Experimental Investigation on Microhardness, Surface Roughness, and White Layer Thickness of Dry EDM

Abstract In this research, the environment-friendly dry electrical discharge machining (EDM) process is investigated to improve microhardness, surface finish, and white layer thickness of machined surfaces using graphite-argon gas as a dielectric medium. The graphite powder, mixed with compressed argon gas, has been used replace existing medium in EDM process. Gas pressure, current, pulse width, gap voltage were working input parameters reduce roughness enhance microhardness thickness. Taguchi L16 orthogonal array applied design analysis experimental results. minimum (2.23 μ m) HN31 steel attained by increasing pressure up 1.0 MPa values width (40 s), V), current (6 A). maximum (501.04 HV) obtained at 1.2 120 s 60 V voltage, 18 A current. (16.24 achieved (1.2 MPa), (160 (70 V) (18 SEM had done reveal recast SR increased layer, pores, microcracks on surfaces. Finally, multi-criteria optimization technique: Weight Product Method (WPM) predict optimum parameter settings: GP: MPa, PW: s, GV: 50 V, DC: meet best performances (MH = 493.32 HV, WLT 14.28 m, 3.82 m). validation tests confirm predicted results both WSM methods.