Experimental Study on Machining Super Alloy Using µ-EDM with Nanopowder Blended Dielectric

Material removal using micro-electrical discharge machining (µ-EDM) has gained importance over the past few years. µ-EDM helps in the machining of complex metals and alloys which are electrically conductive in nature. Though this process has advantages, its low Material Removal Rate (MRR) and high surface roughness (Ra) limit the range of applications. To minimize this problem, a study has been conducted to investigate whether mixing graphene nanopowders with the dielectric medium will increase the metal removal rate and improve the super alloy’s surface quality. Taguchi design is employed to carry out the experiments considering both plain and powder-mixed dielectric as input parameters. The effect of machining factors in µ-EDM such as voltage, capacitance, and pulse on-time on MRR and Overcut (OC) is explored and analyzed for their significance. While juxtaposed to the standard dielectric, it has been found that the nanopowder-mixed dielectric medium provides a better surface quality and a higher rate of metal removal. Subsequently, the machined surface has been observed under Scanning Electron Microscopy (SEM), which reveals a significant reduction of micro-cracks, micro-holes, and uneven surfaces during the nanopowder-mixed µ-EDM process.