三维调制靶模板的快速刀具伺服加工技术

Fabrication of 3D Perturbation Target Mould Using Fast Tool Servo System

采用快速刀具伺服技术(FTS)实现了非回转对称三维调制靶模板的精密车削加工.阐明了调制靶模板车削加工的基本原理,并提出一种基于坐标变换的金刚石刀具几何参数选择方法,推导了车削加工此类表面时金刚石刀具刀尖圆弧半径、前角和后角所需满足的条件.基于此提出了一种基于三次Hermite插值的刀尖圆弧半径补偿算法,并详细讨论了插值节点的计算方法.由刀尖圆弧半径补偿仿真结果可以看出,此补偿算法精度优于2 nm.在自行研制的精密金刚石车床上实现了X、Y方向上波长均为100μm、幅值均为0.7μm的正弦网格调制结构的加工.采用白光干涉仪对所加工的调制结构进行测量,并提取二维轮廓进行分析,其轮廓误差为0.31μm,表面粗糙度为13.3 nm.测量结果表明采用基于快速刀具伺服的非回转对称车削是实现三维调制靶模板制作的有效手段.

3D non-rational symmetrical perturbation target mould was fabricated using fast tool servo （FTS）. The fabrication principle of the perturbation target mould was illustrated and a geometry selection method of diamond cutting tool was put forward which was based on the coordinate transformation tech- nique. Requirements of tool nose radius, rake angle, and clearance angle for turning these surfaces were deducted. A tool nose radius compensation algorithm based on cubic Hermite interpolation was proposed, and the calculating method of interpolation node was also discussed in detail. The simulation result shows that the accuracy of this compensation algorithm is less than 2 nm. Then a sinusoidal grid surface with the wave length of 100μm and the amplitude of 0. 7μm in both X and Y directions was fabricated on the self-developed diamond turning machine. White light interferometer was adopted to survey the machined surface, and a 2D contour line was extracted with the profile error of 0.31 ~m and the surface roughness of 13.3 nm. The measurement results show that the FTS based non-rotational symmetrical turning technique is an effective way to fabricate 3D perturbation target mould.