Electric discharge machining using rapid manufactured complex shape copper electrode: Parametric analysis and process optimization for material removal rate, electrode wear rate and cavity dimensions

The present investigation addresses the machining outcome of electric discharge machining using a rapid manufactured complex shape copper electrode. Developed rapid manufacturing technique using an amalgamation of polymer 3D printing and pressureless sintering of loose powder as rapid tooling has been used to fabricate copper electrode from the computer-aided design model of the desired shape. The fabricated electrode was used for the electric discharge machining of the D-2 steel workpiece. Central composite design was employed to study the electric discharge machining parameters (pulse duration, duty cycle and peak current) effect on the electric discharge machining characteristics such as material removal rate, electrode wear rate and cavity dimensional deviation as overcut from electrode computer-aided design model. Analysis of variance was executed to attain significant parameters along with interactions. Peak current was found to be the utmost dominating parameter for three responses. The high percentage of carbon was observed on the electrode surface after electric discharge machining at the high level of pulse duration and resulted in low electrode wear rate. The high percentage of dimensional deviation was noticed at the maximum duty cycle and maximum peak current by the substantial interactions. Genetic algorithm-based multi-objective optimization was employed for the electric discharge machining parameters optimization to maximize material removal rate, minimize electrode wear rate and dimensional deviation. The multi-feature complex copper electrode was fabricated and used for electric discharge machining as the case study to check the efficacy of the optimized process. It was witnessed that the process was competent to fabricate complex shape cavity as per the desired computer-aided design model shape with efficient material removal rate and electrode wear rate.