光学玻璃复杂型面的高效低损伤超声振动辅助精密铣磨加工技术基础

Optical glass is a typical brittle material with a wide application in defense and high technology fields. Conventional grinding, lapping and polishing process does not meet the demands for fast production rate, low cost and high accuracy in machining glass optics with complex surfaces. In order to solve the problems faced in high-efficiency low-damage precision machining of glass optics with complex surfaces, this project will investigate systematically the evolvement mechanism and transition conditions of brittle and ductile material removal modes in machining of optical glass under the effect of mechanical-ultrasonic coupling, which will provide a basis for the effective control of the material removal modes. The formation mechanisms of the machined surface and sub-surface damage will be studied in ultrasonic vibration assisted mill-grinding of optical glasses for exploring the strategy for reducing the degree of sub-surface damage.The critical machining conditions for low-damage ultrasonic vibration assisted mill-grinding will be proposed. Based on the above-mentioned works, ultrasonic vibration assisted mill-grinding tests of optical glasses will be conducted to find out the the relationship between the processing conditions, the machining efficiency and the machined surface quality. The knowledge generated from this work will provide a theoretical and technological basis for high-efficiency low-damage precision ultrasonic vibration assisted mill-grinding of glass optics with complex surfaces.The successful fulfillment of this project is of great significance for expanding the application area of precision ultrasonic vibration assisted mill-grinding, enriching precision machining theory, and for developing novel advanced technologies.

光学玻璃是典型的硬脆材料，在国防和高技术领域有广泛的应用需求。对于复杂型面光学玻璃元件，采用传统的磨削研磨和抛光工艺，不但加工效率低、成本高，而且加工精度也难以保证。本课题针对光学玻璃复杂型面元件的高效低损伤精密加工所面临的问题，系统地研究机械-超声复合能场作用下光学玻璃脆塑性去除模式演变机制及迁移条件，为实现光学玻璃材料去除模式的有效控制提供理论基础；研究光学玻璃材料超声振动铣磨表面创成与亚表层损伤形成机理，探寻减免亚表层损伤的技术措施，提出低损伤超声振动铣磨的临界加工条件；在此基础上，进行光学玻璃超声振动铣磨加工优化工艺研究，揭示超声振动铣磨工艺条件与加工效率和表面质量的映射关系，为实现复杂型面光学玻璃元件的高效低损伤超声振动精密铣磨加工提供理论基础与工艺技术支撑。研究结果对拓展超声振动精密铣磨加工技术的应用领域、丰富精密加工理论和发展高新尖端技术均具有重要理论意义和应用价值。

本项目针对光学玻璃复杂型面元件精密加工所面临的加工效率低、表面和亚表面损伤严重等问题，开展了机械-超声复合能场作用下光学玻璃脆塑性去除模式迁移条件、加工表面创成及亚表层损伤形成机理、高效低损伤超声振动精密铣磨工艺优化等方面的研究。借助于变切深超声振动刻划及显微压痕实验，获得了超声振动作用对光学玻璃裂纹生成、扩展和粉末化去除、以及脆-塑性转变临界切削力和临界切削深度的影响规律。基于塑性去除模式和脆性去除模式的切削比能随切削深度变化的计算分析，建立了BK7光学玻璃脆-塑性转变临界切削深度的数学模型。通过光学玻璃二次显微印压及旋转超声刻划实验，分析了准静态载荷及动态冲击载荷作用下裂纹扩展交互作用机制，揭示了动态冲击载荷作用下材料去除及表面创成机理。基于加工亚表面裂纹微观形貌特征的观测与分析，阐明了超声振动效应对不同特征亚表面裂纹损伤形成的影响机制。建立了光学玻璃超声振动铣磨加工表面粗糙度及亚表面裂纹损伤最大深度的预测模型，为探索提高加工表面质量、减小亚表面裂纹损伤的工艺措施提供了理论依据。在此基础上，进行了光学玻璃超声振动铣磨加工优化工艺研究，揭示了BK7光学玻璃超声振动铣磨加工工艺条件与加工效率和表面质量的映射关系。本项目的研究结果为实现光学玻璃材料高效低损伤超声振动精密铣磨加工提供了理论基础和工艺技术支撑。.结合项目研究成果，在国际和国内期刊上已发表学术论文6篇（其中SCI检索4篇、EI检索1篇、国内核心期刊1篇）；培养研究生4人，其中博士研究生1人（已毕业），硕士研究生3人（已毕业）。