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Beitrag in Sammelwerk/Tagungsband

  • Stefan Anthuber
  • Michael Benisch
  • Rolf Rascher

Industry 4.0 in the fabrication of optical components: development, presence, and requirements

pg. 118530D.

  • (2021)

DOI: 10.1117/12.2595037

Optics and photonics are considered as an enabling technology for innovations in other technological fields (e. g. astronomy, medicine, military, …). Their first applications date back to jewellery processing in ancient times. In the medieval age Vikings on Gotland (1050) buried the Visby lenses. They have a quality of workmanship and imaging comparable to a high quality lens made in the mid-20th century. The specific use of spectacles to correct long-sightedness or presbyopia is known from the 13th century. Around the transition from the 16th to the 17th century, the microscope and the telescope were invented, combining several lenses for the first time. This shows that the exploitation of the optical properties of materials can be dated back very early in human history. In particularly, today`s optics industry is still based on personal knowledge which results in a relatively workmanship production environment. The challenges of globalisation and the current pandemic situation demonstrate that increasing the degree of automation is a possible way to keep a leading position in the market. This is not only important due to the high quality of optical components but also by enabling competitive prices for production through reducing the labour costs. The third industrial revolution established the digitalisation of production and the usage of CNC-machinery. In most industries including optics industries this is the status quo of production. The target of industry 4.0 and internet of things is to lead into a new industrial revolution. The German government developed the buzzword “Industrie 4.0” (eng. Industry 4.01 ). This concept includes the contradiction of mass production and production according to individual customer requests. This should be carried out by connecting all production units with the goal of an intelligent factory. Among other things this includes seamless monitoring of the manufacturing processes along all steps and remote access to involved machines. A further target is manufacturing under the constraint of a small batch size down to one piece. This publication aims to present the current situation in the manufacturing of optical components and compare this with manufacturing of metallic components. It will outline, which measures are necessary to ensure a comprehensive transformation of the optical industry in accordance with the Industry 4.0 idea and which benefits can be expected.
  • TC Teisnach Optik
  • DIGITAL
Beitrag in Sammelwerk/Tagungsband

  • Olga Kukso
  • Michael Benisch
  • Rolf Rascher
  • S. Sundar
  • M. Hacker
  • M. Duschl
  • M. Nussbaum

Acoustic measurements for optics

pg. 118530K.

  • (2021)
The aim of the research was the development of a measurement and analysis method that enables the detection of errors and malfunctions within a machine tools and in the manufacturing process using acoustic sensors (microphones).
  • TC Teisnach Optik
  • DIGITAL
Beitrag in Sammelwerk/Tagungsband

  • Simon Killinger
  • Johannes Liebl
  • Rolf Rascher

Interferometric measurement with robot kinematics

pg. 114870I.

San Diego, United States

  • (2020)

DOI: 10.1117/12.2568348

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.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
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Beitrag in Sammelwerk/Tagungsband

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

Force and pressure analysis during overarm polishing

pg. 114780H.

Bellingham, WA, USA

  • (2020)

DOI: 10.1117/12.2564903

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.
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Vortrag

  • Christian J. Trum
  • M. Zäh
  • Rolf Rascher

Steigerung der Effizienz chemisch-mechanischer Polierprozesse durch eine systematische Auswahl und Anpassung von Poliersuspension und Poliermittelträger

In: 3. Ko-op Symposium

Graduate Center der Munich School of Engineering Garching

  • 26.11.2020 (2020)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Beitrag in Sammelwerk/Tagungsband

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

Mid spatial frequency error prevention strategies for the grinding process

pg. 114780E.

Bellingham, WA, USA

  • (2020)

DOI: 10.1117/12.2565261

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.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
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Zeitschriftenartikel

  • M. Pohl
  • Olga Kukso
  • R. Boerret
  • Rolf Rascher

Mid-spatial frequency error generation mechanisms and prevention strategies for the grinding process

In: Journal of the European Optical Society, Rapid Publications vol. 16

  • (2020)

DOI: 10.1186/s41476-020-00140-9

The research presented in this paper 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 developed and verified.
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Beitrag in Sammelwerk/Tagungsband

  • Michael Benisch
  • O. Fähnle
  • Rolf Rascher

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

pg. 1148704.

San Diego, United States

  • (2020)

DOI: 10.1117/12.2567885

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.
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel

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

Zerspanung von Hochleistungswerkstoffen mit ultrasonisch modulierter Schnittgeschwindigkeit

In: ZWF - Zeitschrift für wirtschaftlichen Fabrikbetrieb vol. 115 pg. 2-5.

  • (2020)

DOI: 10.3139/104.112255

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.
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Vortrag

  • Rolf Rascher

Produktion aus dem Home Office – Fiktion oder Zukunftsmodell

In: Hausmesse online

Firma Stock Konstruktion Online

  • 23.11.2020 (2020)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • DIGITAL
Beitrag in Sammelwerk/Tagungsband

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

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

pg. 114871L.

San Diego, United States

  • (2020)

DOI: 10.1117/12.2568400

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:
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Simon Killinger
  • Johannes Liebl
  • Rolf Rascher

First steps towards an automated polishing process chain using one robot

pg. 114780I.

Bellingham, WA, USA

  • (2020)

DOI: 10.1117/12.2564840

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.
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

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

Octopus: A simple and effective tool for polishing slurry monitoring

San Diego, United States

  • (2020)

DOI: 10.1117/12.2567952

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.
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Vortrag

  • M. Jung
  • Christian J. Trum
  • Rolf Rascher

Hybrid Process Chain for Polishing of Optics Made from Glass

In: LaP 2020 - 4th Conference on Laser Polishing

Fraunhofer-Institut für Lasertechnik (ILT) Aachen (video conference)

  • 16.09.2020 (2020)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
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Beitrag in Sammelwerk/Tagungsband

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

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

pg. 114780G.

Bellingham, WA, USA

  • (2020)

DOI: 10.1117/12.2566547

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.
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Michael Benisch
  • O. Fähnle
  • Rolf Rascher

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

  • (2020)

DOI: 10.1051/epjconf/202023803003

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.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
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Vortrag

  • Sebastian Sitzberger
  • M. Zäh
  • Rolf Rascher

Untersuchungen zu einer durchgängigen Werkstückaufnahme für die Herstellung von Hochpräzisionsoptiken

In: 3. Ko-op Symposium

Graduate Center der Munich School of Engineering Garching

  • 26.11.2020 (2020)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
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Beitrag in Sammelwerk/Tagungsband

  • Armin Reif
  • Sebastian Sitzberger
  • Rolf Rascher

Cutting high-performance materials with ultrasonically modulated cutting speed

Bellingham, WA, USA

  • (2020)

DOI: 10.1117/12.2565757

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.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
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Beitrag in Sammelwerk/Tagungsband

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

On the metrology and analysis of MSF error

pg. 1147809.

Bellingham, WA, USA

  • (2020)

DOI: 10.1117/12.2566251

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.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
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Beitrag in Sammelwerk/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

pg. 1147804.

Bellingham, WA, USA

  • (2020)

DOI: 10.1117/12.2564801

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.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
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Vortrag

  • Sebastian Sitzberger
  • Rolf Rascher
  • M. Zäh

Steigerung von Fertigungsgenauigkeit und -geschwindigkeit bei der Herstellung von Präzisionslinsen

In: 2. Ko-op Symposium

Graduate Center der Munich School of Engineering Garching

  • 28.11.2019 (2019)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

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

MSF-error prevention strategies for the grinding process

pg. 11171061-11171067.

Bellingham, WA, USA

  • (2019)

DOI: 10.1117/12.2526581

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.
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Vortrag

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

Ultraschallunterstützte Zerspanung von Advanced Materials

In: 3. Wissenschaftliches Forum zur ULTRASONIC-Bearbeitung

Jena

  • 23.05.2019 (2019)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Michael Benisch
  • Werner Bogner
  • Rolf Rascher

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

  • (2019)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Vortrag

  • Christian J. Trum
  • Rolf Rascher
  • M. Zäh

Steigerung der Effizienz chemisch-mechanischer Polierprozesse durch eine systematische Auswahl und Anpassung von Poliersuspension und Poliermittelträger

In: 2. Ko-op Symposium

Graduate Center der Munich School of Engineering Garching

  • 28.11.2019 (2019)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
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Vortrag

  • Simon Killinger
  • Alexander Haberl
  • Rolf Rascher

Analysis of residual errors during computer controlled polishing

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

World of Photonics Congress München

  • 24.-26.06.2019 (2019)
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.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
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Vortrag

  • Sebastian Sitzberger
  • J. Reitberger
  • Rolf Rascher

Clamping system for optical components for adaptation in optical production

In: 10th HLEM 2019 - High Level Expert Meeting Asphere Metrology on Joint Investigations

Physikalisch-Technische Bundesanstalt Braunschweig

  • 19.-20.03.2019 (2019)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
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Beitrag in Sammelwerk/Tagungsband

  • Simon Killinger
  • Johannes Liebl
  • Rolf Rascher

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

pg. 111710G1-111710G8.

Bellingham, WA, USA

  • (2019)

DOI: 10.1117/12.2528114

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.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
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Beitrag in Sammelwerk/Tagungsband

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

Zero-point clamping systems in optical production

pg. 111710J1-111710J10.

Bellingham, WA, USA

  • (2019)

DOI: 10.1117/12.2528774

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.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
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Beitrag in Sammelwerk/Tagungsband

  • O. Fähnle
  • O. Dambon
  • M. Doetz
  • F. Klocke
  • Christian Vogt
  • Rolf Rascher

Ductile grinding of tungsten carbide applying standard CNC machines: a process analysis

pg. 34.

  • (2018)

DOI: 10.1117/12.2315338

  • TC Teisnach Optik
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Vortrag

  • Alexander Haberl
  • H. Harsch
  • Gerald Fütterer
  • Johannes Liebl
  • C. Pruß
  • Rolf Rascher
  • W. Osten

Model based error separation of power spectral density artefacts in wavefront measurement

In: SPIE Optical Engineering + Applications Conference on Interferometry XIX

San Diego, CA, USA

  • 19.-23.08.2018 (2018)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Vortrag

  • Christian Vogt
  • O. Fähnle
  • E. Langenbach
  • Rolf Rascher

In situ laser monitoring of laser polishing

In: 119. Jahrestagung der Deutschen Gesellschaft für angewandte Optik (DGaO)

Technische Hochschule Aalen

  • 23.05.2018 (2018)
A novel fabrication parameter controlling method for laser polishing is presented, measuring within the footprint the smoothening process in real time. Recently, a new method for in situ measuring level of surface roughness has been developed [1] where a HeNe laser beam is being reflected from within the sample at the surface under test and the intensity of its reflected beam is being monitored.In this paper we report on an experimental study where this method has been applied to laser polishing. The internal local surface area under test is chosen to be located at the very spot where the laser polishing footprint is located from the outside of the sample melting its surface locally. Because fused silica is not transparent at the operating CO2 laser wavelength, the intensity of the reflected beam can be monitored enabling an in situ control of the laser polishing process. Consequently, the optimum dwell time can be determined, a footprint needs to stay at a certain point before moving further enabling a more stable and cost optimized polishing. [1] O.Fähnle,“In process monitoring of optics fabrication”, SPIEconference “PrecisionOptics Manufacturing”2017
  • TC Teisnach Optik
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Beitrag in Sammelwerk/Tagungsband

  • Christian J. Trum
  • Christian Vogt
  • O. Fähnle
  • Sebastian Sitzberger
  • Rolf Rascher

First experiences with Filled-Up-Microscopy (FUM) to evaluate the depth of sub-surface damages on ground surfaces

  • (2018)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Beitrag in Sammelwerk/Tagungsband

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

On the metrology of the MSF errors

pg. 108290F.

