Melt spun aluminium alloys for moulding optics

Gubbels, G.; Tegelaers, L.; Senden, Roger

doi:10.1117/12.2030181

Cited by 5 publications

(3 citation statements)

References 2 publications

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“…Aluminium disc samples with a 47 mm diameter were made from the rapidly solidified aluminium alloy materials Al6061 and Al905 (RSP Technology) [24,25]. The diamondturned surfaces were cleaned with acetone prior to ion beam processing.…”

Section: Methodsmentioning

confidence: 99%

Reactive ion beam figuring of optical aluminium surfaces

Bauer

Frost

Arnold

2017

J. Phys. D: Appl. Phys.

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Ultra-smooth and arbitrarily shaped reflective optics are necessary for further progress in EUV/XUV lithography, x-ray and synchrotron technology. As one of the most important technological mirror optic materials, aluminium behaves in a rather difficult way in ultraprecision machining with such standard techniques as diamond-turning and subsequent ion beam figuring (IBF). In particular, in the latter, a strong surface roughening is obtained. Hence, up to now it has not been possible to attain the surface qualities required for UV or just visible spectral range applications. To overcome the limitations mainly caused by the aluminium alloy structural and compositional conditions, a reactive ion beam machining process using oxygen process gas is evaluated. To clarify the principle differences in the effect of oxygen gas contrary to oxygen ions on aluminium surface machining, we firstly focus on chemicalassisted ion beam etching (CAIBE) and reactive ion beam etching (RIBE) experiments in a phenomenological manner. Then, the optimum process route will be explored within a more quantitative analysis applying the concept of power spectral density (PSD) for a sophisticated treatment of the surface topography. Eventually, the surface composition is examined by means of dynamic secondary ion mass spectrometry (SIMS) suggesting a characteristic model scheme for the chemical modification of the aluminium surface during oxygen ion beam machining. Monte Carlo simulations were applied to achieve a more detailed process conception.

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Section: Methodsmentioning

confidence: 99%

Reactive ion beam figuring of optical aluminium surfaces

Bauer

Frost

Arnold

2017

J. Phys. D: Appl. Phys.

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“…The experiments were performed on aluminum planar disc samples with 47-mm in diameter made of RSA Al905 and RSA Al6061 (RSP technology). 21 The ion beam process parameter for IBP processes and direct aluminum machining are summarized in Table 2.…”

Section: Ion Beam Etching Parametersmentioning

confidence: 99%

Ion beam planarization of optical aluminum surfaces

Ulitschka

Bauer

Frost

et al. 2020

J. Astron. Telesc. Instrum. Syst.

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For fabrication of high-performance mirror devices, technical aluminum alloys Al6061 or Al905 are widely used. The surface error topography after manufacturing by singlepoint diamond turning is applicable in the infrared spectral range. For increasing demands on the optical surface quality in the shortwave visible and ultraviolet spectral range, further improvement of the surface roughness is required. Hence, a promising alternative process to attain the required surface quality is evaluated. Within the ion beam planarization technique, a photoresist layer is deposited by conventional spin coating or spray coating technologies exhibiting an ultrasmooth surface. When removing the resist by reactive ion beam etch (RIBE) processing using nitrogen process gas, the ultrasmooth surface topography of the resist is transferred into the substrate. We optimized the photoresist thermal pretreatment to realize roughness preservation and a steady-state material removal rate during RIBE machining. The optimum preparation steps are explored based on roughness evaluation, chemical modification, and etch resistance of the negative photoresist. Reactive ion beam etching-based planarization is conducted on single-point diamond turned RSA Al905 and RSA Al6061 samples made of rapidly solidified aluminum (RSA) in a two-step process. The optimum process and the roughness evaluation are explored by topographic analysis applying a combination of white light interferometry and atomic force microscopy measurements. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…For instance polymer injection moulding is used for production of small sized optical elements, such as micro-lenses used in smart phones and contact lenses, but also for large size optics as spectacle lenses and car-body panels. Gubbels et al [3] argued that in order to increase production yield it is important to minimize cycle time, decrease production steps and increase the mould tool life. It can be that said a number of factors need to be considered in order to achieve longer tool life; amongst those is the optimization of the mould material.…”

Section: Introductionmentioning

confidence: 99%

Diamond Insert Wear when Turning Rapidly Solidified Aluminium RSA 443 of High-Silicon Content

Mkoko

Abou-El-Hossein

2015

MSF

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Rapid solidification of molten metals has been recently used to generate a new group of alloys having ultra-fine microstructures and high end mechanical properties. Therefore, such alloys can be successfully used in the optics industry to produce diamond machined mirrors and mould inserts for plastic lens injection. Rapidly solidified aluminium grades characterised by their ultra-fine grains can be used to replace traditional optical aluminium such as 6061-T6 which has coarse microstructure when making optics. However, there is currently no data available on the performance of these new grades in terms of diamond tool wear when machined in single-point diamond turning operation. This paper reports on the wear mechanisms of natural diamond tools when turning RSA 443 which is a new aluminium grade produced by rapid cooling process. Although this new aluminium grade enjoys fine microstructure, it is harder than traditional optical aluminium because of its increased content of silicon (about 40%). Therefore, there is a need to establish a deeper understanding of diamond tool performance when using diamond turning of optical components from this material. In this study, three machining parameters, namely cutting speed, feed rate, and depth of cut, were varied at three levels and the edge wear of the diamond inserts was observed using scanning electron microscopy after 4 km of cutting distance. The first observations from this preliminary study show that tool wear of diamond is more sensitive to the change in cutting speed than it is for other cutting parameters. Wear is relatively high (12 µm) at the lowest cutting speed (500 rpm). However, at high cutting speed (3000 rpm) the edge wear was small (3 µm). This could be attributed to the increased impacts of cut the material on the cutting edge. The study also reports on the surface finish obtained at the different combinations of cutting parameters.

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Melt spun aluminium alloys for moulding optics

Cited by 5 publications

References 2 publications

Reactive ion beam figuring of optical aluminium surfaces

Reactive ion beam figuring of optical aluminium surfaces

Ion beam planarization of optical aluminum surfaces

Diamond Insert Wear when Turning Rapidly Solidified Aluminium RSA 443 of High-Silicon Content

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