InformaApp - Publikationen

Investigations on Magnetorheological Finishing of High-Quality Optical Surfaces with Varying Influence Function (Proceedings of Optical Fabrication and Testing 2010; Jackson Hole, WY, USA; June 13-17, 2010)

Optical Fabrication and Testing on CD-ROM, Washington, DC, USA

2010

DOI: 10.1364/OFT.2010.OWD3

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen Hochschulleitung und -einrichtungen Maschinenbau und Mechatronik

Beitrag (Sammelband oder Tagungsband)

Christian Vogt, Markus Schinhärl, Rolf Rascher, Peter Sperber, Florian Schneider

Relationship between influence function accuracy and polishing quality in magnetorheological finishing

Proceedings of the 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies (Dalian, China; April 26-29, 1010), vol. 7655

2010

DOI: 10.1117/12.865508

Abstract anzeigen

Magnetorheological finishing is a typical commercial application of a computer-controlled polishing process in the manufacturing of precision optical surfaces. Precise knowledge of the material removal characteristic of the polishing tool (influence function) is essential for controlling the material removal on the workpiece surface by the dwell time method. Results from the testing series with magnetorheological finishing have shown that a deviation of only 5% between the actual material removal characteristic of the polishing tool and that represented by the influence function caused a considerable reduction in the polishing quality. The paper discusses reasons for inaccuracies in the influence function and the effects on the polishing quality. The generic results of this research serve for the development of improved polishing strategies, and may be used in alternative applications of computer-controlled polishing processes that quantify the material removal characteristic by influence functions.

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen Hochschulleitung und -einrichtungen Maschinenbau und Mechatronik

Beitrag (Sammelband oder Tagungsband)

Christian Vogt, Markus Schinhärl, Roland Maurer, Rolf Rascher, R. Stamp, Peter Sperber, G. Smith, Florian Schneider

Effects of mechanical inaccuracies on the measurement result in metrology systems

Proceedings of the 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, vol. 7656

2010

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen Maschinenbau und Mechatronik

Vortrag

Markus Schinhärl, Rolf Rascher

Relationship between influence function accuracy and polishing quality in magnetorheological finishing

5th SPIE International Symposium on Advanced Optical Manufacturing and Testing Technologies, Dalian, China

2010

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen Hochschulleitung und -einrichtungen Maschinenbau und Mechatronik

Vortrag

Christian Vogt, Markus Schinhärl, Roland Maurer, Rolf Rascher, R. Stamp, Peter Sperber, G. Smith, Florian Schneider

Strategies for grinding optical free-forms using ball-shaped grinding wheels

SPIE Optifab, Rochester, NY, USA

2009

Abstract anzeigen

The demand for non-spherical surfaces and free-forms is steadily growing. Aspherical lenses can reduce the number of necessary lenses in optical systems e.g. used for lithographic devices for production of microprocessors. Parabolic mirrors can be used to focus light beams highly efficiently because of low absorption rates without colour distortion. Combined optical devices with included mechanical functions for assembly reduce necessary production steps. The most common pre-machining method for small numbers of high-precision lenses and mirrors is grinding. Depending on the required shape there are different options for generating surfaces e. g. spheres, parabolic mirrors or combined forms. The most flexible ones are grinding with (i) workpiece and ball-shaped tool rotating and (ii) fixed workpiece with ball-shaped tool rotating. In this manuscript grinding strategies dealing with meander and spiral tool paths are investigated in order to define which strategy works best for machining off-axis parabolic mirrors.

