半导体硅电极多通道放电机理研究

Study on Multi-channel Discharge Mechanism of Semiconductor Silicon Electrode

为了实现电火花加工同一时刻形成多个放电通道蚀除工件,克服现有放电加工理论中同一时刻仅有一个放电通道蚀除工件的限制,提出了采用半导体材料作为电极进行放电加工的新方法。首先,通过试验证明以半导体硅为电极加工金属可以形成多通道放电;其次,建立了半导体电极单通道放电等效电路模型,发现半导体电极在放电加工时不是一个等势体,并进行了电势差分布试验,验证了多通道放电形成的原因是远离放电点处的电势较高,可以同时形成击穿产生放电;最后,进行了半导体硅电极单脉冲放电试验及成型加工试验。试验结果显示,半导体硅电极通过1次脉冲放电同时形成多个放电通道,有效地分散放电能量,相较于金属电极,每个放电坑的直径和深度都显著减小。在相同放电参数下,对比钢电极,用硅电极进行电火花加工的表面粗糙度值下降71.7%。

A novel approach for discharge machining with semiconductor electrode is presented in order to produce multi-channel discharge in electrical discharge machining(EDM) for overcoming the current limitations of discharge machining theory. Firstly, it is experimentally proved that the multi-channel discharge could be formed by processing metal with semiconductor silicon as an electrode. Secondly, the equivalent circuit model of a single-channel discharge with a semiconductor electrode is developed. The results show that a silicon electrode is not an equipotential material in the discharge machining. Additionally, an experiment regarding the potential distribution of electrode is conducted as well. The findings confirm that the formation of the multi-channel discharge is due to the high voltage at areas far from the discharge point where the breakdown discharge can be simultaneously formed. Eventually, a single-pulse discharge experiment and EDM processing experiments are conducted using semiconductor silicon electrodes. In the single-pulse discharge experiment, 15 discharge channels are simultaneously formed in a single-pulse discharge. And the outcomes reveal that multi-channel discharge with silicon electrode could efficiently disperse the discharge energy, while the depth and diameter of each erosion crater are significantly decreased in comparison with metal electrodes. Moreover, under the same discharge parameters, compared with steel electrodes, the surface roughness value of EDM with silicon electrodes decreased by 71.7%.