Abstract: Cost-effective electrochemical fabrication of a vast number of high-quality metal microstructures without patterned seams by has still faced great challenge. A novel rotating through-mask electrochemical transferring technology (RTM-ECT) is proposed, in which the microstructures are fabricated in a rotary electrochemical etching manner that overcomes some inherent disadvantages and limitations of the traditional face-to-face through-mask electrochemical machining processes. Electric field distribution characteristics and their spatial evolution with time, geometric profile evolution of the forming microstructures was investigated via numerical simulations. Experimental studies in which the effect of key process parameters on surface morphologies, geometric profile change and machining accuracy were carried out, followed by evaluation on effect of fabricating massive arrayed metal microstructures on the cylindrical and planar workpiece. The results showed that, the temporal and spatial distribution characteristics of the electric field over individual active machining area are nearly the same although the anode, cathode and through-mask of RTM-ECT are in motion, and the geometric profile evolution and the final geometric profile of the microstructures are mainly controlled by the rotational speed and interelectrode voltage; by using the optimized process parameters, massive arrayed microdimples and arrayed micro-holes with significantly consistent geometric profiles can be fabricated both on the cylindrical and on the planar stainless-steel workpiece. Fabricating 2 266 microdimples (89 μm in depth) evenly distributed on the entire cylindrical surface (360°) takes only 125 seconds, with their coefficient of variation (CV) values of diameter and depth being down to 3.21% and 3.68%, respectively, and their surface roughness Ra being less than 0.65 μm. Fabricating 8 360 micro-holes (50 μm in depth) on the planar workpiece takes only 460 seconds, with their diameter CV values being down to 2.19%, and the diameter deviation between inlet and outlet being only 1.06%-3.22%. The newly proposed RTM-ECT shows a significant and promising potential competitiveness in cost-effectively fabricating high-quality and high-precision microstructures on the cylindrical and planar (ultra-long, large-area) metal workpiece.

Key words: rotating through-mask electrochemical transferring, through-mask electrochemical machining, massive microstructures, arrayed microdimple, arrayed micro-hole