positive and opposite polarities to a gap between a wire electrode (1a) and a workpiece (2), there is provided a controller (14) for applying a first voltage pulse to the gap for predetermined time T1 and then applying a second voltage pulse of a polarity opposite to the first voltage pulse for predetermined time T2a necessary for the gap voltage to become a predetermined voltage lower than or equal to a voltage Va capable of starting an electric discharge after a lapse of predetermined time t set for prevention of breakage of a switch. The apparatus is used in machining for performing at least two machining operations selected from machining in machining liquid, machining in mist and machining in gas. Wire electric discharge machining with high reliability suitable for high-accurate machining can be implemented.

Abstract: A wire electric discharge machine capable of preventing a straightness error from being caused by consumption of a wire electrode, to thereby eliminate insufficient machining. A correction angle &phgr; is predetermined for preventing the straightness error of the workpiece due to consumption thereof. Correction amounts d1′, d2′ on a program plane and an upper surface of a workpiece, respectively, are determined based on the predetermined correction angle &phgr;, and are added to or subtracted from a predetermined offset amount depending on a wire electrode radius and an electric discharging gap, to thereby determine corrected offset amounts d1, d2 on the program plane and the upper surface of the workpiece, respectively. Correction amounts dlo, dup for lower and upper wire guides in an offset direction are obtained based on the corrected offset amounts d1, d2, respectively, so that motion paths of upper and lower wire guides relative to the workpiece are determined.

Abstract: The wire electric-discharge machining apparatus is provided with an inter-pole voltage correction unit 109 which corrects a voltage corresponding to an inter-pole voltage according to a correction coefficient which increases with an elongation of discharge stop time. A corrected voltage corresponding to the inter-pole voltage output from the inter-pole voltage correction unit 109 is given to a control unit 106 to allow a wire electrode 101 and a workpiece 102 to relatively move according to the corrected voltage corresponding to the inter-pole voltage.

Abstract: In an electric discharge machining power supply system that can apply a voltage of both positive and negative polarities between an electrode and a workpiece, there is provided a controller that applies a first voltage pulse between the electrodes for a predetermined time T1, and then applies a second voltage pulse having a polarity opposite to the first voltage pulse for a predetermined time T2a required until the voltage between the electrodes is lowered to a predetermined voltage that is less than an electric discharge starting voltage Va, after a predetermined time t that is set to prevent breakdown of a switching circuit has lapsed. In electric discharge machining using this electric discharge machining power supply system, the stable machining having high machining quality can be accomplished by causing a remaining voltage between the electrodes to fall down quickly and remove.

Abstract: An automatic breakthrough detection device for drilling electric discharge machine is provided. The automatic breakthrough detection device utilizing the facts of the variations of high frequency spectrum components of the provided discharge voltage and the variation of servo-feed-rate of the electrode as drilling discharge. The device includes a high frequency spectrum detecting analyzer to produce digital logic determining signals and a breakthrough judging logic device to judge the breakthrough by the electrode on the workpiece. Accordingly, the drilling electric discharge machine automatically adjusts the discharge parameters and the electrode withdrawals from the drilled hole and continues the next drilling hole on the workpiece. The present invention also provides a method of the same.

Abstract: An electrode discharge machining apparatus includes a first holder for holding a workpiece to be subjected to electro discharge machining, an electrode provided opposing the workpiece held by the first holder, a capacitor for supplying electric charge to the electrode and the workpiece so as to generate pulse electro discharge between the workpiece and the electrode, a power source for applying a voltage to the capacitor, a switching element provided between the capacitor, and at least one of the electrode, the workpiece and the power source, a switch controller for controlling on and off of the switching element, a current detecting element for detecting a current flowing between the workpiece and the electrode, and a control unit for, based on the current detected by the current detecting element, judging whether or not a short circuit occurs between the workpiece and the electrode.

Abstract: In a power supply apparatus of an electric spark (discharge) machine for generating high frequency pulse by a switching circuit from a DC power supply, stepping up the voltage by a high frequency transformer, generating a dire current by a rectifier, and feeding the DC power to the electric spark gap, the voltage of OP amplifier (221) for detecting an output voltage and an OP amplifier (222) for detecting an output current and converting it to a voltage are inputted to a summation OP amplifier (223). The output voltage and the output current are controlled so as to have a negative proportional linear relation via feedback circuit (220) for performing feedback to a fly-back switching circuit (210) through a voltage comparison/subtraction OP amplifier (224) for comparing and subtracting the sum of the voltages with and from a reference voltage.