| 摘要 |
PURPOSE:To prevent galvanic corrosion due to electrolytic phenomenon and enhance reliability in contact sensing by applying a pulse voltage having a specified period and a specified pulse width between a machining electrode and a contacted sensing body to perform the contact sensing. CONSTITUTION:Contact sensing is performed by applying a voltage from a contact sensing power source section 8 between a machining electrode 1 and a work 2 which is a contacted sensing body, with the voltage corresponding to a specified period and a specified pulse voltage under conditions of a contact point 10-2 being off and 10-1 being on. In this case, if a condition occurs in succession in which contact sensing is performed at least once with a contact sensing section 21 within a pulse voltage generating time outputted in every period, a contact sensing signal outputted from a flip-flop 20 is held and maintained for a specified period of time. That condition is determined to be an occurrence of a contact condition between the machining electrode 1 and the work 2. In this way, the voltage application time during the performance of the contact sensing can be substantially shortened, galvanic corrosion due to electrolytic phenomenon can be prevented, and the reliability in the contact sensing can be enhanced.
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