多模式组合抛光技术在光学加工中的应用

介绍了将经典抛光方法与数控加工技术有机结合的多模式组合抛光技术.描述了多模式组合抛光的关键技术之一,材料去除率仿真模型的建立方法.通过设置抛光盘因子和元件因子,多模式组合抛光的材料去除模型不仅包含抛光模式、速度等加工参数,还将抛光模形状、边角效应、元件面形误差等因素对材料去除的影响一并考虑入内,可以根据抛光阶段的不同,...     

电解-机械-磁力便携式抛光机的研制

针对具有高硬度、高韧性、高强度和低导热性的大型平面或曲面的难加工材料的工件,应用电解—机械—磁力复合抛光工艺原理,研制了便携式抛光机。试验证明,将与工件母材机械性能无关的电解作用和柔性抛光片的机械作用,以及磁场磁力作用的相结合,提高了抛光的效率和质量,解决了不便搬运的大型难加工材料工件的就地抛光问题。     

磁流体辅助抛光工件表面粗糙度研究

给出了磁流体辅助抛光的机理,以及依据Preston方程建立的磁流体辅助抛光的数学模型。并通过实验详细研究了磁流体辅助抛光后工件的抛光区形状,以及抛光区内表面粗糙度情况。最终加工出了表面粗糙度为0.76 nm(rms值)的光学元件,其高频表面粗糙度达到0.471 nm(rms值),满足了对一定短波段光学研究的要求。结果表明:磁流体辅助抛光可以用于对光学元件进行超光滑加工;在磁流体辅助抛光过程中,较大粒度的磁流体抛光液有利于工件表面粗糙度快速降低,较小粒度的磁流体抛光液可以获得更加光滑的光学表面。     

基于三维激光扫描的移动大尺寸圆柱体工件长度快速检测系统

针对移动大尺寸圆柱体工件两端的表面形貌特征,利用三维激光扫描仪设计了一种快速长度在线检测系统。基于三维激光扫描仪可在短时间内连续高速获取大量测量数据的特点,系统在虚拟环境下构造出自适应测量形状的虚拟测量基准面,采用二维误差分离方法抑制系统误差和运动误差,识别定位工件两端端点并计算其到虚拟测量基准面的位移;最后结合多传感器融合模型获取三维位移场测量结果。另外,测试前用三坐标测量机精密测量过的相似形状圆柱体工件对系统进行了校准修正。为验证系统的精度和可靠性,分别对处于（1 000±25）mm内不同直径的圆柱体工件进行了长度检测。结果显示,系统可在1 s完成直径约为50 mm工件的长度测量,检测分辨力为0.010 mm,检测精度达到0.050 mm。实际运行结果表明,该设计系统具有高自动性和高效性,可满足在线生产中对大尺寸工件控制和检测的要求。     

Self-calibration and compensation of setting errors for surface profile measurement of a microstructured roll workpiece

Microstructured roll workpieces have been widely used as functional components in the precision industries. Current researches on quality control have focused on surface profile measurement of microstructured roll workpieces, and types of measurement systems and measurement methods have been developed. However, low measurement efficiency and low measurement accuracy caused by setting errors are the common disadvantages for surface profile measurement of microstructured roll workpieces. In order to shorten the measurement time and enhance the measurement accuracy, a method for self-calibration and compensation of setting errors is proposed for surface profile measurement of microstructured roll workpieces. A measurement system is constructed for the measurement, in which a precision spindle is employed to rotate the roll workpiece and an air-bearing displacement sensor with a micro-stylus probe is employed to scan the microstructured surface of the roll workpiece. The resolution of the displacement sensor is 0.14 nm and that of the rotary encoder of the spindle was 0.15r~. Geometrical and mathematical models are established for analyzing the influences of the setting errors of the roll workpiece and the displacement sensor with respect to the axis of the spindle, including the eccentric error of the roll workpiece, the offset error of the sensor axis and the zero point error of the sensor output. Measurement experiments are carded out on a roll workpiece on which periodic microstructures are a period of 133 i~m along the circumferential direction. Experimental results demonstrate the feasibility of the self-compensation method. The proposed method can be used to detect and compensate the setting errors without using any additional accurate artifact.     

