具有半导体特性的往复走丝电火花线切割研究

Study on High-Speed Wire Electrical Discharge Machining With Semiconductor Characteristics

针对超高厚度切割、细丝切割、金属基陶瓷复合材料切割等一系列具有半导体特性的电火花线切割,提出一种具有半导体特性的电火花加工理论体系。其实质是:由于工件、电极丝或者两者已具有不可忽略的电阻,从而具有了半导体特性,已不能将其作为传统电火花加工中的等势体对待。分析了半导体特性下的往复走丝电火花线切割的加工特征及采用传统电火花线切割加工伺服控制方法失效的原因,提出了使用辨识度更高、基于电流脉冲概率的检测来判断极间的加工状态;同时为了做到长久稳定切割,对于往复走丝时正反向走丝差异明显的工况,应采用正反向不同的伺服控制策略。

For wire electrical discharge machining(WEDM)with semiconductor characteristics,including superhigh-thickness cutting,ultra-fine wire cutting,metal matrix ceramic composite cutting,etc.,a theoretical system of EDM with semiconductor characteristics is proposed.The performance of semiconductor characteristics is that the workpiece,wire or both have non negligible resistance,which cannot be treated as equipotential in traditional WEDM.The machining characteristics of high-speed WEDM with semiconductor characteristics are analyzed,and the reasons for the failure of traditional WEDM servo control methods are explained.A method based on current pulse probability detection with higher identification is proposed to judge the machining status between electrodes.To achieve stable cutting for a long time,different servo control strategies should be employed for the positive and negative traveling direction to adapt to the processing conditions with obvious differences in reciprocating traveling-wire mode.