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Suche nach „[E.] [Willenborg]“ hat 2 Publikationen gefunden
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    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Beitrag (Sammelband oder Tagungsband)

    Christian J. Trum, M. Jung, Beate Schmidbauer, Sebastian Sitzberger, E. Willenborg, Rolf Rascher

    Hybrid-process-chain for polishing optical glass lenses – HyoptO

    Proceedings of SPIE Optical Engineering + Applications (24 August - 04 September, 20208; Optical Manufacturing and Testing XIII; online conference), San Diego, United States, vol. 11487

    2020

    DOI: 10.1117/12.2568400

    Abstract anzeigen

    A number of process steps that build on one another are required to manufacture optical components from glass. The polishing steps are the most time-consuming and therefore cost-intensive parts of the process chain. Low removal rates and the depth of the Sub Surface Damage (SSD) to be removed contribute to this. An alternative for the complete removal of the SSD-penetrated material using contactless polishing methods such as Ion Beam Figuring (IBF) is the healing of the SSD. Due to the induced energy during laser-polishing, the material is remelted at the defects and the SSD are closed. However, laser-polishing is also associated with disadvantages in terms of shape accuracy and surface quality. The project HyoptO is therefore devoted to the development of a hybrid-process-chain consisting of laser processing and conventional polishing. It is expected that the healing times of the SSD can significantly reduce the process times in the subsequent polishing steps. However, there are a few questions to be answered regarding the economic use of the hybrid-process-chain. These include:

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Beitrag (Sammelband oder Tagungsband)

    M. Jung, Christian J. Trum, Beate Schmidbauer, E. Willenborg, Rolf Rascher

    Non-ablative removal of sub surface damages in ground optical glass substrates by controlled melting of thin surface layers using CO2-laser radiation

    Proceedings of SPIE 11478 (Seventh European Seminar on Precision Optics Manufacturing [8 July 2020; Teisnach]), Bellingham, WA, USA

    2020

    DOI: 10.1117/12.2564801

    Abstract anzeigen

    The form generation of optical surfaces by grinding and mechanical polishing results in small sub surface damages in the form of micro cracks that conventionally have to be removed by further removal of the damaged surface layers. In order to reduce process time and material cost non-ablative methods for removal of micro cracks are desired. Utilising the low optical penetration depths of less than 10 μm for CO2-laser radiation in glass, the laser energy can be used to heat up and melt thin surface layers. Using a 1.5 kW CO2-laser, a quasi-line focus formed by a scanner unit and a constant feed speed, it is possible to close all micro cracks present in the rough grinded test surfaces (max. SSD-depth ~ 63 μm), while achieving a process time of less than 2 seconds for a Ø 30 mm N-BK7 lens, respectively 7.5 seconds for fused silica. With a Sa as low as 50 nm and low distortion from the original shape the surfaces can directly be conventionally polished, further reducing the process chain complexity.