摘要 |
An electric discharge machine includes a machining power supply for applying a voltage to a machining gap between a machining electrode and its opposite workpiece and detecting a contact between the machining electrode and the workpiece. The machining power supply includes a first power supply circuit whose output voltage is equal to or less than an arc voltage, a second power supply circuit for supplying a pulse current to the machining gap, and a control unit. When the first power supply circuit detects a contact between the machining electrode and the workpiece, the control unit operates to supply a pulse current from the second power supply circuit to the machining gap while the machining electrode and the workpiece are in contact with each other.
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