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen Hochschulleitung und -einrichtungen Maschinenbau und Mechatronik

Vortrag

K. Fathima, Christian Vogt, Andreas Geiss, Markus Schinhärl, Rolf Rascher, Christian Schopf, Peter Sperber

Ultraschallunterstütztes Schleifen von Linsen

Siebtes Symposium - Zukunft Glas - von der Tradition zum High-Tech-Produkt, Zwiesel

2008

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen Hochschulleitung und -einrichtungen Maschinenbau und Mechatronik

Vortrag

K. Fathima, Christian Vogt, Andreas Geiss, Markus Schinhärl, Rolf Rascher, Christian Schopf, Peter Sperber

Precision finishing of aspherical optical components using ELID grinding

Siebtes Symposium - Zukunft Glas - von der Tradition zum High-Tech-Produkt, Zwiesel

2008

Maschinenbau und Mechatronik

Vortrag

Markus Schinhärl

Schneller und genauer - Optimale Polierstrategie durch variable Abtragsfunktion

BayTech Optik Seminar, Deggendorf

2008

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen Hochschulleitung und -einrichtungen Maschinenbau und Mechatronik

Beitrag (Sammelband oder Tagungsband)

K. Fathima, Christian Vogt, Andreas Geiss, Markus Schinhärl, Rolf Rascher, Christian Schopf, Peter Sperber

Ultraschallunterstütztes Schleifen von Linsen

Siebtes Symposium - Zukunft Glas - von der Tradition zum High-Tech-Produkt

2008

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen Hochschulleitung und -einrichtungen Maschinenbau und Mechatronik

Beitrag (Sammelband oder Tagungsband)

K. Fathima, Christian Vogt, Andreas Geiss, Markus Schinhärl, Rolf Rascher, Christian Schopf, Peter Sperber

Precision finishing of aspherical optical components using ELID grinding

Siebtes Symposium - Zukunft Glas - von der Tradition zum High-Tech-Produkt

2008

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen Elektrotechnik und Medientechnik Hochschulleitung und -einrichtungen Maschinenbau und Mechatronik

Zeitschriftenartikel

Andreas Geiss, Markus Schinhärl, Rolf Rascher, R. Stamp, Peter Sperber, Elmar Pitschke, L. Smith, G. Smith

Advanced techniques for computer-controlled polishing

Current Developments in Lens Design and Optical Engineering IX, vol. 7060, no. 70600Q ff.

2008

DOI: 10.1117/12.808036

Abstract anzeigen

Computer-controlled polishing has introduced determinism into the finishing of high-quality surfaces, for example those used as optical interfaces. Computer-controlled polishing may overcome many of the disadvantages of traditional polishing techniques. The polishing procedure is computed in terms of the surface error-profile and the material removal characteristic of the polishing tool, the influence function. Determinism and predictability not only enable more economical manufacture but also facilitate considerably increased processing accuracy. However, there are several disadvantages that serve to limit the capabilities of computer-controlled polishing, many of these are considered to be issues associated with determination of the influence function. Magnetorheological finishing has been investigated and various new techniques and approaches that dramatically enhance the potential as well as the economics of computer-controlled polishing have been developed and verified experimentally. Recent developments and advancements in computer-controlled polishing are discussed. The generic results of this research may be used in a wide variety of alternative applications in which controlled material removal is employed to achieve a desired surface specification, ranging from surface treatment processes in technical disciplines, to manipulation of biological surface textures in medical technologies.

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen Hochschulleitung und -einrichtungen Maschinenbau und Mechatronik

Beitrag (Sammelband oder Tagungsband)

Christian Vogt, Andreas Geiss, Markus Schinhärl, Rolf Rascher, R. Stamp, Peter Sperber, L. Smith, G. Smith

Forces acting between polishing tool and workpiece surface in magnetorheological finishing

Proceedings of SPIE, Volume 7060, Current Developments in Lens Design and Optical Engineering IX (Optical Engineering + Applications, San Diego, CA, USA; August 10-14, 2008)

