Abstract Fixed abrasive machining, which overcomes the lack of determinacy and efficiency of current loose abrasive polishing or lapping processes, is an alternative technology for fabricating large-aperture aspheric surfaces with high finishing efficiency and high-quality surface finish. A novel fixed abrasive lapping (NFAL) tool, which combines computer-controlled optical surfacing and conventional fixed abrasive lapping process, is introduced in this study to produce off-axis aspheric surfaces efficiently while surface state is controlled and subsurface damage (SSD) is avoided. The removal mechanism analysis shows that fused quartz glass is primarily removed in ductile regime and the SSD depth is 14.7 μm when the tool load is 25 N. The material removal volume is linear with the machining time under the ductile removal mode. The material removal and surface generation models are developed on the basis of the calculation of the spatial distribution of abrasive particles, the pad–particle–workpiece interactions, the single-particle abrasion mechanism, and the linearly cumulative removal of surface generation in the NFAL process. The models are verified through a series of spot and surface lapping experiments. Results show that the theoretical model can be successfully used to predict and optimize the NFAL process. The spot lapping experiments indicate that the material removal volume is linear with the rotation speed, and the maximum depth is limited to the specific value that depends on the stiffness of lapping tool. The surface roughness Ra and Rz values of the measured and simulated surface data decrease with the increase in feed rate and increase with the increase in raster spacing. The power spectral density analysis indicates that high feed rate can distinctly improve the high-frequency errors, and the selection of the raster spacing can principally affect the low-frequency and middle-spatial frequency errors.

中文翻译：

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新型固定磨具光学表面研磨材料去除及表面生成的理论与实验分析

摘要 固定磨料加工克服了目前松散磨料抛光或研磨工艺缺乏确定性和效率的问题，是一种具有高精加工效率和高质量表面光洁度的大孔径非球面加工技术。本研究介绍了一种新型固定磨料研磨 (NFAL) 工具，它结合了计算机控制的光学表面处理和传统的固定磨料研磨工艺，可在控制表面状态和避免亚表面损伤 (SSD) 的同时有效地生产离轴非球面. 去除机理分析表明，熔融石英玻璃主要在延性状态下被去除，当刀具载荷为25 N时，SSD深度为14.7 μm。在延性去除模式下，材料去除量与加工时间呈线性关系。材料去除和表面生成模型是在计算磨粒空间分布、垫-颗粒-工件相互作用、单粒子磨损机制以及 NFAL 过程中表面生成的线性累积去除的基础上开发的. 这些模型通过一系列的点和表面研磨实验得到验证。结果表明，该理论模型可以成功地用于预测和优化NFAL过程。点研磨实验表明，材料去除量与转速成线性关系，最大深度限制在具体值，具体值取决于研磨工具的刚度。实测和模拟表面数据的表面粗糙度Ra和Rz值随着进给速度的增加而减小，随着光栅间距的增加而增加。功率谱密度分析表明，高进给速度可以明显改善高频误差，光栅间距的选择主要影响低频和中频误差。