Experimental studies on wire electric discharge cutting of SiC p/6061 aluminum metal matrix composites

Abstract

This paper reports about the experimental findings on the wire electric discharge cutting (WEDC) of 6061 aluminum metal matrix composite (MMC) reinforced with silicon carbide particulates (i.e. SiCp/6061 Al). Four WEDC parameters namely servo voltage, pulse-on time, pulse-off time and wire feed rate were varied to study their effect on the quality of cut in SiCp/6061 aluminum MMC using average cutting rate and microstructure of the cut surface as response parameters. The experiments were conducted using one-factor-at-a-time experiment strategy in which only one input parameter was varied while keeping all other input parameters as constant. The experimental results indicate that the average cutting speed is mainly affected by pulse-on time, pulse-off time, and voltage and the changes are more prominent for the MMC 7.5% SiCp. The characteristics of the surface produced by WEDC were analyzed by scanning electron microscopy (SEM). Analysis of SEM images of the cut surface has revealed that the depth of micro-voids and micro-cracks slightly increases as the voltage and pulse-on time increases and as pulse-off time and wire feed rate decreases. there seems to be trade-off between the average cutting speed and better quality of cut for Al-SiCp MMC as far the values of pulse-on time, pulse-off time are considered and final choice will depend upon the type of application. An optimum range of the input parameters has been bracketed as the final outcome of this work for carrying out further research to develop the models for WEDC of SiCp/6061 aluminum MMC and to optimize the WEDC parameters for the best quality of cut and to minimize the wire breakage frequency.