Novel Mathematical Techniques for Advanced Tool-paths to Transform High-value Optical Fabrication

用于先进刀具路径的新颖数学技术，以改变高价值光学制造

• 批准号: ST/L001950/2
• 负责人: David Walker
• 金额: $ 6.31万
• 依托单位: University of Huddersfield
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FL001950%2F2
• 关键词: Novel; Mathematical; Techniques; Advanced; Tool

Precision lenses and mirrors are used for a host of applications - ground-based telescopes for astronomy, satellites looking up at space or down at the ground, machines to make semiconductor 'chips' (for computers to mobile phones...), defence systems, laser-systems and numerous other applications.The manufacture of precision optics is basically a two-stage process. First a glass blank is ground with a hard grinding wheel that cuts the material, to hog out the glass to the basic curved form. The glass is then polished using some form of pad that rubs the surface, using a water-slurry of a polishing compound - red rouge in the old days, white cerium oxide powder today. Over the last decade, the optics industry has experienced a revolution in computer numerical control (CNC) of both the grinding and polishing processes. The project involves two partner companies pre-eminent in both types of machine and processes. Zeeko Ltd (originally spun out of UCL research in this field) manufactures CNC polishing machines and measurement equipment. Cranfield Precision Ltd (a division of Cinetic Landis) produces CNC grinding machines. Such CNC machines almost always move the grinding or polishing tool across the surface in a standard back-and-forth raster pattern, or in a spiral path (by rotating the work-piece). A raster or spiral is a special case, because it crosses itself nowhere, and this simplifies calculating how the removal adds up. But, just like a tractor ploughing a field, these paths leave regular 'furrows' in the surface. Whilst these might be only nanometres deep (just tens of atoms) they cause stray light around an image in a telescope or camera. There are various ways of smoothing surfaces to remove these regular features, but this takes additional times. Moreover, each extra process leaves its own signature, which itself has to be removed ... in what sometimes seems like an endless circle!The new research will break out of this mould by using advanced mathematical methods to generate more complex tool-paths, which cross each other at myriads of points, and give a natural averaging effect. We call these 'hyper-crossing paths'. Furthermore, the polishing machines are able to change the polishing spot size 'on the fly'. In principle (and with the right mathematics) spot-size could be actively tuned to attack different sizes of surface-feature as the tool moves across a surface. We plan to develop this new idea, and are confident it will lead to a break-through in superior surfaces in less time.And what of the results? These will be incorporated in the standard software of the partner companies, enhancing their competitive position. The results will also be used on the machines at the National Facility for Ultra-precision Surfaces in North Wales, operated by Glyndwr University in partnership with University College London. This will give enhanced capability for manufacturing optics to support British Science and our overseas collaborators. Beyond this we plan to disseminate the findings to the wider UK academic and and manufacturing communities to collaborate on and develop applications and prototypes for applications in high precision surfaces outside of the optics sector e.g. medical - prosthetic joints.

精确镜头和镜子用于多种应用 - 地面望远镜用于天文学，仰望空间或地面上的卫星，用于制造半导体“芯片”的机器（用于计算机到移动电话...），防御系统，激光系统和许多其他应用程序。首先，玻璃空白是地面的，用坚硬的砂轮切割材料，将玻璃刺入基本弯曲形式。然后，使用某种形式的垫子将玻璃杯抛光，该垫子使用抛光化合物的水浸泡 - 在过去，红色胭脂，如今白色氧化葡萄粉。在过去的十年中，光学行业经历了磨削和抛光过程的计算机数值控制（CNC）的革命。该项目涉及两家合作伙伴公司在两种类型的机器和流程中均出名的公司。 Zeeko Ltd（最初是在该领域的UCL研究中脱颖而出）生产CNC抛光机和测量设备。 Cranfield Precision Ltd（Cinetic Landis的一个部门）生产CNC研磨机。这样的CNC机器几乎总是以标准的来回栅格模式或螺旋路径（通过旋转工作人员）将磨削或抛光工具跨越地表。栅格或螺旋是一种特殊情况，因为它无处可去，这简化了计算拆卸的方式。但是，就像拖拉机耕地一样，这些路径在表面上留下了常规的“犁沟”。虽然这些可能只是纳米深（仅数十个原子），但它们会在望远镜或相机中的图像周围引起流浪光。有多种平滑表面以删除这些常规功能的方法，但这需要更多时间。此外，每个额外的过程都会留下自己的签名，该签名本身必须被删除……有时似乎是无尽的圆圈！新的研究将通过使用先进的数学方法来产生更复杂的工具path，从而在无数的点上互相交叉，并产生自然的平均效果。我们称这些“超跨道路”。此外，抛光机能够“飞行”更改抛光点大小。原则上（以及正确的数学）点尺寸可以积极调整以攻击不同尺寸的表面特征，因为该工具在表面上移动。我们计划发展这个新想法，并有信心会在更少的时间内导致出色表面的突破，以及什么结果？这些将纳入合作伙伴公司的标准软件中，从而提高其竞争地位。该结果还将在由Glyndwr University与伦敦大学学院合作运营的国家北威尔士国家超精美表面的机器上使用。这将为支持英国科学和我们的海外合作者的制造光学元素提供增强的能力。除此之外，我们计划向更广泛的英国学术和制造社区传播发现，以在光学领域以外的高精度表面上的应用程序进行合作和开发应用程序和原型，例如医学 - 假体关节。

项目成果

Mid-spatial frequency removal on aluminum free-form mirror.

• DOI: 10.1364/oe.27.024885
• 发表时间: 2019-09
• 期刊: Optics express
• 影响因子: 3.8
• 作者: Hongyu Li;D. Walker;Xiao Zheng;Xing Su;Lunzhe Wu;Christina Reynolds;Guoyu Yu;Tony Li;Peng Zhang

Closing the metrology/process loop in CNC polishing

CNC 抛光中的计量/工艺闭环

• DOI: 10.1117/12.223553
• 发表时间: 2016
• 作者: Walker D.D.

Robotic automation in computer controlled polishing

• DOI: 10.2971/jeos.2016.16005
• 发表时间: 2016-01-01
• 期刊: JOURNAL OF THE EUROPEAN OPTICAL SOCIETY-RAPID PUBLICATIONS
• 影响因子: 1.5
• 作者: Walker, D. D.;Yu, G.;Zhang, P.
• 通讯作者: Zhang, P.

Process Automation in Computer Controlled Polishing

计算机控制抛光的过程自动化

• DOI: 10.4028/www.scientific.net/amr.1136.684
• 发表时间: 2016
• 期刊: Advanced Materials Research
• 作者: Walker D

Insight into aspheric misfit with hard tools: mapping the island of low mid-spatial frequencies

用硬工具洞察非球面失配：绘制低中空间频率岛

• DOI: 10.1364/ao.56.009925
• 发表时间: 2017
• 期刊: Applied Optics
• 影响因子: 1.9
• 作者: Walker D