Performance evaluation of electrical discharge machining on stainless steel 316L using copper impregnated graphite

Abstract

The electrical discharge machining (EDM) is considered as non-conventional machining due to its different method of machining compared to conventional machining. This study presents the results of experimental studies carried out to conduct a comprehensive investigation on the influence of EDM input parameters on the characteristics of EDM process. The machining parameters include peak current, servo voltage, pulse ON time and pulse OFF time. The study was conducted using 2 levels of full factorial method in Design of Experiments (DOE). The design expert version 9software was employed to perform all the data analysis for full factorial and Central Composite Design (CCD) experiments. Basically, this study evaluates the EDM performance on Stainless Steel 316L using Sodick EDM linear motor series AM3Lwhich employed copper impregnated graphite of diameter 7.0 mm as the tool electrode.The machining responses are material removal rate (MRR), electrode wear rate (EWR),surface roughness (SR) and dimensional accuracy. An optimum setting was determined based on DOE and analysis of variance analysis (ANOVA). Result’s showed that peak current was the most significant factors to all machining responses. The servo voltage does not have significant effect to the machining responses in the Response Surface Methodology (RSM). Higher current produced higher MRR, EWR, SR and dimensional accuracy. Maximum MRR was obtained at peak current ranging from 27amp to 38amp,pulse on time range from 120μs to 145μs and 60μs of pulse off time. Maximum EWR was obtained at peak current ranging from 27amp to 37amp, pulse on time range from140μs to 160μs and 60μs of pulse off time. Lower dimensional accuracy and SR obtained at 5amp of pulse on time. Higher pulse off time produced lower MRR and EWR.