Wire electrochemical micromachining of high-aspect ratio microstructures on stainless steel 304 with 270-μm thickness

Abstract

High-aspect ratio microstructures made of stainless steel 304 have found its extensive applications in the microsystem industry. Using a nanosecond pulse generator, high-aspect ratio components can be obtained by wire electrochemical micromachining (WEMM). Mass transport is substantially vital in WEMM to achieve high aspect ratio. Combining traveling and vibrating anode can effectively improve mass transport and consequently enhances machining result. When workpieces become thicker, mass transport would get worse. Many researchers have investigated the fabrication of microstructures on 304SS plate with thickness of 100 μm using WEMM. However, not enough attention has been paid to the machining of microstructures on 304SS plates with thickness of more than 100 μm which is an alternative to obtain high aspect ratio. Moreover, the parameters used for 100-μm-thick 304SS are not suitable for thicker 304SS. Therefore, it is necessary to investigate the fabrication of high-aspect ratio microstructures on 304SS plates with thickness of more than 100 μm. In this work, the machining of micro slits on 270-μm-thick 304SS plates by WEMM was investigated. A combination of traveling wire and vibrating anode was also employed to enhance mass transfer. The effects of traveling wire parameters and vibrating anode parameters on the slit width and slit profile were researched. Experimental results show that the stroke and traveling speed of the traveling wire together with frequency and amplitude of the vibrating anode for 270-μm-thick 304SS plates are higher than those for 100-μm-thick 304SS plates. The average slit width machined with optimized parameters using WEMM is 26 μm and the standard deviation is about 1.3. In the meantime, the slit profile is smooth, and the average aspect ratio is about 10.