| 摘要 |
PURPOSE:To stably perform machining, by changing the preset pulse current duration time on the basis of a detected discharge current duration time so as to prevent a pulse break with a discharge current being interrupted. CONSTITUTION:A control unit 2, allowing an electric current to flow in each base of a switching transistor 1, electrifies each switching transistor. In this way, a machine, allowing a discharge current to flow across an electrode 5 and a work 6, electric discharge machine the work 6. A comparator circuit 11, comparing the preset pulse current duration time with a discharge current duration time detected by a detector 10, generates a changing command in the control unit 2. The machine detects the actually flowing discharge current duration time by the pulse current detector 10 to be compared with the preset value, and if the actually flowing discharge current duration time is shorter, the machine, operating the control circuit 2 so as to change the preset pulse current duration time to be increased after a fixed sampling period, advances machining. |
