Investigating die-sinking EDM drilling performance on additively manufactured SS316L steel lattice structures

Abstract

Currently, additive manufacturing of lattice structures is extensively investigated in various industrial applications due to its lightweight, high strength-to-weight ratio, and porous architecture. Lattice structures often require additional machining for intended applications such as fastening, implantation, or integration to be effectively utilized. Conventional machining methods, due to direct contact, often lead to substantial deformation, increasing the risk of fractures and cracks, thereby limiting their effectiveness for precision applications. In contrast, Electro-discharge machining (EDM) as a post-processing technique offers effective, crack-less, and precision. This research employed the die-sinking EDM to investigate the hole-drilling in SLM-printed SS316L lattices. L15 Box-Benken design was implemented to investigate the effect of EDM input parameters on output parameters. The input-parameters pulse-on, pulse-off times, and peak current were varied to examine the deterministic EDM characteristics such as material removal rate and overcut of the drilled hole, additionally, the interactions between input and output parameters, and resulting surface morphology were studied. The highest MRR (∼738.2 mg/min) was observed at the highest value of peak current (30 A) and longest pulse on time (160 µs) while it also resulted in the largest overcut (0.337 mm). The results also indicated that among the input parameters peak current makes the largest contribution at 40.42 % to the material removal rate and at 74 % to an increase in overcut