基于三维旋转超声辅助电解-放电展成加工的机理研究及其过程优化控制

Ultrasonic machining, ultrasonic composite / auxiliary copy electrical machining, forming way is single, flexibility is poor, electrode manufacturing is complex, and electrode wear would affect the machining accuracy and utilization, and it is a problem that the circulation of the working fluid is renewed and the product is removed in time. To solve the problem of micro-fine manufacturing on the profiled surface parts with difficult to machining materials, it is proposed that using the coupling effect of rotating axial ultrasonic and radial follow - up ultrasound, assistant stimulating electrolysis - discharge action between the electrodes, electrolytic action removal of materials, discharge and ultrasonic removal of surface passivation and convex point, using rod (or ball) electrode and multi-axis linkage servo feed, so as to achieve the forming processing of profiled surface parts. Developing the machining system of three - dimensional rotating ultrasonic assisted electrolysis - discharge multi - axis linkage; research the characteristics of three-dimensional rotating ultrasonic, electrolysis-discharge mechanism and contour evolution forming laws, the establishment analysis models of efficiency and accuracy, research the two- effect synergistic mechanism of electrode rotation, multi-dimensional ultrasound, discharge – electrolysis , build the control system of on-line parameter detecting, digital processing , establishment the assessment model of real-time machining state, control the key parameters and parameter fluctuation compensation in real-time way , to keep the process stable and efficient; optimizing control software design, by the parameter scanning and detecting method for online parameters in real-time adjustment, optimization, to achieve process optimization of electrolysis - discharge contour evolution machining, so as to realize the flexibility, high efficiency, high precision and low cost of fine machining for materials and profiled surface parts. The research results of the project have important theoretical significance and engineering application prospect for enriching advanced manufacturing technology.

超声及其复合/辅助拷贝式电加工，成形单一、柔性差，异形面电极制作工艺复杂，电极损耗影响加工精度及其利用率，静液加工存在工作液循环更新及产物及时排除问题。对难加工材料、异形面零件的精微制造，项目提出用旋转轴向超声及径向随动超声的耦合作用，激励、辅助电极间电解-放电作用，电解去除材料，放电及超声去除表面钝化及凸起点，采用棒状电极及多轴联动进给，实现异形面展成式加工。研制三维旋转超声辅助电解-放电展成加工系统，研究三维超声系统特性及其辅助电解-放电机理，建立加工效率及精度分析模型；构建在线参数测控系统，建立加工实时状态评估方案，控制多轴联动伺服进给；进行关键参数的实时调控及参数波动补偿，保持加工过程稳定；优化控制软件，用参数扫描及试探法进行参数实时调节、寻优，进行电解-放电展成加工过程优化控制，实现难加工材料、异形面柔性、高效及低成本精微制造，研究成果对丰富先进制造技术有重要理论意义与应用前景。

超声及其复合/辅助加工技术通常采用拷贝式加工成形，复杂形状工具电极的制作是其难点问题之一，另外，拷贝式加工电极磨损难以在线修正与实时补偿，影响其加工精度提高，限制其应用范围。项目采用旋转工具电极，利用轴向及径向超声的耦合作用，激励、辅助加工区的电解-放电作用，以“电解”及“超声”作用去除零件机体材料，微细放电及超声作用去除表面凸起点，实现难加工材料、异形面零部件数控展成高精/高效加工。.项目针对工具电极与工件间的多轴联动展成进给运动关系，设计轴向旋转超声振动装置（电主轴），振幅可达0-20μm，电主轴作周向旋转及轴向超声振动，同时驱动工具电极轴向进给运动；设计二维径向超声振动装置，在电极径向，即沿展成加工面的法向赋予工件二维超声振动，振幅可达0-10μm。分析研究旋转超声复合/辅助电加工材料去除机理及参数优化机制，旋转超声振动可增强工作液循环与更新，有效排除加工产物并对加工面进行超声抛光，径向超声沿加工面法向振动，可形成电解-放电展成加工间隙。设计控制系统调制径向超声振动幅值及电加工电源加电间隙区间范围，可在电极与工件间产生电解-放电作用，工件表面材料被电解及超声作用去除，工件表面局部点由于电解钝化导致电解去除减慢而产生微凸起，当凸起点电场强足够大时，将产生微火花放电，蚀除凸起处材料，保持复合加工过程持续进行。根据极间电参数实时检测结果，控制系统可实时评定加工过程状态，由此进行多轴联动数控展成进给运动控制，保证加工过程持续稳定进行。.项目进行多种材料（硬质合金、PZT压电陶瓷、合金钢、铝基碳化硅陶瓷）、多种加工方式（超声、旋转超声、旋转超声复合/辅助电解）及加工参数（超声振幅、电解电压及电解液等）对比试验及参数优化，试验结果验证了旋转超声及多维旋转超声复合/辅助电解-放电加工方法的技术优势，且旋转超声电加工系统工作稳定可靠。项目研究成果对难加工材料、异形面零部件的高精、高效加工具有重要应用前景。