Mathematical Modeling for Performance Measure on the Electrical Discharge Machining of Inconel 718 by Response Surface Methodology

Present dissertation work has attempted to model the change significant process parameters for Electrical Discharge Machining (EDM) by Response Surface Methodology (RSM). The dependent variables were material removal rate (MRR), electrode wear rate (EWR) and surface roughness (Ra). The Inconel 718 has been used as a workpiece material with copper electrode, discharge current (Ip), flushing pressure (P) and pulse on-time (Ton) were selected as process parameters for this study. A face center composite design was selected for the experiments. The results from the experimental runs were analyzed using Minitab17 software. The significant coefficients were obtained by performing Analysis of Variance (ANOVA) at a 5% level of significance. The obtained results showed that all input parameters (Ip, P and Ton) had a significant effect on the output parameters (EWR, MRR and Ra). Increasing the input parameters resulted in higher values of responses (EWR and MRR). Increasing Ip and Ton resulted in higher values of Ra, whereas an increase in P had the reverse effect. The model sufficiency is very satisfactory as the coefficient of determination (R2) is found to be 99.96, 99.60 and 99.12% for the MRR, EWR and Ra respectively.