光学玻璃的新式抛光法

<正> 一、前言光学玻璃(照相机透镜、棱镜等)的精磨工序,目前基本上已不采用散粒磨料,而采用固着磨料即金刚石精磨片。从而显著缩短了加工时间并改善了工作环境。与此同时在最后的抛光工序中,也试图采用固着磨料。也就是说,试图把氧化铈、氧化锆等用树脂固着起来进行抛光,以代替原来所用的氧化铈、氧化锆等抛光液和泡沫聚氨酯、沥青等抛光模。这种利用固着磨料的新式抛光法,有助于将来实现透镜加工自动化。本文将介绍利用本公司研制的抛光圆片(商品名为Serpet,音译为砂别脱)进行玻璃抛光实验的一些结果。     

光学玻璃研抛用磁流变液的研究

利用智能材料之一的磁流变液 (MRfluids)作为加工工具对光学玻璃进行了精密抛光加工。讨论了适用于光学玻璃抛光的磁流变液的配制机理及磁流变液对光学玻璃抛光效果的影响因素。针对光学玻璃磁流变的抛光原理和特点 ,开发配制了适合于光学玻璃加工用的磁流变液 ,并用该磁流变液对光学玻璃进行了实验加工。结果表明 ,最终得到的光学玻璃表面经过AFM测试 ,得到Ra =1 0 1 5nm。     

金刚石精磨片

<正> 一、引言光学玻璃的精磨,几十年来一直采用散粒磨料加工即所谓自由研磨。其加工效率较低,表面粗糙度也较差。如何提高精磨生产率及零件的表面质量,是国内外光学零件加工中的一个重要问题。采用金刚石精磨片(简称精磨片)对光学零件进行高速精磨的新工艺,在国外是     

光学玻璃加工破坏层研究及粗磨、精磨、抛光工序加工余量的合理匹配

本文通过用五种散粒磨料（碳化硅）、五种固着磨料（金刚石）对八大类常用光学玻璃进行加工，用扫瞄电子显微镜观察其表面形貌，用抛测法测出其破坏层深度，得出一系列破坏层的深度数值，从而找出破坏层与磨料之问的函数关系。以破坏层的绝对深度为依据，得出光学加工中精磨、抛光工序的加工余量的合理匹配值。     

金刚石精磨过程的机理

1 引言普通的光学玻璃零件的表面加工工艺过程包括三个工序:即粗磨、精磨和抛光。最初,由散粒磨料来完成粗磨和精磨两个工序,到四十年代,用金属结合的金刚石磨轮为工具的铣磨机代替了散粒磨料的粗磨,但是,直到六十年代,用金属结合的金刚石工具还没有代替精磨工序中的散粒磨料。金刚石工具作为特殊的应用用于光学零件的精     

围压条件下空化磨料射流的冲蚀特性与机制分析

 磨料射流在水利水电、石油工程和海洋资源开发等领域有着广泛的应用,研究射流的冲蚀特性和破坏物料机制对提高水射流利用效率具有重要意义。利用自行研制的实验装置,研究了围压条件下自振空化、文丘里和锥形3种喷嘴形成的磨料射流冲蚀特性,分析了空化磨料射流冲蚀物料的机制。结果表明：自振空化喷嘴和文丘里喷嘴的冲蚀效果优于锥形喷嘴,空化作用有助于提高磨料射流的冲蚀效果;磨料射流的冲蚀效率随围压的增大而降低,主要原因是围压对纯水射流和空化磨料射流的压力脉动和冲击力具有抑制作用。分析认为,空化磨料射流冲蚀破碎物料的机制主要包括冲蚀、气蚀和共混磨蚀3 种作用。     

ZK、ZF、ZBaF、LaK光学玻璃的腐蚀与防护

ＺＫ、ＺＦ、ＺＢａＦ、ＬａＫ等光学玻璃在抛光过程中及抛光下盘以后的腐蚀问题,长期以来一直影响着这些光学玻璃零件的加工质量和生产效率。通过对光学玻璃在抛光过程中稳定性课题的研究和生产实验,研制并筛选出比较理想的光学玻璃抛光添加剂;即在这些化学稳定性差的光学玻璃抛光液中,添加适当的ｐＨ值调节剂及表面稳定剂,减少了ＺＫ、ＺＦ、ＺＢａＦ、ＬａＫ等系列化学稳定性差的光学玻璃在抛光过程中的腐蚀问题,显著提高了抛光表面质量和合格率,并进一步提高了光学玻璃零件加工的效率和效益及其工艺技术水平     

