Abstract: A power-supply control device includes a high-frequency component detecting unit, a machining voltage level detecting device, a no-load time 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 no-load time detecting device detects delay time of discharge of the discharge voltage at the machining gap. The high-frequency component is compared with a reference value to obtain a first comparison result. The discharge voltage level is compared with a reference level to obtain a second comparison result. The pulse control device controls pulse off time based on the first comparison result and the detected delay time, and cuts off a discharge pulse based on the second comparison result.

Abstract: A discharge pulse control device cuts off a pulse width of the a discharge pulse being produced in a machining gap when a comparison result of a voltage level comparator indicates abnormal electrical discharge. Upon detection of abnormal electrical discharge based on comparison results of a high-frequency component comparator and the voltage level comparator, a quiescent period control unit constructed from a discharge pulse diagnosis device, a first pulse counter, a second pulse counter, and a quiescent pulse control device performs change setting of the quiescent period at the time of occurrence of abnormal electrical discharge and sends that information to the discharge pulse control device. Subsequently, the discharge pulse control device performs change control of the quiescent period at the time of occurrence of abnormal electrical discharge so that the discharge pulse and the quiescent time are optimally controlled.

Abstract: A wire discharge machine includes a wire electrode arranged with a gap from a workpiece, and a constant-voltage power supply that applies a high-frequency voltage between the workpiece and the wire electrode, and generates discharge between the workpiece and the wire electrode by applying the high-frequency voltage to machine the workpiece. The wire discharge machine further includes a current measurement unit that measures a current value of a current flowing from the constant-voltage power supply, a determination unit that determines a state between electrodes, which is a state between the workpiece and the wire electrode, based on a combination of a result of a threshold determination of the measured current value and a result of a threshold determination of a change value in the current value, and a control unit that controls a gap between the workpiece and the wire electrode based on the determined state between electrodes.

Abstract: A method for controlling an electric discharge machining process, wherein a tool electrode is moved relatively to a workpiece with a working gap distance, wherein the process includes a current and at least one previous erosion cycle, the current and the previous erosion cycle each being divided into predetermined time intervals each including at least one discharge pulse, wherein similar working gap conditions are present within a time interval of the previous erosion cycle and of the current erosion cycle, and wherein subsequent erosion cycles are separated by a process pause cycle.

Abstract: An electric discharge machining device that performs processing by applying a voltage pulse to space between the processing electrode and the workpiece and suitably switching the polarity of the voltage pulse attains both desired processing accuracy and desired controllability. The electric discharge machining device is provided with the first to fourth switching elements. The controlling unit that controls these switching elements, when setting a period time in which the first switching element is turned on, a period of time in which the fourth switching element is in an on-state in the same period, and, when setting a period time in which the second switching element is turned on, a period of time in which the third switching element is in an on-state in the same period so that a desired voltage pulse is applied to the space between the processing electrode and the workpiece.

Abstract: An apparatus and method for machining apertures into a conductive workpiece is disclosed. The apparatus has a tank capable of holding a dielectric fluid, and a fixture for holding the workpiece in the tank. An electric discharge machine with an electrode, a power supply connected to the electrode that produces machining pulses for electric discharge machining through the workpiece, and a controller for regulating the power supply and electrode position is also part of the apparatus. Finally, the apparatus has a pressure transducer connected to the fixture, and a process controller in communication with the electric discharge machine controller and pressure transducer.

Abstract: In a waveform of switching signals, which is output from a full-bridge circuit formed of four switching elements, includes a normal polarity pulse group and a reversed polarity pulse group for controlling an output timing of voltage pulses. A duty cycle of the normal polarity pulse group containing a plurality of normal polarity pulses, which apply a positive power-supply polarity to a workpiece and apply a negative power-supply polarity to a machining-purpose electrode, is configured so as to be different from a duty cycle of the reversed polarity pulse group containing a plurality of reversed polarity pulses, which apply a negative power-supply polarity to the workpiece and apply a positive power-supply polarity to the machining-purpose electrode.

