Comparative Micro-EDM Studies on Ni Based X-Alloy Using Coated and Uncoated Tools

Abstract

Nickel based alloys have found their wide range of applications in the automotive, oil and gas, and aerospace industries due to their excellent mechanical and thermal properties. However, these alloys impose greater challenges to conventional machining techniques due to their extreme hardness. Therefore, non-traditional machining process like micro-electro discharge machining, which is a non–contact machining process, comes into consideration. In this study, the machinability of Ni based X-alloy was investigated using micro-EDM process with the aid of coated and uncoated tools. From the experimental results, it was evident that the machining time was reduced with the increase of discharge energy for both the coated and uncoated tools. Increase in discharge energy also resulted in enlargement of entrance diameter and overcut. However, the non-conductive nature of coating caused in the reduction of overcut for machining using coated tools. The tool wear was found to reduce with the increase of discharge energy due to shorter machining time at higher discharge energy. Finally, crater size also increased with the increased discharge energy. The coated tools resulted in bigger crater sizes than uncoated tools at 1000 rpm, however, for higher tool rotation the difference was not significant.