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Suche nach „[Rolf] [Rascher]“ hat 205 Publikationen gefunden
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    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Beitrag (Sammelband oder Tagungsband)

    Michael Benisch, O. Fähnle, Rolf Rascher

    Observation of pressure distribution between tool and surface in different polishing situations

    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: 10.1117/12.2567885

    Abstract anzeigen

    Pressure is a relevant parameter in the polishing of components according to the Preston equation.1, 2 Preliminary investigations have shown that the pressure can vary with inclined position and different polishing pads. It is not constant with regard to its distribution in the contact area between polishing pad and glass surface. In this publication, the pressure distribution during the polishing of glass components is analyzed. For the measurement of the pressure distribution a pressure sensitive foil is used.

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Beitrag (Sammelband oder Tagungsband)

    Michael Benisch, Christian Vogt, Rolf Rascher, O. Fähnle

    Octopus: A simple and effective tool for polishing slurry monitoring

    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: 10.1117/12.2567952

    Abstract anzeigen

    The present paper shows a way for a cost-effective, integrated measurement of the density p of polishing suspensions. It is based on the principle of measuring the turbidity of a solution on the basis of the light transmitted through it, and of calculating back to the density on the basis of the turbidity. The tool is suitable for monitoring polishing agents and for detecting when the density of the polishing slurry leaves the permissible parameter space and can perspectively enable the automated monitoring and adjustment of polishing suspensions. The tool is named after an Octopus. These animals have amazing abilities, for example they can copy the behaviour of other sea animals or act with a plan. Their tentacles each have their own brain and can perform biochemical analyses.

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Beitrag (Sammelband oder Tagungsband)

    Michael Benisch, O. Fähnle, Rolf Rascher

    Application of a pressure measuring film for pressure observation in overarm polishing

    Proceedings of EOSAM 2020 (European Optical Society Biennial Meeting; 7-11 September 2020; online), vol. 238

    2020

    DOI: 10.1051/epjconf/202023803003

    Abstract anzeigen

    In previous publications the inhomogeneous pressure transfer through the polishing tool onto a glass surface could be shown. This experiment shows polishing trials with different polishing materials and the differences in the homogeneity of the pressure transfer through them. Only the properties of the material will be discussed explicitly, the change of the tool constitution through the process will be part of further publications.

    DigitalNachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Beitrag (Sammelband oder Tagungsband)

    Simon Killinger, Johannes Liebl, Rolf Rascher

    Interferometric measurement with robot kinematics

    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: 10.1117/12.2568348

    Abstract anzeigen

    Polishing precision optics is highly depending on the operator. Hence, a good result relies on a skilled optician who controls the process chain. This process chain consists of different manual steps such as loading, cleaning and calibrating different machines. To get more control over the process and to speed up the production we currently build an operator independent polishing cell using a single robot. Therefore, we positioned the robot in the middle of the production cell, which enables the robot to reach and manipulate different tools located around the kinematic. One major issues is the lower positioning accuracy and stiffness of an industrial robot in comparison to standard optic machines. Probably the most challenging step concerning accuracy in precision optics manufacturing is the interferometric measurement. In this paper, we present a method using an ESDI Intellium H2000 interferometer, designed for use in unsteady conditions. The robot positions the surface under test without the use of any additional mechanics to enhance the accuracy. The measurement position was manually teached in and approached several times for a statistically significant evaluation. The results show that the robot is sufficiently accurate and stable to perform interferometric measurements. This is a key element towards a completely operator-independent manufacturing cell for precision optics.

    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)

    Simon Killinger, Johannes Liebl, Rolf Rascher

    First steps towards an automated polishing process chain using one robot

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

    2020

    DOI: 10.1117/12.2564840

    Abstract anzeigen

    Manufacturing precision optics is a complex process chain, which requires many operations on different machines. This is combined with operator-dependent steps such as manual cleaning, loading and measuring. In order to realize this process chain on a smaller shop area and to achieve a higher level of automation we build an operator-independent polishing cell. In this cell, an ABB robot serves as the actuator handling the workpiece. We positioned the robot in the center of the polishing cell to operate several workstations, so the whole process chain works with one single actuator. This arrangement allows a smaller and cheaper system, since no additional handling is required.

