Investigations on Electric Discharge Machining Behaviour of Si3N4 -TiN Ceramic Composite

Abstract

Ceramic composites are deliberated as an important material for their increasing advantages in aircraft, automotive and nuclear industries. But, these composites are very difficult to cut by conventional machining. Hence, the unconventional machining process like electric discharge machining (EDM) is reflected to be an essential machine for its capability to machine at any type of materials irrespective of its natural behaviour. In the present work is, to investigate the effects of EDM parameters on Si3N4-TiN ceramic composite by using taper shape of copper electrode. An L9 orthogonal array experimental plan is utilized to machining the composite by considering three input factors like pulse current, pulse on-time and pulse off-time. The material removal rate (MRR), over cut (OC) and taper ratio (TR) are considered as the machining performance characteristics. Taguchi combined with grey relational analysis (GRA) are employed to determine the best combination of EDM factors on multiple responses. An experimental result shows that, the optimal combination of parameters found to be pulse current at level 2 (1.0 amps), pulse on-time at level 1 (3 μs) and pulse off-time at level 2 (4 μs). ANOVA results noticed that pulse current is atmost impact parameter with influence of 65.47% subsequently by pulse on-time with contribution of 21.12% respectively. Finally, the confirmation test was conducted to validate the experimental results by using the optimized parameters.