Liquid-phase alloy as a microfluidic electrode for micro-electro-discharge patterning

This study reports on the first patterning method based on micro-electro-discharge machining (mu EDM) that uses microfluidic electrodes in a liquid form. This novel method is developed to address a variety of problems associated with electrode wear, which is one of the most fundamental issues with mu EDM technology. During the machining process, a liquid electrode is continuously supplied to a metallic micro capillary nozzle to eliminate the impact of its "wear" or liquid consumption on the removal process. Experiments show that Galinstan, a nontoxic liquid alloy, can be used as the electrode material to create discharge pulses and perform microscale removal on the samples. Controlled discharge generation and scanning-mode arbitrary patterning are experimentally demonstrated using the microfluidic Galinstan electrodes. The process is evaluated with varying discharge conditions to reveal the dependence of the patterned geometry on the parameters. It is also shown that a Parylene C coating is effective for protecting the nozzle from discharging. The elemental analysis of the processed samples indicates that the process does not cause detectable Galinstan contamination on the patterned surfaces.