| 摘要 |
PURPOSE:To work a minute hole having fine surface roughness with a high machining speed by forming an electrode for electric discharge machining for carrying-out the machining for the minute hole through revolution, into stepped form. CONSTITUTION:An electric discharge machining electrode 4e made of wolfram has a stepped form having a stage 9a and is sent vertically, through revolution during machining, by a vertical driving mechanism. Since a prepared hole is worked by the thin part of the electrode 4e at first, the worked area is small even with the fine roughness of the worked surface, and the top edge of the electrode 4e is not made concaved. When machining is performed by the stage 9b of the electrode 4f under the same conditions to the above-described, the accumulation of chips and gas 8d into the gap between the electrode 4f and a workpiece 5f is prevented, since the prepared hole has been formed already. Thus, high-speed machining with the superior surface accuracy is permitted. |
