GB1062562A - An apparatus for controlling gap size in electro-erosion machines - Google Patents

Abstract

1,062,562. Electro-erosion. EXPERIMENTAL'NY NAUCHO - ISSLEDOVATEL'SKY INSTITUTE METALLOREZHUSHCHIKH STANKOV "ENIMS." Aug. 29, 1963, No. 34182/63. Heading B3V. [Also in Division G3] In an electro-erosion machine, the gap between the electrode and the workpiece is automatically maintained at an optimum size by a control system utilizing signals representative of current and voltage across the gap, and means are provided to take account of false signals caused, for example, by the presence of carbonized particles in the gap. As shown, the electrode 2 and the workpiece 3 are supplied from a pulsegenerator over a resistor 4 by way of input terminals 1. Current pulses through the resistor 4 are detected by devices 5, 6 producing signals, limited in amplitude and width and proportional to the current, which are applied to a device 9. Similar signals dependent on the voltage across the working gap are applied to device 9 from devices 7 and 8. At no load there are no current signals and the output from device 9 operates a motor 10 to adjust a potentiometer 11, thereby actuating a regulator 12 and an electrode feed motor 13 which operate to move the electrode 2 towards the workpiece 3. When the electrode touches the workpiece the device 9 receives current signals but no voltage signals, and the electrode 2 is then caused to move away from the workpiece. In normal operation the device 9 receives both current and voltage signals, and the motor 10 operates only when the limiting conditions are effective, whereby the gap size is kept substantially at an optimum value. False current indications which may arise with a small gap are detected by the device 14 which applies a signal to device 9 so that the electrode is caused to move away from the workpiece. Suitable circuit arrangements for the devices 5 to 11 and 14 are described with reference to Fig. 3 (not shown).