  • (2018)

DOI: 10.1117/12.2318675

The aim of our research is to study middle spatial frequency errors (MSFE) on optical surfaces. We investigate the surfaces after all manufacturing processes to find out the main affecting factors and to choose the proper processing parameters to minimize the size of the errors. In this paper we describe some middle spatial frequency errors, which occur during grinding. As there are limited possibilities to measure ground surfaces, their analysis from the point of measurement is most difficult. Therefore, it is of utmost importance to optimally organize the measurement guaranteeing sufficient data for the reconstruction of the toolpath and avoidance of aliasing effects. In the paper discuss possible classifications and some difficulties during measuring of grinded surfaces.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Beitrag in Sammelwerk/Tagungsband

  • Christian Vogt
  • O. Fähnle
  • E. Langenbach
  • Rolf Rascher

In situ monitoring of laser polishing

  • (2018)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Vortrag

  • Rolf Rascher

Grinding and polishing of glass - Basis for a perfect coating

In: 12th International Conference on Coatings on Glass and Plastics (Joint session of DGG-Glasforum and the ICCG): The Glass Surface - The Basis for Innovative Coatings

Würzburg

  • 11.06.2018 (2018)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • DIGITAL
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Beitrag in Sammelwerk/Tagungsband

  • Christian Vogt
  • Rolf Rascher
  • O. Fähnle
  • Dae Kim

Closed-loop next generation laser polishing

pg. 34.

  • (2018)

DOI: 10.1117/12.2318749

  • TC Teisnach Optik
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

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

Simulation of MSF errors using Fourier transform

pg. 1082903.

  • (2018)

DOI: 10.1117/12.2317484

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 first publication focuses on the parameters of the grinding step. The Goal is to understand and avoid the appearance of the mid spatial frequency error and develop a simulation which is able to predict the resulting mid spatial frequency error for/of a manufacturing process.
  • TC Teisnach Optik
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Beitrag in Sammelwerk/Tagungsband

  • O. Fähnle
  • Christian Vogt
  • Rolf Rascher

Load controlled process window analysis of feed controlled CNC grinding

pg. 32.

Frankfurt, Germany

  • (2018)

DOI: 10.1117/12.2315336

  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Alexander Haberl
  • H. Harsch
  • Gerald Fütterer
  • Johannes Liebl
  • C. Pruß
  • Rolf Rascher
  • W. Osten

Model based error separation of power spectral density artefacts in wavefront measurement

pg. 107490T.

  • (2018)

DOI: 10.1117/12.2321106

  • TC Teisnach Optik
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  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • O. Fähnle
  • Christian Vogt
  • Rolf Rascher
  • M. Doetz
  • O. Dambon
  • F. Klocke

From turning to grinding: ductile machining with gPVA

pg. 30.

San Diego, United States

  • (2018)

DOI: 10.1117/12.2323246

  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Johannes Liebl
  • Christian Schopf
  • Rolf Rascher

DefGO

pg. 108290I.

  • (2018)

DOI: 10.1117/12.2318704

The manufacturing of optical lenses has various steps. Generally, the manufacturing can be split up into the following steps: the workpiece is pre-ground with a coarse tool; it is then fine-ground with a finer tool. As the final polishing is a demanding and time-consuming process that cannot manage large removal rations not can it equalise rough shape errors, the starting quality and surface quality needs to be as high as possible. According to the current state of technology, ground lenses must be measured with tactile measuring techniques in order to detect shape errors. This is timeconsuming and expensive, and only two dimensional profiles can be measured. DefGO’s project objective is to introduce deflectometry as a new, three dimensional lens measuring standard. A problem with the application of deflectometry is that the object to be measured has to reflect enough light, which is not the case for ground glass with rough surfaces. DefGO’s solution is to wet the lens with a fluid to create a closed reflecting surface.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Beitrag in Sammelwerk/Tagungsband

  • Christian J. Trum
  • Sebastian Sitzberger
  • Rolf Rascher

Improved performance of CMP processes through targeted adjustment of polishing slurry and polish pad

pg. 20.

San Diego, United States

  • (2018)

DOI: 10.1117/12.2321031

Chemical-mechanical polishing (CMP) of optical glasses is widespread and forms the basis for many high-precision polishing processes. The pads, slurries and glass materials used in polishing have many different properties. The effects of these properties on the process results are often unknown. The right choice and combination is therefore often a challenge. By means of a plan processing of N-BK7 and SF56 samples by a plan-polishing process, the influence on the process results, material removal rate (MRR), micro roughness and cleanliness caused by slurry and polishing pad is shown. It turns out that the type of polish pad has the biggest impact on the results. The easy-to-process material N-BK7 shows only little influence by the type of slurry used. The more challenging SF56, however, shows significant effects, especially in the area of the resulting micro roughness and the appearance of surface damages like orange peel. Especially the use of Auerpol® PZ500 shows clear advantages here. For a selection of three out of nine polishing pads, the effect of density variation of the slurry was also investigated. Lower particle concentrations lead to lower material removal rates. This applies to both materials. The more sensitive SF56 shows a reduction in micro roughness by the use of a less dense slurry. The correct selection of the polishing pad has a positive effect on the material removal rate and/or the micro roughness in all tested materials. An adaptation of the type and concentration of the slurry is especially important for more sensitive materials and in combination with the right polishing pad. In view of the development towards special materials and small lot sizes, the targeted and correct selection of polishing slurries and pads becomes more and more important. The information required for this purpose on the behavior of the pads and slurries available on the market must therefore first be determined in a targeted manner and clearly presented.
  • TC Teisnach Optik
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Beitrag in Sammelwerk/Tagungsband

  • O. Fähnle
  • M. Doetz
  • O. Dambon
  • F. Klocke
  • Christian Vogt
  • Rolf Rascher

Ductile mode single point diamond turning (SPDT) of binderless tungsten carbide molds

pg. 15.

San Diego, United States

  • (2018)

DOI: 10.1117/12.2323244

  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Christian Vogt
  • M. Doetz
  • Rolf Rascher
  • O. Fähnle

Standardized evaluation of grinding tools for brittle and ductile mode grinding . Invited Paper

  • (2018)
  • TC Teisnach Optik
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Beitrag in Sammelwerk/Tagungsband

  • O. Fähnle
  • Christian Vogt
  • Rolf Rascher
  • M. Doetz
  • O. Dambon
  • F. Klocke

Ductile grinding of tungsten carbide molds applying standard CNC machines

pg. 24.

San Diego, United States

  • (2018)

DOI: 10.1117/12.2323245

  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Vortrag

  • Christian Schopf
  • Florian Schneider
  • Rolf Rascher

ArenA – Foi: Erprobung des ADAPT-Polierwerkzeugs . Posterpräsentation

In: 5. Tag der Forschung

Technische Hochschule Deggendorf Deggendorf

  • 08.03.2018 (2018)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Zeitschriftenartikel

  • Christian J. Trum
  • Rolf Rascher
  • M. Zäh

Effizientes chemisch-mechanisches Polieren (CMP)

In: Werkstattstechnik online-wt-online pg. 174-179.

  • (2018)

  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
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Vortrag

  • Sebastian Sitzberger
  • Rolf Rascher
  • M. Zäh

Vorrichtungssystem für eine beidseitige hochgenaue Bearbeitung von Linsen

In: 1. Ko-op Symposium

Graduate Center der Munich School of Engineering Garching

  • 29.11.2018 (2018)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • M. Doetz
  • O. Dambon
  • Christian Vogt
  • Rolf Rascher
  • E. Langenbach
  • O. Fähnle

Enlarging process window of ductile mode machining of WC molds

  • (2018)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • DIGITAL
  • NACHHALTIG
Vortrag

  • Rolf Rascher
  • Christian Vogt
  • O. Fähnle
  • E. Langenbach

Closed-loop laser polishing of glass

In: LaP 2018 - 3rd Conference on Laser Polishing

Fraunhofer-Institut für Lasertechnik (ILT) Aachen

  • 12.09.2018 (2018)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Beitrag in Sammelwerk/Tagungsband

  • Christian Vogt
  • O. Fähnle
  • Rolf Rascher

gPVA: a system for the classification of grinding tools

pg. 26.

  • (2018)

DOI: 10.1117/12.2318695

  • TC Teisnach Optik
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Sebastian Sitzberger
  • Christian J. Trum
  • Rolf Rascher
  • M. Zaeh

Workpiece self-weight in precision optics manufacturing: compensation of workpiece deformations by a fluid bearing

pg. 108290A.

  • (2018)

DOI: 10.1117/12.2318577

The effects, the extent and the importance of workpiece deformations, particularly lenses, caused by the weight of the workpiece itself, were examined in a previous paper1 . The considered deformations are in the single-digit to two-digit nanometer range. The investigation was carried out by FEM calculations. The conclusion of the previous aper was that a full-surface support of a workpiece in the processing of one surface presumably produces the best results. Furthermore, it was found that if the second functional surface is not to be touched in the process, a full contact lens mounting on its circumference is advisable. An alternative method for fixing precision lenses is therefore desirable. This can be accomplished in two steps. As a first step, the lens must be gripped at its periphery so that none of the optically functional surfaces of the lens is compromised. However, the complete circumference has to be fixated gaplessly because a punctual fixation has the disadvantage of deforming the lens surface asymmetrically. As a second step, the freely hanging lens surface should be supported to minimize deformation. An approach had to be found that supports the surface like a solid bearing but at the same time does not touch it. Therefore, the usage of an incompressible fluid as a hydrostatic bearing for full-surface support is pursued. For this purpose, the bottom side of the lens has to be stored on water. The results of the FEM simulation showed that with a fluid bearing the resulting deformations can be drastically reduced in comparison to a freely hanging surface. Furthermore, under the right conditions, a resulting deformation comparable to a full surface solid support can be achieved. The content of this paper is a test series under laboratory conditions for a first validation of the theoretical results. Therefore, a prototype model to test a lens fixation with a fluid bearing was developed and manufactured. The resulting deformations were measured with an interferometer and the effects are discussed.
  • TC Teisnach Optik
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Vortrag

  • Sebastian Sitzberger
  • Christian J. Trum
  • Rolf Rascher
  • M. Zaeh

Workpiece self-weight induced deformation in precision optics manufacturing . Posterpräsentation

In: 5. Tag der Forschung

Technische Hochschule Deggendorf Deggendorf

  • 08.03.2018 (2018)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Vortrag

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

EmmaV - Entstehungsmechanismen mittelfrequenter Fehler und deren aktive Vermeidung . Posterpräsentation

In: 5. Tag der Forschung

Technische Hochschule Deggendorf Deggendorf

  • 08.03.2018 (2018)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • Christian J. Trum
  • Sebastian Sitzberger
  • Rolf Rascher

Improved performance of CMP processes through targeted adjustment of polishing slurry and polish pad

In: SPIE Optical Engineering + Applications 2018

San Diego, CA, USA

  • 2018 (2018)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Christian J. Trum
  • Christian Vogt
  • Sebastian Sitzberger
  • Rolf Rascher
  • O. Fähnle

Filled-Up-Microscopy (FUM): a non-destructive method for approximating the depth of sub-surface damage on ground surfaces

pg. 11.

  • (2018)

DOI: 10.1117/12.2318576

  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Vortrag

  • Christian Vogt
  • Rolf Rascher

grinding Process Validation Approach (gPVA) . Posterpräsentation

In: 5. Tag der Forschung

Technische Hochschule Deggendorf Deggendorf

  • 08.03.2018 (2018)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel

  • O. Fähnle
  • Rolf Rascher
  • Christian Vogt
  • D.W. Kim

Closed-loop laser polishing using in-process surface finish metrology

In: Applied Optics vol. 57 pg. 834-838.