第十章 光学介质

10.1 光学玻璃光学玻璃是光学系统中最常用的介质材科,相对来讲,容易制造和加工,并可熔炼成具有相当高的光学特性和机械特性,其中许多特性在通常条件下很稳定。光学玻璃可制成直径达一米的透镜(在某些情况下可达四米),制作反射镜时直径可以更大。     

前混合磨料射流切割聚变堆第一壁钨材料研究

针对聚变堆第一壁钨材料的加工问题,开展前混合磨料射流切割钨试验,研究切面表面形貌,分析射流压力和切割速度对切面粗糙度、切面光滑区深度的影响.结果表明:切割速度对粗糙度影响较大,减小切割速度可以降低切面粗糙度;射流压力对粗糙度影响略小,提高射流压力可以增加切面光滑区深度,改善切面质量.试验发现切面存在拖尾纹、残余楔角和冲...     

基于散粒磨料振动抛光非球面加工技术研究

鉴于非球面光学元件的应用日益广泛,非球面加工技术成为研究热点,提出一种基于散粒磨料振动抛光非球面的加工方法。非球面元件待抛光表面与磨粒均匀接触,通过振动抛光装置为游离磨粒提供抛光作用力,使材料去除均匀,降低表面粗糙度。以材料为ZK-10L、尺寸为Φ55 mm的光学元件为实验对象,分析了振动幅度、抛光液浓度、磨粒粒径和抛光时间对抛光效果的影响,当振动幅度为5 mm、抛光液浓度为80 g/L、磨粒粒径为1 mm时,振动抛光8 h后试件的表面粗糙度从84.4 nm降低到9.4 nm,而试件的面形精度基本不变,从而在保证面形的前提下达到抛光的目的。     

Free upper-disk rotational speed under loose abrasive grinding in conventional machines

Equations representing stable upper-disk rotational speed under loose abrasive grinding processes of flat optical elements, using conventional machines, are introduced. Solution was reached via two interpolations on a wide set of experimental data. Experimental upper-disk rotational speeds were interpolated by means of a power function on six enhanced variables. Enhanced variables are combinations of physical variables that interconnect independent machine and upper-disk three-dimensional experimental spaces. The exponents found were subsequently least-squares interpolated in upper-disk and machine experimental spaces. This process was performed twice to provide two perspectives on loose abrasive wear: one where machine variables lead both interpolations and upper-disk variables to play a secondary role through enhanced variables. On the second representation, disk and machine variables interchange roles.     

Relative velocity and loose abrasive wear in conventional grinding machines

A model to compute relative velocity for arbitrary tool-work point pairs in conventional grinding machines is presented. This model is based on experimental data collected by means of an electronic system to measure kinematics variables in real time. Exact machine kinematics equations and an approximate equation representing upper disk rotational speed as a function of machine operation regime are introduced. With these equations, it became possible to calculate relative velocity among arbitrary tool-work point pairs. As a consequence, the amount of wear produced on optical elements, applying Preston's or Kumanin's abrasive wear equations, can be calculated.     

An optional explanation for nickel sites of nickel-zinc phosphate glasses by their optical spectra and EPR g factor

In this paper, the nickel site, optical spectra and electron paramagnetic resonance (EPR) g factor of nickel-zinc phosphate glasses have been studied by ligand-field theory. The orbital mixing effect between p and d orbits has been included in the calculation by two-spin-orbit parameter model. The present study shows that nickel occupies the tetrahedral zinc site with cubic symmetry in nickel-zinc phosphate glasses. Unlike the result of previous study that assigns nickel to an octahedral interstitial site, it is an optional explanation for nickel sites in nickel-zinc phosphate glasses by analysing the optical absorption spectra and EPR g factor.     

Subsurface damage of Nd-doped phosphate glasses in optical fabrication

We present a destructive method for detecting and measuring subsurface damage of Nd-doped phosphate glasses. An instrument based on the dimple method - a destructive method - was developed. Subsurface damage depth produced in each fabrication procedure was obtained. We extend the surface roughness-subsurface damage relation to Nd-doped phosphate glasses. The constant ratio of subsurface damage and surface roughness was obtained as well. We also analyse the relation of abrasive size and subsurface damage experimentally. From a measurement of the surface roughness or abrasive size, one can obtain an accurate estimate of the damage layer thickness that must be eliminated by polishing or subsequent grinding operations.     

