| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric discharge machining device determining the penetration accurately without erroneous detection. SOLUTION: The electric discharge machining device includes: a machining electrode 1; a penetration detecting plate 4 provided opposite to the machining electrode; and a machining power supply 1 applying a voltage between a workpiece 3 and the machining electrode. In an electric discharge machining machine that forms a through-hole in the workpiece arranged between the machining electrode and the penetration detecting plate in a manner not to touch the penetration detecting plate, the electric discharge machining device further includes: a penetration detecting-plate electric potential comparator 9 having a first input terminal connected with the penetration detecting plate and a second input terminal, and comparing the electric potential of the first input terminal and the electric potential of the second input terminal; a reference power supply applying the second input terminal with a voltage on the basis of the workpiece; and a penetration detection power supply 6 applying the penetration detecting plate via a resistor with a voltage with the same polarity as the reference power supply and an absolute value larger than that of the reference power supply on the basis of the workpiece. COPYRIGHT: (C)2011,JPO&INPIT
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