Current Trends in Electric Discharge Machining Using Micro and Nano Powder Materials- A Review

Abstract

Powder mixed electric discharge machining (PMEDM) has clearly proven its advantages over EDM without additives. When controlled size and concentration of metal particles are mixed in the dielectric medium of Electrical discharge machining it helps to improve the various machining parameters like increased MRR, reduced surface roughness, reduced tool wear rate and improved topological properties like reduction in microholes, micropores, thin recast layer and improved corrosion resistance of the machined surface. Therefore, PMEDM have attracted the attention of many researchers since last few decade. This paper present a summary of some important research work done on PMEDM by mixing micro and Nano size particle in the dielectric fluid of EDM. Further this review article discuss not only the effect of micro or nano particle size and concentration on the EDM performance but also unfold the other factors like thermal conductivity, electric resistivity and density of micro or nano particles and optimal machine parameters such as peak current, pulse on time andpulse off time which affects the machining performance. From literature review, it has been found that surface finish in PMEDM increases with the decreased particle size and increased powder concentration upto certain limit, but increasing powder concentration beyond the optimal value create short circuit between the tool electrode and workpiece and hence reduces the surface finish. Furthermore micro or nano particles transfer less heat to workpiece by increasing the electrode gap approximately twice as compare to EDM without micro or nano particle, hence improved surface finish and reduced tool wear rate were achieved. Authors have also identified the research gap for further research purpose.