Effect of Tool Geometry on the Machining Characteristics amid SiC Powder Mixed Electric Discharge Drilling of Hybrid Metal Matrix Composite

Abstract

The manufacturing of hybrid metal matrix composites (HMMCs) combines two or more reinforcing materials exhibiting distinct properties, with a steady metal matrix phase. Such combinations display improved mechanical properties and abilities to potentially satisfy the needs of progressive engineering applications. However, non-traditional machining techniques are required for the adequate subtractive manufacturing of HMMCs for the specific purposes. In this research, powder mixed electric discharge drilling (PM-EDD) of Al6063/ 5% SiC / 2.5% Gr / 2.5% Al2O3 HMMC was performed with tool electrodes of dissimilar geometries at 5 g/l silicon carbide (SiC) powder particle concentration. A set of solid conical and hollow cylindrical tool electrodes made up of quenched copper, were used in the present work. Discharge-current, duty-factor, tool-speed, and flushing-pressure were chosen to be the governing input control variables. The performances of the two tool electrodes were experimentally examined and compared in terms of material removal rate (MRR), tool wear rate (TWR), and surface roughness (SR) during PM-EDD of the HMMC. However, material removal rate (MRR) was considered to be the foremost benchmark for the comparative analysis of the two tool electrodes. An implementation of response surface methodology (RSM) was executed to optimize the responses. The hollow cylindrical tool electrode could achieve 33.79% higher MRR as compared to solid conical tool electrode. The results displayed that the discharge-current had the most remarkable influence on the PM-EDD process compared to other input control variables.