Abstract: The present invention relates to an electric discharge machining device. The electric discharge machining device includes: a first switch provided between the positive pole of a power supply and a work piece; a second switch provided between the negative pole of the power supply and the work piece; a third switch provided between the negative pole of the power supply and a tool electrode; a fourth switch provided between the positive pole of the power supply and the tool electrode; and a pulse generating device. In order to supply current pulses with a straight polarity, the pulse generating device repeatedly switches on and off either the first or third switch while the other switch is on. In order to supply current pulses with a reverse polarity, the pulse generating device repeatedly switches on and off either the second or fourth switch while the other switch is on.

Abstract: The present invention relates to an electric discharge machining device. The electric discharge machining device includes: a first switch provided between the positive pole of a power supply and a work piece; a second switch provided between the negative pole of the power supply and the work piece; a third switch provided between the negative pole of the power supply and a tool electrode; a fourth switch provided between the positive pole of the power supply and the tool electrode; and a pulse generating device. In order to supply current pulses with a straight polarity, the pulse generating device repeatedly switches on and off either the first or third switch while the other switch is on. In order to supply current pulses with a reverse polarity, the pulse generating device repeatedly switches on and off either the second or fourth switch while the other switch is on.

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

Abstract: A motor control system for controlling a plurality of motors for moving an object in respectively different axial directions that includes a plurality of target devices, each target device including a (pulse width modulation) PWM signal generator that generates a PWM signal for driving a motor using a triangular signal, and a host device for supplying a synchronization signal to each of the target devices, wherein each target device is arranged with a corresponding motor, and each PWM signal generator resets the triangular signal in response to the synchronization signal.

Abstract: A computerized numerical control system includes a human interface computer (1), a PCI bus (4) which is adapted to couple to the human interface computer, and a numerical control device (3). The numerical control device includes an embedded processor (30) and a local bus (34) coupled to the embedded processor. A first and second low cost shared memories such as SDRAMs (10, 11) and a dual bus memory controller (2) are provided. The first and second shared memories are shared by the human interface computer and the embedded processor. The dual bus memory controller is configured for concurrent communication with the PCI bus and the local bus and is adapted to couple to the first and second shared memories.

Abstract: A motor control system for controlling a plurality of motors for moving an object in respectively different axial directions that includes a plurality of target devices, each target device including a (pulse width modulation) PWM signal generator that generates a PWM signal for driving a motor using a triangular signal, and a host device for supplying a synchronization signal to each of the target devices, wherein each target device is arranged with a corresponding motor, and each PWM signal generator resets the triangular signal in response to the synchronization signal.

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

Abstract: A communication control system and method of communicating between a numerical control device and a plurality of servomotors, includes connecting the numerical control device to a plurality of servoamps of the plurality of servomotors in a loop configuration via bi-directional serial communication cables, splitting command data in the numerical control device, outputting a first portion of command data to one of the plurality of servoamps from the numerical control device in a counter-clockwise direction and a second portion of command data to one of the plurality of servoamps from the numerical control device in a clockwise direction, splitting feedback data in one of the plurality of servoamps, transmitting a first portion of feedback data to the numerical control device in a counter-clockwise direction from the one of plurality of servoamps in response to the first portion of command data, and transmitting a second portion of data to the numerical control device from the one of the plurality of servoamps i

Abstract: A wire cut electrical discharge processing device comprising a device (6) which takes up a wire electrode, the wire electrode (1) traveling along a wire conveying path; a servo motor (4B) which applies tension to the traveling wire electrode; a NC device which generates signals which indicate a set value for the tension; a force detector (9) which detects the tension applied to the wire electrode and generates signals which indicate the detected value; and a tension control device (13) which processes signals which indicate the set value of the tension and the signals which indicate the detected value of the tension and which supplies speed command signals which direct the speed of rotation of the servo motor. The tension control device comprises two continuously connected notch filters (19 and 20) which check different frequencies.

