Effects of Electro-discharge Machining on Aluminium Metal Matrix Composite

A. Mouangue Nanimina, A.M. Abdul-Rani, F. Ahmad, A. Zainuddin and S.H. Jason Lo

Abstract: Aluminium Metal Matrix Composites (AMMCs) are making inroads in various engineering applications requiring higher strength and stiffness than those offered by conventional aluminium alloys. Traditional machining of AMMCs however is difficult due to the hard reinforcement present in the AMMC material which tends to wrap around the cutting tool-bit leading to tool breakage. Electro-Discharge Machining (EDM) has been successfully applied on standard aluminium alloy such as Al 6061 but yet to be tested on 30% (by volume) Al2O3 reinforced AMMC. In this study, specific machining performance characteristics on AMMC reinforced with 30 % Al2O3 is assessed in comparison with Al 6061. The characteristics under study are Material Removal Rate (MRR) and Tool Wear Ratio (TWR). Key process parameters such as the peak current, pulse and pause durations (ON-time and OFF-time), were varied to determine their influences on the MRR and TWR of 30% Al2O3 reinforced AMMC. Results indicate that 30% Al2O3 reinforced aluminium metal matrix composite can be machined using EDM to obtain acceptable result in terms of MRR and TWR. A high value of peak current and ON-time increase rapidly MRR of Al 6061 rather than AMMC while it decreases with increasing of OFF-time. Tool wears more at low peak current and ON-time than OFF-time.