2008

DOI: 10.1117/12.794196

Abstract anzeigen

Magnetorheological finishing is a computer-controlled polishing technique that is used mainly in the field of high-quality optical lens production. The process is based on the use of a magnetorheological polishing fluid that is able, in a reversible manner, to change its viscosity from a liquid state to a solid state under the control of a magnetic field. This outstanding characteristic facilitates rapid control (in milliseconds) of the yield stress, and thus the pressure applied to the workpiece surface to be polished. A three-axis dynamometer was used to measure the forces acting between the magnetorheological fluid and the workpiece surface during determination of the material removal characteristic of the polishing tool (influence function). The results of a testing series using a QED Q22-X MRF polishing machine with a 50 mm wheel assembly show that the normal forces range from about 2 to 20 N. Knowledge of the forces is essential, especially when thin workpieces are to be polished and distortion becomes significant. This paper discusses, and gives examples of, the variation in the parameters experienced during a programme of experiments, and provides examples of the value of this work.

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen Hochschulleitung und -einrichtungen Maschinenbau und Mechatronik

Zeitschriftenartikel

K. Fathima, Andreas Geiss, J. Slabeycius, Markus Schinhärl, Rolf Rascher, Peter Sperber

Material removal study at silicon nitride molds for the precision glass molding using MRF process

Current Developments in Lens Design and Optical Engineering IX, vol. 7060, no. August

2008

DOI: 10.1117/12.794583

Abstract anzeigen

High-technology applications which are using high precision optic components in high and medium quantities have increased during recent years. One possibility to mass-produce e.g. such lenses is the precision glass molding (PGM) process. Especially for aspheric and free-form elements the PGM process has certain advantages. Premise is to manufacture accurate press molds, which have to feature smaller figure errors as the required lenses and may be made of materials, which are difficult to machine, like silicon nitride ceramics. These work pieces have to be machined in economical and steady process chains. However, due to the complex shapes and the corresponding accuracy an error dependent polishing is required. The Magnetorheological Finishing (MRF) as a high precision computer controlled polishing (CCP) technique is used and will further be presented in this work. To achieve the postulated demands a previous study of the material removal at selected machining parameters is needed. Changing machining parameters modify the removal, which is presented through values like the peak and volume removal rate. The value changes during the controlled variation of process parameters are described and discussed. Magnetorheological Finishing (MRF) provides one of the best methods to finish PGM molds that are relatively inaccurate to high precision in an economical, steady and efficient way. This work indicates the MRF removal selection and removal interference for the correction and finishing of precise silicon nitride molds for the precision glass molding.

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen Hochschulleitung und -einrichtungen Maschinenbau und Mechatronik

Beitrag (Sammelband oder Tagungsband)

K. Fathima, Andreas Geiss, J. Slabeycius, Markus Schinhärl, Rolf Rascher, Peter Sperber

Material influence of silicon nitride at Magnetorheological Finishing (MRF)

Proceedings of the 12th International Research/Expert Conference ”Trends in the Development of Machinery and Associated Technology” TMT 2008, Istanbul, Türkei, 26.-30.08.2008

2008

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen Hochschulleitung und -einrichtungen Maschinenbau und Mechatronik

Beitrag (Sammelband oder Tagungsband)

K. Fathima, L. Hajduchova, Andreas Geiss, J. Slabeycius, Markus Schinhärl, Rolf Rascher, Peter Sperber

Examination of surface and subsurface damages on silicon wafers using dimple polishing

Proceedings of the 13th International Conference on Problems of Material Engineering, Mechanics and Design, Rajeke, Slowakei, 26.-29.08.2008

2008

Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen Hochschulleitung und -einrichtungen Maschinenbau und Mechatronik

Beitrag (Sammelband oder Tagungsband)

K. Fathima, Christian Vogt, Andreas Geiss, J. Slabeycius, Markus Schinhärl, Rolf Rascher, Peter Sperber

Magnetorheological Finishing of silicon nitride moulds

Proceedings of the 10th Anniversary International Conference of the European Society of Precision Engineering and Nanotechnology, Zürich, Schweiz, Volume 2

2008

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