  • (2018)

DOI: 10.1364/AO.57.000834

This paper lays out the trail onto a closed-loop polishing process of optical elements enabling the application of the optimum polishing time needed. To that aim, an in-process testing method for monitoring an inclusive micro surface quality (e.g., comprising surface roughness and scratch-and-dig) within the polishing spot is analyzed and its applicability to closed-loop polishing for classical loose-abrasive full-aperture polishing as well as for computer controlled laser polishing is experimentally tested and verified. This enables the determination of the optimum local dwell time resulting in a stable and cost optimized polishing.
  • TC Teisnach Optik
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Beitrag in Sammelwerk/Tagungsband

  • Alexander Haberl
  • Johannes Liebl
  • Rolf Rascher

ABC-polishing

pg. 1082906.

  • (2018)

DOI: 10.1117/12.2318549

In the past, steadily increasing demands on the imaging properties of optics have led more and more precise spherical apertures. For a long time, these optical components have been produced in a satisfying quality using classic polishing methods such as pitch polishing. The advance of computer-controlled subaperture (SA) polishing techniques improved the accuracy of spheres. However, this new machine technology also made it possible to produce new lens geometries, such as aspheres. In contrast to classic polishing methods, the high determinism of SA polishing allows a very specific correction of the surface defect. The methods of magneto-rheological finishing (MRF) [1], [2] and ion beam figuring (IBF) [3], [4] stand out in particular because of the achievable shape accuracy. However, this leads to the fact that a principle of manufacturing "As exact as possible, as precise as necessary" [5] is often ignored. The optical surfaces often produced with unnecessary precision, result at least in increased processing times. The increasing interconnection of the production machines and the linking with databases already enables a consistent database to be established. It is possible to store measurements, process characteristics or tolerances for the individual production steps in a structured way. The difficulty, however, lies in the reasonable evaluation of the measurement data. This is where this publication comes in. The smart evaluation of the measurement data with the widespread Zernike polynomials should result in a classification, depending on the required manufacturing tolerance. In combination with the so-called ABC analysis, all surface defects can be categorized. In this way, an analytic breakdown of a - initially confusing - overall problem is made. With the aid of cost functions [6] an evaluation and consequently a deduction of actions is made possible. Thus, for example, the isolated processing of rotationally symmetrical errors in spiral mode, setup times and machining times can be reduced while avoiding mid spatial frequency errors (MSFE) at the same time.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Vortrag

  • Christian J. Trum
  • Rolf Rascher
  • M. Zäh

Steigerung der Effizienz chemisch-mechanischer Polierprozesse durch Anpassung der Poliersuspension

In: 1. Ko-op Symposium

Graduate Center der Munich School of Engineering Garching

  • 29.11.2018 (2018)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Sebastian Sitzberger
  • Christian J. Trum
  • Rolf Rascher

Analysis of the influence of the workpiece self-weight in precision optics manufacturing using FEM simulation

pg. 103260O.

  • (2017)

DOI: 10.1117/12.2273023

  • TC Teisnach Optik
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  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Christian Vogt
  • O. Fähnle
  • Rolf Rascher

Force-controlled analysis tool for optimization of precision CNC grinding processes

pg. 103260M.

  • (2017)

DOI: 10.1117/12.2272713

  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Robert Schneider
  • Alexander Haberl
  • Rolf Rascher

Parametrization of a Subaperture Polishing Tool - Analysis of the Path Tests

vol. Paper OM3B.2

Washington, D.C., USA

  • (2017)

  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Beitrag in Sammelwerk/Tagungsband

  • Christian Vogt
  • O. Fähnle
  • Rolf Rascher

Setting-up high-end cnc grinding processes: a Preston-based approach

  • (2017)
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.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
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Beitrag in Sammelwerk/Tagungsband

  • Christian Schopf
  • Rolf Rascher
  • Johannes Liebl

Cheap and fast measuring roughness on big surfaces with an imprint method

pg. 1044822.

  • (2017)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Zeitschriftenartikel

  • Christian Vogt
  • C. Faehnle
  • Rolf Rascher

Grinding Process Validation Approach (gPVA)

In: Journal of Physical Science and Application vol. 7

  • (2017)

DOI: 10.17265/2159-5348/2017.05.004

  • TC Teisnach Optik
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Beitrag in Sammelwerk/Tagungsband

  • Christian Vogt
  • O. Fähnle
  • Rolf Rascher

Three wagons Approach Applied to Optimization of Industrial Grinding Processes

pg. OTu2B.2.

Washington, D.C., USA

  • (2017)

DOI: 10.1364/OFT.2017.OTu2B.2

  • TC Teisnach Optik
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Beitrag in Sammelwerk/Tagungsband

  • Rolf Rascher
  • Christian Vogt
  • C. Faehnle

In situ laser polishing optimization method: Control of LASer Surface Optimisation (C-Lasso)

  • (2017)
Laser polishing is achieved by local absorption of laser power within the polishing spot causing the surface and its sub-surface region to melt and flow reducing surface roughness and removing sub-surface damage. In this paper we present a novel fabrication controlling method for laser polishing processes called C-Lasso (Control of LASer Surface Optimization, Patent Pending), monitoring in situ the surface smoothening process. It is possible to determine and control the minimum dwell time a footprint needs to stay at a certain point before moving further. C-Lasso enables to avoid unnecessarily long local dwell times. Besides the functioning principle, a proof of concept will be presented as well as experimental data demonstrating the in situ monitoring.
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Beitrag in Sammelwerk/Tagungsband

  • Robert Schneider
  • Alexander Haberl
  • Rolf Rascher

Polishing tool and the resulting TIF for three variable machine parameters as input for the removal simulation

pg. 1032602.

  • (2017)

DOI: 10.1117/12.2267415

  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Beitrag in Sammelwerk/Tagungsband

  • Engelbert Hofbauer
  • Rolf Rascher
  • Felix Friedke
  • R. Kometer

Resolution, measurement errors and uncertainties on deflectometric acquisition of large optical surfaces "DaOS"

pg. 1032603.

  • (2017)

DOI: 10.1117/12.2267513

  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Beitrag in Sammelwerk/Tagungsband

  • Alexander Haberl
  • Rolf Rascher

Yet one more dwell time algorithm

pg. 1032606.

  • (2017)

DOI: 10.1117/12.2270540

  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Beitrag in Sammelwerk/Tagungsband

  • Bin Dong
  • Christian Vogt
  • Rolf Rascher

Wear detection of brass bond diamond grinding wheel by spectral coherence of grinding forces

pg. 221-222.

  • (2017)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Beitrag in Sammelwerk/Tagungsband

  • Christian J. Trum
  • Sebastian Sitzberger
  • Rolf Rascher

Advanced method for the characterization of polishing suspensions

pg. 103260I.

  • (2017)

DOI: 10.1117/12.2272431

  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Beitrag in Sammelwerk/Tagungsband

  • Christian J. Trum
  • Rolf Rascher

Improving efficiency of chemo-mechanical polishing processes by systematic selection and conditioning of the polishing suspension

  • (2016)

DOI: 10.1117/12.2236000

During design of optical systems or individual components, customers and designers already predetermine the way through production and the necessary resources. They define the tolerances that are required for their application like shape, micro-roughness and cleanliness, as well as the glass material that is necessary for the targeted optical effect. By the tolerances, they have also an influence on the manufacturer and his decisions on the production environment, measurement technology and the process chain that in his opinion is necessary to meet the specification. In most cases the type of polishing suspension and its parameters are also predetermined by the use of central polishing supply systems. With this paper, the authors want to give a prospect of a currently running research with the aim of increasing the efficiency of chemo-mechanical polishing processes by a systematic selection and conditioning of the polishing suspension. They want to show that small amounts of well-conditioned and stabilized polishing suspension could be a tool to improve the efficiency in CMP processes under the influence of the global trend to products that are more individual and down to one piece flow production. Main parts of this research are the identification of influences of polishing suspensions on the quality criteria of optical components and the creation of a method to find well-working suspension parameters in a deterministic and reproducible way. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
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Vortrag

  • Rolf Rascher

Innovationsentwicklung mit der Technischen Hochschule Deggendorf

In: Innovationsworkshop "Innovation in der Photonik" im Rahmen der 13. Optatec 2016 - Internationale Fachmesse für optische Technologien, Komponenten und Systeme

Frankfurt am Main

  • 07.06.2016 (2016)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Beitrag in Sammelwerk/Tagungsband

  • Sebastian Sitzberger
  • Rolf Rascher

An investigation on the efficiency of the manufacturing of components in precision optics

  • (2016)

DOI: 10.1117/12.2236137

By adaption and coordination of successive process steps the efficiency of producing optics can be improved. In the beginning of this investigation, the focus is on two crucial process steps of the optical manufacturing process. First, there is the optical and mechanical design of the optical part and system. In this context, it is important to consider what modifications compared to the current standard design are possible respectively useful. Thus, the modifications will only concentrate on parts of the optic that do not interfere with the optical functionality. Furthermore in this part of the study the main aspect is the clamping situation of the optical part in a holder or an optical system. It will be discussed, whether it is useful to add special clamping surfaces respectively a clamping flange in contrast to the standard design. The faultless functioning of the optics has always first priority. Second, the manufacturing process itself has a great number of single steps. Therefore, a main part of the research is the investigation of current clamping situations in optics manufacturing, with prospect to improve them in order to work perfectly with the design modifications, as mentioned above. This part of the investigation focuses on the clamping system for the lens on each machine necessary for manufacturing. In the scope of this paper the authors want to summarize characteristics and deficits of current clamping systems and workpiece mounts and give a prospect of the following course of action. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Vortrag

  • Rolf Rascher
  • Christine Wünsche
  • Christian Schopf

Aspects in laser polishing of precision optical components

In: LaP 2016 - 2nd Conference on Laser Polishing

Aachen

  • 26.-27.04.2016 (2016)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Beitrag in Sammelwerk/Tagungsband

  • Engelbert Hofbauer
  • Rolf Rascher
  • Manon Schilke
  • Johannes Liebl
  • J.-P. Richters

Deflectometric acquisition of large optical surfaces (DaOS) using a new physical measurement principle: vignetting field stop procedure

  • (2016)

DOI: 10.1117/12.2236134

  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Christian Vogt
  • S. Sinzinger
  • Martin Rohrbacher
  • Rolf Rascher

Prediction of grinding tool wear and lifetime by using a test bench

  • (2016)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Christian Schopf
  • Rolf Rascher

Reducing forces during drilling brittle hard materials by using ultrasonic and variation of coolant

pg. 1015107.

  • (2016)

DOI: 10.1117/12.2257106

The process of ultrasonic machining is especially used for brittle hard materials as the additional ultrasonic vibration of the tool at high frequencies and low amplitudes acts like a hammer on the surface. With this technology it is possible to drill holes with lower forces, therefor the machining can be done faster and the worktime is much less than conventionally. A three-axis dynamometer was used to measure the forces, which act between the tool and the sample part. A focus is set on the sharpness of the tool. The results of a test series are based on the Sauer Ultrasonic Grinding Centre. On the same machine it is possible to drill holes in the conventional way. Additional to the ultasonic Input the type an concentration of coolant is important for the Drilling-force. In the test there were three different coolant and three different concentrations tested. The combination of ultrasonic vibration and the right coolant and concentration is the best way to reduce the Forces. Another positive effect is, that lower drilling-forces produce smaller chipping on the edge of the hole. The way to reduce the forces and chipping is the main issue of this paper.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Zeitschriftenartikel

  • Engelbert Hofbauer
  • Rolf Rascher
  • Manon Schilke
  • Johannes Liebl
  • J.-P. Richters

Deflectometric Acquisition of Large Optical Surfaces “DaOS” Using a New Physical Measurement Principle: Vignetting Field Stop . (Reprinted from Proceedings of SPIE Volume 10009: Third European Seminar on Precision Optics Manufacturing, 100090Y [Teisnach, April 12th 2016] doi:10.1117/12.2236134)

In: Bavarian Journal of Applied Sciences pg. 146-161.

