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: 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 apparatus of asynchronous electric discharge machine for wire cut adopted for use in machine industries employs a first electric discharge machine unit and a second electric discharge machine unit to provide electric energy to a cutting wire to generate alternate ignition and discharge on a work piece. The asynchronous operation uses two different discharge circuits in two different time sequences to reduce the probability of occurring discharge at the same spot and effectively reduce pause time, and prevent the cutting wire from rupturing, thereby to reduce production cost and improve operation efficiency.

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 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: A wire electrical discharge machining apparatus for machining a workpiece (2) by supplying discharge energy to a gap between a wire electrode (1a) and the workpiece (2) by a working-electric-power source (16) having a dc power supply (17) and switches (19a, 19b, 19c, and 19d) for switching an output voltage of the dc power supply (17), and by relatively moving the wire electrode (1a) and the workpiece (2) by a positioning device that includes: a controller (20) which, during machining in a gas, controls the turning on and off of the switches (19a, 19b, 19c, and 19d) so that the voltage is set to reverse polarity whereby the polarity of the wire electrode (1a) is made positive and the polarity of the workpiece (2) is made negative.

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: 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 electrical discharge machining apparatus for machining a workpiece (2) by supplying discharge energy to a gap between a wire electrode (1a) and the workpiece (2) by working-electric-power supplying means (16) having a dc power supply (17) and switching means (19a, 19b, 19c, and 19d) for switching an output voltage of the dc power supply (17), and by relatively moving the wire electrode (1a) and the workpiece (2) by positioning means includes: controlling means (20) which, during machining in a gas, controls the turning on and off of the switching means (19a, 19b, 19c, and 19d) so that the voltage is set to reverse polarity whereby the polarity of the wire electrode (1a) is made positive and the polarity of the workpiece (2) is made negative.

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 electric discharge machining apparatus includes a wire electrode for machining a workpiece, and a first voltage applying unit for applying a voltage pulse. The voltage pulse has a rise time longer than a discharge formative time lag when a rectangular voltage pulse is applied, when a distance between the workpiece and the wire is an average value in machining, and rises to the same voltage as the rectangular voltage pulse.

Abstract: A method and apparatus for electrical discharge or electrochemical machining of workpieces, in which a machining electrode is moved relative to a workpiece, the machining is performed in cycles, and the appropriate process parameters are adjusted for machining of the current cycle with consideration of process parameters of the current cycle. To improve this method and the apparatus to the extent that improved geometric machining accuracy is made possible without time losses, stored process parameters of at least one previous cycle are also considered for adjustment of the process parameters of the current cycle.

Abstract: Charge accumulated in a capacitor is used to provide a processing current flow between a target and an electrode. When a diode is turned on, a first dc power supply is used to provide the processing current flow between the target and the electrode. In this state, after a lapse of a predetermined time, the current supply using the first dc power supply is stopped, and an induced electromotive voltage, induced by two floating reactors, is used to rapidly drop the processing current flowing between the target and the electrode, while charging the capacitor.

Abstract: An electrical discharge state detecting device for an electrical discharge machining machine which detects an electrical discharge state during an electrical discharge machining operation. The detecting device includes a high-pass filter for detecting a high-frequency component superimposed on an electrical discharge voltage or an electrical discharge current at a machining clearance between an electrode and a workpiece, a rectifying circuit for outputting a rectified component of the high-frequency component, a first integration circuit for integrating the rectified component, a reference voltage circuit, a second integrating circuit for integrating the reference voltage, a comparator for comparing the two integrated values, an electrical discharge generation detecting circuit for controlling starting and ending of the integrating circuits, a logic circuit, and a delay circuit and reset circuits.

Abstract: The process and device for machining by electroerosion are arranged so as to produce during each erosive discharge the following succession of phases: a delay phase (tD) during which an alternating voltage is applied between the tool and the piece at a frequency such that the ions present in the machining fluid follow shorter oscillating paths than the machining distance, separating the tool and the piece, a sparking phase (tA) including a lag period (tR) and an erosive discharge phase (tC) and a pause phase (tB) during which no voltage is applied so that the ionized path through the machining fluid disappears. There is thus obtained the complete suppression of all phenomena of electrolysis and deterioration of the tool and of the piece and a high efficiency of triggering and machining.

Abstract: An abnormality detecting apparatus in which noise is rejected in determining the condition of each of rotating electrical machines, so that a partial discharge of a rotating electric machine is detected with high accuracy. The abnormality detecting apparatus includes partial discharge detectors for detecting a partial discharge of a rotating electrical machine, a switching unit for selecting a partial discharge detector, a partial discharge measurement section for measuring the signal from the selected switch, a computer for selecting the respective partial discharge detectors or sequentially selecting respective partial discharge detectors for measurement, noise rejection, insulation diagnosis judgement, and data management for the respective discharge detectors, and for displaying measurement results, and a control section for controlling the switching unit and the partial discharge measurement section through the computer.

Abstract: An electro discharge machining apparatus comprises 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: A power supply for an electric discharge machine which provides electrical power intermittently for discharge machining in a machining gap formed between an electrode and a work piece. The power supply comprises a direct current power source, a switching element connected between the direct current power source and the processing gap, a gate pulse generating circuit which generates a gate pulse signal for energizing the switching element and a protection network connected between the switching element and the gate pulse generating circuit.

Abstract: A power supply (100) and a method for electric discharge machining by repeatedly providing a current pulse to a working gap (3) formed between a tool electrode (1) and a workpiece (2) includes a d.c. power source (E), first switching elements (Tr1-Trn) connected between the d.c. power source and the working gap, capacitors (C1-C8) connected in parallel with the working gap, second switching elements (67) for controlling current flow from the capacitor to the working gap, a detector (50) for detecting start of an electric discharge, and a controller (20) for controlling the first switching elements and the second switching elements in response to the detector. Current is supplied from the d.c.

