自由曲面超精密车削加工路径优化设计

加工路径优化设计是提高自由曲面超精密车削表面质量和形状精度的关键技术．采用NURBS插补模型进行自由曲面的描述，提出柱面坐标加工模型进行自由曲面超精密车削加工分析，借助矢量数学对刀位点进行刀具参数的优化补偿，并采用螺旋投影驱动方式实现加工路径的规划．对各种类型自由曲面进行加工实验，表面粗糙度达到5．16nm，路径优化设计后加工形状精度提高近10倍实验结果表明，提出的路径优化设计方法可以高效可靠地加工光学质量表面的自由曲面。

Optimized Design of Cutting Path for Freeform Surface in Ultra-Precision Turning

Design of cutting path is critical to improving the roughness and form precision of freeform surfaces using ultraprecision turning. The typical non-uniform rational B-splines （NURBS） interpolation model was used to define freeform surface. The cylindrical coordinate machining （CCM） method was proposed,in which the compensation for tool geometry was considered using vector mathematics. Finally,the cutting path was generated according to the spiral projection driver model. Typical freeform surfaces fabricated by the cutting method were presented,and the roughness of 5.16 nm and an improvement of form precision about 10 times as great are obtained. Experimental results show that the proposed method is efficient and robust to cutting optical freeform surface.