  • (2016)
The vignetting field stop procedure uses a deflectometric approach to acquire big Optical Surfaces – DaOS – and it offers the possibility to measure nearly any shape or form using a scanning routine. The basic physical measurement principle in DaOS is the vignettation of a quasi-parallel light beam emitted by an expanded light source in auto collimation arrangement with a reflecting element. Thereby nearly any curvature of the specimen, is measurable. Due to the fact, that even sign changes in the curvature can be detected, also aspheres and freeform surfaces of any size can be evaluated. In this publication the vignetting field stop procedure is discussed. Additionally the deflectometric setup is described. Because of some typical influences of beam deflection to the accuracy of angle measurement by using the vignetting principle, suitable methods of calibration for the sensor are examined and the results of these methods are presented. Furthermore, the technical principle of deflectometric measurements using an angle detecting device is explained inclusive of all random and systematic errors generated by the setup. The last part of this publication shows the actual result of test measurements with calculated absolute deviation of errors with a large lateral dimension as well as the determination of the maximal achievable lateral resolution by detecting mid frequent structures on flat and spherical test parts with a diameter of 300 mm. These measurements are compared critically to reference results which are recorded by interferometry and further scanning methods.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Vortrag

  • Rolf Rascher
  • C. Weingarten

Hybridfertigung optischer Oberflächen

In: F.O.M.-Konferenz 2016 - Innovative Industrien unterstützen

Forschungsvereinigung Feinmechanik, Optik und Medizintechnik e.V. Berlin

  • 02.11.2016 (2016)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Beitrag in Sammelwerk/Tagungsband

  • Johannes Liebl
  • Horst Linthe
  • Sebastian Sitzberger
  • Rolf Rascher

Interferometric measurement of highly accurate flat surfaces

  • (2016)

DOI: 10.1117/12.2235525

The most important part in manufacturing precision optics is a reliable measurement procedure which provides results a few times more accurate than the quality to be produced. In general two specific values are important, the repeatability of several measurements which are done in a row and the absolute accuracy which is mostly defined by the systematical error of the measurement device. The repeatability can be improved relatively simple, by increasing the number of measurements and a following averaging step. To increase the absolute accuracy of a measurement device in the field of precision optics is far more challenging. In this paper several interferometer absolute testing methods to measure flat surfaces are compared. The main objective was to name a value for the achievable accuracy. Therefor four different methods were analyzed: 1. The three flat test, a method which is already used several decades to determine the quality of a flat surface. As a result, two absolute measured profiles, horizontal and vertical, can be calculated. 2. The multi rotation test, an extension of the classical three flat test. The big advantage of this method is a fully three dimensional map of the systematical error. 3. The systematical error calculated by the SSI-A. Hereby several subapertures are measured over the whole surface. The redundant information’s of the overlapping regions can be used to calculate the systematical error of the system. 4. The rotation of the transmission flat relatively to the interferometer. Thereby the rotation unsymmetrical errors can be calculated and subtracted. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Vortrag

  • Christian Schopf
  • Rolf Rascher

Reducing forces during drilling brittle hard materials by using ultrasonic and variation of coolant

In: Optics and Measurement International Conference 2016

SPIE, The International Society for Optics and Photonics Liberec, Tschechische Republik

  • 11.10.2016 (2016)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Zeitschriftenartikel

  • Engelbert Hofbauer
  • Rolf Rascher

Deflectometric Acquisition of Large Optical Surfaces DaOS . Using a new physical measurement principle: vignetting field stop procedure

In: Optik&Photonik vol. 11 pg. 40-44.

  • (2016)

DOI: 10.1002/opph.201600036

  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Christian Vogt
  • Martin Rohrbacher
  • Rolf Rascher
  • S. Sinzinger

Dependency between removal characteristics and defined measurement categories of pellets

pg. 95730N.

  • (2015)

DOI: 10.1117/12.2189987

  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel

  • Heiko Biskup
  • Christian J. Trum
  • Rolf Rascher

Stabilität im Polierprozess

In: Newsletter Bayern Photonics (Innovationsnetzwerk Optische Technologien)

  • (2015)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Engelbert Hofbauer
  • Rolf Rascher
  • Felix Friedke
  • Thomas Stubenrauch
  • Johannes Liebl
  • J.-P. Richters

The vignetting field stop procedure: A new physical measurement principle for the Deflectometric acquisition of big Optical Surfaces - DaOS

  • (2015)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Heiko Biskup
  • Alexander Haberl
  • Rolf Rascher

Surface errors in the course of machining precision optics

pg. 95750O.

  • (2015)

DOI: 10.1117/12.2189991

Precision optical components are usually machined by grinding and polishing in several steps with increasing accuracy. Spherical surfaces will be finished in a last step with large tools to smooth the surface. The requested surface accuracy of non-spherical surfaces only can be achieved with tools in point contact to the surface. So called mid-frequency errors (MSFE) can accumulate with zonal processes. This work is on the formation of surface errors from grinding to polishing by conducting an analysis of the surfaces in their machining steps by non-contact interferometric methods. The errors on the surface can be distinguished as described in DIN 4760 whereby 2nd to 3rd order errors are the so-called MSFE. By appropriate filtering of the measured data frequencies of errors can be suppressed in a manner that only defined spatial frequencies will be shown in the surface plot. It can be observed that some frequencies already may be formed in the early machining steps like grinding and main-polishing. Additionally it is known that MSFE can be produced by the process itself and other side effects. Beside a description of surface errors based on the limits of measurement technologies, different formation mechanisms for selected spatial frequencies are presented. A correction may be only possible by tools that have a lateral size below the wavelength of the error structure. The presented considerations may be used to develop proposals to handle surface errors. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Beitrag in Sammelwerk/Tagungsband

  • Patrick Schäfer
  • Christine Wünsche
  • Rolf Rascher

Quantification of synthetic lens surface characteristics by an optical measurement system as stylus instrument

pg. 944219.

  • (2015)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • NACHHALTIG
Vortrag

  • Heiko Biskup
  • Christian Schopf
  • Rolf Rascher

Surface roughness testing below 0.5 nm Sq . Measuring of Sub-Nanometer Surface Texture by White-Light Interferometry

In: 6. Fachtagung Produktionsmesstechnik für die Praxis

NTB - Interstaatliche Hochschule für Technik Buchs, Schweiz

  • 03.09.2015 (2015)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Zeitschriftenartikel

  • Johannes Liebl
  • Heiko Biskup
  • S. Draxinger
  • Rolf Rascher
  • Christine Wünsche

Process developement fort the reproducible roughness measurement of optical surfaces using white light interferometry

In: International Journal of Metrology and Quality Engineering (EDP Sciences) vol. 5 pg. 29-35.

  • (2014)

  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Beitrag in Sammelwerk/Tagungsband

  • O. Fähnle
  • E. Langenbach
  • F. Frost
  • A. Schindler
  • Heiko Biskup
  • Johannes Liebl
  • Christine Wünsche
  • Rolf Rascher

Generation and field testing of roughness reference samples for industrial testing of surface roughness levels below 0.5nm Sq

pg. 216-218.

  • (2014)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • S. Draxinger
  • Christian J. Trum
  • Heiko Biskup
  • Christine Wünsche
  • Rolf Rascher

Active Fluid Jet Polishing - Behaviour on Different Materials

In: Optical Fabrication and Testing (OF&T)

The Optical Society of America (OSA) Kohala Coast, HI, USA

  • 22.-26.06.2014 (2014)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Beitrag in Sammelwerk/Tagungsband

  • Engelbert Hofbauer
  • Rolf Rascher
  • K. Wühr
  • Felix Friedke
  • Thomas Stubenrauch
  • B. Pastötter
  • S. Schleich
  • C. Zöcke

3D-optical measurement system using vignetting aperture procedure

pg. 913206.

  • (2014)

DOI: 10.1117/12.2052631

  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • Rolf Rascher

Technologies and results for the mirror production in Teisnach

In: 1st European Seminar on Precision Optics Manufacturing

Technische Hochschule Deggendorf Teisnach

  • 01.04.2014 (2014)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • Thorsten Gerdes
  • K. Kyrgyzbayev
  • A. Rosin
  • A. Saberi
  • A. Füller
  • Rolf Rascher
  • Christine Wünsche

Aims for the development of new optical glass materials

In: 1st European Seminar on Precision Optics Manufacturing

Technische Hochschule Deggendorf/Technologie Campus Teisnach Teisnach

  • 01.-02.04.2014 (2014)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

  • Patrick Schäfer
  • Christine Wünsche
  • Rolf Rascher

Quantification of synthetic lens surface characteristics by an optical measurement system as stylus instrument

In: Optics and Measurement International Conference 2014

Liberec, Tschechische Republik

  • 07.-10.10.2014 (2014)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • Rolf Rascher
  • Johannes Liebl
  • Paul Schötz
  • P. Frieder

Automatische Kratzererkennung an hochpräzisen Drehteilen . „Projekt KonoScan“

In: SENSOR + TEST

Nürnberg

  • 04.06.2014 (2014)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Beitrag in Sammelwerk/Tagungsband

  • Christian Vogt
  • S. Sinzinger
  • Rolf Rascher

A Study on Elastic Grinding Tools

In: Proceedings of the International Optical Design Conference. Part of Classical Optics 2014 ; 22-26 June 2014, Kohala Coast, Hawaii, United States (OSA Technical Digest (online)) pg. OTu3B.3.

Washington, DC

  • (2014)

DOI: 10.1364/OFT.2014.OTu3B.3

This paper reports on results of testruns with experimental grinding tools. The ball shaped tools comprise of abrasive layers with diamond grits, on top of an elastic layer. The tool’s design allows dwell time based corrections on simple and complex shapes, such as spheres and parabolic shapes.
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

  • Christian Vogt
  • S. Sinzinger
  • Rolf Rascher

A study on elastic grinding tools

In: Optical Fabrication and Testing (OF&T)

The Optical Society of America (OSA) Kohala Coast, HI, USA

  • Juni 2014 (2014)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Zeitschriftenartikel

  • Christian Schopf
  • Rolf Rascher
  • Christine Wünsche

Rauhigkeitsmessungen an großen und schwer zugänglichen Bauteilen

In: MM Industriemagazin-Maschinenmarkt pg. 40-41.

  • (2013)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Beitrag in Sammelwerk/Tagungsband

  • Engelbert Hofbauer
  • Rolf Rascher
  • Thomas Stubenrauch
  • Johannes Liebl
  • Roland Maurer
  • et al.

Approach to the measurement of astronomical mirrors with new procedures

  • (2013)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

  • Rolf Rascher

Fertigung präziser Optikflächen – schleifen und polieren oder pressen?

