采用辅助电极法,对绝缘性陶瓷材料Si3N4的电火花加工进行了实验研究。指出了正常脉冲放电实现除去材料加工,长脉冲放电生成导电膜,正常脉冲放电和长脉冲放电的交替,使电火花加工在去除材料加工和生成导电膜的交替中不断进行,最终使工件成形的绝缘材料电火花加工机理。得出了单位加工时间内正常脉冲比例越大,加工速度越快;单位加工时间内长脉冲比例越大,生成导电膜厚度越厚的结论。

Research of Mechanism in EDM of Insulating MaterialsXU Xiao-bing1,2,MO Yi-min1,CHEN Wei-hong2(1.School of Mechanical and Electrical Engineering,Wuhan University of Technology,Wuhan 430070,China;2.School of Mechanical Engineering,Yangtze University,Jingzhou 434023,China)To research mechanism in electrical discharge machining(EDM) of insulating materials,the experimental researches were done in EDM of insulating ceramics Si3N4 by using assisting electrode method.It was pointed out that the mechanism in EDM of insulating materials on the basis of the experiments.It could be known that insulating material was removed when pulse discharge was normal and new conductive layer was formed when long pulse discharge appears through the experiments.It was clear that EDM of insulating materials could be realized continuously.It depended on the alternation between normal and long pulse discharge.Finally, surface profile to be machined was finished.The research results showed that the larger percentage of normal pulse discharges in a period time was,the faster machining rate would be and the larger percentage of long pulse discharges in a period time was,the thicker thickness of forming electrical conductive layer will be.insulating material;electrical discharge machining(EDM);machining mechanism;assisting electrode method;forming electrical conductive layer