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Beitrag (Sammelband oder Tagungsband)

    Michael Benisch, O. Fähnle, Rolf Rascher, Werner Bogner

    Force and pressure analysis during overarm polishing

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

    2020

    DOI: 10.1117/12.2564903

    Abstract anzeigen

    The Preston-equation implies, that, besides the relative speed υrel and a specific constant KP, the pressure p plays a significant role for the removal rate when polishing an optical component. This paper demonstrates a possibility for a qualitative evaluation of the pressure distribution before the polishing process. A pressure-sensitive foil is used as a gauge for pressure measurement. The effectiveness of this measuring method is explained. Specific weaknesses and limitations in the use of these foils are discussed. A method for an integrated evaluation of the pressure on different spots of the polishing pad is proposed at the end of the paper.

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Beitrag (Sammelband oder Tagungsband)

    M. Pohl, R. Börret, Olga Kukso, Rolf Rascher

    Mid spatial frequency error prevention strategies for the grinding process

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

    2020

    DOI: 10.1117/12.2565261

    Abstract anzeigen

    This research is focused on the link between manufacturing parameters and the resulting mid-spatial frequency error in the manufacturing process of precision optics. The goal is to understand the generation mechanisms of mid-spatial frequency errors and avoid their appearance in the manufacturing process. Also, a simulation which is able to predict the resulting mid spatial frequency error from a manufacturing process is desired.

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Beitrag (Sammelband oder Tagungsband)

    Olga Kukso, Rolf Rascher, M. Pohl, R. Börret

    On the metrology and analysis of MSF error

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

    2020

    DOI: 10.1117/12.2566251

    Abstract anzeigen

    The aim of our research was to study middle spatial frequency errors (MSFE) on optical surfaces. We investigate the surfaces after manufacturing processes to find out the main affecting factors and to choose the proper processing parameters to minimize the size of the errors. To find an appropriate parameter window we have to be able not only to define the factors, which lead to MSFE, but also to analyze the change of the error after next following production steps.

    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.

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Beitrag (Sammelband oder Tagungsband)

    Sebastian Sitzberger, Johannes Liebl, Christian J. Trum, Rolf Rascher

    Concept of a two-part clamping system for lenses in optical metrology

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

    2020

    DOI: 10.1117/12.2566547

    Abstract anzeigen

    The developed concept represents a universally applicable clamping system designed to fit in any measuring machine with any measuring principle. The design ensures that, as long as the lens remains clamped, the measurement results are reproducible. Form errors due to tension remain constant across all measuring and processing steps. The version presented in this paper was developed especially for small lenses in the diameter range up to 40 mm. On the one hand, the design allows for fast measurement of loose lenses. On the other hand, the device can also be used for measurement comparisons, since lenses can also be mounted permanently. In the following, the concept and first results of measurement tests are presented.

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Beitrag (Sammelband oder Tagungsband)

    Armin Reif, Sebastian Sitzberger, Rolf Rascher

    Cutting high-performance materials with ultrasonically modulated cutting speed

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

    2020

    DOI: 10.1117/12.2565757

    Abstract anzeigen

    The continuing trend towards lightweight construction and the associated machining rates of up to 95 % lead to an increased use of high-performance materials. The ever growing demands on the strength and quality of components and the associated use of materials which are hard to machine require the further development of new, economical machining techniques. In ultrasonic-assisted machining, an additional high-frequency vibration is superimposed on the conventional machining process. The vibration of the tool is usually excited axially or longitudinally to the workpiece, i.e. vertical to the cutting direction. An additional vibration overlay around the rotation axis (torsional) of the tool is also possible. This generates a vibration overlay in the cutting direction. The vibration initiation causes vibration amplitudes in the range of a few micrometers at the tool cutting edge. This leads in turn to a high-frequency change in the cutting speed or feed rate. Overall, an additional torsional vibration overlap can further reduce cutting forces, increase tool life and improve workpiece quality. In order for a grinding tool to generate a torsional vibration, a special tool was required that had to be designed by simulation. The formation of a torsional vibration was achieved by helical slots in the sonotrode. Depending on the angle of rotation and the length of the slots, a part of the axial vibration is converted into a torsional vibration by an axial excitation of the sonotrode. The aim in designing the slots was to achieve the highest possible vibration amplitude. Following the simulation, the slots were inserted into the tool in the corresponding optimum geometric position. Afterwards, the specially designed grinding tool was validated by machining the brittle-hard glass-ceramic material Zerodur. The first test results with the torsionally vibrating tool are presented in the following.