In: DGG-Glasforum

Wertheim-Bronnbach

  • 26.09.2013 (2013)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

  • Rolf Rascher

Moderne Optikfertigung

In: 6. Optikseminar - Agenda zur modernen Optikfertigung

Technische Hochschule Deggendorf/Technologie Campus Teisnach Teisnach

  • 12.03.2013 (2013)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Beitrag in Sammelwerk/Tagungsband

  • Roland Maurer
  • Florian Schneider
  • Christine Wünsche
  • Rolf Rascher

Calculation of the reference surface error by analyzing a multiple set of sub-measurements

  • (2013)

DOI: 10.1117/12.2024003

In the field of precision optics the interferometry is the most applied measurement method to test spherical and flat objects. In principle, a standard interferometer setup is limited to these surface geometries, but interferometric systems may be modified with the aid of CGH’s or the stitching technology. As a consequence aspherical shapes and even freeform optics are measurable up to a certain extent. In an interferometric measurement the measured variable is the optical path difference (OPD) between the reference wave and the test wave. Based on the detected OPD the surface error of the test object is calculated by phase shifting methods for instance. It is evident, that the error from the reference surface affects the determination of the test object surface error. One option to face this problem is the calibration of the system prior to the measurement. For this the determination of the reference surface error may be realized with the aid of a two sphere test or a random ball test e.g. [1]. In the well-known SSI-technology from QED technologies the reference surface error is calculated on the basis of the sub-measurements. Due to the self-calibrating nature of the QED stitching principle [2-4] a calibration of the system prior to the measurement is not necessary. The University of Applied Sciences Deggendorf has implemented a similar algorithm to estimate the reference wave front error, or to be exact the error of the whole optical system, based on a multiple set of sub-measurements. This paper describes the applied algorithm in detail and discusses the results. To verify the implemented tool the results are compared to the outcomes of the QED stitching software. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Beitrag in Sammelwerk/Tagungsband

  • Roland Maurer
  • Heiko Biskup
  • Christian J. Trum
  • Rolf Rascher
  • Christine Wünsche

Determination of a suitable parameter field for the active fluid jet polishing process

In: Optifab 2013. null (Proceedings of SPIE)

  • (2013)

DOI: 10.1117/12.2028752

In 2012 a well-known company in the field of high precision optics assigned the University of Applied Sciences Deggendorf to determine a suitable parameter field for the active fluid jet polishing (AFJP) process in order to reach a surface accuracy of at least lambda / 5. The active fluid jet polishing is a relatively new and an affordable sub-aperture polishing process. For a fast and precise identification of the parameter field a considered design of experiment is necessary. The available control variables were the rotational speed of the nozzle, the distance between the test object and the jet, the feed rate, the material of the pin inside the nozzle and the material of the test object itself. In order to reach a significant data density on the one hand and to minimize the number of test runs on the other hand a meander shaped tool path was chosen. At each blank nine paths had been driven whereby at each path another parameter combination was picked. Thus with only one test object nine parameter settings may be evaluated. For the automatized analysis of the tracks a software tool was developed. The software evaluates ten sections which orthogonally intersect the nine tracks on the test-lens. The significant measurement parameters per section are the width and the height of each path as well as the surface roughness within the polished tracks. With the aid of these parameters and further statistical evaluations a suitable parameter field for the goal to find a constant and predictable removal spot was determined. Furthermore up to now over 60 test runs have been successfully finished with nine parameter combinations in each case. As a consequence a test evaluation by hand would be very time-consuming and the software facilitates it dramatically.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • S. Draxinger
  • Christine Wünsche
  • Rolf Rascher

Subaperture-polishing with variable spots

In: Renewable Energy and the Environment, Freeform Optics (Freeform)

The Optical Society of America (OSA) Tucson, AZ, USA

  • 03.-06.11.2013 (2013)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • M. Willert-Porada
  • Thorsten Gerdes
  • A. Rosin
  • A. Saberi
  • A. Füller
  • Rolf Rascher
  • Christine Wünsche

Flexiplant: schmelzebasierte kontinuierliche Herstellung von low TG-Glas-Preformen (mittels Minimeltertechnologie)

In: 87. Glastechnische Tagung

HVG-DGG: Service und Forschung für die Glasherstellung Bremen

  • 27.-29.05.2013 (2013)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Beitrag in Sammelwerk/Tagungsband

  • Christian Vogt
  • Florian Schneider
  • Rolf Rascher

Grinding Processes for Silicon Carbide (CSiC) Materials

vol. 2 pg. 285-288.

Berlin

  • (2013)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

  • Heiko Biskup
  • Rolf Rascher
  • Christine Wünsche

Laserdiffraktometrie - Korngrößenverteilung in Poliermitteln . Posterbeitrag

In: 5. Optikseminar

Technische Hochschule Deggendorf/Technologie Campus Teisnach Teisnach

  • 30.07.2012 (2012)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • Rolf Rascher
  • Johannes Liebl
  • et al.

Hochgenaue Optische Abstandssensoren in Messtechnik und Qualitätssicherung

In: 1. Optence Messtechnik Symposium

Darmstadt

  • 15.11.2012 (2012)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • Heiko Biskup
  • Rolf Rascher
  • Christine Wünsche

Laserdiffraktometrie zur Charakterisierung von Korngrößen und deren Verteilung in Poliermitteln

In: 5. Optikseminar

Technische Hochschule Deggendorf/Technologie Campus Teisnach Teisnach

  • 30.07.2012 (2012)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • Heiko Biskup
  • Rolf Rascher
  • Christine Wünsche

Poliermittelerprobung II

In: Spectaris - 6. Treffen des Industriekonsortiums Seltene Erden

Mainz

  • 23.02.2012 (2012)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

  • Paul Schötz
  • Johannes Liebl
  • Rolf Rascher
  • Christine Wünsche
  • Engelbert Hofbauer
  • Karlheinz Penzkofer

Metrology at Technologie Campus Teisnach

In: 8th Workshop Asphere Metrology

Physikalisch-Technische Bundesanstalt (PTB)/Kompetenzzentrum Ultrapräzise Oberflächenbearbeitung e.V. Braunschweig

  • 12.-13.11.2012 (2012)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Beitrag in Sammelwerk/Tagungsband

  • M. Fuchs
  • Rolf Rascher
  • Alois Kasberger
  • Christian Wistl

Precision Glass Molding of lenses by using the nanotech molding process - a practical summary . Joint Poster Session (JTu5A)

  • (2012)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • Johannes Liebl
  • Rolf Rascher
  • Katharina Dieser

GF-Projekt Optasens - Combination and evaluation of different optical and tactile sensor and measuring methods for analysis and global form-measurement on optical surfaces . Posterpräsentation

In: F.O.M.-Marktplatz der Forschungsprojekte

Berlin

  • 29.11.2012 (2012)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • Heiko Biskup
  • Rolf Rascher
  • Christine Wünsche

Poliermittelerprobung I

In: Spectaris - 4. Treffen des Industriekonsortiums Seltene Erden

Technische Hochschule Deggendorf/Technologie Campus Teisnach Teisnach

  • 13.07.2011 (2011)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Beitrag in Sammelwerk/Tagungsband

  • Roland Maurer
  • Florian Schneider
  • Christian Vogt
  • Markus Schinhärl
  • Peter Sperber
  • Rolf Rascher

Physical marker based stitching process of circular and non-circular interferograms

  • (2011)

DOI: 10.1117/12.889491

  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Hochschulleitung und -einrichtungen
  • Maschinenbau und Mechatronik
Zeitschriftenartikel

  • Rolf Rascher
  • Igor Makarenko

Use of ELID-grinding on brittle-hard materials

In: International Journal of Mechatronics and Manufacturing Systems vol. 4 pg. 553-568.

  • (2011)

DOI: 10.1504/IJMMS.2011.044105

Abstract: Electrolytic in-process dressing (ELID) is a grinding technology which enables to manufacture surfaces in a quality that is close to polished on advanced, brittle-hard materials such as used in optics. ELID grinding requires exactly aligned machining pa rameters of the grinding process. Sapphire is, due to its crystal structure, difficult to m achine. There is a request for thin, i.e., below 0.2 mm thickness, sub-surface dama ge free wafers. To grind sapphire, the material’s behaviour is to be c onsidered. Studies on the necessary oxide layer on the ELID grinding wheel and influe nces on its build-up process will be presented. In-feed and grinding velocity are varied and the results on wear, removal rate and surface quality are shown. The influence of the coolant and the stiffness of the machine, the grinding forces and pressure are evaluated. The ELID grinding is compared to conventio nal grinding. The achieved excellent surface roughness on sapphire is discussed
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Zeitschriftenartikel

  • Christian Vogt
  • S. Sinzinger
  • H. Adelsberger
  • Roland Maurer
  • Florian Schneider
  • R. Mandler
  • L. Kuepper
  • Rolf Rascher
  • Peter Sperber

An Experimental Study on a Flexible Grinding Tool

In: Advanced Materials Research vol. 325 pg. 91-96.

  • (2011)

DOI: 10.4028/www.scientific.net/AMR.325.91

  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Maschinenbau und Mechatronik
  • Hochschulleitung und -einrichtungen
Beitrag in Sammelwerk/Tagungsband

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

Effects of mechanical inaccuracies on the measurement result in metrology systems

vol. 7656 pg. 765611 ff..

  • (2010)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Maschinenbau und Mechatronik
  • Hochschulleitung und -einrichtungen
Beitrag in Sammelwerk/Tagungsband

  • Christian Schopf
  • Rolf Rascher
  • Peter Sperber

Vor- und Nachteile der Ultraschalltechnologie beim Schleifen von optischen Flächen

pg. 59-72.

  • (2010)
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • Markus Schinhärl
  • Rolf Rascher

Relationship between influence function accuracy and polishing quality in magnetorheological finishing

In: 5th SPIE International Symposium on Advanced Optical Manufacturing and Testing Technologies

Dalian, China

  • 26.-29.04.2010 (2010)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Maschinenbau und Mechatronik
Beitrag in Sammelwerk/Tagungsband

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

Investigations on Grinding Tools for Silicon Carbide Based Advanced Materials

In: International Optical Design Conference 2010 (13-17 June 2010, Jackson Hole, WY, USA). null (Proceedings of SPIE. 2004-) pg. OWD2 ff..

Bellingham

  • (2010)
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Maschinenbau und Mechatronik
Vortrag

  • Igor Makarenko
  • Rolf Rascher

ELID supported grinding of thin Sapphire wafers

In: 5th SPIE International Symposium on Advanced Optical Manufacturing and Testing Technologies

Dalian, China

  • 26.-29.04.2010 (2010)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Maschinenbau und Mechatronik
Beitrag in Sammelwerk/Tagungsband

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

Relationship between influence function accuracy and polishing quality in magnetorheological finishing

pg. 76550Y ff..

  • (2010)

DOI: 10.1117/12.865508

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.
  • Hochschulleitung und -einrichtungen
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

  • Florian Schneider
  • Christian Vogt
  • Roland Maurer
  • Rolf Rascher
  • Peter Sperber

Effects of mechanical inaccuracies on the measurement result in metrology systems

In: SPIE Conference

Dalian, China

  • 2010 (2010)
  • Hochschulleitung und -einrichtungen
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
Beitrag in Sammelwerk/Tagungsband

  • Igor Makarenko
  • Christian Vogt
  • Rolf Rascher
  • Peter Sperber
  • Thomas Stirner

ELID supported grinding of thin sapphire wafers

pg. 76550S ff..

