F: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenF: Elektrotechnik und MedientechnikF: Maschinenbau und MechatronikI: Hochschulleitung und -einrichtungenZeitschriftenartikel
Markus Schinhärl, Andreas Geiss, Rolf Rascher, Peter Sperber, R. Stamp, L. Smith, G. Smith, Elmar Pitschke
Coherences between influence function size, polishing quality and process time in the magnetorheological finishing
Current Developments in Lens Design and Optical Engineering VII, vol. 6288
2006
DOI: 10.1117/12.678720
Abstract anzeigen
Magnetorheological finishing (MRF) is a computer controlled polishing process (CCP), which is commonly used in the field of high quality optical lens production. The process uses the material removal characteristic of the polishing tool (influence function) and the surface error-profile to calculate individual, surface error-profile dependent polishing sequences. At the University of Applied Sciences Deggendorf a testing series with a magnetorheological finishing machine has been performed, and effects of the influence function size and its removal capacity on the polishing quality and the process time have been investigated. The result of the research shows that the influence function size has a major effect on the process time, whereas the polishing quality is nearly independent of the influence function size. During the testing series the process time was significantly reduced using an appropriate influence function size. The process time decreased about 9% relating to the original influence function.
F: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenF: Elektrotechnik und MedientechnikF: Maschinenbau und MechatronikI: Hochschulleitung und -einrichtungenZeitschriftenartikel
Andreas Geiss, Markus Schinhärl, Elmar Pitschke, Rolf Rascher, Peter Sperber, J. Slabeycius
Sedimentations on high-precision surfaces of advanced materials by magnetorheological finishing
Current Developments in Lens Design and Optical Engineering VII, vol. 6288
2006
Abstract anzeigen
Magnetorheological finishing (MRF) is a computer controlled polishing (CCP) technique for high precision surfaces. The process uses a magnetorheological fluid which stiffens in a magnetic field and thus acts as the polishing tool. A standard MR fluid consists of magnetic carbonyl iron (CI) particles, nonmagnetic polishing abrasives and liquid. To delaying oxidation of the iron particles and avoiding agglomeration the liquid consists of water completed with stabilizers. For the material removal and smoothing of the surface mostly cerium oxide or diamond is used. The materials to be polished may tend toward to different sedimentations of the MR fluid on the machined surface. These sedimentations result from the machining and may develop a polishing layer with MR fluid components. At the University of Applied Sciences Deggendorf analysis of the machined surface are made by the scanning electronic microscope (SEM) to determine the sedimentations of the finishing. The results of the research display the influence for the surface properties due to developing polishing layer by magnetorheological finishing.
F: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenF: Elektrotechnik und MedientechnikF: Maschinenbau und MechatronikI: Hochschulleitung und -einrichtungenZeitschriftenartikel
Elmar Pitschke, Markus Schinhärl, Peter Sperber, Rolf Rascher, R. Stamp, M. Smith, L. Smith
Correlation between influence- function quality and predictability of a computer-controlled polishing process
Optical Engineering, vol. 45, no. 6
2006
DOI: 10.1117/1.2213630
Abstract anzeigen
A mathematical method has been developed to analyze influence functions that are used in a computer-controlled polishing process. The influence function itself is usually generated by some kind of calibration where the exact procedure is dependent on the process used. The method is able to determine asymmetries in an influence function. Application of this method yields a value that may be used to judge the quality of an influence function. That quality is also an indicator of the variance of the evolving surface error profile, since a close relationship between it and the polishing process exists. On the basis of an ideal, theoretical process, a model to handle and quantify the result of a real polishing process is described. Practical application of this model demonstrates the effect of influence-function quality on the polishing result. Based on this model, the predictability of the polishing result is evaluated. This initiative to judge influence functions by their quality is an important contribution to the development of computer-controlled polishing. Due to improved process reliability, the reject rate will decrease, and the result will be more economic manufacture.
F: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenF: Elektrotechnik und MedientechnikF: Maschinenbau und MechatronikI: Hochschulleitung und -einrichtungenVortrag
Markus Schinhärl, Elmar Pitschke, Andreas Geiss, Rolf Rascher, Peter Sperber, R. Stamp, L. Smith, G. Smith
New viscosity measurement for magnetorheological polishing fluid
Optical Manufacturing and Testing VI, San Diego, CA, USA
2005
F: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenF: Elektrotechnik und MedientechnikF: Maschinenbau und MechatronikI: Hochschulleitung und -einrichtungenVortrag
Elmar Pitschke, Markus Schinhärl, Andreas Geiss, Peter Sperber, Rolf Rascher, R. Stamp, L. Smith, M. Smith
A new approach to predict computer-controlled polishing results
Optical Manufacturing and Testing VI, San Diego, CA, USA
2005
Abstract anzeigen
A novel approach to handle and quantify a computer controlled polishing process will be introduced. This approach will be compared to real data. This comparison indicates the correctness of this approach. Based on it a formula has been developed to predict the results of a computer controlled polishing process. The formula will be used to predict real polishing processes and the results will be compared to the real results. The limits when using this formula will be shown along with suggestions when the formula would be useful. This rough prediction of the computer controlled polishing results may be used to enhance the automation of a computer controlled polishing process. Also a way to improve the formula itself will be introduced. It is the opinion of the author that by further stabilizing of the whole computer controlled polishing process the whole system becomes more robust, the prediction more accurate and the whole system improves in reliability and the results become better.
