Experimental Analysis and Multi-objective Optimization for Wedm Machining of Armour Steel

Armour steel is commonly used in armoured vehicles, military equipment, and structural components that require high resistance to penetration. Cutting armour steel poses several challenges due to its exceptional strength and hardness. Overcoming these difficulties in armour steel cutting requires the use of advanced cutting technologies, specialized tools, and careful process planning. The present research paper focused on an experimental study of wire electrical discharge machining (WEDM) process variables and multi-objective optimization to achieve the optimal cutting rate (CR) and surface roughness (SR) for armour steel. This study has been carried out using the fractional factorial method, with peak current (C), pulse on time (A), wire feed (E), spark voltage (D), and pulse off time (B) as machining parameters and workpiece thickness (F) as a material parameter. The main effect plot, interaction plot, and ANOVA have been used to analyse the effect of the input parameters on the response parameters, followed by developing regression modelling. The results of the study demonstrated that the Ton and workpiece thickness have the major contributions to CR and SR, respectively, with 55.25% and 21.77% contribution for CR, and 67.87% and 8.72% contribution for SR. A2B1C2D1E2F1 and A1B2C1D2E1F2 are the optimal set of input parameters for CR (0.71 [mm/min]) and SR (2.46 [microns]), respectively. The study employed the desirability function approach (DFA) for multi-objective optimization, and the results indicated that the composite desirability for CR and SR is 0.6414. The combination of 1.1 µs Ton and 38 µs Toff, 140 A I, 20 V V, 10 m/min WF, and 146.97 mm workpiece thickness is the optimum set of input parameters.