Electrical control circuit for spark-erosion machining unit - has electrode and workpiece forming transverse branch of bridge circuit such that current direction can be reversed

摘要

Spark erosion machining of workpiece (1b) using an electrode (1a) and two parallel voltage sources (3a,3b) decoupled from one another by a diode (4) and connected to the machining assembly (1a,1b) via series resistances (5a,5b), has the novelty that the machining assembly forms the transverse branch (e) of a bridge circuit. The branches of the bridge comprise at least four switches (2a-2d) regulated by a control unit (6) so that the current direction in the transverse branch (e) is reversable or the connections for the machining assembly can be short-circuited. ADVANTAGE - The design enables a wider range of machining applications to be undertaken because, e.g., the current direction can be varied through the working gap.