Experimental investigations and multi-response optimisation of wire electric discharge machining of hypereutectic Al-Si alloys

Wire electrical discharge machining (WEDM) is a non-traditional machining process, which is used for machining of difficult to machine materials, like composites and inter metallic materials. In the present paper, an attempt is made to machine hypereutectic Al-Si alloys using WEDM as these materials are widely used in automotive, aerospace and electronic fields because of its attractive properties. In the study, the WEDM machining parameters, such as pulse on time, pulse off time, wire feed rate and variation of percentage of silicon are taken as controlling factors for experimentation. In the present manuscript, an attempt is made to study the influence of percentage of silicon in the alloy system on the performance measures, such as material removal rate (MRR) and surface roughness (SR) of machining. Further, the influence of various input process parameters on the responses has also been studied. In order to optimise the said performance characteristics, two multi-objective optimisation methodologies namely grey relational analysis (GRA) and principal component analysis (PCA) are implemented. It has been observed that principal component analysis is found to perform better than grey relational analysis. [Received 9 October 2015; Revised 26 May 2016; Accepted 21 June 2016]