摘要 |
PROBLEM TO BE SOLVED: To perform continuous and excellent machining by preventing the occurrence of leak due to powder in a machining liquid and to maintain the surface coarseness of a machined surface in an excellent state. SOLUTION: Powder 7 is mixed in a machining liquid with which a treating tank 1 is filled and a pulse voltage is applied between the poles of an electrode 27 and a work 5 and electric discharge machining is applied on the work 5 as the electrode 27 and the work 5 are relatively moved. In this case, it is decided by a leak deciding means 35 whether the occurrence frequency of leak phenomenon at every given period between the poles of the electrode 27 and the work 5 exceeds a threshold. Then it is decided that the occurrence frequency exceeds the threshold, the powder 7 in the treating tank 1 is recovered by powder recovering means 45, 47, 49, and 51.
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