Experimental study on surface characteristics and improvement of microelectrode machined by low speed wire electrical discharge turning

Electrical discharge machining (EDM) as the nontraditional machining process has a unique superiority in fabricating microelectrodes due to its non-contact removal mechanism. Therefore, the method of LS-WEDT (low speed wire electrical discharge turning) is firstly proposed to fabricate microelectrodes in this study. More importantly, the multiple cutting strategy is introduced to divide the machining process into rough cut (RC), trim cut (TC) and finishing trim cut (FTC). Experimental results showed that the ridges will appear after RC, the spherical droplets congregation phenomenon can be observed after TC and the surface will be covered with refined grains in nano level after FTC, which disclosed the unique surface characteristics of LS-WEDT. After FTC, the microelectrode of 90 μm in diameter and 1000 μm in length is successfully and firstly fabricated by LS-WEDT method, moreover, it has good surface quality with Ra of 0.59 μm and high dimensional precision with surface profile accuracy of 3.22 μm. Additionally, the comparative analysis was made to investigate the LS-WEDTed and LS-WEDMed surface, the discharge craters distributed in LS-WEDTed surface are longer than LS-WEDM. Finally, the surface quality machined by LS-WEDT after FTC is better than LS-WEDM, which is attributed to the point contact and good flushing conditions.