  • (2010)
  • Hochschulleitung und -einrichtungen
  • Maschinenbau und Mechatronik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • Florian Schneider
  • Rolf Rascher

Effects of mechanical inaccuracies on the Measurement result in metrology systems

In: 5th SPIE International Symposium on Advanced Optical Manufacturing and Testing Technologies

Dalian, China

  • 26.-29.04.2010 (2010)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Maschinenbau und Mechatronik
Vortrag

  • Rolf Rascher

Erfahrungen zum ELID-Schleifen hochfester, spröder Werkstoffe

In: 8. Seminar Moderne Schleiftechnologie und Feinstbearbeitung

Hochschule Furtwangen Furtwangen

  • 11.03.2010 (2010)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

  • Christian Schopf
  • Peter Sperber
  • Rolf Rascher

Forschung für die Industrie im Technologiecampus Teisnach, Hochschule für Angewandte Wissenschaften – FH Deggendorf

In: Achtes Symposium - Zukunft Glas - von der Tradition zum High-Tech-Produkt

OTTI e.V., Zwiesel Zwiesel

  • 2010 (2010)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Hochschulleitung und -einrichtungen
Vortrag

  • Christian Schopf
  • Rolf Rascher
  • Peter Sperber

Vor- und Nachteile der Ultraschalltechnologie beim Schleifen von optischen Flächen

In: Achtes Symposium - Zukunft Glas - von der Tradition zum High-Tech-Produkt

OTTI e.V., Zwiesel Zwiesel

  • 2010 (2010)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Hochschulleitung und -einrichtungen
Beitrag in Sammelwerk/Tagungsband

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

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)

pg. OWD3 ff..

Washington, DC, USA

  • (2010)

DOI: 10.1364/OFT.2010.OWD3

  • TC Teisnach Optik
  • Hochschulleitung und -einrichtungen
  • Maschinenbau und Mechatronik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

  • Christian Schopf
  • Rolf Rascher

Ultraschalluntersütztes Bearbeiten optischer Materialien

In: 4. Optikseminar

Technologie Campus Teisnach Teisnach

  • 20.-21.04.2010 (2010)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

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

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

In: SPIE Optifab

SPIE - The International Society for Optical Engineering Rochester, NY, USA

  • 11.05.2009 (2009)
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
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
  • Hochschulleitung und -einrichtungen
Vortrag

  • Rolf Rascher
  • et al.

2^nd Design ‐ Kosten senken in der 2. Runde

In: Fachsymposium Faszination Kleben

3M Neuss

  • 2009 (2009)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

  • Rolf Rascher
  • et al.

Vortrag ELSA Grind ‐ ELID supported grinding of thin micro-structured sapphire wafers

In: 2. Internationale Konferenz zum Ultrapräzisions- und

Fraunhofer IPT Aachen

  • 17.-18.11.2009 (2009)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

  • Rolf Rascher
  • Christian Vogt

Strategies for grinding optical free forms using ball shaped grinding wheels

In: Optifab 2009: Conference TD06

SPIE, The International Society for Optics and Photonics Rochester, NY, USA

  • 11.-14.05.2009 (2009)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Zeitschriftenartikel

  • H. Sporer
  • Rolf Rascher

Second Design ‐ Der große Wurf

In: AUTOMOBIL PRODUKTION pg. 24.

  • (2009)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Beitrag in Sammelwerk/Tagungsband

  • Christian Schopf
  • Rolf Rascher

Ultrasonic assisted drilling of brittle hard materials

pg. 455-458.

  • (2009)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Zeitschriftenartikel

  • Elmar Pitschke
  • Markus Schinhärl
  • Rolf Rascher
  • Peter Sperber
  • L. Smith
  • R. Stamp
  • M. Smith

Simulation of a complex optical polishing process using a neural network

In: Robotics and Computer-Integrated Manufacturing vol. 24 pg. 32-37.

  • (2008)

DOI: 10.1016/j.rcim.2006.07.003

Most modern manufacturing processes change their set of parameters during machining in order to work at the optimum state. But in some cases, like computer-controlled polishing, it is not possible to change these parameters during the machining. Then usually a standard set of parameters is chosen which is not adjusted to the specific conditions. To gather the optimum set of parameters anyway simulation of the process prior to manufacturing is a possibility. This research illustrates the successful implementation of a neural network to accomplish such a simulation. The characteristic of this neural network is described along with the decision of the used inputs and outputs. Results are shown and the further usage of the neural network within an automation framework is discussed. The ability to simulate these advanced manufacturing processes is an important contribution to extend automation further and thus increase cost effectiveness.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Elektrotechnik und Medientechnik
  • Hochschulleitung und -einrichtungen
  • Maschinenbau und Mechatronik
Zeitschriftenartikel

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

Mathematical modelling of influence functions in computer-controlled polishing. Part II

In: Applied Mathematical Modelling vol. 32 pg. 2907-2924.

  • (2008)
Computer-controlled polishing (CCP) is commonly used to finish high-quality surfaces, such as optical lenses. Based on magnetorheological finishing (MRF), a mathematical model to calculate the polishing tool characteristic (influence function) was developed and verified experimentally. The second part of this paper describes the calculation of the distribution of material removal within the size of an influence function and is based on Preston’s fundamental polishing equation. The complete influence function model was implemented using MATLAB. The result is a user-friendly and easy-to-use software tool that enables fast computation of MRF influence functions without the current cumbersome determination procedure, and thus gives improved and more economical production of high-quality surfaces.
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
  • Elektrotechnik und Medientechnik
Beitrag in Sammelwerk/Tagungsband

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

Material influence of silicon nitride at Magnetorheological Finishing (MRF)

  • (2008)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Maschinenbau und Mechatronik
  • Hochschulleitung und -einrichtungen
Beitrag in Sammelwerk/Tagungsband

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

Precision finishing of aspherical optical components using ELID grinding

pg. 191-203.

  • (2008)
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Maschinenbau und Mechatronik
Zeitschriftenartikel

  • Markus Schinhärl
  • Rolf Rascher
  • R. Stamp
  • L. Smith
  • G. Smith
  • Peter Sperber
  • Elmar Pitschke

Utilisation of time-variant influence functions in the computer-controlled polishing

In: Precision Engineering vol. 32 pg. 47-54.

  • (2008)

DOI: 10.1016/j.precisioneng.2007.04.005

In the computer controlled polishing, a polishing tool moves in a well-defined manner across the workpiece surface in order to individually remove the surface error-profile. The commonly used technique to calculate the moving of the polishing tool is the dwell time method. Based on a constant (time-invariant) removal characteristic of the polishing tool (influence function) the amount of material to be removed is controlled via the dwell time. The longer the polishing tool is in contact with a particular area of the workpiece, the more material is removed at this position. Mathematical basics to calculate dwell time-profiles are shown, and a new approach considering time-variant influence functions for the computer controlled polishing is introduced. The results point out that time-variant influence functions may contribute to further decrease the process time, and thus to make a computer controlled polishing process more efficient. The reduction of the process time was observed to approximately 35% using a combination of the dwell time method with time-variant influence functions.
  • Hochschulleitung und -einrichtungen
  • Elektrotechnik und Medientechnik
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Zeitschriftenartikel

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

Advanced techniques for computer-controlled polishing

In: Current Developments in Lens Design and Optical Engineering IX vol. 7060

  • (2008)

DOI: 10.1117/12.808036

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
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
  • Elektrotechnik und Medientechnik
  • Hochschulleitung und -einrichtungen
Beitrag in Sammelwerk/Tagungsband

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

Ultraschallunterstütztes Schleifen von Linsen

pg. 191-203.

  • (2008)
  • Hochschulleitung und -einrichtungen
  • TC Teisnach Optik
  • Maschinenbau und Mechatronik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Zeitschriftenartikel

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

Mathematical modelling of influence functions in computer-controlled polishing. Part I

In: Applied Mathematical Modelling vol. 32 pg. 2888-2906.

  • (2008)
Computer-controlled polishing (CCP) is commonly used to finish high-quality surfaces, such as optical lenses. Based on magnetorheological finishing (MRF), a mathematical model to calculate the polishing tool characteristic (influence function) was developed and verified experimentally. The first part of this paper introduces the model to predict the size and shape of an influence function. The second part of this paper describes the calculation of the distribution of material removal within the size of an influence function. The model supersedes the current cumbersome procedure for determining an influence function and thus results in considerably improved and more economical manufacture. Furthermore, the model enables the quality of the final surface to be enhanced when polishing complex, for example aspherical or free-form, workpiece geometries and provides the first step in the application of time-variant influence functions.
  • Elektrotechnik und Medientechnik
  • Hochschulleitung und -einrichtungen
  • Maschinenbau und Mechatronik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

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

Ultraschallunterstütztes Schleifen von Linsen

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

OTTI e.V., Zwiesel Zwiesel

  • 04.-05.06.2008 (2008)
  • TC Teisnach Optik
  • Maschinenbau und Mechatronik
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

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

Precision finishing of aspherical optical components using ELID grinding

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

OTTI e.V., Zwiesel Zwiesel

  • 04.-05.06.2008 (2008)
  • Hochschulleitung und -einrichtungen
  • Maschinenbau und Mechatronik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Beitrag in Sammelwerk/Tagungsband

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

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

  • (2008)
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Maschinenbau und Mechatronik
Vortrag

  • Rolf Rascher

Advanced technologies in precision optics manufacturing - a view to 2015?

Meopta-Optika Prerov, Tschechische Republik

  • 2008 (2008)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Zeitschriftenartikel

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

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

In: Current Developments in Lens Design and Optical Engineering IX vol. 7060 pg. 706007 ff..

  • (2008)

DOI: 10.1117/12.794583

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
  • TC Teisnach Optik
  • Maschinenbau und Mechatronik
  • Hochschulleitung und -einrichtungen
Vortrag

  • Rolf Rascher
  • Peter Sperber

Blick in die Zukunft - Eine Agenda zur Optikfertigung 2015?

In: BayTech Optik Seminar

Deggendorf

  • 2008 (2008)
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Beitrag in Sammelwerk/Tagungsband

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

Forces acting between polishing tool and workpiece surface in magnetorheological finishing

vol. 7060 pg. 706006 ff..

  • (2008)

DOI: 10.1117/12.794196

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.
  • Hochschulleitung und -einrichtungen
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
Beitrag in Sammelwerk/Tagungsband

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

Magnetorheological Finishing of silicon nitride moulds

  • (2008)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
  • Hochschulleitung und -einrichtungen
Vortrag

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

Calculation of MRF influence functions

In: Optical Manufacturing and Testing VII, SPIE

San Diego, CA, USA

  • 2007 (2007)
  • Hochschulleitung und -einrichtungen
  • Elektrotechnik und Medientechnik
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
Beitrag in Sammelwerk/Tagungsband

  • Andreas Geiss
  • Markus Schinhärl
  • Elmar Pitschke
  • Rolf Rascher
  • Peter Sperber
  • K. Fathima
  • J. Slabeycius

Subsurface damages detecting on standard optical glass by dimple method

pg. 13 ff..

  • (2007)
  • Maschinenbau und Mechatronik
  • Elektrotechnik und Medientechnik
  • Hochschulleitung und -einrichtungen
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Zeitschriftenartikel

  • Markus Schinhärl
  • Rolf Rascher
  • R. Stamp
  • G. Smith
  • L. Smith
  • Elmar Pitschke
  • Peter Sperber

Filter algorithm for influence functions in the computer-controlled polishing of high-quality optical lenses

In: International Journal of Machine Tools and Manufacture vol. 47 pg. 107-111.

