Abstract: The invention relates to a method for forming of perforations in a substrate, said perforations being formed by means of an intermittently operating plasmatron, the plasmatron forming an electrical discharge arc between a cathode and the substrate, and material being removed at the position where the arc strikes the substrate material, in the present case forming perforations.

Abstract: A power supply apparatus for electric discharge machining is provided with a current loop including a diode, which is supplied with a forward current at the same time a voltage for generating a discharge is output or before it; and a resistor. Supply of forward current to the diode is blocked the moment a discharge is generated. By doing so, a reverse recovery current of the diode is supplied in a gap between an electrode and a workpiece to be machined.

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 (L1, L1). Switching means (SW1, SW2) permit producing by selective connection of said branches at least two increasing current slopes and at least two decreasing current slopes.

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 micro-electro-discharge machining apparatus includes a substrate, a plurality of electrically conductive electrodes on the substrate arranged in an array, and a plurality of electrical interconnect lines formed on the substrate extending to one or more of the electrodes. An electrical power source is connected from one of its terminals through a resistor to each of the interconnect lines and from its other terminal to a workpiece to be machined. The electrodes connected to different interconnect lines may charge and discharge independently of each other, speeding up the machining process. An interconnect line may extend individually to each electrode so that all of the electrodes can charge and discharge independently of the others. The capacitor that is charged to produce the discharge voltage may be a separate discrete capacitor or a conductive substrate.

Abstract: A device for quality decision of a machining state of an electric spark machine to apply voltage in a pulse form to a machining space between an electrode and a workpiece for contour machining by pulse discharging includes a plurality of machining state detection apparatus each of which detects a different physical quantity that denotes a machining state. The physical quantity being machining speed, machining voltage, machining current, on and off times of voltage applied to an electrode, total number of discharges, number of abnormal discharges, abnormal discharging rate, and discharging frequency. Furthermore, a machining state evaluation and quality decision apparatus (49) synthetically evaluates the machining state and quality decision of the machining state based on a combination of comparison of the physical quantities detected by the machining state detection apparatus with predetermined standard values for each of the physical quantities.

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: 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 means 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 to 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: 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: A tool attachable to a machine tool in the same way as an ordinary tool, capable of being driven and operating without connecting with an external power supply etc., and made small enough to enable automatic changing, provided with a generator for generating power by energy of compressed air supplied from the outside, a motor driven by power generated by the generator, and a cutting tool driven by the motor for cutting the workpiece.

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: A discharge pulse generator for supplying power between a pair of electrodes (1 and 2), comprises a distribution constant line (8) of a predetermined length being connected at one termination to the electrodes (1 and 2), charging means (16) being connected to the distribution constant line (8) for charging the capacitance of the distribution constant line (8), rectification means (13) being connected to an opposite termination of the above-mentioned distribution constant line (8) in a direction in which no current flows relative to voltage of the above-mentioned charging means (16), and a resistor (10) being connected in series to the above-mentioned rectification means (13) and having a resistance value equal to the characteristic impedance of the above-mentioned distribution constant line (8). For example, to use the discharge pulse generator for electric discharge machining, a workpiece can be worked on with higher accuracy and higher quality at higher speed.

Abstract: An electrical discharge machining (EDM) apparatus includes a plurality of work stations, where each work station has at least one electrode. The EDM apparatus further includes one or more power supplies and a power transfer switch for alternately supplying power to various sets of the electrodes. The power transfer switch has a first state wherein each power supply is connected to a corresponding first electrode in one of the work stations and a second state wherein each power supply is connected to a corresponding second electrode in another work station.

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 processing parameter storage means that stores processing parameters, means that stores a relationship between the nozzle heights and the amount of processing energy, processing energy determining means that determines the amount of processing energy, for example, during rough processing based on such relationship, and processing parameter changing means that changes the processing parameters based on the amount of 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 power supply for electro-erosion machine includes a capacitive network in series connected in the current loop for limiting or controlling the current flow through the gap formed by electrode and work-piece a switching device is adapted to change the direction of charging and discharging current of the capacitive network, a driving circuit (firing circuit) is adapted to drive the switching device on and off so as to control current flow through the capacitive network. This lower resistance circuit eliminates huge power loss and reduces switching stress of the switching device. The electro-erosion ON-OFF time signal and the current-pattern control along with the circuit, constitutes a compact, low electrode wear and low electromagnetic noise electro-erosion machine power supply.

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 the first pulse width T1 of an electric discharge current, the group of switching elements (10) are controlled by the control means (11) and the first peak value Ip1 is set at a predetermined value and the electrode material is emitted so that a predetermined quantity of electrode material can be supplied, and the thus emitted electrode material is made to adhere to the workpiece (2) so as to compose the electrode component (15a). In the second pulse width T2 of an electric discharge current, the second peak value Ip2 is set so that the emission of electrode material can be suppressed and the electrode component (15a) adhering to the workpiece (2) can be melted, and the electrode component (15a) is melted and a hard coat composed of the electrode component (15b) melted on the workpiece (2) is formed. In this way, an excellent hard coat, the crystal grains of which are fine, can be formed on the workpiece (2).

