Abstract
As a method for processing cemented carbide with a fine hole, wire electrical discharge machining (WEDM) is generally used. However, surface defects such as cracks and micro-craters are generated on the inner wall of the hole by WEDM. It is desirable that these surface defects are removed. Lapping of the inner wall of the hole has usually been performed by finishing by hand using a bar daubed with diamond paste. However, this method requires considerable time to finish the hole. A recently developed high-speed flow finishing method seems to give an excellent performance in polishing the cemented carbide with a fine hole. However, it is difficult for the surface defects to be completely removed in this method. Thus, a combined polishing method, for the purpose of completely removing the surface defects, was developed in this study. This method combined the surface modification using an oxidizing treatment with flow polishing using an abrasive. As a result, the surface defects generated by WEDM could be completely removed in only 10 minutes by this combined polishing. Thus, this combined polishing method will be effective for polishing cemented carbide with a fine hole.