  • (2007)
Computer controlled polishing (CCP) is widely used in the production of high-quality optical lenses. CCP enables surface error-profile-dependent calculation of polishing sequences prior to processing, and facilitates the cost-effective manufacture of high-quality optical surfaces. Calculation of an individual polishing sequence requires knowledge of the surface error-profile in addition to knowledge of the material removal characteristic (influence function) of the polishing tool. Measurement errors during both determination of the surface error-profile, and the influence function, may lead to an incorrect polishing sequence calculation, which in turn may result in an inadequate product quality. A new method has been developed which minimises the effects of measurement errors on the influence function. The resulting algorithm renders an influence function symmetrical and filters noisy data. Practical polishing tests with magnetorheological finishing have been performed to verify this new technique. The improvement of the peak-valley (PV) value of the surfaces polished with the symmetrical rendered influence function was observed to average 14% greater than that which related to the PV value improvement of those surfaces which were polished with the unmodified influence function. The algorithm developed is based on software and is easily implemented. Thus, artificial enhancement of an influence function is a straightforward technique to improve the result of the polishing process.
  • Maschinenbau und Mechatronik
  • Elektrotechnik und Medientechnik
  • TC Teisnach Optik
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Zeitschriftenartikel

  • Elmar Pitschke
  • Peter Sperber
  • Rolf Rascher
  • R. Stamp
  • M. Smith
  • L. Smith
  • Markus Schinhärl

Lens production enhancement by adoption of artificial influence functions and a knowledge-based system in a magnetorheological finishing process

In: Optical Manufacturing and Testing VII vol. 6671 pg. 66711J ff..

  • (2007)

DOI: 10.1117/12.761356

High quality optical lenses are usually finished by magnetorheological finishing (MRF). In this process an abrasive fluid, with the ability to stiffen in a magnetic field, is used as the polishing tool in a computer-controlled machine tool. Although the machine is automated it is necessary for a skilled operator to set the machine and make judgments with regard to its operation. An investigation has been under way to examine the detailed operation of the MRF process, and the information that is necessary to establish best practice. This has resulted in the incorporation of a knowledge based system (KBS) into the machine control regime, and a methodology for the creation of artificial polishing tool characteristics, the machine influence function. The incorporation of the these elements has been instrumental in the operation of an enhanced MRF machine. This has been subject to extensive test procedures, and it has been demonstrated that the production process may be enhanced significantly and consistently. Batch production time may be significantly reduced, a figure in excess of a 50% reduction was met consistently during prolonged operation. Furthermore the incorporation of the KBS is instrumental in increasing the automation of the MRF process, reducing the levels of manual input necessary to manage machine operation.
  • Elektrotechnik und Medientechnik
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Hochschulleitung und -einrichtungen
Vortrag

  • Andreas Geiss
  • Markus Schinhärl
  • Elmar Pitschke
  • Rolf Rascher
  • Peter Sperber
  • K. Fathima
  • J. Slabeycius

Subsurface damages detecting on standard optical glass by dimple method

In: The 12th International Conference on Problems of Material Engineering, Mechanics and Design

Jasna, Slowakei

  • 29.-31.08.2007 (2007)
  • TC Teisnach Optik
  • Elektrotechnik und Medientechnik
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
Beitrag in Sammelwerk/Tagungsband

  • K. Fathima
  • Andreas Geiss
  • Rolf Rascher
  • Peter Sperber
  • Markus Schinhärl
  • Elmar Pitschke

Design and development of a novel computer-controlled power device for electrical-assisted optical grinding

pg. TD0406-1 ff..

  • (2007)
  • Elektrotechnik und Medientechnik
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
Zeitschriftenartikel

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

Calculation of MRF influence functions

In: Optical Manufacturing and Testing VII vol. 6671 pg. 66710Y ff..

  • (2007)
Magnetorheological finishing (MRF) is a commonly used computer-controlled polishing (CCP) technique for high precision optical surfaces. The process is based on a magnetorheological abrasive fluid, which stiffens in a magnetic field and may be employed as a sub-aperture polishing tool. Dependent upon the surface error-profile of the workpiece and the polishing tool characteristic (influence function) an individual polishing procedure is calculated prior to processing. However, determination of the influence function remains a time consuming and laborious task. A user friendly and easy to use software tool has been developed, which enables rapid computation of MRF influence functions dependent on the MRF specific parameters, such as, magnetic field strength or fluid viscosity. The software supersedes the current cumbersome and time consuming determination procedure and thus results in considerably improved and more economical manufacture. In comparison with the conventional time period of typically 20 minutes to ascertain an influence function, it may now be calculated in a few seconds. An average quality improvement of 57% relating to the peak-valley (PV) value, and approximately 66% relating to the root-mean-square (RMS) of the surface error-profiles was observed during employment of the artificial computed influence functions for polishing.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Elektrotechnik und Medientechnik
  • Maschinenbau und Mechatronik
  • Hochschulleitung und -einrichtungen
Beitrag in Sammelwerk/Tagungsband

  • Andreas Geiss
  • Markus Schinhärl
  • Elmar Pitschke
  • K. Fathima
  • Rolf Rascher
  • Peter Sperber
  • J. Slabeycius

Correcting silicon carbide and silicon nitride moulds by Magnetorheological Finishing

pg. 360-363.

  • (2007)
  • Maschinenbau und Mechatronik
  • Elektrotechnik und Medientechnik
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • Rolf Rascher

Ultraschallbearbeitung von Glas

In: 5. Technologietreff

Österreichische Arbeitsgruppe für Zerspanungstechnik AFA e.V.

  • 2007 (2007)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Beitrag in Sammelwerk/Tagungsband

  • Andreas Geiss
  • Markus Schinhärl
  • Elmar Pitschke
  • Rolf Rascher
  • Peter Sperber

Rauhigkeitsentwicklung bei der Bearbeitung von Komponenten für die Präzisionsoptik mit Diamantwerkzeugen

pg. 143-153.

  • (2006)
  • Hochschulleitung und -einrichtungen
  • Elektrotechnik und Medientechnik
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
Zeitschriftenartikel

  • Andreas Geiss
  • Markus Schinhärl
  • Elmar Pitschke
  • Rolf Rascher
  • Peter Sperber
  • J. Slabeycius

Sedimentations on high-precision surfaces of advanced materials by magnetorheological finishing

In: Current Developments in Lens Design and Optical Engineering VII vol. 6288 pg. 62880R ff..

  • (2006)
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.
  • Elektrotechnik und Medientechnik
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
Vortrag

  • 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

In: Current Developments in Lens Design and Optical Engineering VII

San Diego, CA, USA

  • 2006 (2006)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
  • Elektrotechnik und Medientechnik
  • Hochschulleitung und -einrichtungen
Vortrag

  • Rolf Rascher
  • Peter Sperber

Aktuelle Ergebnisse aus dem Labor Optical Engineering der FH Deggendorf zu den Arbeiten auf den Gebieten Ultraschallunterstütztes Schleifen und ELID-Schleifen

In: BayTech Optik Seminar

Deggendorf

  • 2006 (2006)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Hochschulleitung und -einrichtungen
Zeitschriftenartikel

  • 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

In: Optical Engineering vol. 45 pg. 063401 ff..

  • (2006)

DOI: 10.1117/1.2213630

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.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
  • Hochschulleitung und -einrichtungen
  • Elektrotechnik und Medientechnik
Zeitschriftenartikel

  • Elmar Pitschke
  • Markus Schinhärl
  • Rolf Rascher
  • Peter Sperber
  • L. Smith
  • R. Stamp
  • M. Smith

Simulation of a complex optical polishing process using a neural network

In: Robotics and Computer-Integrated Manufacturing vol. 24 pg. 32-37.

  • (2006)

DOI: 10.1016/j.rcim.2006.07.003

Most modern manufacturing processes change their set of parameters during machining in order to work at the optimum state. But in some cases, like computer-controlled polishing, it is not possible to change these parameters during the machining. Then usually a standard set of parameters is chosen which is not adjusted to the specific conditions. To gather the optimum set of parameters anyway simulation of the process prior to manufacturing is a possibility. This research illustrates the successful implementation of a neural network to accomplish such a simulation. The characteristic of this neural network is described along with the decision of the used inputs and outputs. Results are shown and the further usage of the neural network within an automation framework is discussed. The ability to simulate these advanced manufacturing processes is an important contribution to extend automation further and thus increase cost effectiveness.
  • Hochschulleitung und -einrichtungen
  • Maschinenbau und Mechatronik
  • Elektrotechnik und Medientechnik
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Zeitschriftenartikel

  • 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

In: Current Developments in Lens Design and Optical Engineering VII vol. 6288 pg. 62880Q ff..

  • (2006)

DOI: 10.1117/12.678720

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.
  • TC Teisnach Optik
  • Maschinenbau und Mechatronik
  • Elektrotechnik und Medientechnik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Hochschulleitung und -einrichtungen
Vortrag

  • Andreas Geiss
  • Markus Schinhärl
  • Elmar Pitschke
  • Rolf Rascher
  • Peter Sperber
  • J. Slabeycius

Sedimentations on high-precision surfaces of advanced materials by magnetorheological finishing

In: Current Developments in Lens Design and Optical Engineering VII

San Diego, CA, USA

  • 13.08.2006 (2006)
  • Hochschulleitung und -einrichtungen
  • Elektrotechnik und Medientechnik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
Beitrag in Sammelwerk/Tagungsband

  • Andreas Geiss
  • Markus Schinhärl
  • Elmar Pitschke
  • Rolf Rascher
  • Peter Sperber
  • J. Slabeycius

Deposits and damages on high precision surfaces of advanced materials

  • (2006)
  • Elektrotechnik und Medientechnik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
  • Hochschulleitung und -einrichtungen
Vortrag

  • Andreas Geiss
  • Markus Schinhärl
  • Elmar Pitschke
  • Rolf Rascher
  • Peter Sperber
  • J. Slabeycius

Deposits and damages on high precision surfaces of advanced materials

In: 5th Youth Symposium on Experimental Solid Mechanics

Puchov, Slowakei

  • 10.-13.05.2006 (2006)
  • Hochschulleitung und -einrichtungen
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
  • Elektrotechnik und Medientechnik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Beitrag in Sammelwerk/Tagungsband

  • Andreas Geiss
  • Markus Schinhärl
  • Elmar Pitschke
  • Rolf Rascher
  • Peter Sperber

Rauhigkeitsentwicklung bei der Bearbeitung von Komponenten für die Präzisionsoptik mit Diamantwerkzeugen

  • (2006)
  • TC Teisnach Optik
  • Hochschulleitung und -einrichtungen
  • Elektrotechnik und Medientechnik
  • Maschinenbau und Mechatronik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

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

Comparison of different magnetorheological polishing fluids

Jena

  • 12.09.2005 (2005)
  • Maschinenbau und Mechatronik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Hochschulleitung und -einrichtungen
  • Elektrotechnik und Medientechnik
Zeitschriftenartikel

  • 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

In: Optical Manufacturing and Testing VI vol. 5869 pg. 94-102.

  • (2005)

DOI: 10.1117/12.616780

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.
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
  • Hochschulleitung und -einrichtungen
  • Elektrotechnik und Medientechnik
Vortrag

  • Rolf Rascher

Labor Optical Engineering – Moderne Fertigungstechnik im Fokus

In: BayTech Optik Seminar

Deggendorf

  • 2005 (2005)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Zeitschriftenartikel

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

Comparison of different magnetorheological polishing fluids

In: Optical Fabrication, Testing, and Metrology II vol. 5965 pg. 659-670.

  • (2005)

DOI: 10.1117/12.656430

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.
  • Hochschulleitung und -einrichtungen
  • Maschinenbau und Mechatronik
  • Elektrotechnik und Medientechnik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Vortrag

  • Elmar Pitschke
  • Markus Schinhärl
  • Peter Sperber
  • Rolf Rascher

Utilizing a TII aspherical measurement machine in a computer-controlled polishing process

In: Optical Measurement Systems for Industrial Inspection IV

München

  • 13.06.2005 (2005)
  • Hochschulleitung und -einrichtungen
  • Elektrotechnik und Medientechnik
  • Maschinenbau und Mechatronik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Zeitschriftenartikel

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

New viscosity measurement for magnetorheological polishing fluid

In: Optical Manufacturing and Testing VI vol. 5869 pg. 133-141.