变向恒速平动研磨机的研制

所研制的变向恒速平动研磨机,其工件平面相对于研磨盘的运动速度大小恒定,而方向沿圆周轨迹的切线方向循序渐变.分析与试验表明该实验机可获得高的研磨质量和高的生产率,并具有长寿命、对加工及安装精度要求低等特点.     

超薄石英晶片超精密抛光实验的研究

为了解决超薄石英晶片高表面质量的加工问题,以及寻求一种高效低成本的加工方法,将一种新的超精密抛光工艺应用到超薄石英晶片的加工中。给出了加工过程中的抛光原理,制定出了在研磨和抛光过程中的最优实验条件,并对加工后超薄石英晶片的粗糙度和厚度做了详细的分析;讨论了磨粒的尺寸对表面粗糙度和材料去除率的影响,同时对加工过程的材料去除机理做了论述,以表面粗糙度和厚度为评价目标对超薄石英晶片的加工特性和表面质量进行了评价。研究结果表明：使用该实验的工艺加工超薄石英晶片可以得到厚度为99．4μm、表面粗糙度为0．82nm的超光滑表面;同时,该研究还发现通过延长抛光时间可以减小石英晶片的表面残余应力,可有效控制石英晶片四角“翘曲”现象,得到更好的平面度和平行度。     

无磨料低温抛光的工艺方法研究

对无磨料低温抛光这种全新的工艺方法进行了系统的研究,包括抛光设备、抛光冰盘的制备、工件盘的制备、抛光盘的修整、抛光后工件的清洗、抛光后表面粗糙度的测量等。并用此种方法对石英晶体进行了抛光实验,得到了Ra0．53mm的超光滑表面,结果证明这是一种获得超光滑表面的新方法。     

纳米胶体自激脉冲空化射流抛光技术

为了满足光学复杂曲面的精密、高效加工,提出一种利用空化效应促进射流加工效率的光学表面加工方法——纳米胶体自激脉冲空化射流抛光,并研制了加工系统。采用流体动力学对纳米胶体自激脉冲空化射流抛光中的喷射过程进行了仿真,获得了周期为0.3s的自激脉冲射流典型时刻下加工流场的流体动、静压力、速度、空化效应分布规律。进行了纳米胶体自激脉冲空化射流抛光试验,结果表明该系统能够产生效果良好的自激脉冲空化射流。采用该方法对单晶硅表面进行加工可以得到表面粗糙度为Ra0.904nm(Rms1.225nm)的超光滑表面,此加工表面粗糙度质量与相同加工条件下的普通纳米胶体射流抛光相当,但其加工效率较普通纳米胶体射流抛光能够提升20%左右,能够满足光学表面高效精密加工的需要。     

Development of surface reconstruction algorithms for optical interferometric measurement

Optical interferometry is a powerful tool for measuring and characterizing areal surface topography in precision manufacturing. A variety of instruments based on optical interferometry have been developed to meet the measurement needs in various applications, but the existing techniques are simply not enough to meet the ever-increasing requirements in terms of accuracy, speed, robustness, and dynamic range, especially in on-line or on-machine conditions. This paper provides an in-depth perspective of surface topography reconstruction for optical interferometric measurements. Principles, configurations, and applications of typical optical interferometers with different capabilities and limitations are presented. Theoretical background and recent advances of fringe analysis algorithms, including coherence peak sensing and phase-shifting algorithm, are summarized. The new developments in measurement accuracy and repeatability, noise resistance, self-calibration ability, and computational efficiency are discussed. This paper also presents the new challenges that optical interferometry techniques are facing in surface topography measurement. To address these challenges, advanced techniques in image stitching, on-machine measurement, intelligent sampling, parallel computing, and deep learning are explored to improve the functional performance of optical interferometry in future manufacturing metrology.     