Abstract: A sinker electric discharge machining apparatus for machining a workpiece by generating electric discharge in a work gap by applying a voltage having an OFF time, may include a discriminator for generating a first signal representing an abnormal state of the work gap, and a second signal representing a normal state of the work gap; and a pulse controller, in which a first extension factor and a second extension factor that is smaller than the first extension factor are set and a first reduction factor and a second reduction factor that is smaller than the first reduction factor are set. The pulse controller extends the OFF time using either the first or the second extension factor if the first signal is received. The pulse controller reduces the OFF time using either the first or the second reduction factor if the second signal is received.

Abstract: An electric discharge machine includes a machining power supply for applying a voltage to a machining gap between a machining electrode and its opposite workpiece and detecting a contact between the machining electrode and the workpiece. The machining power supply includes a first power supply circuit whose output voltage is equal to or less than an arc voltage, a second power supply circuit for supplying a pulse current to the machining gap, and a control unit. When the first power supply circuit detects a contact between the machining electrode and the workpiece, the control unit operates to supply a pulse current from the second power supply circuit to the machining gap while the machining electrode and the workpiece are in contact with each other.

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: A method for controlling a wire electric discharge machine comprising the steps of: determining of at least one predefined contour deviation (Esmax) of a predefined contour to be cut into the workpiece; determining a curvature of at least one geometry element defining at least one section of the contour to be cut into the workpiece; calculating a displacement (s) of an upper guide (WGU) and a lower wire guide (WGL) based on the predefined contour deviation (Esmax) and on the curvature of the at least one predefined geometry element; and setting the displacement (s) by moving the upper guide (WGU) relative to the lower wire guide (WGL) such that the wire electrode guided by the upper (WGU) and lower wire guides (WGL) is inclined in a current cutting direction of the workpiece during cutting of the geometry element into the workpiece.

Abstract: An electric discharge machining apparatus having a gate signal generator for generating a gate signal, a power source for applying a voltage across a work gap formed between a tool electrode and a workpiece, a gap voltage detector for detecting a gap voltage of the work gap, an electric discharge detector for supplying an electric discharge detection signal representing electric discharge to the gate signal generator. The electric discharge detector includes a counter for generating a sample clock having a frequency greater than the frequency of the gate signal, and a comparator for receiving the gap voltage and determining that a fall in the gap voltage is larger than a specified voltage difference in each sample clock. The electric discharge detection signal is generated in response to an output signal of the comparator.

Abstract: A self-adjusting power device for high efficiency electrical discharge machining and method thereof is disclosed. A high-voltage arc unit and a low-voltage discharge unit provide a high voltage arc pulse and a low voltage discharge pulse to an electrode respectively. The electrode machines a workpiece and feeds back a gap voltage to a discharge pulse generation unit. The discharge pulse generation unit determines whether the gap voltage is lower than a predetermined voltage or not. If yes, a discharge channel between the electrode and the workpiece is conducted, and the discharge pulse generation unit shuts down the high-voltage arc unit and the low-voltage discharge unit is still operating at ON time and shuts down at OFF time. If no, looping the determination of the discharge pulse generation unit. Therefore, discharge machining energy is accurately controlled and high efficient power saving is achieved.

Abstract: A wire electric discharge machining apparatus includes guide rollers and a single electrode wire that is wrapped around each of the guide rollers to form cut wire portions that are spaced from one another between pairs of the guide rollers. A processing power supply feeds electric power to the individual cut wire portions through a power feed element. A high frequency insulator includes wound coils of the electrode wire that are located between adjacent cut wire portions, and cores which close respective magnetic circuits of the individual coils. The magnetic circuits 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 at high frequencies by the individual coils. Voltages are impressed on the individual cut wire portions independently, so discharges can be generated simultaneously, in parallel.

