| 摘要 |
This is an addn. to 876728, which described the formation of a polygonal hole contg. sharp edges by spark erosion. The novelty in the present invention is that a tool electrode is used with a cross-section including corresp. sharp edges. A point (P) is selected on one edge of the tool, corresp. to one point (P1) on one edge of the required hole. A circular orbit with centre (P) is then imposed on the tool electrode. The plane of the orbit is at 90 deg. w.r.t. the longitudinal axis of the tool electrode; a polygonal orbit may also be used. Sharp corners with min. radii can be obtd. in the eroded hole. |
