Improving Surface Quality and Machining Efficiency of Microgrooves by WECMM in H3PO4-C2H5OH Solution

Abstract

Microgrooves used in microelectromechanical systems (MEMS) are small, precise and usually made of hard-to-machine material, whose surface roughness significantly affects their performance and service life. Wire electrochemical micromachining (WECMM) has been used to machine them. Sometimes, it takes extra time to polish the microgrooves produced by WECMM when they couldn't meet the requirement of some special products in terms of surface quality. In this study, a new method is proposed to produce high quality surface efficiently that simultaneously implements electrochemical cutting and polishing in phosphoric acid (H3PO4). Ethanol, which has a lower density than water, was added to the electrolyte to improve mass transport and the flatness of the microgrooves. The polarization curves were measured to explain the principle of WECMM in H3PO4 solution. The effects of the composition of the electrolyte and machining parameters on curvature and surface roughness were studied theoretically and experimentally. In optimal conditions, a microgroove with a surface roughness of Sa = 0.039μm and Ra = 0.033μm was obtained.