Development of mirror like surface characteristics using nano powder mixed electric discharge machining (NPMEDM)

This paper reports the results of an experimental study to develop mirror-like surface finish on the surface of AISI-D2 die steel by electric discharge machining (EDM) using carbon nanotubes (CNTs). The CNTs will be mixed into the dielectric fluid of EDM in defined proportion to develop and analyze the surface characteristics of AISI-D2 die steel. The newly developed proposed technology is called nano powder mixed electric discharge machining (NPMEDM). This research presents the influence of various processing parameters namely concentration of CNTs, peak current, and pulse duration on surface topography of workpiece machined by NPMEDM. The obtained experimental results indicate significantly improved performance of NPMEDM over EDM. The appropriate addition of CNTs into dielectric fluid of EDM increases the machining rate and decreases the surface roughness. At 3A peak current, 0.2 mm(3)/min MRR has been obtained by EDM which has been increased to 1 mm(3)/min after addition of CNTs into dielectric fluid of EDM. Similarly, the surface roughness has been reduced to 0.4 from 1.2 mu m after mixing the CNTs into dielectric fluid of EDM. The improvement in SR and MRR is obtained at the CNT concentration of 4 g/l mixed into the dielectric fluid. The experimental results further indicate that the CNTs concentration and peak current are the most influential variables.