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MOS4: Manufacturing of Optical Systems: Fabrication 3
8:30 - 10:00
Session Chair: Xue Jun Zhang, Changchun Institute of Optics, Fine Mechanics & Physics
Location:Room 21, 2nd floor, ICM MOS
8:30 - 8:45 Invited
Ultrasonic Assisted Diamond Machining of Micro-Structured Molds for Optical Applications
Fraunhofer IPT, Germany
8:45 - 9:00
Polishing shape correction of flat hardened steel samples
Rui Pedro Almeida1, Rainer Börret1, Mario Pohl1, David K. Harrison2, Anjali K.M. DeSilva2
1Aalen University, Germany; 2Glasgow Caledonian University, United Kingdom
This paper focuses on the controlled correction of the surface geometry of hardened steel samples. The aim of this work is to use a polishing correction technique to improve and correct the flatness. The described correction technique was tested with very challenging parameters and could still improve surface´s flatness by up to 75%.
9:00 - 9:15
Manufacturing high precision mild cylinders using classical stressed mirror polishing, MRF and SSI technologies
Bartosz Szterner1, Chris Maloney2, Paul Dumas2, Jean Pierre Lormeau2, Slawomir Gogler3
1Solaris Optics S.A. Company, Józefów, 05-410, Poland; 2QED Technologies International Inc., United States of America; 3Institute of Optoelectronics, Military University of Technology, Warsaw, 00-908, Poland
The process for long radius cylinder manufacturing for use as a telescope mirror is discussed. The process begins with stress mirror polishing (SMP) of a Zerodur flat to introduce the cylinder surface form. After the cylinder shape has been introduced by SMP, Magnetorheological Finishing (MRF) is used to correct the residual error from the SMP process to <65 nm PVr over the full aperture. Throughout the process, Subaperture Stitching Interferometry (SSI) is used to monitor the improvement and provide target maps for the MRF process. In this paper, the evolution of the sample preparation will be presented and we will show that by using this process, we can achieve results that are significantly better than the full aperture specification.
9:15 - 9:30
Setting-up high-end cnc grinding processes: a Preston-based approach
The design of grinding processes is commonly based on the principle of trial and error. In most cases this will end up with a usable setup that delivers acceptable results. On the other hand this method is unlikely to reveal the process's total potential. Allthough the principles of grinding and polishing are entirly different, the preston approach can be used to design grinding processes more intelligent and highly efficient.
Carrying out a testing procedure for grinding tools reveals the tool's removal properties on different materials. This allows to choose ideal sequences of pre and fine-grinding. Furthermore it is possible to choose the optimum machining parameters to optain a maximum output.
9:30 - 9:45
Influence of different coolants on ductile mode processing through ultra-sonic assisted diamond turning of tungsten carbide
Marius Doetz1, Olaf Dambon1, Fritz Klocke1, Oliver Faehnle2
1Fraunhofer Institute for Production Technology IPT, Germany; 2Fisba AG, Switzerland
One request for the optical machining of hart and brittle materials such as tungsten carbide is not to exceed the critical depth of cut characterized by the transition point from ductile to brittle material removal. Investigations have proved that the calculation by the widely used formula by Bifano shows insufficiently results.
This paper focusses in particular on the influence of different coolants while machining different types of tungsten carbide with monocrystalline diamond tools and ultra-sonic assistance. At this, basic ruling experiments with a steadily increasing depth of cut have been performed and analyzed by white light interferometry. As a result, a deeper understanding of the influence of coolant on the mechanical process of diamond machining is created.
9:45 - 10:00
Tolerancing Aspheres Based on Large Batch Size Manufacturing
Sven Kiontke, Ulrike Fuchs
asphericon GmbH, Germany
The use of aspheric surfaces in optical design offers many advantages concerning optical function,
weight and size reduction. Additionally, it was possible over the last years to establish high precision serial manufacturing of those lenses. Therefore, a considerable large amount of aspheres were produced in large batches of up to several thousand pieces. Due to the cause of manufacturing at asphericon, every single one of them was measured with respect to several different parameters. This huge database with an incredible amount of information was used to investigate the correlation between the given tolerance values and measured data sets. The resulting probability distributions of these measurement data sets were analyzed aiming for a robust optical tolerancing process.