大口径光学镜面超精密加工机床的研制

设计制作了最大加工直径为φ880 mm的光学镜面超精密加工机床.该机床采用大理石床身、4轴数控联动、全气浮支承和零传动结构,以实现光学球、非球及自由形面的超精密切削.介绍了机床整体结构特点和性能参数,描述了气浮电主轴、气浮直线导轨、直驱回转工作台等关键技术及部件.该机床主轴回转精度0.05μm,直线伺服轴分辨力1.25 nm,回转工作台角位移分辨力0.009.″在硬铝和无氧铜材料上分别加工出了面形精度0.5μm、表面粗糙度5 nm的φ400 mm球面和面形精度0.5μm/φ100 mm、表面粗糙度8 nm的非球形面.

Development of Ultra-Precision Machine for Large-Sized Mirror Surface

An ultra precision machine for mirror surface with the maximum workpiece diameter of φ880 mm was designed and manufactured,which had massive granite base,four axes CNC,aerostatic bearings and direct drive motors,and was able to process spherical,aspheric and freeform optical surfaces with ultra-high accuracy.The configuration features and performance parameters of the machine were presented,and the key technologies including aerostatic-bearing motorized spindle,linear aerostatic slideways and direct drive rotary table were described.Result shows that the rotation error of spindle is 0.05 μm,positional feedback resolution of slideways is 1.25 nm,and angular feedback resolution of the rotary table is 0.009″.In the cutting experiments,a spherical surface with roughness of 5 nm,profile accuracy of 0.5 μm,and diameter of φ400 mm was obtained on duralumin alloy,and an aspheric surface with roughness of 8 nm and profile accuracy of 0.5 μm/φ100 mm was gained on oxygen-free copper.