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: A wire-cut EDM method and apparatus for machining to a fine surface roughness of 1 .mu.m Rmax or less. Two power supplies and a electrode polarity switching system are used. A first high energy power source is used for initial profile cutting and may also be used for one or more later cuts while the machining pulse parameters, and feed rate and offset are adjusted for increasing less rough surface finishes. The wire electrode is held at negative machining potential. A second power supply and smaller offset values are used for later cuts to create lower values of surface roughness, while still maintaining the wire electrode at a negative machining potential. Finally, in order to create a fine finished surface (Rmax.ltoreq.1 .mu.m), the offset is further reduced and the wire electrode polarity is reversed.

Abstract: A wire cut electric discharge machine including a device (6) for pulling a wire electrode (1) such that it travels along a wire transport path, a servo motor (4B) which applies tension to the traveling wire electrode, an NC device which generates a signal indicating a tension setting value; a tension detector (9) which detects the tension applied to the wire electrode and generates a signal indicating the detected value, and a tension control device which processes the signal indicating the tension setting value and the signal indicating the tension detection value, and commands the servo motor rotational speed. The tension control device includes a non-essential frequencies setting circuit (20) which sets non-essential frequencies and generates a signal indicating that setting value, and an electric filter device (19), which blocks non-essential frequencies based on the non-essential frequencies setting circuit output signal.

Abstract: An electrical discharge detector (30) which detects electrical discharge generated at a machining gap; a pulse generator (41) which generates a pulse signal which stops after the commencement of electrical discharge in response to the electrical discharge detector; first switching circuits (22A, 22D) which apply voltage pulses of one polarity in response to the pulse signal; second switching circuits (22B, 22C), which apply voltage pulses of the opposite polarity to the machining gap in response to the pulse signal; a flip-flop (46) which retains one of two states; a gate circuit (42, 43) which supplies a pulse signal to the first switching circuit when one state is retained in the flip-flop, and supplies a pulse signal to the second switching circuit when the other state is retained in the flip-flop; circuits (CK, 48, 49) which supply a high frequency pulse to the flip-flop for the duration of the pulse signal; a circuit (44) which supplies a single pulse to the flip-flop each time the pulse signal is inacti

Abstract: A power supply circuit (8) incorporates a DC power supply (8A), a switching element (8B), and a diode (8C). A transformer (12) incorporates a ring core (13), a primary windings (13B), and secondary windings (13C). The switching element (8B) goes ON and OFF on the basis of a signal pulse supplied from a pulse generating device (5), so that a DC current pulse is supplied to the primary side of the transformer (12). An inverting device (15) connected across the power supply circuit (8) and transformer (12) incorporates switches (151), (152), (153), and (154), and is controlled by a signal from a relay circuit. When the switches (151) and (152) are closed, the switches (153) and (154) are open. The first half-wave of the voltage pulse of the current induced on the secondary side of the transformer (12) is supplied to a machining gap formed between a wire (1) and work piece (3) in the direction of the work piece (3). The subsequent half-wave is then supplied to the machining gap in the direction of the wire (1).

Abstract: A contact position measurement method including moving either a wire-shaped tool electrode or a workpiece relative to the other within a plane, and causing the wire to approach a reference position on the workpiece; applying a voltage between the wire and the workpiece with the wire oriented perpendicular to the plane; detecting contact between the workpiece reference position and the wire; placing the workpiece reference position generally at the center of vibration of the wire, determined in accordance with the number of occurrences of detected contact; generating coordinate data indicating the position of the wire with respect to the workpiece; and determining the position of contact based on the coordinate data.

Abstract: A transformer converts high frequency pulses, transmitted through a coaxial cable from a power supply unit positioned at a distance from a gap formed between a tool electrode and a workpiece and having a direct current power supply and switching element, into high frequency alternating current pulses, and is connected to that gap. The transformer includes a ring core, a primary winding connected to the coaxial cable, and a secondary winding connected to the gap. Preferably, these windings will have a minimum number of turns. Further, a bypass means is provided which selectively passes the direct current pulse from the direct current power supply or the alternating current pulse induced in the transformer to the gap. It is preferable to house the bypass means and the transformer in a single case positioned in the vicinity of the gap.