Electrochemical Micromachining of Square Holes in Stainless Steel in H2SO4

Abstract

A method for fabricating micro square holes with small corner radius is proposed, which could find applications in the aerospace and aviation industries. The machining process includes three steps: (i) the hole is first fabricated by electrochemical drilling; (ii) the square hole is then rough machined by electrochemical milling; and (iii) finally the hole is finished by electrochemical milling to reduce the corner radius. To improve the stability and quality of machining, double-pulsed electrochemical machining (ECM) was applied to remove electrolysis products adhering to the electrode. Using optimal parameters, square holes with a radius of 12 μm and a width of 100 μm were fabricated on 321 stainless steel with a thickness of 0.1 mm.