Optimization of Machining Parameters on Turning of Hybrid Metal Matrix Composite

Abstract

Hybrid metal matrix composite constitutes a tough metal matrix with reinforcement of at least two ceramic particulates and exhibit superior mechanical and thermal properties. The difficulties in machining metal matrix composites are obtaining good surface finish, consumption of more electrical power, involving excessive cutting forces and greater tool wear as it contain very hard ceramic particulates. This factor restrict the wide spread application of these kind of materials. Hence the study of machining characteristics and the optimization of the cutting parameters are prime importance. In this paper aluminium alloy is taken as metal matrix and the silicon carbide (SiC 10% by wt.) and boron carbide (B4C 5% by wt.) taken as ceramic reinforcement. This material is fabricated in the form of cylindrical rod using stir casting method. Turning operations are carried out in medium duty lathe using poly crystalline diamond (PCD) cutting tool insert. Taguchis design of L09orthogonal array is followed selecting three machining factors namely cutting speed, feed and depth of cut at three levels. Optimal cutting conditions are arrived by Signal-Noise ratio method with respect to surface roughness. The results are validated by (ANOVA) analysis of variance and the percentage of contribution of cutting speed, feed rate and depth of cut for better surface finish are determined and it is found that the vital parameter is feed followed by cutting speed and then by depth of cut.