PROCESS PARAMETRIC STUDY OF MACHINING OF METAL MATRIX COMPOSITE BY EDM PROCESS

Abstract

The need of materials with exceptional combination of properties has resulted in the development of advanced materials such as composites. In the last few decades, the use of advanced materials such as polymeric matrix, ceramic matrix and metal matrix composite materials has increased manifold. As the application areas multiply, there is an imminent need of developing cost-effective high quality processing routes for machining of these composite materials. Metal matrix composites (MMCs) are the materials, based on a metal matrix, the reinforcement of which is realized by ceramic fibers, particles or whiskers of boron carbide, aluminium oxide or silicon carbide. However, conventional machining of MMC is difficult due to serious tool wear caused by the hard reinforcement. In view of high tool wear and high cost of tooling with conventional machining, non-contact material removal process offers an attractive alternative. Using un-conventional machining techniques in shaping advanced composite materials has generated a lot of interest. Among the many unconventional processing techniques, electric discharge machining (EDM) has proved to be effective in composite materials. The machinability of EDM depends on the electrical conductivity of the work material. Despite the low electrical conductivity and high thermal resistance of the SiC reinforced particles, which ultimately reduces the overall electrical and thermal conductivity of the work material, the research work reported, indicate that Al—SiCp composite can be machined effectively using EDM. In order to exploit the potential industrial applications of MMCs, it is important to investigate suitability of EDM for their reliable and economical machining. This study reports some of the results of experimental investigations related to EDM of A356-15%SiC MMC with regard to various process parameters and their individual and combined effects on the quality characteristics of the machined part