A5072616705- Advanced Surface Polishing Techniques
- Advanced Measurement and Metrology Techniques
- Adaptive optics and wavefront sensing
- Advanced machining processes and optimization
- Astronomy and Astrophysical Research
- Optical measurement and interference techniques
- Laser Material Processing Techniques
- Optical Systems and Laser Technology
- Stellar, planetary, and galactic studies
- Surface Roughness and Optical Measurements
- Advanced optical system design
- Medieval Literature and History
- Manufacturing Process and Optimization
- History and Developments in Astronomy
- Astronomical Observations and Instrumentation
- Diamond and Carbon-based Materials Research
- Historical Studies of British Isles
- Atmospheric Ozone and Climate
- Scottish History and National Identity
- Superconducting and THz Device Technology
- Astrophysics and Star Formation Studies
- Space Satellite Systems and Control
- Cardiac, Anesthesia and Surgical Outcomes
- American Constitutional Law and Politics
- CCD and CMOS Imaging Sensors
University of Huddersfield
2016-2024
Sci-Tech Daresbury
2019-2024
Canadian Medical Protective Association
2023
Harbin Institute of Technology
2023
LightMachinery (Canada)
2023
Energy Sciences Network
2022
Albany Law School
2021
The Princess Grace Hospital
2021
University College London
2011-2020
Informa Healthcare
2020
The PrecessionsTM process has been developed for the control of texture ('polishing'), preservation form during polishing, and ('figuring'), on flat, spherical aspheric surfaces. In this first introductory paper, we summarize need aspherics, review some technologies, then distill a 'wish-list' attributes an process. Within context, focus special properties Precessions tools, their use in family 7-axis CNC polishing machines, present experimental results.
In this paper we first contrast classical and CNC polishing techniques in regard to the repetitiveness of machine motions. We then present a pseudo-random tool path for use with sub-aperture report results from equivalent random raster tool-paths. The tool-path used - unicursal employs seed generate pattern which never crosses itself. Because property, is directly compatible dwell time maps corrective polishing. can be polish any continuous area boundary shape, including surfaces interior...
Segment-edges for extremely large telescopes are critical observations requiring high contrast and SNR, e.g. detecting exo-planets. In parallel, industrial requirements edge-control emerging in several applications. This paper reports on a new approach, where edges controlled throughout polishing of the entire surface part, which has been pre-machined to its final external dimensions. The method deploys compliant bonnets delivering influence functions variable diameter, complemented by small...
Edge mis-figure is regarded as one of the most difficult technical issues for manufacturing segments extremely large telescopes, which can dominate key aspects performance. A novel edge-control technique has been developed, based on 'Precessions' polishing and accurate stable edge tool influence functions (TIFs) are crucial. In first paper in this series [D. Walker Opt. Express 20, 19787-19798 (2012)], multiple parameters were experimentally optimized using an extended set experiments. The...
Abstract Several recent business reports have described the global growth in demand for optical and photonic components, paralleled by technical on growing shortage of skilled manufacturing staff to meet this demand. It is remarkable that producing ultraprecision surfaces remains so dependent people, contrast other sectors economy, e.g., car manufacturing. Clearly, training can play some role, but ultimately, only process automation provide solution. This paper explores why a challenge...
We report on the development of a novel industrial process, embodied in new robotic polishing machine, for automatically grinding an aspheric optics. The machine is targeted at meeting growing demand inexpensive axially symmetric but aspherical lenses and mirrors industry science, non-axisymmetric conformal optics many kinds, planarization silicon wafers associated devices, controlling form texture other artifacts including prosthetic joints. describe both physics implementation process. It...
The Precessions process polishes complex surfaces from the ground state preserving ground-in form, and subsequently rectifies measured form errors. Our first paper introduced technology focused on novel tooling. In this we describe unique CNC machine tools how they operate in polishing correcting form. Experimental results demonstrate both '2D' '2(1/2)D' form-correction modes, as applied to aspheres with rotationally-symmetric target-form.
We present a simulation technique to predict tool influence functions (TIFs) based on the Precessions polishing process, which is driven by addressing mass fabrication of European Extremely Large Telescope mirror segments. requires accurate and predictable TIFs optimize multiple process parameters, particularly when sequential runs are performed different tools. In this paper, static dynamic simulated Preston equation. The velocity distribution calculated according geometry precession...