磁流变抛光工艺参数的研究

磁流变抛光是一种新型的光学零件加工方法,它不仅可以精确控制抛光后光学零件的面型,还能得到较高的表面质量和较高的加工效率。本文在介绍磁流变抛光基本原理的基础上,重点分析了磁流变液与工件相对速度对磁流变抛光最终效果的影响规律,在一定速度大小范围内,随着相对速度的提高,抛光加工的效率也会随之提高,光学零件的表面粗糙度会随之降低,并且还提出在抛光过程中保持相对速度一致的必要性和保持相对速度一致的方法,通过实验验证了该方法的正确性。     

大型环抛机蜡盘平面度的测量

针对大口径平面光学元件全频谱面形技术指标的高效率、高精度收敛,研究了环形抛光技术。考虑环抛机沥青蜡盘的平面度直接影响工件面形的收敛效率,本文利用准直激光束作为参考,设计研制了测量精度高,重复性精度达到±1μm的大型环抛机抛光蜡盘平面度测量专用装置。分析了环抛过程中蜡盘表面平面度和工件面型PV值之间的变化规律和相关性,根据测量数据得出了蜡盘平面度数据和工件面形的对应关系。实验显示:当平面度和面形曲线相差较大时,工件面形可快速收敛至1λ左右,并由粗抛向精抛工序快速过渡。提出的大型环抛机抛光蜡盘平面度监测装置实现了对湿滑胶体平面的高精度、快速测量,为环抛的确定性抛光工艺提供了重要的技术支持。     

介电泳效应磨粒流抛光中的电极形态

针对薄壁陶瓷工件内表面抛光，提出一种基于介电泳效应的磨粒流抛光方法。将非均匀电场布置于陶瓷工件外表面，极化磨粒，实现陶瓷工件内表面高效抛光。仿真分析发现:电极间隙比为2时，SiC磨粒具有最好的介电泳效应，参与抛光的磨粒最多。陶瓷工件初始内表面粗糙度值Ra为(208±5)nm时，抛光10 h后，无介电泳效应的磨粒流抛光工件内表面粗糙度值Ra为51 nm，有介电泳效应的磨粒流抛光工件内表面粗糙度值Ra为23 nm。     

小型非球面数控抛光技术的研究

用计算机控制抛光的方法对小型非球面数控抛光技术进行了研究。对计算机控制小磨头抛光的材料去除作用进行了计算机模拟;依据计算机模拟结果,调整驻留时间函数,进行抛光补偿;最后,在自行研制的三轴联动非球面数控抛光原理样机上高效地完成了70 mm左右非球面的抛光,各项指标达到了中等精度要求,表面粗糙度为2.687 nm,面形精度为0.45 μm,且重复精度良好。结果表明,该技术有效提高了小型非球面光学零件的批量生产效率。     

单片微机控制的激光扫描式热轧加工质量测控系统

开发了由单片微机控制的激光扫描式热轧加工质量测控系统 ,介绍了激光扫描测量原理以及测控系统的硬、软件设计。该系统可在恶劣工况条件下实现对热轧件外径尺寸的非接触式在线自动测量及加工质量监控。     

用于大尺寸工件的动态长度测量系统

针对移动大尺寸工件的表面形貌特点,利用二维激光三角法构造出水平和垂直虚拟测量基准面;结合多传感器融合准则,建立了一种新型的大尺寸工件测量模型,并利用该模型实现了移动工件两端端面到虚拟测量基准面的位移非接触测量。采用误差分离方法自修正理论误差和运动误差的影响;结合人机交互界面,研制了高精度、低成本的移动大尺寸工件长度自动检测系统。利用该系统对在(1 000±25)mm内以不同速度运动的圆柱体大尺寸工件长度进行检测,得到的检测分辨力为10μm、检测精度为100μm、工件移动速度为5cm/s。实际运行结果表明,该系统安全、稳定、快速,可满足工业在线生产中对同类型规则的大尺寸工件控制和检测的要求。     

