Optimisation of multiple response characteristics in orbital electro discharge machining of Inconel 718 using Taguchi's loss function

In present study, a multi response optimisation method using Taguchi's loss function is proposed for electro discharge machining of Inconel 718 under orbital tool actuation. Orbital tool radius and orbital speed along with machining parameters viz. current, gap voltage, pulse on time and duty factor are considered at five levels as input parameters. Twenty five experiments as per Taguchi's L25 orthogonal array are conducted to measure material removal rate, tool wear rate and surface roughness. A combination of input parameters is devised which provides combined optimisation of the responses namely material removal rate, tool wear rate and surface roughness. Multi response signal to noise ratio is used to measure combined effect of all responses. Analysis of variance (ANOVA) is employed to identify the level of importance of the input parameters on the multiple performance characteristics considered. Confirmation experiments have been conducted to identify the effectiveness of the proposed optimisation method. A good improvement is observed by multi response optimisation method.