Study on the Electrical and Geometrical Parameters of Micro Electrical Discharge Machining

Introduction: Micro-Electrical Discharge Machining (μEDM) is a technique for non-contact machining of conductive or semiconductor materials. It is mainly adapted to machining hard materials. Its principle is based on the creation of electrical discharges between the micro tool and the workpiece, which are immersed in a dielectric. Methods: It is a complementary process to mechanical or laser micromachining techniques or microelectronics (RIE, DRIE, LIGA). These methods can reach a resolution of 50 nm, but their main drawback is that they are mainly dedicated to silicon. The μEDM process depends on several physical, geometrical, and/or electrical parameters that need to be optimized in order to achieve a resolution lower than 5 μm in a reproducible way. The objective of this paper is to study the effect of the applied voltage VEE and the micro-tool diameter on the machining performances (removed volume, lateral gap, machining depth, and crater shape). Result: The optimal parameters were used during drilling holes. An applied voltage of VEE = 50V was used as an optimal parameter. Conclusion: Concerning the diameter of the micro tool, we propose to use large diameter wires (Φ=250 μm; Φ=125 μm) during the roughing phase for machining complex structures and small diameter micro tools (Φ=80 μm; Φ=40 μm; Φ=20 μm) during the finishing phase.