The EMM Array Cathode Design And Process Research Based On Micro-machining Technology

With the rising demand for micro-components and micro system, there is a rapid development in micro-machining technology. Electrochemical micromachining(EMM) has a great potential for developing due to its high efficiency, low cost, wide range of machinable material, machined surface without stress, heat distortion, etc. EMM, using anodic dissolution of electrochemical action, shapes the work-piece. In the EMM process, timely refreshing of the electrolyte in the smaller machining gap is one of the important factors for the machining accuracy. And EMM array cathode structure has important influence on the flow of the electrolyte.From the view of the stability of the flow field analysis, based on careful study of the mechanism of the EMM process, a multi-physical field model of the EMM process was established. Through the analysis of the numerical model, a method was proposed to improve the stability of flow field in the gap. Hollow structure cathode allowing radial flow electrolyte could guarantee the stability of the electrolyte flow during the process, by timely refreshment of electrolyte in the gap. The effects of the machining voltage, power pulse parameters and electrolyte flow rate of the EMM molding accuracy were analyzed. The influence of the electrode structure on the temperature stability was studied as well. The results show that the temperature stability is improved with a hollow cathode.On the basis of above analysis, we propose a novel structure of the hollow array electrode. Using photolithography and micro electroforming techniques, the EMM micro-array electrode were prepared with a minimum diameter of 60μ m and a length of 2000μm. The electrophoresis process was proposed for sidewall insulation of the electrode. An experiment platform to preliminarily validate the positive role of the new structure array electrode is built up as well.Finally, we have implemented micro-electrochemical etching experiments at different voltages and different electrolyte flow rates. And the resulting micro porous morphology of the etched holes was observed using optical microscopy and scanning electron microscopy(SEM). The results show that the precision and sidewall roughness with hollow structure cathode has been improved compared to the solid cathode.