材料晶界和晶粒对电火花微细加工的影响研究

摘要

为了在电火花微细加工中确定合理的工具损耗补偿工艺与加工工艺,提高微小零件微细加工的质量,通过在合金材料上选择晶粒和晶界部位大量加工微孔以及其后的统计分析,研究了微细电火花加工过程中工件材料晶粒与晶界对放电间隙、材料去除速度以及电极体积相对损耗等加工特性的影响。研究结果表明,由于工件材料中晶粒和晶界在成分、熔点、热导率以及机械性能等方面的差异,当用微细电火花进行微细加工,特别是当加工尺度小于工件材料的晶粒尺寸时,晶粒和晶界的加工特性具有明显差别,制订工具损耗补偿工艺和加工工艺时应该考虑到材料微观结构对加工过%In micro EDM,in order to select reasonable machining parameters to compensate the tool wear and to improve the quality of machined micro feature,a statistical analysis was used to study the influences of grain and grain boundary of the workpiece material on the material removal rate,tool wear ratio and the discharge gap by drilling micro holes in grain and grain boundary of the alloy.Due to the material characteristic difference between grain and grain boundary,such as composition,melting point,thermal conductivity and mechanical properties,the results vary.When the size of a machined feature is smaller than the grain size of the materials,the machining performance of grain and the grain boundary are different.Therefore,it is necessary to take micro structure of workpiece material into account when the tool wear is compensated.