Role of Powder in the Machining of Al10%Sicp Metal Matrix Composites by Powder Mixed Electric Discharge Machining

ABSTRACT: This article reports the results of an experimental study conducted with the objective to understand the mechanism of material removal (role of silicon powder) in powder mixed electric discharge machining (PMEDM) while machining the Al10%SiCP metal matrix composites. PMEDM is relatively a new development in the direction of enhancement of process capabilities of EDM. A new experimental set-up has been developed in the laboratory for experimentation. This research points out how the suspended powder helps in improving the performance of EDM. Further, the effect of the suspended powder and other selected parameters on process perfor-mance (machining rate (MR) and surface roughness (SR)) and subsequent optimal settings of the variables have been obtained using Taguchi method. The obtained experimental results indicate significantly improved performance of PMEDM over EDM. The appropriate addition of silicon powder into the dielectric fluid of EDM increases the MR and decreases the SR. The experimental results further indicate that the powder concentration, peak current, and pulse duration are the significant vari-ables, while the supply voltage is an insignificant variable. The results were verified by conducting confirmation experiments with optimal process conditions. KEY WORDS: powder mixed EDM, metal matrix composites, machining rate, surface roughness, process optimization