ワイヤ放電加工におけるオンザマシン表面改質技術の開発

抄録

 As a method of processing cemented carbide, wire electrical discharge machining (WEDM) is generally used. However, typical surface defects, such as cracks, microcraters and recast layer, lead to a decreased surface integrity, probably resulting in a short tool life. Therefore, it is desirable to eliminate these surface defects by some methods. Thus, an on-the-machine surface modification technology in WEDM, for the complete elimination of surface defects, was developed in this study. The surface defects are eliminated using a wire electrical discharge machine by introducing surface integrity cut (SI cut) after applying a large number of WEDM finishing cuts. SI cut is carried out as follows. Wires are passed through the same contour with a wire offset of 0μm in SI cut after the final finishing cut by WEDM. It can be considered that a recast layer including cracks is selectively eliminated by the dissolution of cobalt based on the electrolytic action during SI cut. As a result, the surface defects generated by WEDM could be completely eliminated by incorporating SI cut into WEDM. Thus, this surface modification technology is effective for finishing cemented carbide machined by WEDM.