Effect of material and machining features in electric discharge machining of 6061Al/rock dust composites

Abstract

The current research investigates the effect of electric discharge machining (EDM) and material parameters on material removal rate (MRR), tool wear rate (TWR) and surface roughness (Ra) while machining the novel aluminium rock dust composite. Experiments have been performed in Vidyunt EM 150 EDM machine by considering parameters namely discharge current, pulse ON time, pulse OFF time, reinforcement size and level. The composites have been prepared through stir casting method by reinforcing various sizes (10, 20 & 30 μm) of rock dust particles with aluminium 6061 and at different levels (5, 10 & 15%). Since the number of input parameter is more, Taguchi’s design of experiments has been used to reduce the number of trials and grey relational analysis (GRA) technique has been used for optimization. Analysis of variance has been performed to identify the significance of the parameters and it has been found that all the considered parameters have significant effect on response variables. But in the case of multi performance characteristics analysis, only pulse ON time and pulse OFF time have the significance over GRG. Pulse ON time has the highest influence (55.36 %) on the GRG followed by pulse OFF time with 17.6% and rock dust weight % with 7.8%. From the confirmation experiments, it could be well said that the developed regression equations predicts the response parameters with minimal error and the grey relational grade has been improved significantly.