Electrical discharge machine (spark erosion machine)

摘要

An electrical discharge machine is used for applying a pulsed voltage to an operating gap between an electrode and a workpiece lying opposite. An insulating dielectric fluid, which consists either of oil or of water with an added compound, is arranged in the gap. A voltage of positive polarity and a voltage of opposite polarity are applied to the operating gap via switches and associated impedances in order to generate a discharge for machining the workpiece. The impedance values may be optionally adjusted and the switching of the voltages may be controlled in such a way that a voltage of positive polarity is applied at the stop time to a pulsed voltage of opposite polarity, as a result of which the mean voltage approaches a predetermined value, preferably zero, during the stop time. The voltage control during the stop time results in a high speed and good finishing, in particular for the purpose of carrying out control in association with intermittent operation.