Modelling and analysis of MRR, EWR and surface roughness in EDM milling through response surface methodology

This study reports on the experimental investigations of Material Removal Rate (MRR), Electrode Wear Ratio (EWR) and surface Roughness (Ra) in EDM milling of stainless steel AISI 304. This research establishes empirical relations regarding machining parameters and the responses in analyzing the machinabihty of the stainless steel. The machining factors used are voltage, rotational speed of electrode and feed rate over the responses MRR, EWR and Ra. Response surface methodology was used to investigate the relationships and parametric interactions between the three controllable variables on the MRR, EWR and Ra. Central composite experimental design was used to estimate the model coefficients of the three factors. The responses were modeled using a response surface model based on experimental results. The significant coefficients were obtained by performing Analysis of Variance (ANOVA) at 95% level of significance. The developed models show that voltage and rotary motion of electrode are the most significant machining parameters influencing MRR, EWR and Ra. These models can be used to get the desired responses within the experimental range.