面向复杂薄壁件高速加工的CAM/CNC制造系统基础问题研究

Complicated thin-walled parts are widely used in complex equipments with high performance requirements such as aerospace equipment etc. and the extreme condition performance of the equipments is directly affected by their manufacturing precision and machining quality. In order to improve the processing accuracy of the complicated thin-wall parts, the following two aspects of research plans are put forward in this project. Firstly, based on the micro-lubricating condition of the thin wall parts and the high-speed cutting force model with consideration of cutting vibration and deformation, high speed machining process parameters of cutting a thin-walled work-piece are optimized and high-speed machining parametrical library is established and fulfilled. Five-axis machining tool path calculation method is presented for high-speed machining of thin-walled parts; The other aspect is the methods for realizing high speed transition of 5-axis machining cutter locations in the CNC system, processing the discrete 5-axis cuter locations as spline and look-ahead controlling of path velocity adaptive to high speed and high precision machining are thoroughly researched from the point on five axis high speed machining tool path accurately control. The new principle and mechanism with CAM system calculation of five axis high speed machining tool position directly into CNC system for trajectory control are also proposed in this project. Eventually the high speed machining technology of complex thin wall castings for CAM / CNC integrated manufacturing system and method is established and perfected. The basic scientific problems being deeply put forward and developed in this project have important theoretical significance and practical application value for promoting the 5-axis high-speed precision manufacturing technology level of the complicated thin-walled parts.

复杂薄壁件在航空航天等有极高性能要求的复杂装备上的应用日益广泛，其制造精度和加工质量将直接影响装备的极限工况性能。为提高复杂薄壁件的加工精度，本项目提出以下两大方面的研究内容：基于薄壁件在微量润滑条件下考虑高速切削振动与变形时的切削力模型，优化薄壁件高速切削加工工艺参数，建立并完善面向薄壁件的高速切削加工工艺参数库，提出薄壁件高速加工的五轴加工刀位轨迹计算方法；从面向五轴高速加工刀位轨迹精确控制的角度出发来研究在CNC系统内部实现五轴加工刀位间的高速转接、五轴离散刀位的样条化处理以及适应高速高精加工的轨迹速度前瞻控制的方法，提出将CAM系统计算的五轴高速加工刀位直接输入CNC系统进行轨迹控制的新原理和机制，最终建立并完善复杂薄壁件高速加工CAM/CNC集成制造工艺系统与方法。本项目相关基础问题的深入开展和研究，对提升复杂薄壁件五轴高速精密制造技术水平具有重要的理论意义和实际应用价值。

针对复杂薄壁件的五轴高速高精加工数控装备领域的关键问题，本项目着重研究了五轴CAM/CNC集成制造系统的构建技术及其高速加工刀轨处理机制等方面。具体开展的研究内容有：（1）从球头刀刀刃曲线数学模型入手，推导了瞬时螺旋角与滞后角，通过计算切削面积，利用实测平均切削力的方法回归计算了切削力系数，基于Taguchi方法并结合对实验样本进行方差分析的方法分别分析了切削工艺参数对切削力及切削力系数的影响程度，使薄壁件高速切削五轴刀轨的生成有了理论依据；（2）针对高速加工时是一种高速数据流的特点，本项目还开展关于五轴CAM/CNC制造系统内部高速海量数据处理机制，优化了数据运行效率，同时提出了一种数据量小但高效简洁的多项式样条插补方法，通过对其插补精度、速度的分析表明该样条插补方法在CAM/CNC制造系统中有较好的适用性；（3）由于CAM/CNC制造系统本身还具备CAM功能，因此项目还研究了相邻高速加工路径段间的速度衔接机制和段内的加减速处理方法，通过研究实例表明提出的方法即使在高曲率加工路径段间也完全可以实现高速转接；（4）研究了五轴样条高速高精密插值方法和五轴样条插补数据流算法，基于曲率圆误差控制的方式提出了在高速五轴加工时的样条段内的加减速处理方法，通过验证表明该方法能满足插补误差要求条件下，实现对样条曲线尖角处实时调整进给速度，提高插补精度并满足插补误差的要求，对五轴样条插补进行加减速速度规划使得五轴高速加工CAM/CNC制造系统具有良好的适应性，高速加工过程会更加平稳且更能有效减轻高加速度对薄壁件加工结果的影响。通过本项目开展的上述研究工作，基本解决了五轴高速铣削加工复杂薄壁件的数控工艺装备的基础问题，以期对未来相关数控制造系统的设计制造方面会具有较好的理论意义和应用价值。