An experimental investigation of wire breakage and performance optimisation of WEDM process on machining of recycled aluminium alloy metal matrix composite

In this research, a novel aluminium metal matrix composite (AMMC) was developed using recycled aluminium alloy as a matrix with 5% alumina as reinforcement. The machining experiments were conducted by varying the input parameters such as voltage (V_s), wire feed rate (F_w), current (I_p), pulse on time (ON_T) and pulse off time (OFF_T), on wire breakage. The effect of voltage level and wire breakage frequency was analysed. The parameter combinations for machining the slot of size 5 mm width and 10 mm height with high machining rate (MR) and less surface roughness (R_a) were analysed using the CRiteria Importance Through Intercriteria Correlation (CRITIC) and simple additive weighting (SAW) methods. The wire breakage frequency is lesser at minimum peak current. The optimal parameter combination for higher MR and lower R_a is found to be at 30 V, 7 mm/min, 30 A, 120 μs (ON_T) and 70 μs (OFF_T). Analysis of variance (ANOVA) is performed to understand the significant factors affecting the WEDM process. ANOVA results predict that wire feed rate and voltage contribute 47.82% and 21.23%, respectively, to MR; and pulse on time shows a 23.06% influence on surface roughness. Scanning electron microscopy (SEM) was used to ascertain the pattern of wire breakage in WEDM, and based on the results obtained from employing this technique, it is inferred that the erosion and breakage of the wire are not instantaneous and that a cone shape is formed on the either portion of the wire.