单晶硅非球面抛光工艺实验研究

发布时间：2018-05-06 17:37

本文选题：轮式抛光技术 + 广义Preston方程　；参考：《哈尔滨工业大学》2015年硕士论文

【摘要】：现今,光学元件以其良好的性能在各个领域得到了广泛的应用。非球面元件具有消除像差、减少色散、简化结构和降低成本的作用。在红外光学系统中,质地硬脆、热变形小、红外波段透过率高的非球面单晶硅透镜需求量越来越大,并且对表面粗糙度和面形的要求也越来越高。而传统的硅透镜加工,无论是从生产效率还是加工精度都无法满足光学系统对硅透镜提出的极高加工和表面粗糙度的要求。因此,研究出一种高效、高精度的光学非球面技术具有重要意义。本文重点介绍了一种新形式的抛光技术:轮式抛光技术,即通过计算机控制抛光轨迹,利用自行开发的柔性抛光轮通过抛光液中的氧化铝颗粒正压力作用下,对工件表面材料进行微磨削作用,在非球面表面准确进行材料去除,从而获得较好的表面粗糙度和面形精度。为此本文主要研究了以下内容:结合轮式抛光技术需要法向加载抛光压力的特点,搭建了基于B轴的抛光平台。针对抛光主轴安装在B轴中心的偏置误差会使得抛光压力改变的问题,分析安装偏置误差影响规律,并提出了三种偏置误差测量方式,并通过设计的三维微位移调整台进行调整,波纹面车削实验结果表明面形误差在3μm左右。结合本抛光平台特点,设计了离线超精密抛光轮修整方案,圆跳动在14μm。结合Hertz接触相关理论知识,分析了抛光轮与工件接触区域的大小、压力分布等。在此基础上运用运动学和Preston假设的知识,建立轮式抛光技术的半经验去除函数模型,并对此种抛光技术对平面工件加工情况进行了仿真分析。在理论模型的基础上,设计了关于抛光压力、抛光时间和抛光轮转速的定点单因素工艺实验,获得了不同参数下的抛光去除体积以及形貌,根据去除坑轮廓的不对称性,将压力模型下进行了修正,更加贴近实际加工。通过数据拟合计算出广义Preston系数以及速度修正指数。设计环带正交抛光工艺实验,分析了抛光工艺参数对轮式抛光技术加工单晶硅表面的抛光去除效率和表面粗糙度的影响规律,最后结合抛光特点优选出最佳的抛光工艺参数。最后结合去除函数通过离散矩阵算法计算驻留时间,并对口径为30mm的单晶硅平面、半径300mm的凸球面以及非球面进行了抛光加工实验,得到表面粗糙度分别为3.8nm、4.3nm和4.6nm,并且面形也得到一定的改善,验证了轮式抛光技术良好的加工性能。
[Abstract]:Nowadays, optical elements have been widely used in various fields because of their good performance. Aspheric elements can eliminate aberration, reduce dispersion, simplify structure and reduce cost. In infrared optical system, the demand for aspheric monocrystalline silicon lens with hard and brittle texture, small thermal deformation and high transmittance in infrared band is increasing, and the demand for surface roughness and surface shape is also increasing. However, the traditional silicon lens processing, whether from the production efficiency or machining accuracy, can not meet the optical system for silicon lens processing and surface roughness requirements. Therefore, it is of great significance to develop an efficient and accurate optical aspherical technique. In this paper, a new type of polishing technology, wheeled polishing, is introduced, which is controlled by computer, and the flexible polishing wheel is developed under the positive pressure of alumina particles in the polishing fluid. The surface of workpiece is ground by micro-grinding, and the material is removed accurately on the aspherical surface, so that the better surface roughness and surface shape accuracy can be obtained. The main contents of this paper are as follows: the polishing platform based on B axis is built according to the characteristic that the wheel polishing technology needs normal loading polishing pressure. Aiming at the problem that the bias error of the polishing spindle installed in the center of the B axis will cause the change of the polishing pressure, this paper analyzes the influence law of the installation bias error, and puts forward three ways to measure the bias error. The experimental results of corrugated surface turning show that the error of surface shape is about 3 渭 m. According to the characteristics of the polishing platform, an off-line ultra-precision polishing wheel dressing scheme is designed. The circle runout is 14 渭 m. Based on the theory of Hertz contact, the size and pressure distribution of contact area between polishing wheel and workpiece are analyzed. Based on the knowledge of kinematics and Preston hypothesis, the semi-empirical removal function model of wheel polishing technology is established, and the machining of planar workpiece is simulated and analyzed. On the basis of theoretical model, single factor experiments on polishing pressure, polishing time and rotation speed of polishing wheel are designed. The removal volume and morphology of polishing are obtained under different parameters. The pressure model is modified to get closer to the actual processing. The generalized Preston coefficient and velocity correction index are calculated by data fitting. The experiment of ring belt orthogonal polishing was designed, and the influence of polishing parameters on the removal efficiency and surface roughness of single crystal silicon surface was analyzed. Finally, the best polishing process parameters were selected according to the polishing characteristics. Finally, the dwell time is calculated by the discrete matrix algorithm combined with the removal function, and the polishing experiments are carried out on the single crystal silicon plane with the aperture of 30mm, the convex sphere with radius 300mm and the aspheric surface. The surface roughness is 3.8 nm and 4.6 nm, respectively, and the surface shape is improved to a certain extent, which verifies the good machinability of wheel polishing technology.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN305.2

【引证文献】