Liquid alloy electrode for no-wear micro electrical discharge machining

A micro electrical discharge machining (μEDM) method that utilizes liquid phase alloy as the processing electrode is proposed and developed to solve various issues arising from electrode wear. The liquid alloy is held in a microcapillary needle such that a liquid microelectrode forms at the bottom of the needle. A discharge pulse generator is connected to the liquid and a workpiece for generating pulses thermally erodes the workpiece material. During the machining process, the liquid electrode is continuously supplied to the needle to eliminate effects of liquid consumption on the erosion process. Experimental results show that discharge pulses can be stably generated and sustained with the liquid electrode and that these pulses generated on the silicon sample are effective in implementing microcavities on its surface. Coating an electrically passivated material on the needle will protect the needle tip from the thermal action of the pulse discharge. The process is also evaluated under various experimental conditions for revealing the dependence of the material removal rate (MRR) and liquid alloy consumption rate (LACR) on the parameters.