抛光对光纤连接器回波损耗的影响

分别选用氧化铝和氧化硅材料的抛光砂纸,在施加不同抛光压力、抛光时间,以及抛光助剂等工艺条件下,实验研究了抛光对连接器回波损耗的影响规律。通过实验发现:氧化铝砂纸干式抛光使光纤连接器的回波损耗仅保持在32～38dB之间;氧化硅砂纸干式抛光会造成光纤端面污损,使得连接器的回波损耗降低到20dB以下;氧化铝与氧化硅砂纸湿式抛光均可使光纤连接器的回波损耗提高到45～50dB,但氧化铝砂纸湿式抛光会造成80nm以上的光纤凹陷。因此,制作高回波损耗的光纤连接器应优先选用氧化硅砂纸湿式抛光工艺,抛光时间应控制在20～30s。     

塑性加工条件下射流颗粒冲击去除效应

针对在微观上存在尖锐突起、凹坑和划痕等缺陷的光学元件,提出用低质量分数磨料水射流冲击的方式对其进行处理。从弹性接触出发,对射流中粒子与元件发生塑性接触的临界速度进行了推导,并引入了塑性转入脆性加要的临界速度,从而对射流的塑性去除阶段作了明确的界定。针对常用的两种光学材料K9和石英玻璃,结合具体参数对使其处于塑性去除阶段的射流速度进行了模拟计算,利用单颗粒冲击去除模型,在塑性去除范围内对两种材料的冲击去除进行了模拟计算。结果表明:石英玻璃进入塑性去除的临界速度高于K9玻璃,而进入脆性去除的临界速度低于K9玻璃,因而使石英玻璃处于塑性去除阶段的射流速度范围为K9玻璃相应速度范围的子区间;在塑性去除阶段,各材料的去除量皆随着冲击速度的增大而增大,但较硬的石英玻璃更不耐冲击,较K9玻璃更容易被去除。     

Optical band gap studies and estimation of two photon absorption coefficient in alkali bismuth borate glasses

The optical absorption spectra of the glasses with composition xBi₂O₃·(30???x)R₂O·70B₂O₃ (R?Li, Na, K) and xBi₂O₃·(70???x)B₂O₃·30Li₂O (0?≤?x?≤?20) have been recorded in the wavelength range 350–650?nm. The glass samples were prepared by the normal melt–quench technique. The fundamental absorption edge for all the series of glasses is analyzed using the theory of Davis and Mott. The position of absorption edges and the values of optical band gap are dependent on the mol% of Bi₂O₃. The absorption in these glasses is associated with indirect transitions. The values of Urbach's energy and band tailing parameters are reported. The two photon absorption coefficient, β, in these glasses has also been estimated from the optical band gap and its value ranges from 1.3 to 11.6?cm/GW. The relationship between β and glass composition has also been discussed in terms of the electronic structure of the glass system.     

Loose abrasive edge wear effects and final surface topography in conventional grinding machines

Applying Cordero-Davila's edge ring pressure increase to upper disk kinematics equations has led to excellent agreement between theoretical loose abrasive wear computer simulations and their experimental counterparts. Experiments to verify Cordero's ring equations over long grinding periods, up to 40 min, and their computer simulations are presented in detail. These experiments led to a new improved version of Kumanin's loose abrasive wear equation. Maximum wear rate and final topography errors, between theory and experiment, were slightly larger than instrumental uncertainty. Now it became possible to compute exact pressure, relative speed and wear, at any contacting point pair and over the entire upper free disk surface.     

Preparation of monodisperse polystyrene/silica core-shell nano-composite abrasive with controllable size and its chemical mechanical polishing performance on copper

Monodisperse silica-coated polystyrene (PS) nano-composite abrasives with controllable size were prepared via a two-step process. Monodisperse positively charged PS colloids were synthesized via polymerization of styrene by using a cationic initiator. In the subsequent coating process, silica formed shell on the surfaces of core PS particles via the ammonia-catalyzed hydrolysis and condensation of tetraethoxysilane. Neither centrifugation/water wash/redispersion cycle process nor surface modification or addition surfactant was needed in the whole process. The morphology of the abrasives was characterized by scanning electron microscope. Transmission electron microscope and energy dispersive X-ray analysis results indicated that silica layer was successfully coated onto the surfaces of PS particles. Composite abrasive has a core-shell structure and smooth surface. The chemical mechanical polishing performances of the composite abrasive and conventional colloidal silica abrasive on blanket copper wafers were investigated. The root mean square roughness decreases from 4.27 nm to 0.56 nm using composite abrasive. The PS/SiO₂ core-shell composite abrasives exhibited little higher material removal rate than silica abrasives.