| 摘要 |
PURPOSE:To prevent a work machined surface from rust with electrode waste adhering to the work machined surface, by controlling average machining voltage to a side of voltage of reverse polarity, in the case of voltage of positive polarity and reverse polarity applied across an electrode and a work. CONSTITUTION:A machine, if it turns on a transistor T1, applies voltage of positive polarity from a DC power supply E1 to generate an electric discharge between an electrode P and a work W. Next the machine, turning off the transistor T1 while turning on a transistor T2, applies voltage of reverse polarity from a power supply E2. While the machine changes a value of variable resistance RV1 through a variable resistor RV1, smoothing circuit 1, comparator 2, voltage dividing resistors R3, R4, etc. in a control circuit controlling the transistors T1, T2, and the machine, changing an output VL of the smoothing circuit 1, varies an applying time of the voltage of reverse polarity. And if machining is performed by setting a pulse width for applying the voltage of reverse polarity so that average machining voltage becomes the voltage of reverse polarity, the machine, even if it interrupts machining, prevents a machined surface from rust by coating the machined surface with electrode waste adhering to the surface.
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