| 摘要 |
PURPOSE:To prevent the softening of the worked surface and improve energy efficiency by setting the polarity of a workpiece to negative electrode on dielectric breakdown and to positive electrode on the generation of main electric discharge, when working is performed by the main electric discharge for working which is generated in the working gap after dielectric breakdown. CONSTITUTION:A condenser 20e for electric discharge is charged by turning-ON a switching element 20b and turning-OFF a switching element 21b. Then, the electric discharge for dielectric breakdown is started in a working gap Q, and said dielectric breakdown is detected by a voltage detecting circuit 22a, and output into a pulse control circuit 22b is performed. Then, the switching element 20b is turned-OFF, and the switching element 21b is turned-ON for the time t1. At this time, the dielectric breakdown voltage can be arbitrarily set. When a prescribed time t2 lapses after the switching element 21b is turned-OFF, the switching element 20b is turned-ON, and the above-described procedures are repeated. Thus, the softening of the worked surface can be prevented, and the dimension precision can be improved, and the energy efficiency can be improved, and the dielectric breakdown voltage can be arbitrarily set. |