接触式大型非球面镜面形测量中测量点分布的确定

为准确有效地检测大型非球面光学元件的面形,研究了接触式测量光学元件的测量点分布方式.使用不同密度的径向分布及均匀分布的测量点分别对以不同Zernike多项式表示的面形偏差进行采样,然后计算采样所得面形相对给定面形PV值及RMS值的最大相对误差,并对计算结果进行了分析.对1.8m抛物面镜面形实测结果表明:在镜面加工的成型及粗磨阶段,由于面形偏差主要呈旋转对称分布,低密度径向分布测量点即可满足继续加工的检测需求;在精磨及初抛阶段,面形偏差主要为像散或其它非对称面形偏差,测量点均匀分布是提升测量精度的有效手段.此分析方法可以指导测量点的排布方式,从而确保由测量点分布引入的测量误差小于镜面本身面形误差的1/5,提高检测效率.     

Optical,in situ,three-dimensional,absolute shape measurements in CNC metal working lathes

Temperature drifts, tool deterioration, unknown vibrations, as well as spindle play are major effects which decrease the achievable precision of CNC lathes and lead to shape deviations of the processed workpieces. Since currently no measurement system exists for precise, in situ, 3D shape monitoring, much effort is required to simulate and compensate these effects. In this article, we propose an optical measurement principle for first part quality manufacturing. The absolute shape, meaning the diameter and surface profile, of the workpiece is determined from its tangential velocity and the surface distance. In order to allow keyhole access, both measurands are determined simultaneously with a single sensor. Measurements inside a metal working lathe show that the standard uncertainty for the absolute shape measurement is below 1 μm. The measurement uncertainty is nearly independent of the lateral surface velocity and roughness. The in situ measurements are compared to measurements with a tactile coordinate measurement machine for reference.     

A swing arm method for profile measurement of large optical concave surfaces in the lapping process

Generally, optical components are fabricated by grinding, lapping, and polishing. Usually, these processes take a long time to obtain high surface quality. Therefore, in the case of large optical components, on-machine inspection (OMI) is essential, because the workpiece is fragile and difficult to set up for fabricating and measuring. This paper describes a swing arm method for measuring the surface profile of large optical concave mirrors. The measuring accuracy and uncertainty for the method are studied. Experimental results show that this method is especially useful in the lapping process, where an accuracy of 3–5 μm is obtained. Inspection data is also provided to correct the residual figuring error in lapping or polishing processes .     

基于准布儒斯特角法研究抛光过程中光学材料的表面质量

光学硬脆材料在机械加工过程中不可避免地形成表面/亚表面损伤,对器件性能、使用寿命等具有至关重要的影响。相较于磨削、研磨两种前道工艺,抛光阶段材料的损伤逐渐减少至极其微量的程度,而最终残留的损伤将伴随材料的使用全周期,研究抛光阶段表面质量的变化过程对掌握抛光的工艺质量十分必要,但测量难度高。针对这一问题,本文在总结抛光阶段损伤形式的基础上,首先仿真分析了准布儒斯特角法检测表面质量的原理和优势,随后以Nd∶GGG激光晶体为研究对象,利用椭偏仪对不同抛光工艺下样品表面质量的变化进行了实验研究。通过与白光干涉法测量的表面形貌进行对比,准布儒斯特角偏移量和相位角变化曲线斜率准确地反映了抛光过程中表面质量的变化,展现了该方法的无损伤和高灵敏度特性,以及辅助研究抛光工艺的可行性。最后,对准布儒斯特角法在表面质量检测方面面临的问题进行了分析和展望。