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: In an electric discharge machining, in order to reduce damage of an object to be machined and an electrode and to achieve machining velocity enhancement and reduction of electrode wear amount by appropriately controlling a short-circuit current that flows when the electrode and the object to be machined are short-circuited, an electric-discharge-machining power supply apparatus for machining an object to be machined by interrupting every predetermined time period pulse trains that are turned on and off at predetermined timing, to supply electric power to a machining gap between a machining electrode (2) and the object (3) to be machined includes: a short circuit detecting means (11) for detecting a short circuit at the machining gap between the machining electrode (2) and the object (3) to be machined; and a pulse halting means (12) for, when the short circuit detecting means (11) detects a short circuit occurrence at the machining gap, halting generation of particular pulses in the pulse train so as to halt

Abstract: An EDM die sinking device includes a tank for holding a fluid, and at least one electrode in the tank having a shape for imparting to a first portion of a workpiece. A workpiece holder positions the workpiece at least partially immersed in the fluid and alternately moves the workpiece between an inoperable position and a first operable position of the first electrode at which electric discharge machining occurs on the first portion. A pulse generator creates an electric discharge between the first portion and the first electrode to remove material from the first portion in response to the workpiece being in the first operable position. Movement of the workpiece from the electrode flushes particle containing fluid away from the workpiece and the electrode. A segmented electrode includes a separate pulse generator for each segment may also be employed.

Abstract: The present invention is a device for coating surfaces of metallic work pieces with an electrically conductive material by employing short duration high current packets of pulses in which the work piece forms the cathode and the consumable coating material forms the anode, which are connected to a generator for generating pulses by charging and discharging a bank of capacitors using a MOSFET. The invention is also a device for controlling the on and off time of a metal oxide semiconductor field effect transistor (MOSFET).

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: The methods and devices enable a reliable and rapid automatic threading process on spark-erosive wire-cutting machines with closed round guides without complicated entry of parameters. A heat-output control device with an optimized output characteristic curve is supplied from a DC voltage source of the erosion generator. Through an at least partial feedback loop of heating current and source voltage, the characteristic curve is modified in such a way that different wire types or different annealing lengths for the wire provide optimal results for stretching, straightening and separating the wire electrode without controlled intervention. With adaptive control it is possible to thread future wire types automatically without reprogramming.

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

Abstract: The present invention includes steps of, determining a search starting position; setting a center position, and a first position and a second position with a distance provided therebetween; obtaining a measurement point group including measurement points of the center position, the first position, and the second position; and determining a measurement point closest to the tip portion in the measurement point group based on positions of the measurement points in a second direction and selecting a position of the measurement point in a first direction as a selected position. When the measurement point group is obtained initially after the determination of the search starting position, the search starting position is set as the center position; and when the measurement point group is obtained after the selection of the selected position, the selected position is set as the center position. The distance is narrowed for every selection of the selected position.

Abstract: A wire electric discharge machining apparatus for machining a workpiece (7) by supplying current pulses to a work gap formed between a wire electrode (8) and the workpiece comprises a person detection sensor (10) for generating a person detection signal (EX) when the existence of a person is detected, and an NC device (20) that is configured to receive the person detection signal. When the NC device receives the person detection signal, it selects first machining conditions which improve machining speed. When the NC device does not receive the person detection signal, it selects second machining conditions which reduce the risk of wire breakage.

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. The machine further includes a first power feed contact and a second power feed contact that respectively feed power to the wire electrode; a first machining-current loop in which a first machining current flows from the first power feed contact toward the workpiece; a second machining-current loop in which a second machining current 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 invention relates to a device and a method for electrical discharge machining of a work piece by means of a working electrode. A sequence of working pulses is applied on the work gap between the working electrode and the work piece. The working pulses comprise eroding pulses for eroding material off the work piece and measuring pulses during which an ignition voltage is applied on the work gap in order to initiate a discharge within the work gap and to measure the corresponding, ignition delay time. The ignition voltage and/or the gap width are adjusted such that the ignition delay time is smaller than an oscillation time of the working electrode oscillating within the work gap due to the electrostatic attraction force and the mechanical restoring force.

Abstract: A method for electrical discharge machining a workpiece includes dividing machining time into a sensing interval during which reference values are captured from machining pulses and into a machining interval during which no reference values are captured. The sensing interval includes either a first sensing interval after implementation of a jump motion of the electrode in the working gap or a second sensing interval after application of an extended pause time to at least some of the machining pulses. The extended pause time is longer than a pause time of other ones of the machining pulses. The method also includes sensing an electrical parameter of a current machining pulse and deriving at least one characteristic value from the sensed electrical parameter. The method further includes comparing characteristic value to at least one of the captured reference values and initiating an action depending on a result of the comparison.

