Optimizing electric discharge machining parameters using Taguchi method and ANOVA: A study on AISI D2 steel machining with copper electrodes and materials science progress

The present study employed the Taguchi technique to investigate and optimize the parameters of Electric Discharge Machining (EDM). The focus was on three critical process parameters: discharge current (Ip), pulse-on time (Ton), and pulse-off time (Toff). Utilizing an L27 orthogonal array, the study examined the effects of these parameters and their interactions on the response variables, including Material Removal Rate (MRR), Tool Wear Rate (TWR), and Surface Roughness (SR). Copper electrode was utilized in order to machine the hardened AISI D2 steel. The results demonstrated that increasing the discharge current from 3 amps to 7 amps yielded a remarkable 200 % increase in MRR, escalating from 5 mg/min to 15 mg/min. Additionally, extending the pulse-on time from 50 µs to 200 µs resulted in a 133 % enhancement in MRR, from 6 mg/min to 14 mg/min. However, these productivity improvements were accompanied by a significant increase in tool wear, with TWR escalating by 300 %, from 1 mg/min to 4 mg/min, and an adverse effect on surface quality, as SR deteriorated by 140 %, increasing from 2.5 µm to 6 µm at higher current levels. Analysis of Variance (ANOVA) was utilized to quantify the contributions of each parameter and their interactions to achieve optimal machining performance. The findings underscored the importance of maintaining a discharge current of 5 amps, a pulse-on time of 150 µs, and a pulse-off time of 40 µs, which resulted in a balanced performance, yielding an acceptable SR of 3.5 µm—a 36 % improvement compared to a shorter Toff of 20 µs, which recorded a SR of 5.5 µm. ANOVA results confirmed that the discharge current was the most significant factor influencing surface roughness, with critical interactions observed between discharge current and duty factor, as well as between pulse-on time and duty factor.