This study investigates the tool-wear-reduction mechanism of graphite-powder mixed kerosene (GPMK) in micro electric-discharge machining (EDM). RC discharge circuits produce small, short discharge pulses and are therefore widely used in micro-EDM, rather than transistor circuits. In this case, given that an anode has higher energy proportion than a cathode by the massive electron collision to the positively charged workpiece, a tool electrode is negatively charged for a high material-removal rate (MRR) and low tool-wear length (TWL). In the discharge phase, however, the stray inductance of the RC discharge circuit reverses the direction of the current before the discharge plasma channel disappears; a reverse current increases the TWL and reduces processing efficiency. In this study, the TWL was decreased with GPMK by creating a circumstance that facilitates the early extinction of discharge plasma channel before the generation of the reverse current in two ways. The widening of the discharge gap by GPMK reduces the intensity of the discharge energy and enables the plasma channel to be extinguished before the reverse current generation. Furthermore, as the tool electrode approaches the workpiece, a small amount of energy discharges before the capacitor is fully charged, and these initial discharges quickly disappear before the reverse current flows. The machining performance and the quality of micro ED milling with GPMK were evaluated and compared with those of pure kerosene. With optimal machining conditions, MRR was increased by 61%, and GPMK decreased the TWL and surface roughness by 61% and 23%, respectively. This technique was also successfully applied to micro-molding fabrication.

本研究研究了石墨粉混合煤油 (GPMK) 在微放电加工 (EDM) 中的刀具磨损减少机制。RC 放电电路产生小而短的放电脉冲，因此广泛用于微型 EDM，而不是晶体管电路。在这种情况下，考虑到阳极通过与带正电工件的大量电子碰撞而具有比阴极更高的能量比例，工具电极带负电以实现高材料去除率 (MRR) 和低工具磨损长度 (TWL) ）。然而，在放电阶段，RC放电电路的杂散电感在放电等离子体通道消失之前使电流方向反转；反向电流会增加 TWL 并降低处理效率。在这项研究中，用 GPMK 降低了 TWL，它通过两种方式创造了一种促进放电等离子体通道在产生反向电流之前提前消失的环境。GPMK 加宽放电间隙降低了放电能量的强度，并使等离子体通道在反向电流产生之前熄灭。此外，随着工具电极接近工件，在电容器完全充电之前会有少量能量放电，这些初始放电在反向电流流动之前迅速消失。对GPMK微电火花铣削的加工性能和质量进行了评估，并与纯煤油进行了比较。在最佳加工条件下，MRR 提高了 61%，GPMK 分别将 TWL 和表面粗糙度降低了 61% 和 23%。