| 摘要 |
PURPOSE:To improve accuracy of machining depth and finish the bottom surface of a work to uniform roughness, by connecting an electric discharge between a machining electrode and the work in such a manner that the machining depth is not increased from a preset value after it reaches said value. CONSTITUTION:A movable electrode 23, vertically moving with a machining electrode 1 in electric discharge machining work, fixed electrode 24, located at a face-to-face position to said electrode 23, and a gap voltage detecting power source 25, producing an electric discharge between these facing electrodes 23, 24, are provided to constitute a machining depth detecting device, and machining depth, when reaching a preset value in a state of gap voltage between the before said facing electrodes lowered below preset voltage between the machining electrode 1 and work 2, is detected by a gap voltage detecting circuit 7 to reversely operate electrode feed while perform forward electrode feed when exceeding said preset voltage, thus the feed operation is repeated. |
