Prof. Adam Woźniak

Warsaw University of Technology, Poland

Machine tool metrology, industrial CT

All keynote details TBC,

Prof. Dr.-Ing Michael Marxer, Eastern Switzerland University of Applied Sciences, Institute for Microtechnology and Photonics, Competence Centre for Production Metrology

Aperture Calibration at 0 °C: Metrological Challenges Beyond Established Standards

High-precision apertures are a key enabling element for radiometric measurements on Earth and in space, for example for determining the radiative power density of celestial bodies such as the Sun. Their calibration directly affects the reliability of climate monitoring, long-term solar observation, and space-based measurement systems. Despite their importance, aperture calibration is often treated as a well-established task—an assumption that quickly breaks down when moving beyond standard laboratory conditions.

This keynote reflects on practical experience gained from the manufacturing and calibration of high-precision apertures at the OST – Eastern Switzerland University of Applied Sciences, in close collaboration with RhySearch. A particular focus is placed on the calibration of apertures at 0 °C, rather than the conventional reference temperature of 20 °C. This shift introduces fundamental challenges related to thermal behavior, measurement uncertainty, traceability, and the validity of established metrological concepts.

Dedicated calibration procedures based on multisensor coordinate measuring systems were developed to achieve the lowest possible measurement uncertainty under these non-standard conditions. Different measurement strategies and sensor concepts are critically discussed, highlighting their strengths, limitations, and practical applicability. Special attention is given to the question of traceability at 0 °C, which proved to be one of the central challenges of the work.

Rather than presenting a single solution, this keynote aims to share lessons learned at the interface of ultra-precision manufacturing and production metrology. It highlights how metrological challenges evolve when measurement conditions deviate from established standards, and discusses the implications for future high-accuracy measurements in space instrumentation, radiometry, and climate observation.

Biography

Michael Marxer is Professor of Production Metrology at the OST – Eastern Switzerland University of Applied Sciences, where he leads the Production Metrology Group and serves as Head of the Production Metrology Measurement Laboratory in Buchs, Switzerland.

He studied Precision Engineering at the NTB Buchs (University of Applied Sciences Buchs) from 1993 to 1996. He received his doctorate from Friedrich-Alexander University Erlangen-Nuremberg under the supervision of Prof. Albert Weckenmann, with his research focusing on coordinate metrology, with particular emphasis on multisensor coordinate measuring systems and sensor development.

Following the merger of several universities into OST, Prof. Marxer took on responsibility for the SCS calibration laboratory (Swiss Calibration Service) and the STS testing laboratory (Swiss Testing Service) at OST, ensuring traceability and quality assurance for industrial metrology applications, including roughness metrology, which is offered as a dedicated calibration service.

He is President of CMTrain e.V., an association dedicated to education and training in coordinate metrology using blended learning concepts, and a member of the guideline committee VDI 2617 in Germany.

His professional interests include production metrology, multisensor coordinate metrology, sensor development, calibration and traceability, roughness metrology, and industrial measurement processes, with a strong focus on bridging academic research and industrial application.