  • (2005)

DOI: 10.1117/12.616690

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.
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Elektrotechnik und Medientechnik
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
Zeitschriftenartikel

  • Elmar Pitschke
  • Markus Schinhärl
  • Peter Sperber
  • Rolf Rascher

Utilizing a TII aspherical measurement machine in a computer-controlled polishing process

In: Optical Measurement Systems for Industrial Inspection IV vol. 5856 pg. 987-993.

  • (2005)

DOI: 10.1117/12.612597

The demand on quality of optical surfaces is increasing from year to year. Computer controlled polishing is one way to fulfill these demands. The process depends on the error-profile of the optical surface. In this paper the usage of the TII measurement machine is discussed to manufacture optical surfaces.
  • Maschinenbau und Mechatronik
  • Hochschulleitung und -einrichtungen
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Elektrotechnik und Medientechnik
Vortrag

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

New viscosity measurement for magnetorheological polishing fluid

In: Optical Manufacturing and Testing VI

SPIE, The International Society for Optics and Photonics San Diego, CA, USA

  • 31.07.2005 (2005)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
  • Elektrotechnik und Medientechnik
  • Hochschulleitung und -einrichtungen
Vortrag

  • Peter Sperber
  • Elmar Pitschke
  • Markus Schinhärl
  • Rolf Rascher

MRF in der Praxis – Optimierung der Wirtschaftlichkeit

In: BayTech Optik Seminar

Deggendorf

  • 19.04.2005 (2005)
  • Elektrotechnik und Medientechnik
  • TC Teisnach Optik
  • Hochschulleitung und -einrichtungen
  • Maschinenbau und Mechatronik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

  • Andreas Geiss
  • Markus Schinhärl
  • Elmar Pitschke
  • Rolf Rascher
  • Peter Sperber

Analysis of thermal sources in a magnetorheological finishing (MRF) process

In: Optical Manufacturing and Testing VI

San Diego, CA, USA

  • 31.07.2005 (2005)
  • TC Teisnach Optik
  • Elektrotechnik und Medientechnik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Hochschulleitung und -einrichtungen
  • Maschinenbau und Mechatronik
Vortrag

  • 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

In: Optical Manufacturing and Testing VI

San Diego, CA, USA

  • 31.07.2005 (2005)
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.
  • Maschinenbau und Mechatronik
  • Hochschulleitung und -einrichtungen
  • Elektrotechnik und Medientechnik
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Zeitschriftenartikel

  • Andreas Geiss
  • Markus Schinhärl
  • Elmar Pitschke
  • Rolf Rascher
  • Peter Sperber

Analysis of thermal sources in a magnetorheological finishing (MRF) process

In: Optical Manufacturing and Testing VI vol. 5869 pg. 111-120.

  • (2005)

DOI: 10.1117/12.616751

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.
  • Maschinenbau und Mechatronik
  • Elektrotechnik und Medientechnik
  • TC Teisnach Optik
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

  • Elmar Pitschke
  • Markus Schinhärl
  • Rolf Rascher
  • Peter Sperber

Erzeugung hochpräziser Oberflächen auf optischen Bauelementen für die Präzisionsoptik mit magnetorheologischem Finishing (MRF)

In: Fünftes Symposium - Zukunft Glas - Von der Tradition zum High-Tech-Produkt

Zwiesel

  • 17.06.2004 (2004)
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
  • Elektrotechnik und Medientechnik
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Vortrag

  • Markus Schinhärl
  • Elmar Pitschke
  • Rolf Rascher
  • Peter Sperber
  • R. Stamp
  • L. Smith
  • G. Smith

Temporal stability and performance of MR polishing fluid

In: Current Developments in Lens Design and Optical Engineering V

SPIE, The International Society for Optics and Photonics San Diego, CA, USA

  • 2004 (2004)
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Elektrotechnik und Medientechnik
  • Hochschulleitung und -einrichtungen
Zeitschriftenartikel

  • Markus Schinhärl
  • Elmar Pitschke
  • Rolf Rascher
  • Peter Sperber
  • R. Stamp
  • L. Smith
  • G. Smith

Temporal stability and performance of MR polishing fluid

In: Current Developments in Lens Design and Optical Engineering V vol. 5523 pg. 273-280.

  • (2004)

DOI: 10.1117/12.558897

The lifetime of standard magnetorheological (MR) polishing fluids, used for example in polishing machines for optical applications, is limited. Scanning electron microscope examinations as well as chemical analyses of the fluid had been undertaken in order to investigate reasons for limited lifetime. We found out that the removal rate decreases during the course of time. However, the usable fluid life is most limited by the point of time when the critical minimum amount of fluid, necessary to ensure circulation, is reached. The results in association with a new fluid conditioner show, that a standard MR polishing fluid may be used for longer periods than common periods of about 2 weeks.
  • Maschinenbau und Mechatronik
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Elektrotechnik und Medientechnik
  • TC Teisnach Optik
Beitrag in Sammelwerk/Tagungsband

  • Elmar Pitschke
  • Markus Schinhärl
  • Rolf Rascher
  • Peter Sperber

Erzeugung hochpräziser Oberflächen auf optischen Bauelementen für die Präzisionsoptik mit magnetorheologischem Finishing (MRF)

pg. 89-98.

  • (2004)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Hochschulleitung und -einrichtungen
  • Maschinenbau und Mechatronik
  • Elektrotechnik und Medientechnik
  • TC Teisnach Optik
Vortrag

  • Elmar Pitschke
  • Markus Schinhärl
  • Peter Sperber
  • Rolf Rascher
  • R. Stamp
  • L. Smith
  • M. Smith
  • A. Hammer

Comparison of a new contact topographical measurement system for spherical and aspherical surfaces with interferometry

In: Current Developments in Lens Design and Optical Engineering V

Denver, CO, USA

  • 02.08.2004 (2004)
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Elektrotechnik und Medientechnik
  • Maschinenbau und Mechatronik
Zeitschriftenartikel

  • Elmar Pitschke
  • Markus Schinhärl
  • Peter Sperber
  • Rolf Rascher
  • R. Stamp
  • L. Smith
  • M. Smith
  • A. Hammer

Comparison of a new contact topographical measurement system for spherical and aspherical surfaces with interferometry

In: Current Developments in Lens Design and Optical Engineering V vol. 5523 pg. 225-234.

  • (2004)

DOI: 10.1117/12.558899

Since end of 2003 the TII-3D - the new contact topography measuring device for measuring aspherical and spherical surfaces - is available on market. Due to its novel technology, the system is specified to measure a large range with λ/10 accuracy, therefore being a very flexible tool for pre- and post-measurements in high quality zonal polishing processes like MRF. At the University of Applied Sciences Deggendorf a testing series has been carries out to compare the results of the TII-3D with CGH-interferometric measurements on aspherical surfaces. An analysis of the measurement errors is shown and ranking of the different metrology systems for production processes of high quality aspherical lenses is given.
  • Maschinenbau und Mechatronik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Hochschulleitung und -einrichtungen
  • Elektrotechnik und Medientechnik
Vortrag

  • Elmar Pitschke
  • Peter Sperber
  • R. Stamp
  • Rolf Rascher
  • L. Smith
  • M. Smith
  • Markus Schinhärl

Prediction of MRF polishing by classification of the initial error with Zernike polynomials

In: Optical Manufacturing and Testing V

San Diego, CA, USA

  • 03.08.2003 (2003)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Hochschulleitung und -einrichtungen
  • Maschinenbau und Mechatronik
  • Elektrotechnik und Medientechnik
Vortrag

  • Elmar Pitschke
  • Peter Sperber
  • Rolf Rascher
  • R. Stamp
  • M. Smith
  • L. Smith
  • Markus Schinhärl

Lens production enhancement by adoption of artificial influence functions and a knowledge-based system in a magnetorheological finishing process

In: Optical Manufacturing and Testing VII

San Diego, CA, USA

  • 03.08.2003 (2003)
  • Maschinenbau und Mechatronik
  • Elektrotechnik und Medientechnik
  • Hochschulleitung und -einrichtungen
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Zeitschriftenartikel

  • Elmar Pitschke
  • Peter Sperber
  • R. Stamp
  • Rolf Rascher
  • L. Smith
  • M. Smith
  • Markus Schinhärl

Prediction of MRF polishing by classification of the initial error with Zernike polynomials

In: Optical Manufacturing and Testing V vol. 5180 pg. 115-122.

  • (2003)

DOI: 10.1117/12.507652

The magnetorheological finishing (MRF) process makes use of a magnetically stiffened magnetorheological abrasive fluid to polish the surface of a workpiece in a precise fashion. The process may be used to finish the surface of high quality optical lenses. Investigations have been undertaken to quantify the operation of MRF and to identify those parameters key to an optimal operation of this lens production process. A correlation has been developed to relate the parameters important to the removal characteristics and to the precision of the polishing result and to the duration of polishing. A relationship to indicate the most appropriate MRF processing parameters for a lens is presented. In the examples discussed Fringe-Zernike polynomials are used to quantify the error on a lens.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • Maschinenbau und Mechatronik
  • TC Teisnach Optik
  • Hochschulleitung und -einrichtungen
  • Elektrotechnik und Medientechnik
Beitrag in Sammelwerk/Tagungsband

  • Rolf Rascher
  • Peter Sperber

IFHEM – Innovatives Fertigungskonzept für High Tech-Flächen durch Einsatz von MRF-Technologie

  • (2002)
  • Hochschulleitung und -einrichtungen
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Zeitschriftenartikel

  • Florian Schneider
  • Roland Maurer
  • A. Bickert
  • R. Stamp
  • G. Smith
  • Rolf Rascher

SG-Sensor – an affordable tactile alternative

  • (2002)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
  • Maschinenbau und Mechatronik
Zeitschriftenartikel

  • Rolf Rascher

Experimentelle Untersuchungen zur Technologie der Kugelherstellung

In: wt (Werkstattstechnik) Produktion und Management vol. 81 pg. 663-664.

  • (1991)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Zeitschriftenartikel

  • Rolf Rascher

Entwicklungstendenzen beim Schleifen von Kugeln

In: MM Industriemagazin-Maschinenmarkt vol. 97 pg. 34-38.

  • (1991)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Monographie

  • Rolf Rascher

Experimentelle Untersuchungen zur Technologie der Kugelherstellung

In: iwb Forschungsberichte

Springer Berlin Heidelberg Berlin, Heidelberg

  • (1989)
  • TC Teisnach Optik
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
Zeitschriftenartikel

  • Rolf Rascher

IMTS ‘88 in Chicago

In: maschine + werkzeug - Fertigungstechnik pg. 88-97.

  • (1988)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Monographie

  • Rolf Rascher

Practical analysis of the process of producing balls for ball bearings

Springer Verlag

  • (1988)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Zeitschriftenartikel

  • Rolf Rascher

Integration im Verborgenen – Die 7. EMO in Mailand

In: Moderne Fertigung pg. 90-98.

  • (1987)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Beitrag in Sammelwerk/Tagungsband

  • Rolf Rascher

Technologie metallischer und keramischer Verbundwerkstoffe

pg. 34-44.

  • (1986)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik
Zeitschriftenartikel

  • Rolf Rascher

Schleifmaschinen auf der 6. EMO in Hannover

In: maschine + werkzeug - Fertigungstechnik pg. 48-54.

  • (1985)
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TC Teisnach Optik