面向大口径非球面光学元件的流体动压磨抛工艺加工理论与试验研究

Large aspherical optical elements are widely used in modern precision optical devices. But the current processing technology is difficult to satisfy the dual need of processing efficiency and quality, especially it lacks the rapid polishing process from the grinding surface to the super smooth surface, and restricting the major national engineering process seriously. In order to solve the problem of rapid grinding and polishing machining of large aspherical optical elements, the center-supplied hydrodynamic grinding and polishing technology is proposed in this project, and preliminary research results are obtained. However, there are still some deficiencies in basic theoretical research. This project adopts the method of combining the theoretical analysis with scientific experiments, the fluid-solid coupling relations of multi-factor systems, such as fixed abrasive tool parameters, grinding trajectory, grinding and polishing fluid and workpiece, are established, it reveal the relationship with the model of liquid film flow field between grinding tool and workpiece, motion characteristics of abrasive particles and micro-cutting Mechanism; The characterization parameter model of particles in matrix material, the removal model for hard and brittle material under static and dynamic condition and coupling action of multiple abrasive particles are established, to reveal the removal mechanism of fixed particles in fluid hydrodynamic fixed abrasive grinding processing; The mapping relationship between process parameters, machining efficiency and machining precision grade is established, and the quantitative prediction of grinding effect is realized. It provides theoretical basis and technical support for the extension and application of this process in the field of hard and brittle materials processing.

大口径非球面光学元件广泛应用于现代精密光学设备中，当前诸多加工工艺都难以同时满足加工效率和质量的双重需求，特别是缺乏从磨削前表面到超光滑表面的快抛工艺，严重制约着国家重大工程的进程。本项目针对大口径非球面光学镜面的快速磨抛问题，提出中心供液流体动压磨抛技术，并取得初步研究成果，但基础理论研究方面仍存在不足。拟采用理论分析和科学实验结合的方法，建立快速磨抛过程中固结磨料磨抛工具、磨抛轨迹、磨抛液、工件参数等多因素系统的流固耦合关系，揭示磨抛工具与工件间的液膜流场、磨粒运动特性及微观切削机理间关系；建立微粒在磨抛垫基体材料表征参数模型、动静态作用下硬脆材料去除模型以及多磨粒耦合作用下材料去除模型，揭示流体动压磨抛技术中磨粒对元件表面材料去除机理；建立工艺参数、加工效率和加工精度等级之间的映射关系，实现磨抛效果的定量化预测，为这种工艺在超光滑光学表面加工领域的扩展应用提供理论依据和技术支持。

随着现代先进光学设备在航天领域广泛使用，具有诸多优点的大口径非球面光学元件应用需求越来越多。研磨和抛光是制造光学元件的重要加工手段，随着技术发展人们对于加高效率、高质量、可控性高的加工工艺的探索和尝试从未停止。针对大口径非球面光学元件制造，本文提出了流体动压磨抛工艺加工技术。从机理探究、仿真建模、实验分析等多个方面对熔融石英玻璃的固结磨料确定性研磨工艺进行探究。本项目所提出的基于中心供液的流体动压固结磨料磨抛技术。该技术能够填补了大口径非球面光学元件加工中从磨削前表面到超光滑表面的快抛工艺不足。本项目从理论分析和实验验证两方面对该工艺的基本加工机理做了分析，为这种工艺在大口径超光滑光学元件表面加工领域的扩展应用提供理论依据和技术支持。. 在光学表面流体动压固结磨料磨抛加工工艺方面，针对磨削加工后光学表面轮廓误差和损伤层特征，将固结磨料磨抛加工技术用于光学表面快速磨抛工艺中，并设计相应的加工工具。通过研究固结磨料磨抛技术中磨抛表面形貌和质量特征演化规律，以揭示加工表面材料去除特征和去除机理。研究磨抛表面及亚表面微裂纹的损伤特征，揭示加工工艺参数对加工表面及亚表面损伤层深度的影响规律。实验表明，载荷对加工表面材料去除特征和亚表面损伤特征最为显著。根据材料去除机理，建立固结磨料磨抛技术工艺过程中材料去除理论模型，用于加工表面形貌特征的预该工艺为光学表面低频误差和部分中频误差的修正提供理论依据。. 在固结磨料磨抛工艺材料去除机理研究方面，针对当前大口径光学元件磨抛成型中材料损伤和去除机理在实验及理论研究中存在的不足，以解耦固结磨料端面抛光过程为切入点，系统提出了一种切合实际工况的硬脆材料去除机理探究理论与方法——次摆线划痕理论。该方法解决了现有划痕线速度与磨削加工过程中磨粒线速度无法匹配的问题，且可用于高速、连续、自相交、互干涉、变曲率和应变率等因素对材料去除机理的影响研究。