| 摘要 |
PURPOSE:To drill a hole with high roundness and straightness in a workpiece by forming an electrode element into a circular cylinder with high roundness and straightness and subjecting the workpiece to electrical discharge machining by means of the electrode element positioned in close vicinity of the workpiece while keeping a state of the electrode element on a machining main shaft. CONSTITUTION:In a process of drilling an about 0.6mm. hole in a workpiece 3 by means of an electrode element 8 having a diameter of 1-2mm. by making use of electrical discharge machining, a table 1 is first moved to guide an electrode forming block 4 to a position below the element 8, and then a machining main shaft 6 is lowered to make the element 8 approach one side surface of the forming block 4. Thereupon, potential of the element 8 is set to be opposite polarity to that in usual electrical discharge machining. Furthermore, the table 1 is delicately moved to set the potential of the element 8 to be reverse to that in usual electrical discharge machining. Since the element 8 is rotated, all the circumference of the element 8 is worn out. Thus, the workpiece can have a desired diameter (e.g., 6mm.) of high roundness and straightness formed therein. |