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: A micro-electro-discharge machining apparatus includes a substrate, a plurality of electrically conductive electrodes on the substrate arranged in an array, and a plurality of electrical interconnect lines formed on the substrate extending to one or more of the electrodes. An electrical power source is connected from one of its terminals through a resistor to each of the interconnect lines and from its other terminal to a workpiece to be machined. The electrodes connected to different interconnect lines may charge and discharge independently of each other, speeding up the machining process. An interconnect line may extend individually to each electrode so that all of the electrodes can charge and discharge independently of the others.

Abstract: An electrical discharge machining (EDM) apparatus includes a plurality of work stations, where each work station has at least one electrode. The EDM apparatus further includes one or more power supplies and a power transfer switch for alternately supplying power to various sets of the electrodes. The power transfer switch has a first state wherein each power supply is connected to a corresponding first electrode in one of the work stations and a second state wherein each power supply is connected to a corresponding second electrode in another work station.

Abstract: An electroerosion machining device to machine a piece (14) by milling successive layers, comprises a member (30) to drive in rotation an electrode-tool (31) of tubular shape and a digital control unit (CN) to control the three-dimensional movement (x, y, z) between the electrode-tool and the piece (14). A regulation module (MR) is adapted to simulate the longitudinal wear of the electrode-tool and to compensate it along its path. According to the type of geometric configuration between the electrode-tool and the piece, namely the presence or absence of an opening below the electrode-tool and the presence or absence of one or two walls, different values of longitudinal wear are provided and transmitted to the digital control unit (CN). There is thus obtained a high precision and planarity of machining.

Abstract: A power supply for electro-erosion machine comprises a capacitive network in series connected in the current loop for limiting or controlling the current flow through the gap formed by electrode and work-piece, a switching device is adapted to change the direction of charging/discharging current of the capacitive network, a driving circuit (firing circuit) is adapted to drive the switching device on and off so as to control current flow through the capacitive network. This lower resistance circuit eliminates huge power loss and reduces switching stress of the switching device. The electro-erosion ON-OFF time signal and the current-pattern control along with the circuit, constitutes a compact, low electrode wear and low electromagnetic noise electro-erosion machine power supply.

Abstract: An electrical discharge power supply modular device for electrical discharge machine includes at least a discharge power supply motherboard having a discharge power supply control signal bus and a plurality of coupling devices of discharge power supply circuits for flexibly accommodating several discharge power supply modules, finishing circuit modules, and special processing circuit modules to form a multistage discharge power supply controlled by a discharge signal generator for providing discharge clock pulses to all the discharge power supply circuits so as to proceed electrical discharge.

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: 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: Charge accumulated in a capacitor is used to allow a processing current to flow between a target and an electrode. When a diode is turned on, a first dc power supply is used to allow the processing current to 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: A wire-discharge machining apparatus for machining a workpiece by generating discharges between a wire electrode and the workpiece. In machining, the apparatus can detect all portions where wire-breakage frequently occurs and strictly discriminate between a condition detected and a control result, achieving wire-breakage prevention. This wire-discharge machining apparatus has an evaluating device and a controller. The evaluating device measure cycles, frequencies, or ignition delay times of the discharges as a measured value, evaluates the dispersion of the measured values, and outputs an evaluation value. The controller controls machining conditions according to the evaluation value.

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 electric discharge machining apparatus capable of sufficiently reducing stray capacitance between an electrode and a workpiece to improve surface roughness of a machined workpiece by electric discharge machining. A first switching device is provided in a feeding line between an electrode and a first machining power source for supplying a first electric discharge energy for a rough machining, and a second switching device is provided in a feeding line between the workpiece and the first power source in an electric discharge circuit in which the workpiece and a workpiece mounting table are electrically insulated. In performing a finish machining, a second electric discharge energy smaller than the first machining energy is supplied from a second machining power source between the electrode and the workpiece with the first and second switches opened.

Abstract: A switch is disclosed for use in a power supply circuit for supplying electric discharge power between a tool electrode and a workpiece.

Abstract: A power supply device for an electric discharge machine for supplying power to a work gap (6) formed between a work piece and a tool electrode, includes a parallel circuit in which a first power supply (8), a second power supply (36) and a capacitor (34) are connected in parallel and the second power supply can supply a larger voltage and a smaller current than the first power supply to the work gap. A switching element is connected between the parallel circuit and the work gap for pulsing power from the parallel circuit.

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

Abstract: 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: Electrode tools for electroerosion (EDM) where a cavity or a relief is machined by hollowing out the part at great speed and in successive layers or slices by means of a rotating electrode tool of a simple shape which is independent of the cavity to be eroded, called “EDM slices milling”.

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.