Fabricating Micro-Holes Through Micro-EDM Process and Their Circularity Testing

Micro-electrical discharge machining is a significant method for replicating micro-scale features. In this article, microholes were fabricated using a micro-electrical discharge machining (µ-EDM) technique and tested the circularity of the machined holes. Thin nickel sheet (0.1 mm) and tungsten tool (ø650 µm) were the selected work and tool material during the experimentation in EDM oil. The experiments were carried out at a constant open-circuit voltage of 24 V and set peak current of 300 mA, 350 mA, and 400 mA. It was found that the fabricated microholes are varying in their diametral length between 748 and 800 µm. Moreover, there is very little circularity deviation is noted in the fabricated microholes. Some recast layer formation was noted near the edge of the machined holes which is varying between 6.5 and 7.5 µm. Later on, the surface morphology and elemental characterization of the fabricated microholes were observed by high-resolution field emission scanning electron microscopy (FESEM) and the energy-dispersive X-ray spectroscopy (EDX) technique respectively. Micro/nano-electro-mechanical system (MEMS/NEMS) is the area where the microholes application is highly recommended.