JP2717086B2 - Wire cut electric discharge machine - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a wire-cut electric discharge machine for electric discharge machining of a workpiece with a wire electrode. [Prior Art and Problems] Conventionally, power is supplied to a wire electrode in a wire-cut electric discharge machine by contacting current. If the contact between the conducting electrode and the wire electrode is poor, the conduction loss is large, the pulse conduction with a high peak value of the discharge current cannot be performed, the intended constrained discharge machining cannot be performed, or if the contact pressure of the conducting electron is too high, the wire will not work. The movement of the electrodes causes strong friction to act, resulting in increased wear of the electron conduction and shortens the service life. In addition, there is a problem in that the contact state changes due to wear of the conducting electrons during the electric discharge machining, and the stable energization is obstructed. [Means for Solving the Problems] The present invention has been proposed in view of the above points. The present invention relates to the contact between a wire electrode and a current-carrying electrode and the contact state with respect to the current-carrying from an axial direction substantially orthogonal to the axis of the wire electrode. A device for adjusting by relative advance / retreat movement, a detecting device for detecting a change in the contact state between the current-carrying electrode and the wire electrode during electric discharge machining by energizing between them, and a detection signal of the detecting device during electric discharge machining And a control device for controlling the operation of the adjusting device so that the energized state between the conducting electrode and the wire electrode is maintained at a constant energized state. Embodiment The present invention will be described below with reference to an embodiment of the drawings. In the drawing, reference numeral 1 denotes a wire electrode, which is supplied from a reel (not shown) and travels along a path guided by a guide with a predetermined tension and speed by drive control of a brake and a take-up device. Reference numeral 2 denotes a guide for forming a processing portion, and the workpiece 3 is processed so as to face the wire electrode 1 which moves linearly between the guides. Reference numeral 4 denotes a current passing through the wire electrodes above and below the workpiece 3, and a power supply for processing is provided between the current passing 4 and the workpiece 3. The processing power supply supplies a pulse by the discharge of the storage device 6 charged by the DC or pulse power supply 5. 7 is a switch inserted in the charging circuit,
The on / off switching pulse-charges the storage device 6 and discharges it through a switch 8 of a discharge circuit provided as needed. Reference numeral 9 denotes an indenter for supporting the wire electrode 1 pressed by the electricity passage 4 from the opposite side. The position of the indenter 9 in the direction of the arrow perpendicular to the axis of the wire electrode 1 is controlled by the motor 10 by advancing and retreating. And wire electrode 1
Is adjusted. The indenter 9 and the motor 10 constitute an adjusting device for adjusting the contact between the conducting electrode and the wire electrode and the contact state. Reference numeral 11 denotes a detection circuit for applying a voltage between the upper and lower conductive electrodes 4 and the wire electrode 1 to detect a change in the contact state between the conductive electrode and the wire electrode during electric discharge machining, and 12 supplies a detection voltage to the wire electrode 1. Energized brush, 13 is the detection circuit 11
Control for controlling the motor 10 by performing a logical operation process or the like in accordance with the detection signal during the electric discharge machining to send the indenter 9 so that the state of conduction between the wire electrode 1 and the conduction electron 4 is maintained at a constant conduction state. Circuit. A peak value pulse having a peak value Ip of about 1000 A is applied to the gap between the wire electrode 1 and the workpiece 3 by the discharge of the storage device 6. Discharge occurs, low resistance loss or waveform distortion occurs, and the desired high-speed, high-performance processing cannot be performed.
By detecting the contact state between the wire electrode 1 and the wire electrode 4 by the detection circuit 11, the detection voltage decreases when the contact resistance between the wire electrode 4 and the wire electrode 1 is small, and conversely, the detection voltage decreases when the contact is poor. As a result, the change in the contact state during the electric discharge machining can be easily and accurately detected. Therefore, it is possible to set a reference value for the normal contact state in advance, display the comparison output by comparing the detection voltages, and control the contact state by generating a control signal. The control circuit 13 generates a control signal corresponding to the detection signal, controls the motor 10 and controls the position of the indenter 9, thereby bringing the wire electrode 1 into contact with the electron 4 at an appropriate pressure. The energization state between the wire electrodes 1 is maintained at a constant energization state. As a result, even if the conductive electrons 4 are consumed due to friction with the wire electrode 1, the contact energizing state is maintained constant, and the stable energizing of the processing pulse can be performed without current loss and without waveform distortion. High-speed, high-precision electric discharge machining can be continued. In addition, since the power loss to the gap and the occurrence of electric discharge can be prevented, it is possible to perform a stable and highly efficient automatic wire cut electric discharge machining without causing a disconnection accident of the fine wire electrode. In order to detect the contact state between the wire electrode 1 and the conducting electrode 4, the energizing state between the conducting electrode 4 and the indenter 9, or between the conducting electrode 4 and the other conducting electrode opposed to each other with the wire electrode interposed therebetween is determined by a voltage, It may be detected by a current. In this case, the detection power supply is DC,
In addition to using an AC power supply, detection can be performed with high precision by providing a power supply that applies a high frequency and detects the change state of the high frequency. Further, the energized voltage, current, resistance (impedance), and the like can be precisely measured by a bridge, a differential amplifier, a Hall element, an electret element, and the like. Further, the contact adjustment control based on the contact detection may be performed by sending the electron beam 4 to make contact with the wire electrode 1. In addition to the motor control, the feed control may be performed by using an electrostrictive material, a magnetostrictive material, a thermostrictive material element, or a fluid. A control device using pressure, spring pressure, or the like can be used. A brush, a pin, a dice, and the like can be used for the electron transmission, and a pulse power source for processing uses a rectangular wave pulse that switches on and off a direct current without using a capacitor, an AC pulse power source that reverses the polarity, and the like. [Effects of the Invention] As described above, according to the present invention, the adjustment of the contact state between the electron passing and the wire electrode in the processing preparation stage is not performed by relying on intuition as in the related art, but to the optimal contact state. Adjustment and control can be performed accurately.Also, even if the contact state changes due to wear of the electron beam during electrical discharge machining, the change is detected between the electron beam and the wire electrode according to the detection signal detected during electrical discharge machining. Since the control device controls the operation of the adjusting device so that the power supply state of the power supply is maintained at a constant power supply state, power supply loss, waveform distortion, wire electrode disconnection accident, etc., due to poor contact between the current-carrying electrode and the wire electrode occur. High-speed, high-precision wire-cut electric discharge machining can be stably performed without any problem. or,
The contact pressure between the conducting electron and the wire electrode is not excessively increased, so that the conducting electron is not unnecessarily worn.
It is possible to increase the service life of the electron transmission.

