激光辅助水射流近无损伤微细加工关键技术研究

In this project, the waterjet and laser machining technologies are integrated to establish a new laser assisted waterjet micromachining technology and prototype system for damage-free micro-fabrication. In this new technology, the coupled effect of laser heating and softening and waterjet expelling is used to remove the work material elemental by element. Waterjet also takes a cooling action. The combined effect will lead to the high efficient and near damage-free machining of micro-structures at low cost and high quality. The laser and waterjet can be independently controlled to arrive at the best possible process parameters. The underlying theory associated with this new micromachining technology will be systematically investigated, to gain a deep understanding of the interaction between the laser beam, waterjet and work material under the coupled effect of laser heating and waterjet expelling and cooling. The models for the coupled effect of laser and waterjet will be established to understand the interaction mechanisms between laser heating, waterjet expelling and cooling, and work material as well as material removal mechanisms, to enable to improve the material ablation process, minimize the thermal effect, and achieve near damage-free micromachining. The mathematical models for micromachining performance and process optimization will be developed to optimize the process parameters for maximum machining efficiency. The research outcome is expected to have a significant impact to machining theory and the micromachining industry, as well as to promote the innovation and progress of micromachining technology.

本项目融合水射流和激光加工技术于一体，创建一种新的激光辅助水射流近无损伤微细加工技术及系统，采用激光加热并软化工件材料、水射流驱除及冷却的耦合效应去除材料，用于微细结构的高效、低成本、高质量、近无损伤微细加工，并对其基础理论进行系统研究。该技术能够对水射流束和激光束分别进行独立控制，实现水射流束和激光束耦合的加工工艺。研究基于激光加热、水射流驱除及冷却和工件材料相互作用的水射流和激光耦合效应，建立新的水射流-激光耦合效应理论模型，揭示激光加热、水射流驱除及冷却和工件材料之间的相互作用机理及材料去除机理，以便加快材料切除过程，降低热影响，达到近无损伤去除材料的效果。并建立近无损伤微细加工时的工艺参数优化模型和材料去除率模型，优化工艺参数，提高加工效率。本项目的研究成果对于提高微细加工技术的加工效率和加工质量，促进微细加工技术的创新和发展具有重要的理论意义与实际应用价值。

本项目融合水射流和激光加工技术于一体，提出了激光辅助水射流近无损伤微细加工理论与技术，研制了国际上第一台立式高精度激光水辅助射流微细加工系统。采用激光加热并软化工件材料、水射流驱除及冷却的耦合效应去除材料，用于微细结构的高效、低成本、高质量、近无损伤微细加工，并对其基础理论进行系统研究。研究了工艺参数对槽深、槽宽和材料去除率影响的显著性，结果表明，射流偏置距离、射流靶距、扫描速度、激光平均功率和射流压力对槽深、槽宽和材料去除率都有非常显著的影响。建立了槽深、槽宽和材料去除率预报回归模型。研究了激光对材料的加热作用，将激光的热作用等效为一个三维体热源，建立了激光热源方程。研究了水射流对材料的冲击作用，建立了圆形倾斜射流产生的壁面切应力模型。研究了水射流对材料的冷却作用，建立了射流冲击区和壁面射流区的平均对流换热系数方程。研究了水射流对激光的干涉作用，建立了由冲击区向壁面射流区转变的临界偏置距离模型。研究了激光在空气-水交界面的折射并计算了折射后的激光照射在材料表面的光斑直径。构建了一套光束质量因子测量装置，并对水中光束的质量因子进行测量。建立了考虑高温热物理参数变化的激光辅助水射流复合微细加工单晶碳化硅晶片的三维温度场模型；基于热传导方程定解问题的解的结构定理，对温度场模型方程组进行坐标变换，获得了激光辅助水射流复合微细加工单晶碳化硅晶片的三维温度场模型的解析解。建立了4H单晶碳化硅的临界分切应力与温度之间的关系模型；构建了激光辅助水射流复合微细加工4H单晶碳化硅的材料去除有限差分模型，该模型对槽深、槽宽和切口截面轮廓的预报均具有较高的精确度。该技术能够对水射流束和激光束分别进行独立控制，实现水射流束和激光束耦合的加工工艺。本项目的研究成果对于提高微细加工技术的加工效率和加工质量，促进微细加工技术的创新和发展具有重要的理论意义与实际应用价值。