| 摘要 |
<p>PROBLEM TO BE SOLVED: To use a machining power unit with the high-current peak for machining of finishing conditions and machining conditions in a thin wire range without deteriorating machining characteristics, in an electric discharge device. SOLUTION: This power unit is provided with a first power source of a high impedance circuit 10 connected to a D.C. power source in series, and a second power source of a low impedance circuit 20, pulse voltage is intermittently applied to a part between a tool electrode 1 and a workpiece W facing the tool electrode 1 with the specified clearance by the first power unit, and machining current is supplied by the second power unit after electric discharge is generated. A plurality of switching elements 202 connected in parallel, an on-member selecting circuit 211 for controlling the number for simultaneously turning on the switching elements 202, and an on-time control device 212 for variably controlling the on-times of the switching elements 202 are provided on the second power unit.</p> |
