Optimization of micro hardness of Al-SiC 6061 MMC machined by wire EDM with taguchi method

Abstract

The usage of Al-SiC metal matrix composites is constantly increasing since the last many years due to their many unique properties such as light weight, high strength, high specific modulus, high fatigue strength, low density, and high hardness. However, because of their high hardness, their machining, that too within close tolerance limits, is often a big challenge. Wire EDM (Electric Discharge Machining) however offers a good method to machine these deemed difficult to machine alloys. This research work focuses on the wire EDM machining of Al-SiC 6061 metal matrix composite which is one of the most widely used metal matrix composites in the world today. Here, Taguchi approach has been applied to study the work-piece composition and machining parameters during the wire EDM machining and to maximize the micro hardness of the surface obtained after the machining process. Different compositions of the Al-SiC MMC in terms of reinforcement percentages, along with six other operating parameters have been studied. L-16 Orthogonal Array (pronounced as ell-sixteen Orthogonal Array) has been used in the Taguchi approach for this purpose. Contributions of various factors to surface micro hardness have been determined, amongst which, SiC percentage in the Al-SiC MMC had the greatest contribution. The conclusions and future scope of this study have also been discussed.