[Brief description of the drawings] The drawing is a configuration diagram of one embodiment of the present invention. 1 ... wire electrode 2. Guide 3 Workpiece 4. 5 DC power supply 6 ... Capacitor 7,8 …… Switch 9 ... indenter 10 ... Feed motor 11 ... Contact detection circuit 12 .... energizing brush 13 ... Control circuit

Claims (1)

(57) [Claims] A wire electrode that travels and moves with a predetermined tension and speed between the guides and a workpiece are arranged to face each other with a processing gap therebetween, and a current passing through the wire electrode is brought into contact with the wire electrode. Connect the other pole to the workpiece and connect the other electrode to the workpiece, apply a machining voltage pulse intermittently between the wire electrode and the workpiece, and generate a discharge pulse repeatedly to perform a wire cut electrical discharge machine. A device for adjusting the contact and the contact state between the wire electrode and the conducting electrode by a relative advance / retreat movement relative to the conducting electrode from an axial direction substantially perpendicular to the axis of the wire electrode; and A detecting device for detecting a change in the contact state during electric discharge machining by energizing between the two, and an energizing state in which the energizing state between the conducting and wire electrodes is constant according to a detection signal during electric discharge machining of the detecting device. To be maintained in Serial adjusted wire-cut electric discharge machining apparatus according to claim controller and that was provided for the operation control of the device.