Improving machining accuracy in wire electrochemical micromachining using a rotary helical electrode

Wire electrochemical micromachining (WECMM) is becoming more important in fabricating complex microstructures. The machining accuracy of WECMM is usually evaluated by the interelectrode gap width. Faster electrolyte refreshment increases the uniformity of the electrolyte electrical conductivity distribution in the machining gap, the machining stability and the machining accuracy. We propose a method of WECMM using a rotary helical electrode that improves the machining accuracy by increasing the electrolyte refreshment and achieving a faster electrode feed rate and consequently decreasing the machining gap. Simulations of the electric field indicated that the current density was localized for the rotary helical electrode. Experiments verified that the rotary helical electrode decreased the machining gap from 94 to 19 mu m compared with a cylindrical electrode of the same diameter. In addition, the effects of the process parameters on the interelectrode gap width were experimentally investigated. Finally, using optimal parameters, two precision microstructures with clean-cut edges were fabricated.