Patent ID: 9114468
Filing Date: 2015-08-25
Classification: B23H

Abstract:
1. A power supply device for an electric discharge machine comprising: a series circuit that includes a DC power supply and a switching element for supplying a DC or AC current pulse to a machining gap between a machining electrode and a workpiece; and a control unit that controls the switching element, wherein when generating a current pulse having a triangular shape by an inductance component present on the series circuit, the control unit controls on-time and off-time of the switching element such that a peak value of each current pulse in a pulse train including a plurality of current pulses gradually increases toward a maximum value of a peak value or gradually decreases from the maximum value of a peak value, and the control unit controls the switching element such that a current pulse time ratio, which is a ratio between a current-less time of the current pulse during which a current is supplied to the machining gap and a current duration of the current pulse during which a current is supplied to the machining gap, becomes between ⅕ and 1/10.