Electrical Discharge Machining of Inconel 718 using Cryo-Processed Rotary Cu-Electrode

Abstract

This paper focuses on the impact of machining factors on surface quality in electric discharge machining (EDM) of Inconel 718. Drilling has been performed by a cryogenic treated copper tool. Experiments were accompanied by dissimilar machining factors viz. tool diameter, discharge current, pulse on time pulse off time, tool rotation and hole depth. The thickness of work piece material remains constant. Surface roughness is measured by optical surface profiler. Taguchi based L₁₈ orthogonal array of experimental design was employed to accomplish machining. Analysis of variance (ANOVA) has been employed to find out optimum factors for minimum surface roughness (SR). It was found that pulse off time, pulse on time and tool rotation are greatest affecting factors that affects SR for cryo-treated Cu tool electrode. Tool diameter is least affecting factor that affects SR. A linear regression model has been developed to find out optimum combination for SR of Inconel 718 work piece.