Abstract: An object is to enable highly accurate machining by correcting machining conditions by referring to a programmed trajectory to obtain a desired machining shape. A wire electric discharge machining apparatus includes a machining-condition correcting unit that corrects machining conditions in each machining stage corresponding to a circular arc radius of a portion corresponding to a corner portion of a programmed trajectory, in the corner portion formed by changing a direction of relatively moving a wire electrode, when the wire electrode is moved on a wire center trajectory, which is offset from the programmed trajectory prestored in order to obtain a desired machining shape to perform finish machining in each machining stage with an offset amount being changed.

Abstract: A power supply device comprises a DC power supply (12), a current sensor (14) for detecting gap current (Igap) flowing through the machining gap, a first switching element (16) connected in series between the DC power supply and the tool electrode (2), a first reverse current prevention diode (22) connected in parallel with the DC power supply and connected in series with the first switching element (16), a second switching element (18) connected in series between the DC power supply and the workpiece (3), a second reverse current prevention diode (24) connected in parallel with the DC power supply and connected in series with the second switching element (18), and a pulse controller (20) for controlling the first and second switching elements in response to gap current (Igap). From a first time (t1) when electric discharge is generated across the machining gap, until a second time (t2) when the gap current reaches the peak current during the ON time, both of the first and second switching elements are on.

Abstract: A portable EDM device and system thereof for producing calibration reflectors on a pipe includes a base mountable on the pipe, a motor mounted on the base, a cutting tool operably connected to the motor, an electrode operably connected to the cutting tool, a power source mounted on the base and operably connected to the electrode and operably connectable to the pipe, and a source of dielectric fluid mounted on the base. The power source is configured to electrically discharge a voltage from the electrode to the pipe to remove material from the pipe. The source of dielectric fluid is in fluid communication with the pipe to remove the material removed from the pipe.

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 electric discharge machine to process a work piece includes a plurality of electrodes, and a plurality of discharge power supply units. The plurality of electrodes generate a plurality of discharges with the work piece, respectively. The plurality of discharge power supply units apply voltages for the plurality of electrodes, respectively and independently.

Abstract: A switching element operates to be turned on or off at a frequency in the order of megahertz. A reactor supplies a resonance current generated by resonance of the reactor with a floating capacitance between electrodes to between the electrodes. The resonance current does not flow in a direct-current power supply. By turning a capacitor and a floating inductance into a serial resonant state, the reactor ideally supplies the resonance current to between the electrodes without influence of the floating inductance. A high-frequency voltage asymmetric in positive and negative polarities is applied to between the electrodes and a current pulse can be made into a short pulse. Therefore, finish machining with high surface roughness can be performed.

Abstract: An electric discharge machining apparatus includes: electrodes the total quantity of which is equal to N; an alternating-current power source; and capacitors the total quantity of which is equal to N. The alternating-current power source applies an alternating voltage commonly to the electrodes. One end of each of the capacitors is connected to a corresponding one of the electrodes, whereas the other ends of the capacitors are commonly connected to the alternating-current power source.

Abstract: Based on a discharging gap value and machining allowance value stored in a corner-control-information storing means 20, a speed-ratio calculating means 23 being a machining-volume calculating means calculates machining volumes of a straight line portion and a corner portion to calculate a volume ratio therebetween. A corner-portion-speed calculating means 24 calculates a machining feed speed at the corner portion based on a volume ratio calculated by the speed-ratio calculating means 23, and then outputs to a servo amplifier 8 on the basis of the length of a pre-corner section outputted by a pre-corner-section calculating means 21 and the length of a post-corner section outputted by a post-corner-section calculating means 22, instructions about machining feed speeds from entering the pre-corner section till getting out of the post-corner section.

