Exploring micro-machining performance: Drilling versus EDM for high-quality micro-holes in AM 17-4 PH stainless steel

Abstract

Micro machining techniques are widely used for manufacturing miniature precision components in biomedical, aerospace, and electronics applications. This study compares micro-holes (800 µm) in AM 17-4 PH stainless steel fabricated by micro-drilling and electrical discharge machining (EDM). Key parameters evaluated include material removal rate (MRR), overcut, taper angle, circularity, and surface roughness. Micro-drilling employed a solid carbide drill with Ti–Al–N coating, while EDM used a copper electrode. Nine holes were produced with each method and analyzed. Micro-drilling achieved a significantly higher MRR of 1.955 mm³/min and a lower overcut of 0.011 mm, while EDM recorded a taper angle as low as 0.021° and circularity of 0.987. Additionally, EDM produced a superior surface roughness of 0.11 µm compared to 0.33 µm for micro-drilling. Overall, micro-drilling excels in machining speed and dimensional accuracy, while EDM offers better geometric precision and surface quality.