Electrochemical micromachining of micro-dimple arrays using a polydimethylsiloxane (PDMS) mask

摘要

Micro-dimple arrays on the surfaces of engineering parts play an important role in the behaviour of these parts. Through-mask electrochemical micromachining (TMEMM) is a popular method for generating micro-dimple arrays with controlled size, location and density. However, in conventional TMEMM, the electrochemical machining must be preceded by photolithography, which is time-consuming and expensive in mass production. In this paper, a polydimethylsiloxane (PDMS) mask is used in TMEMM for generating high-quality micro-dimple arrays. Compared with photolithography, this has the advantage that the PDMS mask can be re-used and has a micro-scale pattern. This technique could therefore replace photolithography in the application of TMEMM to generate micro-dimple arrays. With a PDMS mask being used for generating micro-dimple arrays, three electrolyte flow modes are investigated, and a modified forward mode with a multi-slit structured cathode is proposed for the generation of arrays that have uniform micro-dimple distributions and dimensions. Using this method, arrays are generated with average micro-dimple dimensions of 106 mu m diameter and 10 mu m depth, with a low standard deviation (STDEV). In addition, the results show that both direct current and pulsed current can be used to generate micro-dimple arrays with a high degree of localization, although pulsed current produces deeper micro-dimples. (C) 2015 Elsevier B.V. All rights reserved.