Study on material removal rate and surface roughness using graphene as dielectric additives in micro-electric discharge machining

Abstract

Micro-electric discharge machining is the most distinguished micro-manufacturing process for engineering micro-parts of different geometric features. The slow material removal rate owing to the low energy short-pulsed electric discharge is the major bottleneck of the process in batch scale production. This paper is an attempt to increase the material removal rate (MRR) and enhance the surface integrity in micro-EDM using graphene as an additive in dielectric liquid. Graphene sheets synthesized using Hummers method followed by reduction and subsequent heating was dispersed in hydrocarbon based dielectric liquid by ultrasonication at temperature near to the flash point. The INCONEL 718 workpiece electrode has been immersed in the graphene suspended dielectric medium where as tungsten carbide of diameter 200µm has been used as tool electrode. It has been found that the MRR increases by 47 % in terms of volume of material removed and the surface roughness reduces by 73 % for graphene additive based dielectric medium as compared with dielectric without additive.