Abstract: The electric discharge machining apparatus comprises a wire electrode for machining a workpiece, and a first voltage applying unit for applying a voltage pulse. The voltage pulse is such that it has a rise time longer than a discharge formative time lag when a rectangular voltage pulse is applied when a distance between the workpiece and the wire is an average value in machining and rises up to the same voltage value as the rectangular voltage pulse.

Abstract: In the process of machining by electroerosion, there is adjusted during a first transitory phase the machining current increase of the discharges after triggering a discharge between the electrode and the piece, such that a parameter connected to this increase will be substantially equal to a reference value corresponding to a minimum wear value of the electrode. Then, the machining current is maintained during a second phase at a reference value. The adjustment is carried out by acting on the adjustable internal voltage of a low impedance adjustable voltage source connected between the electrode and the piece. The adjustment can be carried out by a servo control loop with a regulator of the internal voltage, a device for generating discharges, parts adapted to determine the slope of increase of the current of a discharge, a member determining the mean slope of N discharges and a member adapted to compute the difference between the mean slope and a pre-established reference slope.

Abstract: An electrical discharge state detecting device for an electrical discharge machining machine which detects an electrical discharge state during an electrical discharge machining operation. The detecting device includes a high-pass filter for detecting a high-frequency component superimposed on an electrical discharge voltage or an electrical discharge current at a machining clearance between an electrode and a workpiece, a rectifying circuit for outputting a rectified component of the high-frequency component, a first integration circuit for integrating the rectified component, a reference voltage circuit, a second integrating circuit for integrating the reference voltage, a comparator for comparing the two integrated values, an electrical discharge generation detecting circuit for controlling starting and ending of the integrating circuits, a logic circuit, and a delay circuit and reset circuits.

Abstract: A method and apparatus for controlling the position and power of electrodes in an electric-discharge texturing (EDT) machine for texturing a roll includes an actuator for moving an electrode away from and towards a roll to be textured to maintain a desired spacing between the electrode and the roll. The actuator is controlled with a different gain depending upon whether the electrode is to be moved towards or away from the roll. A power source applies a voltage to the electrode for promoting a spark between the electrode and the roll to remove particles from the roll. The power source is controlled to apply the voltage to the electrode until a spark is initiated and then maintains the voltage for a selected time duration after spark initiation to provide a spark having the selected time duration. The power source is further controlled such that voltages applied to a plurality of electrodes are sequenced in a selected fashion.

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 power supply device for electric discharge machining apparatus, for supplying power to a gap formed between a workpiece and a tool electrode comprises a d.c. power source, a bridge circuit supplied with d.c. voltage from the d.c. power source and having switching transistors provided on each side, and a control circuit for controlling the on/off switching operation of switching transistors of the bridge circuit so that a.c. voltage pulses are applied from the bridge circuit to the gap. A first resistor limits current flowing when the workpiece is negatively poled and the tool electrode is positively poled. A second resistor having a larger value than the first resistor limits current flowing when the workpiece is positively poled and the tool electrode is negatively poled.

Abstract: A power supply device for an electric discharge machining apparatus, comprising a d.c. power source (2), a bridge circuit (80) having one pair of opposed switching circuits and the other pair of opposed switching circuits, and a controller (90) for alternately turning on either the one pair of switching circuits or the other pair of switching circuits so that high frequency a.c. voltage pulses are applied from a d.c. power source across a gap (G) formed between a workpiece (61) and a tool electrode (62). The four switching circuits (81, 82, 83, 84) respectively include at least two switching transistors connected in parallel, and the controller alternately turns on the least two transistors for each of the four switching circuits.

Abstract: An electrical discharge state detecting device for an electrical discharge machining machine which detects an electrical discharge state during an electrical discharge machining operation. The detecting device includes a high-pass filter for detecting a high-frequency component superimposed on an electrical discharge voltage or an electrical discharge current at a machining clearance between an electrode and a workpiece, a rectifying circuit for outputting a rectified component of the high-frequency component, a first integration circuit for integrating the rectified component, a reference voltage circuit, a second integrating circuit for integrating the reference voltage, a comparator for comparing the two integrated values, an electrical discharge generation detecting circuit for controlling starting and ending of the integrating circuits, a logic circuit, and a delay circuit and reset circuits.

Abstract: An apparatus and method is provided for use on an electric discharging machine to enhance the working efficiency of the electric discharging machine. The apparatus and method are directed to the control of the ignition delay time of the ignition voltage used to ignite the electric discharges applied to the workpiece for machining the workpiece. The apparatus and method are directed to the objective of making the duty factor as close to unity as possible. The apparatus and method are characterized in that the average discharge voltage is computed by the CNC (computer numerical control) unit instead of an analog voltage averaging circuit as in the prior art. The average discharge voltage is then used for the determination of the average ignition delay time to accordingly adjust the gain of the servo control loop of the discharging. The electric discharging machine then detects the ignition delay time to accordingly adjust the magnitude of the ignition voltage and the length of the discharge off-time.

Abstract: An apparatus and method is provided for generating an electric discharge in an alternating direction on a workpiece for line cutting of the workpiece. In particular, the apparatus and method allows the benefits of preventing the workpiece from being cut apart due to excessive power and also preventing electrolysis that can degrade the surface quality of the workpiece. The apparatus includes a negative ignition voltage source, a positive ignition voltages source, a discharging voltage source, and a pulse generator, which are constructed on an all-transistor architecture.