Nano-electrodes are essential components in electrochemical micromachining, allowing highmachining accuracy and minimum machining size. Liquid membrane electrochemical etchingprocesses twin nano-electrodes with parabolic upper and conical lower nano-electrodessimultaneously. After the lower tip drops off, blunting due to residual current increases the diameter ofthe upper tip. This blunting can be decreased by cutting off the residual current in 5 ms with a newlydeveloped control strategy. Experimental results indicate that the diameters of both nano-electrodesdecrease with the use of lower voltage and electrolyte concentration and shorter lower-end length. Toavoid low etching efficiency or a boiling effect, appropriate parameters should be selected. Bluntingcan also be reduced by using lower voltage and electrolyte concentration. Twin nano-electrodes withupper- and lower-tip diameters of 110 and 80 nm, respectively, have been fabricated and used to makemicro-holes of 2 m diameter by electrochemical micro-drilling.
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