Influence of Process Parameters on the Microstructural Characteristics and Mechanical Properties of Recast Layer Thickness Coating on Die Steel Machined Surface after Electrical Discharge Machining

The surface layer machined after electrical discharge machining (EDM) is different from it after traditional methods, and studying the surface layer structure machined by this method will contribute significantly to the selection of finishing methods. In this study, the surface layer of SKD61 steel after EDM using copper (Cu) electrode was analyzed. Technological parameters including discharge current (Ie), pulse on time (Ton), pulse off time (Tof), and voltage (Ue) were used in the study. The minimum recast layer thickness (RLT) was determined using the Taguchi method. The results showed that Ie, Ton, and Tof were significant influences on RLT, and Ue was insignificant. Minimum, value of RLT = 3.72 µm at process parameters Ie = 1 A, Ton = 50 µs, Tof = 12 µs, and Ue = 30 V. The machined surface layer after EDM is inconsistent with the workability of the product, and it should be removed from the machined surface.