Investigation on the Effect of Input Parameters on Surface Quality During Rotary Tool Near-Dry EDM

Abstract

This paper presents an experimental study on rotary tool near-dry EDM (RT-ND-EDM) of high-speed steel using a two-phase mixture of water and air as a dielectric medium. The RT-ND-EDM is an environmentally friendly process variant of EDM. Parametric investigation was performed to understand the effect of various input parameters on the quality of machined surface. The experimental results revealed that surface roughness (SR) increased with an increase in peak current and pulse on time. An increase in gas pressure first decreased and then increased the SR, and finally SR decreased with increased in liquid flow rate. In addition, analysis of RT-ND-EDMed surface using FE-SEM technique revealed that the machined surface had irregularities such as micro-cracks, debris deposition, micro-holes, micropores.