大行程高频响快速刀具伺服系统的研究

发布时间：2018-10-13 08:56

【摘要】：非回转对称曲面光学元件以其优越的光学性能已成为光电信息技术与光通信技术中的核心元器件,并在空间探索、航空航天、国防以及民生等众多领域被广泛且普遍应用。由于非回转对称曲面光学元件的表面形貌复杂、面形精度要求高,传统的曲面加工技术以及LIGA技术、蚀刻技术等新近发展的曲面加工技术都不能实现非回转对称曲面光学元件高效率、高精度、大批量加工。随着超精密金刚石车床与快速刀具伺服系统的研究发展,基于快速刀具伺服(Fast Tool Servo,FTS)系统的金刚石刀具车削加工技术已经成为了一种高效率、高精度、高柔性的非回转对称曲面光学元件加工技术。其中,渐进式镜片曲面是一种典型的非回转对称曲面,它是一种拥有多个焦距的镜片曲面,区别于传统的老花镜曲面,渐进式镜片曲面没有使用双焦距老花镜时眼球必须不断切换适应不同焦距的疲劳感,已经成为老视人群的最佳选择。但目前渐进式镜片的验配时间长、价格昂贵,实现其高效率、高精度、低价格加工的实现是一个亟待解决的问题。为实现渐进式镜片曲面元件的加工,本文根据给定性能要求设计一款FTS装置。通过对FTS装置设计过程的运动参数尤其是其加速度的进行分析,且根据渐进式镜片曲面面形完成FTS装置的带宽设计,并根据渐进式镜片曲面切削深度确实FTS装置行程。为保证渐进式镜片曲面的加工精度,设计的FTS装置影具有大的带宽,也就是较高的频率响应,由于镜片曲面不同位置的高度差较大,达到毫米级,设计的FYS装置应具备较大的工作行程。并对加工过程中切削力与切削角度变化进行分析,根据分析结果完成FTS装置的布局形式以及导向机构、驱动装置、传感器的选择。根据FTS装置的结构布局和元件选择完成其主要构成部分:空气静压导轨、金刚石刀具刀架等结构设计与有限元分析以及气浮装置的设计与参数计算。并根据上述分析完成FTS装置的整体结构设计。根据渐进式镜片曲面的面形方程完成金刚石刀具几何参数的选择,利用MATLAB完成镜片曲面切削加工轨迹规划并离散出刀具刀尖点位置的数据点,确定机床主轴、X向工作台与FTS装置的运动轨迹曲线。采用等距点法计算刀尖离散数据点在二维径向截面轮廓曲线上的等距点,并采用埃尔米特插值完成离散数据点的刀尖圆弧半径补偿。本文分析了FTS装置通过试切法减少对刀误差和刀具中心高误差对渐进式镜片曲面加工面形精度的影响。为减少FTS装置对刀的刀具中心高误差,基于螺旋微分头设计一台高刚度、高分辨率的精密升降台。基于以上研究,采用FTS装置在自主研究的精密金刚石车床上完成渐进式镜片曲面的加工,并对加工结果进行检测分析,验证FTS装置结构设计和刀具刀尖点运动轨迹规划的正确性。
[Abstract]:Non-rotational curved surface optical elements have become the core components of optoelectronic information technology and optical communication technology due to their superior optical properties and have been widely used in many fields such as space exploration aerospace national defense and people's livelihood. Due to the complexity of surface morphology and the high precision of surface shape of non-rotational symmetric curved surface optical elements, traditional curved surface processing technology and LIGA technology, Recently developed surface machining techniques such as etching technology can not realize high efficiency, high precision and mass machining of non-rotational symmetric curved surface optical elements. With the development of ultra-precision diamond lathe and rapid cutting tool servo system, the diamond tool turning technology based on fast tool servo (Fast Tool Servo,FTS system has become a kind of high efficiency and high precision. High flexible machining technology for non-rotational symmetric curved surface optical elements. Among them, the progressive lens surface is a typical non-rotational symmetric surface, it is a lens surface with multiple focal lengths, which is different from the traditional presbyopic glasses surface. Progressive lens surface without double focus presbyopic glasses has become the best choice for the elderly people because their eyeballs must constantly change and adapt to the fatigue of different focal lengths when they do not use double focus presbyopic glasses. However, it is an urgent problem to realize the high efficiency, high precision and low price processing of the progressive lens because of its long matching time and high price. In order to realize the machining of the progressive lens surface element, a FTS device is designed according to the given performance requirements. Based on the analysis of the motion parameters, especially the acceleration of the FTS device, the bandwidth of the FTS device is designed according to the surface shape of the progressive lens, and the stroke of the FTS device is confirmed according to the cutting depth of the progressive lens surface. In order to ensure the machining accuracy of the progressive lens surface, the FTS device designed has a large bandwidth, that is, a higher frequency response. Because of the large height difference in different positions of the lens surface, it reaches the millimeter level. The designed FYS device should have a larger working stroke. The changes of cutting force and cutting angle during machining are analyzed. According to the analysis results, the layout of FTS device and the selection of guiding mechanism, driving device and sensor are completed. According to the structure layout and component selection of FTS device, the main components are designed and analyzed by finite element method, such as air static guide rail, diamond tool holder, and air floatation device design and parameter calculation. According to the above analysis, the overall structure design of FTS device is completed. According to the surface equation of progressive lens surface, the geometric parameters of diamond tool are selected, and the cutting path planning of lens surface is completed by MATLAB, and the data points of cutter tip position are discretized. Determine the track curve of machine tool spindle, X-direction table and FTS device. The isometric point method is used to calculate the equidistant points of the discrete data points on the 2-D radial section contour curve, and the Hermite interpolation is used to compensate the radius of the cutter tip of the discrete data points. In this paper, the influence of tool error and tool center height error on the machining accuracy of progressive lens surface in FTS device is analyzed by means of trial cutting method. In order to reduce the error of tool center height in FTS device, a precise lifting platform with high stiffness and high resolution was designed based on helical differential head. Based on the above research, the FTS device is used to finish the machining of the progressive lens surface on the precision diamond lathe, and the processing results are tested and analyzed. Verify the correctness of FTS device structure design and tool tip motion trajectory planning.
【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】：2017
【分类号】：TG51

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