The Ultra-High-Resolution Facility (UHRF) has been commissioned at the coudé focus of Anglo-Australian Telescope (AAT), and provides a resolving power R≈106. This is highest spectral resolution ever obtained by an optical astronomical spectrograph, intended mainly for astrophysical studies cool interstellar clouds. paper describes development this ambitious project, which includes diffraction-limited components, very tight specification configuration, new type image slicer allows...
In recent years, Fluid Jet Polishing (FJP) has been studied for its potential as a finishing method on optical lenses, mirrors and molds number of materials, such glass nickel. this paper, the surface integrity binderless tungsten carbide after polishing by FJP was experimentally. Two aspects in particular were focused on: (1) identifying process conditions under which grain boundaries may dislocate (thus leading to unintentional loss grains from substrate) (2) identify abrasive particles...
Precise calorimetric reconstruction of 5-50 MeV electrons in liquid argon time projection chambers (LArTPCs) will enable the study astrophysical neutrinos DUNE and could enhance physics reach oscillation analyses. Liquid scintillation light has potential to improve energy for low-energy over charge-based measurements alone. Here we demonstrate light-augmented calorimetry a single-phase LArTPC using sample Michel from decays stopping cosmic muons LArIAT experiment at Fermilab. electron...
We report on progress developing the Precession Process, that has recently been embodied for first time in a fully-productionised aspheric polishing machine. describe how process uses inflated tools of continuously-variable size and hardness. Despite rapid tool rotation needed to give high removal rates, method produce well-behaved near-Gaussian influence functions, by virtue precession spin axis. then form errors are controlled. The takes influence-function data an error map as input,...
The optical design and performance of the UCLES echelle spectrograph, installed at f/37.7 coude focus 3.9-m AAT in June 1988, are described illustrated with extensive diagrams, drawings, photographs, sample spectra. operates 300-1100 nm resolution 30,000-115,000 adjustable collimated beam size; it employs either 31.6-g/mm or 79-g/mm gratings a train UV-transmitting fused-silica prisms for cross-dispersion. Also discussed focal modifier lenses; Bowen-Walraven image slicer; commissioning...
Development of major optical projects demands great amounts freeform optics, which requires mass-production technology. The atmospheric pressure plasma processing (APPP) based on chemical etching shows the advantage high efficiency in form generation. However, surface texture gets deteriorated with roughness to 60 nm Ra. Bonnet polishing can achieve ultra-smooth using flexible inflated tool. In this study, a combined chain consisting APPP and bonnet was proposed, plays role generation rapid...
We summarize the reasons why aspheric surfaces, including non-rotationally-symmetric are increasingly important to ground and space-based astronomical instruments, yet challenging produce. mainly consider generic problem of producing aspheres, then lightweight segments for primary mirror an Extremely Large Telescope. remark on tension between manufacturability spherical segments, performance with segments. This provides context our presentation novel <i>Precessions</i> process rapid...
This paper describes progress on the development of a new process for producing precision surfaces optics industry, and potentially other sectors including silicon wafer fabrication lapping polishing mechanical surfaces. The marks an important milestone in program, with completion construction first fully-productionized machine results from commissioning process.
We first consider the potential impact of a technology that could deliver polished, accurate aspheric surfaces in routine and automated manner. then summarise technical challenge, present an appraisal performance novel 'Precessions' process, which is major advance this direction. outline design concepts behind productionized CNC polishing machines executes describe progress developing strategies to preserve form when ground surfaces, correct on both pre-ground polished surfaces. Particular...
We present a novel method to accurately measure 3D polishing influence functions by using swing arm profilometer (SAP) and laser tracker. The tracker is used align the SAP parameters of setup before measuring function. instruments measurement are described, together with uncertainty analysis. An function deliberately produced asymmetric form in order create challenging test measured, compared that commercial profilometer. result 48.2 microm PV, 7.271 mm(3) volume. 48.4 7.289 forms two...
The Extremely Large Telescope (ELT) projects presuppose segmented primary mirrors. metrology of the off-axis aspherical segments is particularly challenging in terms global form, mid spatial frequencies and matching base-radius conic constant. We propose to use a swing arm profilometer (SAP) provide verification independent interferometry. In this paper we present results simulation as applied mirror segments, experimental using prototype instrument.
BoX™ grinding technology has been adopted in our E-ELT segment process. The mid-spatial frequency features generated can be removed by several ‘smoothing’ processes. We have reported here a novel method that smooth these whilst avoiding edge down-turn. This process scaled up to fabrication time-scale. It experimentally demonstrated the surface quality is good enough for subsequent Zeeko form correction achieve specifications.