Abstract: A wire-discharge machining apparatus controls a short circuit between a wire electrode and a workpiece and wire-breakage, and makes it easy to improve productivity, by performing power supply control to mix an upper-side power supply state in which a high-frequency pulse voltage is applied from an upper-side power supplying unit, a lower-side power supply state in which the high-frequency pulse voltage is applied from a lower-side power supplying unit, and a both-sides power supply state in which the high-frequency pulse voltage is applied to the wire electrode from both power supplying units in synchronization with each other during a period of electric discharge machining.

Abstract: In a waveform of switching signals, which is output from a full-bridge circuit formed of four switching elements, includes a normal polarity pulse group and a reversed polarity pulse group for controlling an output timing of voltage pulses. A duty cycle of the normal polarity pulse group containing a plurality of normal polarity pulses, which apply a positive power-supply polarity to a workpiece and apply a negative power-supply polarity to a machining-purpose electrode, is configured so as to be different from a duty cycle of the reversed polarity pulse group containing a plurality of reversed polarity pulses, which apply a negative power-supply polarity to the workpiece and apply a positive power-supply polarity to the machining-purpose electrode.

Abstract: A drive device for erosion tools, having a drive shaft, an electrode holder connected to the drive shaft, an axial drive which works on the drive shaft, a rotational drive which works on the drive shaft as a direct drive in a contactless manner, and a radial bearing. The radial bearing is constructed as a ball track.

Abstract: A discharge pulse control device cuts off a pulse width of the a discharge pulse being produced in a machining gap when a comparison result of a voltage level comparator indicates abnormal electrical discharge. Upon detection of abnormal electrical discharge based on comparison results of a high-frequency component comparator and the voltage level comparator, a quiescent period control unit constructed from a discharge pulse diagnosis device, a first pulse counter, a second pulse counter, and a quiescent pulse control device performs change setting of the quiescent period at the time of occurrence of abnormal electrical discharge and sends that information to the discharge pulse control device. Subsequently, the discharge pulse control device performs change control of the quiescent period at the time of occurrence of abnormal electrical discharge so that the discharge pulse and the quiescent time are optimally controlled.

Abstract: An electric discharge machining device that performs processing by applying a voltage pulse to space between the processing electrode and the workpiece and suitably switching the polarity of the voltage pulse attains both desired processing accuracy and desired controllability. The electric discharge machining device is provided with the first to fourth switching elements. The controlling unit that controls these switching elements, when setting a period time in which the first switching element is turned on, a period of time in which the fourth switching element is in an on-state in the same period, and, when setting a period time in which the second switching element is turned on, a period of time in which the third switching element is in an on-state in the same period so that a desired voltage pulse is applied to the space between the processing electrode and the workpiece.

Abstract: The invention relates to a method and generator for generating a time sequence of EDM pulses having a predefined ignition voltage for electrical discharge machining. An AC voltage is generated from a DC voltage, furnished by a bipolar current source. The AC voltage is applied to an isolating transformer disposed between the bipolar current source and the spark gap. A first pulse capacitor is charged by the bipolar current source to a voltage corresponding to the ignition voltage. The ignition voltage provided by the isolating transformer is switched with a selected polarity to the spark gap.

Abstract: In a wire electrical discharge machining apparatus, an upper main-discharge power supply is connected between an upper conducting terminal and a workpiece using an upper main-feeder line capable of configuring outward and homeward paths, and a lower main-discharge power supply is connected between a lower conducting terminal and the workpiece using a lower main-feeder line capable of configuring outward and homeward paths. Moreover, a sub-discharge power supply is connected between the upper conducting terminal and the workpiece and between the lower conducting terminal and the workpiece using an upper and a lower sub-feeder lines that have higher impedances than the impedances of the upper and the lower main-feeder lines and can configure outward and homeward paths.

Abstract: Target fluid is made into electrolyte solution when measured fluid-quality value is lower than a first condition value, by substituting an impurity anion contained in the target fluid with a predetermined anion and substituting an impurity cation contained in the target fluid with a predetermined cation, and purified when the fluid-quality value is higher than a second condition value. The above procedures are repeated, so that the fluid-quality value of the target fluid falls within a predetermined range, to make the target fluid into electrolyte solution with a correlation between pH and conductivity.

