Magnetorheological finishing of large and lightweight optics

Shorey, Aric; Kordonski, William; Tricard, Marc

doi:10.1117/12.559814

Cited by 44 publications

(24 citation statements)

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“…The lightweight design of the 100 mm diameter SiC mirror is shown in Figure 25. Figure 23a shows all the fi gure error, while Figure 23b has the low-order error removed to emphasize the quilt structure [13,14]. The fi gure error was signifi cantly improved from 796 nm PV (212 nm rms) to 64 nm PV (7.6 nm rms) as shown in Figure 26.…”

Section: Mrf Of Lightweight Structures -Cvd Silicon Carbide (Sic)mentioning

confidence: 88%

Subaperture approaches for asphere polishing and metrology

2005

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This paper summarizes some of QED Technologies' latest developments in the fi eld of high-precision polishing and metrology.Magneto-Rheological Finishing (MRF) is a deterministic sub-aperture polishing process that overcomes many of the fundamental limitations of traditional fi nishing. MRF has demonstrated the ability to produce optical surfaces with accuracies better than 30 nm peak-to-valley (PV) and surface micro-roughness less than 0.5 nm rms on a wide variety of optical glasses, single crystals, and glass-ceramics. The MR fl uid forms a polishing tool that is perfectly conformal and therefore can polish a variety of shapes, including fl ats, spheres, aspheres, prisms, and cylinders, with either round or rectangular apertures.QED's Sub-aperture Stitching Interferometer (SSI) complements MRF by extending the effective aperture, accuracy, resolution, and dynamic range of a phase-shifting interferometer. This workstation performs automated sub-aperture stitching measurements of spheres, fl ats, and mild aspheres. It combines a six-axis precision stage system, a commercial Fizeau interferometer, and specially developed software that automates measurement design, data acquisition, and the reconstruction of the full-aperture map of fi gure error. Aside from the correction of sub-aperture placement errors (such as tilts, optical power, and registration effects), our software also accounts for reference-wave error, distortion, and other aberrations in the interferometer's imaging optics. By addressing these matters up front, we avoid limitations encountered in earlier stitching work and signifi cantly boost reproducibility beyond that of the integrated interferometer on its own.

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Section: Mrf Of Lightweight Structures -Cvd Silicon Carbide (Sic)mentioning

confidence: 88%

Subaperture approaches for asphere polishing and metrology

2005

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“…Sometimes, hydrodynamic pressure is applied to improve the material removal rate. Various research and platforms in the area of MR finishing have been reported [136][137][138][139][140][141][142][143].…”

Section: Article In Pressmentioning

confidence: 99%

The use of active materials for machining processes: A review

Park

Bement

Hartman

et al. 2007

International Journal of Machine Tools and Manufacture

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“…Compared with the traditional computer numerically controlled polishing techniques, MRF has some significant advantages such as extremely high precision, high convergence rates and less surface defects and it is capable of polishing many kinds of optics efficiently at a low cost. Nowdays MRF is known as a revolutionary technology [3][4][5][6][7] .…”

Section: Introductionmentioning

confidence: 99%

Research on the magnetorheological finishing (MRF) technology with dual polishing heads

Huang

Zhang

et al. 2014

SPIE Proceedings

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Magnetorheological finishing (MRF) is a key polishing technique capable of rapidly converging to the required surface figure. Due to the deficiency of general one-polishing-head MRF technology, a dual polishing heads MRF technology was studied and a dual polishing heads MRF machine with 8 axes was developed. The machine has the ability to manufacture large aperture optics with high figure accuracy. The large polishing head is suitable for polishing large aperture optics, controlling large spatial length's wave structures, correcting low-medium frequency errors with high removal rates. While the small polishing head has more advantages in manufacturing small aperture optics, controlling small spatial wavelength's wave structures, correcting mid-high frequency and removing nanoscale materials. Material removal characteristic and figure correction ability for each of large and small polishing head was studied. Each of two polishing heads respectively acquired stable and valid polishing removal function and ultra-precision flat sample. After a single polishing iteration using small polishing head, the figure error in 45mm diameter of a 50 mm diameter plano optics was significantly improved from 0.21λ to 0.08λ by PV (RMS 0.053λ to 0.015λ). After three polishing iterations using large polishing head , the figure error in 410mm×410mm of a 430mm×430mm large plano optics was significantly improved from 0.40λ to 0.10λ by PV (RMS 0.068λ to 0.013λ) .This results show that the dual polishing heads MRF machine not only have good material removal stability, but also excellent figure correction capability.

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Magnetorheological finishing of large and lightweight optics

Cited by 44 publications

References 0 publications

Subaperture approaches for asphere polishing and metrology

Subaperture approaches for asphere polishing and metrology

The use of active materials for machining processes: A review

Research on the magnetorheological finishing (MRF) technology with dual polishing heads

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