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Zeitschriftenartikel

    Armin Reif, P. Rinck, Sebastian Sitzberger, Rolf Rascher, M. Zäh

    Zerspanung von Hochleistungswerkstoffen mit ultrasonisch modulierter Schnittgeschwindigkeit

    ZWF - Zeitschrift für wirtschaftlichen Fabrikbetrieb, vol. 115, no. 3, pp. 2-5

    2020

    DOI: 10.3139/104.112255

    Abstract anzeigen

    Die steigenden Anforderungen an die Festigkeit und die Qualität von Bauteilen und die damit verbundene Verwendung hochfester Materialien erfordert die Weiterentwicklung neuer wirtschaftlicher Zerspanungstechniken. Durch eine werkzeugseitige Schwingungsüberlagerung können bei der Bearbeitung von schwer zerspanbaren Werkstoffen die Zerspankräfte und der Werkzeugverschleiß reduziert sowie die Oberflächenqualität verbessert werden.

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Vortrag

    Simon Killinger, Alexander Haberl, Rolf Rascher

    Analysis of residual errors during computer controlled polishing

    EOS Optical Technologies: Conference on Manufacturing, Tolerancing and Testing of Optical Systems (MOS) – Session 7: Plenary Session, München

    2019

    Abstract anzeigen

    In computer controlled subapertur polishing the formation of mid spatial frequency errors (MSFE) needs special attention. In this work the formation of MSFE in feed direction is investigated using the ADAPT tool from Satisloh.

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Vortrag

    Sebastian Sitzberger, P. Rinck, A. Gueray, Rolf Rascher

    Ultraschallunterstützte Zerspanung von Advanced Materials

    3. Wissenschaftliches Forum zur ULTRASONIC-Bearbeitung, Jena

    2019

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Vortrag

    Sebastian Sitzberger, J. Reitberger, Rolf Rascher

    Clamping system for optical components for adaptation in optical production

    10th HLEM 2019 - High Level Expert Meeting Asphere Metrology on Joint Investigations, Braunschweig

    2019

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Beitrag (Sammelband oder Tagungsband)

    Michael Benisch, Werner Bogner, Rolf Rascher

    Using A Digital Temperature Sensor To Measure The Temperature Development During A Polishing Process

    Proceedings of the 2019 EOS Optical Technologies Conference

    2019

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Beitrag (Sammelband oder Tagungsband)

    M. Pohl, U. Bielke, R. Börret, Rolf Rascher, Olga Kukso

    MSF-error prevention strategies for the grinding process

    Proceedings of SPIE 11171 (Sixth European Seminar on Precision Optics Manufacturing, 1117101 [9-10 April 2019, Teisnach]), Bellingham, WA, USA

    2019

    DOI: 10.1117/12.2526581

    Abstract anzeigen

    This research is focused on the link between manufacturing parameters and the resulting mid-spatial frequency error in the manufacturing process of precision optics. This third publication focuses on strategies of avoidance and generation mechanisms of the mid-spatial frequency errors from the grinding process. The Goal is to understand the generation mechanisms of the mid-spatial frequency errors and avoid their appearance in the manufacturing process.

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Beitrag (Sammelband oder Tagungsband)

    Sebastian Sitzberger, Johannes Liebl, J. Reitberger, Rolf Rascher

    Zero-point clamping systems in optical production

    Proceedings of SPIE 11171 (Sixth European Seminar on Precision Optics Manufacturing, 1117101 [9-10 April 2019, Teisnach]), Bellingham, WA, USA

    2019

    DOI: 10.1117/12.2528774

    Abstract anzeigen

    Zero point clamping systems are an integral part of the manufacturing industry. They have only yet to find their way into the optical industry. This article compares the hydraulic expansion holder, a clamping system currently used in the optical industry with a zero-point clamping system. The achievable accuracies of both systems are compared over several measurement series. In addition, the process capability evaluation is used for the comparison. Finally, the results are summarized to provide every researcher and practitioner with a foundation for assessing whether zero point clamping systems meet the requirements for the use in optical manufacturing.

    NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach

    Beitrag (Sammelband oder Tagungsband)

    Simon Killinger, Johannes Liebl, Rolf Rascher

    Mid-spatial frequency errors in feed direction occurring in ADAPT polishing

    Proceedings of SPIE 11171 (Sixth European Seminar on Precision Optics Manufacturing, 1117101 [9-10 April 2019, Teisnach]), Bellingham, WA, USA

    2019

    DOI: 10.1117/12.2528114

    Abstract anzeigen

    Previous work shows the effectiveness of computer controlled polishing (CCP) with the ADAPT tool by Satisloh for correcting form errors in optics manufacturing. This method however has a risk of producing residual errors in the range of mid spatial frequency errors (MSFE). In order to prevent these errors the residual in feed direction is investigated as well as the behavior at different parameters.