Abstract: A sinker electric discharge machining apparatus for machining a workpiece by generating electric discharge in a work gap by applying a voltage having an OFF time, may include a discriminator for generating a first signal representing an abnormal state of the work gap, and a second signal representing a normal state of the work gap; and a pulse controller, in which a first extension factor and a second extension factor that is smaller than the first extension factor are set and a first reduction factor and a second reduction factor that is smaller than the first reduction factor are set. The pulse controller extends the OFF time using either the first or the second extension factor if the first signal is received. The pulse controller reduces the OFF time using either the first or the second reduction factor if the second signal is received.

Abstract: A method for controlling a wire electric discharge machine comprising the steps of: determining of at least one predefined contour deviation (Esmax) of a predefined contour to be cut into the workpiece; determining a curvature of at least one geometry element defining at least one section of the contour to be cut into the workpiece; calculating a displacement (s) of an upper guide (WGU) and a lower wire guide (WGL) based on the predefined contour deviation (Esmax) and on the curvature of the at least one predefined geometry element; and setting the displacement (s) by moving the upper guide (WGU) relative to the lower wire guide (WGL) such that the wire electrode guided by the upper (WGU) and lower wire guides (WGL) is inclined in a current cutting direction of the workpiece during cutting of the geometry element into the workpiece.

Abstract: A power-supply control device includes a high-frequency component detecting unit, a machining voltage level detecting device, a no-load time 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 no-load time detecting device detects delay time of discharge of the discharge voltage at the machining gap. The high-frequency component is compared with a reference value to obtain a first comparison result. The discharge voltage level is compared with a reference level to obtain a second comparison result. The pulse control device controls pulse off time based on the first comparison result and the detected delay time, and cuts off a discharge pulse based on the second comparison result.

Abstract: A Tandem-type micro electro-discharge machining (EDM) apparatus comprises a EDM machining stage, a gradation twin-wire EDM device, an electrode tool, a workpiece, and a resistor-capacitor (RC) EDM circuit. The gradation twin-wire EDM device further comprises a wire supply reel unit, a wire take-up reel unit, a stepped insulating roller, a twin-wire conductor unit, and a discharge circuit unit. With the design of the gradation twin-wire EDM device, only one single EDM procedure is needed to simultaneously perform rough EDM and finish EDM processes together on the electrode tool to form a required micro electrode tool, which can be immediately used to perform micro-hole EDM or scanning EDM on the workpiece. Therefore, the Tandem-micro EDM apparatus of the present invention can be functioned automatically to achieve mass production of micro holes EDM and reduce machining time and improve machining efficiency and product's quality.

Abstract: A wire-discharge machining apparatus controls a short circuit between a wire electrode and a workpiece and wire-breakage, and makes it easy to improve productivity, by performing power supply control to mix an upper-side power supply state in which a high-frequency pulse voltage is applied from an upper-side power supplying unit, a lower-side power supply state in which the high-frequency pulse voltage is applied from a lower-side power supplying unit, and a both-sides power supply state in which the high-frequency pulse voltage is applied to the wire electrode from both power supplying units in synchronization with each other during a period of electric discharge machining.

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 method for controlling an electric discharge machining process, wherein a tool electrode is moved relatively to a workpiece with a working gap distance, wherein the process includes a current and at least one previous erosion cycle, the current and the previous erosion cycle each being divided into predetermined time intervals each including at least one discharge pulse, wherein similar working gap conditions are present within a time interval of the previous erosion cycle and of the current erosion cycle, and wherein subsequent erosion cycles are separated by a process pause cycle.

Abstract: An electric discharge machining apparatus having a gate signal generator for generating a gate signal, a power source for applying a voltage across a work gap formed between a tool electrode and a workpiece, a gap voltage detector for detecting a gap voltage of the work gap, an electric discharge detector for supplying an electric discharge detection signal representing electric discharge to the gate signal generator. The electric discharge detector includes a counter for generating a sample clock having a frequency greater than the frequency of the gate signal, and a comparator for receiving the gap voltage and determining that a fall in the gap voltage is larger than a specified voltage difference in each sample clock. The electric discharge detection signal is generated in response to an output signal of the comparator.