Spark erosion machine - has control unit for semiconducting switches between series of capacitors discharged sequentially across electrode to earthed workpiece

摘要

A spark erosion machine has a series of capacitors connected in parallel between the electrode and the earthed workpiece via the emitter-collector path of semiconducting switches. The live terminal of each capacitor is also connected via a resistance to the battery. The base of each semiconducting switch is connected to a control unit. This opens and closes the switches sequentially for preset periods after the capacitors have charged up so that the electrode can arc to the workpiece. There may be a sensor in series with the electrode to indicate the rate of discharge to the control unit and there may be an additional inductor in series with the electrode. ADVANTAGE - Inexpensive method of increased efficiency with less electrode wear.