超薄光学零件由于径厚比大, 刚度低, 抛光上盘时容易产生较大变形, 影响其最终的面形精度。本文通过Ф50 mm×1 mm熔融石英玻璃的胶粘上盘实验, 结合有限元分析, 研究了不同上盘方式和固化顺序对零件变形的影响, 分析了变形产生机理。研究结果表明上盘变形主要由胶层内胶黏剂先后固化顺序引起, 和零件胶结面面形关联性不明显。此外, 由于固化顺序的随机性, 上盘变形是不对称、不规则的, 没有规律可循。基于弱化固化顺序影响的思路, 通过改变粘接方式, 将固持变形由整面上盘的1.88 μm减小到0.51 μm。采用该上盘方法对熔融石英玻璃薄片进行沥青抛光加工, 下盘后面形精度PV值达到0.46 μm, 有效地抑制了零件下盘后的面形恶化。本文研究有助于进一步揭示上盘固持变形的产生机理, 并对实际超薄光学零件加工具有一定指导作用。

Ultra-thin optical workpieces get significantly deformed when mounted on pressure plates owing to their high aspect ratio and low stiffness, thereby affecting the accuracy in determining the final surface figure. In this study, we mounted a Ф50 mm×1 mm fused silica workpiece using different methods and in a specific curing sequence. The deformation mechanism was analyzed using finite element simulation. The results show that the mounting deformation of the ultra-thin workpiece is asymmetric and irregular and is caused by the curing sequence of the adhesive used instead of the profile of the adhesive surface. With the aim of reducing the effect of the adhesive curing sequence, a mounting method is developed to reduce the mounting deformation from 1.88 μm to 0.51 μm. A flatness of PV 0.46 μm for the fused silica workpiece is achieved post pitch polishing and demounting, and the deterioration is effectively restrained. This study helps to understand the mechanism of mounting deformation and guides the fabrication of ultra-thin optical workpieces.