Investigation into the Electrical Discharge Machining Parameters of DIN 2767 Tool Steel Using Taguchi Method

Abstract

Electrical discharge machining (EDM) is one of the most crucial non-traditional machining methods used in molds and dies manufacturing, and conductive materials machining, which are difficult to machine by traditional methods. The EDM performance is affected by several machining parameters with different contribution percentages. In this study, the experimental investigations were conducted on DIN 2767 tool steel using CuCrZr, Cu and CuCo1Ni1Be (CNB) electrodes. The most influential process parameters were focused on to improve the EDM performance. The value of the process parameters and their levels were discharge current (6, 12 and 25 A), pulse-on time (50, 200 and 800 μs) and pulse-off time (50, 200 and 800 μs). Optimal levels of machining process parameters were obtained by employing the Taguchi L27 orthogonal arrays. The experimental results showed that the optimal combination of the machining parameters for maximum material removal rate was A3B2C1 using a CNB electrode. For minimum tool wear rate, the optimal parametric combination was A1B3C1 and Cu electrode. The optimal parametric combination was A1B3C3 and CuCrZr electrode for minimum surface roughness. The study further revealed the relation and interaction effect between process parameters for the performance measures. Lastly, the process parameters affected and changed the DIN 2767 tool steel workpieces’ surface integrity as evidenced by the scanning electron microscopy images.