F: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenF: Elektrotechnik und MedientechnikF: Maschinenbau und MechatronikI: Hochschulleitung und -einrichtungenZeitschriftenartikel
Markus Schinhärl, Elmar Pitschke, Andreas Geiss, Rolf Rascher, Peter Sperber, R. Stamp, L. Smith, G. Smith
Comparison of different magnetorheological polishing fluids
Optical Fabrication, Testing, and Metrology II, vol. 5965, pp. 659-670
2005
DOI: 10.1117/12.656430
Abstract anzeigen
Magnetorheological Finishing (MRF) is commonly used to finish high quality optical surfaces. The process is based on a magnetorheological fluid, which stiffens in a magnetic field and thus may be used as a polishing tool. The fluid removal characteristic depends on several parameters, for example the magnetic field strength or the relative velocity between workpiece and polishing tool. Another parameter is the fluid itself. Different compositions of polishing abrasives result in different removal characteristics. At the University of Applied Sciences Deggendorf, five different magnetorheological polishing fluids have been analysed. The results of the research are scanning electron microscope analyses as well as spectra analyses. The removal characteristic for each fluid has been determined for different glass materials. Finally, the fluid conditions during polishing have been analysed. For this purpose, the fluid flow rate, the fluid pressure and the fluid viscosity have been investigated.
F: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenF: Elektrotechnik und MedientechnikF: Maschinenbau und MechatronikI: Hochschulleitung und -einrichtungenZeitschriftenartikel
Markus Schinhärl, Elmar Pitschke, Andreas Geiss, Rolf Rascher, Peter Sperber, R. Stamp, L. Smith, G. Smith
New viscosity measurement for magnetorheological polishing fluid
Optical Manufacturing and Testing VI, vol. 5869, pp. 133-141
2005
DOI: 10.1117/12.616690
Abstract anzeigen
In Magnetorheological Finishing (MRF) a magnetic field is applied to a stream of abrasive magnetorheological fluid, in order that the fluid behaves as the polishing tool. The process may be used to finish the surface of high quality optical lenses. The fluid viscosity is one important parameter the polishing tool characteristic depends on. At the University of Applied Sciences Deggendorf a new viscosity measurement, which uses the inductance of the fluid had been tested. The result of the research is a close relationship between viscosity and inductance. The new viscosity measurement is not an absolute, but a comparative system, based on inductance of the flowing fluid and the fluid age.
F: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenF: Elektrotechnik und MedientechnikF: Maschinenbau und MechatronikI: Hochschulleitung und -einrichtungenZeitschriftenartikel
Andreas Geiss, Markus Schinhärl, Elmar Pitschke, Rolf Rascher, Peter Sperber
Analysis of thermal sources in a magnetorheological finishing (MRF) process
Optical Manufacturing and Testing VI, vol. 5869, pp. 111-120
2005
DOI: 10.1117/12.616751
Abstract anzeigen
Magnetorheological finishing (MRF) is a computer controlled polishing (CCP) technique for high quality surfaces. The process uses a magnetorheological fluid which stiffens in a magnetic field and thus acts as the polishing tool. At the University of Applied Sciences Deggendorf thermal sources in a MRF polishing unit have been analysed using an infrared camera. The result of the research is a warming of the fluid in the fluid conditioner caused by the mixer motor. The existing cooling is therefore essential, in order to ensure a constant polishing tool characteristic during polishing runs. A new fluid conditioner, which was developed at the University of Applied Sciences Deggendorf, with the aim of an extended fluid lifetime may be used without cooling, because an increase of the fluid temperature in the conditioner could not been detected. Furthermore, a warming of the workpiece during the polishing process was not ascertainable.
F: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenF: Elektrotechnik und MedientechnikF: Maschinenbau und MechatronikI: Hochschulleitung und -einrichtungenZeitschriftenartikel
Elmar Pitschke, Markus Schinhärl, Andreas Geiss, Peter Sperber, Rolf Rascher, R. Stamp, L. Smith, M. Smith
A new approach to predict computer-controlled polishing results
Optical Manufacturing and Testing VI, vol. 5869, pp. 94-102
2005
DOI: 10.1117/12.616780
Abstract anzeigen
A novel approach to handle and quantify a computer controlled polishing process will be introduced. This approach will be compared to real data. This comparison indicates the correctness of this approach. Based on it a formula has been developed to predict the results of a computer controlled polishing process. The formula will be used to predict real polishing processes and the results will be compared to the real results. The limits when using this formula will be shown along with suggestions when the formula would be useful. This rough prediction of the computer controlled polishing results may be used to enhance the automation of a computer controlled polishing process. Also a way to improve the formula itself will be introduced. It is the opinion of the author that by further stabilizing of the whole computer controlled polishing process the whole system becomes more robust, the prediction more accurate and the whole system improves in reliability and the results become better.
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