Electrical discharge machine with an opposite polarity voltage applied during an electrode jump operation

摘要

A machining pulse control apparatus applies a first polarity pulse voltage during a machining operation and a second opposite polarity voltage in a machining stop period in which the electrode is moved away from and toward the workpiece during a jump operation. Preferably, the second opposite polarity is applied for a period of time sufficient to maintain the voltage across the machining gap at zero voltage. The amount of direct current voltage applied during the jump operation is adaptively controlled.