摘要
电火花线切割半导体加工过程中,工件与钼丝之间的间隙是保证工件表面质量和切割效率的关键参数。分析了单晶硅和钼丝之间的间隙与极间电流的关系,由于该间隙在钼丝切入工件后,无法实时测量,根据电流的变化来实时预估间隙的瞬时变化,从而实时调整工件进给速度以间接保证该间隙。采用系统辨识方法建立极间电流与工件进给速度的控制模型,并利用F检验法估计模型的阶次,选择遗忘因子递推最小二乘在线预估模型参数。设计最小方差自校正控制器对切割过程进行实时控制。试验结果表明所设计的控制器增强了加工系统的稳定性,在保证加工效率的前提下,工件表面有了明显提高。
EDM wire cutting semiconductor process, the gap between the workpiece and molybdenum wire is the key parameter to ensure the workpiece surface quality and cutting efficiency. The relationship between the gap between the silicon single crystal and the molybdenum wire is analyzed. Since the gap can not be measured in real time after the molybdenum wire has been cut into the workpiece, the instantaneous change of the gap can be estimated in real time according to the change of the current between the silicon single crystal and workpiece, and the feed rate of workpiece is used to ensure the gap. The system identification method is used to establish the control model of the current between the silicon single crystal and workpiece and the feed rate, and the order of the model is estimated by the F-test method, and the forgetting least squares is used to on-line estimate the model parameters. The controller of the minimum variance self-tuning controller is designed for real-time control of the cutting process. The experimental results show that the designed controller enhances the stability of the machining system and improves the processing surface quality under the premise of ensuring the processing efficiency.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2018年第17期149-156,共8页
Journal of Mechanical Engineering
基金
国家自然科学基金(51575442)
陕西省自然科学基金(2016JZ011)
陕西省教育厅基金(2014SZS10-Z01)资助项目
关键词
电火花线切割
建模
最小方差自校正控制
单晶硅
WEDM
modeling
minimum variance self-tuning control
silicon single crystal
