Abstract: “Electrical discharge machining (EDM) is one of the earliest non-traditional machining, extensively used in industry for processing of parts having unusual profiles with reasonable precision. In the present work, an attempt has been made to model Surface Roughness (SR) through Response Surface Methodology (RSM) in a die sinking EDM process. The optimization was performed in two steps using one factor at a time for preliminary evaluation and a Box-Benken design (BBD) involving three variables (Pulse on-Time, Pulse off-Time and Pulse Current) with three levels for determination of the critical experimental conditions. A copper electrode having tubular cross section was employed to machine holes of 8 mm height and 12 mm diameter on EN 353 Steel alloy workpiece. The results of analysis of variance (ANOVA) indicated that the proposed mathematical models obtained can adequately describe the performances within the limits of factors being studied. The experimental results reveal that interacti”

Keywords: EDM, hollow tool, response surface methodology, surface roughness, SEM