MULTI-OBJECTIVE OPTIMIZATION OF EDM PROCESS PARAMETERS USING RSM-BASED GRA AND TOPSIS METHOD FOR GRADE 6 TITANIUM ALLOY

In this study, an attempt has been taken to find out the appropriate optimal parameter setting that will provide the best quality product depending on experimental data during Electro Discharge Machining (EDM) of Titanium grade 6 alloy with the help of brass electrode and to compare the optimized results achieved from two optimization techniques. For this study, Face Centered Central Composite Design- (FCCCD) based Response Surface Methodology (RSM) coupled with Technique for order of preference by similarity to ideal solution (TOPSIS) and Grey Relational Analysis (GRA) has been applied to optimize the process parameters i.e. gap voltage ([Formula: see text], peak current ([Formula: see text], pulse on time ([Formula: see text], and duty cycle ([Formula: see text]). Radial overcut (ROC), surface roughness ([Formula: see text], material removal rate (MRR) and tool wear rate (TWR) are selected as output performance characteristics. To find out the significant process parameters, Analysis of variance (ANOVA) test has been performed at 95% confidence level. For validation of the study, confirmation experiments have been performed at optimal parameters setting which show the enhancement of Relative Closeness Coefficient ([Formula: see text] up to 0.144082 using TOPSIS and Grey Relational Grade (GRG) up to 0.198014 using GRA, respectively.