高电阻电极对微细电火花放电加工影响的研究

摘要

In micro electrical discharge machining(EDM), decreasing the material removal per single pulse discharge is important as a result of the material removal per single pulse discharge(discharge crater)mainly deter-mines the minimum machinable size and surface roughness of the micro EDM.For this purpose, high resistance materials such as single-crystal silicon are used as tool electrodes.Analytical results show that the peak value of the discharge current are decreasing with the increase of electrode resistance,whereas the pulse duration increases.In addition,the influence of resistance value on the diameter of crater on workpiece surface was studied and tested when machining stainless steel workpiece using the silicon electrode.Experimental results reveal that the diameter of discharge craters decreases and achieves to 0.5 μm with the increase silicon electrode resistivity, at the same time,the surface roughness of workpiece is reduced to 0.03 μm,and the surface processing quality is improved.%微细电火花放电加工过程中,由于单位脉冲放电的材料去除率(放电凹坑直径)决定了最小加工尺寸以及微细电火花加工的加工表面粗糙度,所以减少单位脉冲放电的材料去除率具有重要作用.为达到此目的,采用具有高电阻材料如单晶硅作为工具电极.分析结果显示,随着工具电极电阻提高,放电电流峰值逐渐降低,脉冲放电时间增加,放电能量减小.另外,研究并测试了硅电极加工不锈钢工件时电阻值对工件表面放电凹坑直径的影响.实验结果表明当硅工具电极电阻值提高时,放电凹坑直径逐渐降低;并达到最小值0.5 μm;同时降低了工件表面粗糙度值0.03 μm;提高了表面加工质量.