Publications without theses

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Erstellt: Fri, 24 Mar 2023 23:10:55 +0100 in 0.0354 sec

Keck, Lorenz; Seifert, Frank; Newell, David; Theska, René; Haddad, Darine
Characterization and alignment of the flexure mechanism for the new Kibble balance at NIST. - In: ASPE Annual Meeting 2022, (2023), S. 80-84

Keck, Lorenz; Schlamminger, Stephan; Seifert, Frank; Newell, David; Theska, René; Hahhdad, Darine
Design of the mechanical system for the quantum electro-mechanical metrology suite. - In: 36th ASPE Annual Meeting 2021, (2022), S. 53-56

Schulze, Sven; Keck, Lorenz; Rogers, Kyle; Simonds, Brian; Artusio-Glimpse, Alexandra; Williams, Paul; Lehman, John; Seifert, Frank; Newell, David; Theska, René; Schlamminger, Stephan; Shaw, Gordon
An electrostatic force balance as a primary standard to measure high laser power by a multiple reflection system. - In: 36th ASPE Annual Meeting 2021, (2022), S. 11-15

Wittke, Martin; Torres Melgarejo, Mario André; Theska, René
Concept of a monolithic stiffness-compensated mechanism for high-resolution force sensors. - In: Sensors and Measuring Systems, (2022), S. 461-464

Monolithic compliant mechanisms with concentrated compliances are often used in high-resolution force sensors and precision balances. Since the measurement resolution is vastly limited by the bending stiffness of the compliant joints, the thinnest part of the joints is reduced to down to 50 µm. A further reduction encounters technological limitations and creates new side effects. Compensation for the "positive" stiffness of the mechanism can be achieved by integrating an element with "negative" stiffness that generates a counteracting force or torque when deflected. In the literature, preloaded tension springs, buckled leaf springs as well as trim masses are predominantly for that purpose. However, most existing approaches are either not monolithic, elaborate to readjust, associated with parasitic forces and torques, or only applicable in a defined orientation relative to the vector of gravity. This paper presents a new concept of monolithic stiffness-compensated mechanisms for use in high-resolution force sensors that is independent of spatial orientation. The negative stiffness is generated by a preloaded spring element of an integrated compensation mechanism. The preload force can be easily adjusted. The compensation force is generated simultaneously with the deflection and transmitted to the main mechanism by a lever and a dedicated coupling element to avoid parasitic effects as much as possible. A suitable design minimizes parasitic motions and avoids buckling of the thin joints as a result of the relatively high preloading force. Finite element simulations are performed to investigate the behavior of the mechanism and to validate the concept.
Layher, Michel; Bliedtner, Jens; Theska, René
Hybrid additive manufacturing : improved large scale additive manufacturing by means of laser tempering. - In: PhotonicsViews, ISSN 2626-1308, Bd. 19 (2022), 5, S. 47-51

Large-scale additive manufacturing (LSAM) is an additive manufacturing process based on the principles of fused filament fabrication but with significantly higher material deposition rates. The novel hybrid process shown in this paper combines LSAM with a laser beam heat treatment. The structure and mechanical properties of parts are improved due to significantly decreased void sizes. The following article details investigations into the vertical and lateral remelting of strands as well as the utilization of a mirror system, which enables beam guidance according to the machine's printing path.
Torres Melgarejo, Mario Andre; Theska, René
Energy storage for powering fine adjustment systems in hermetically sealed ultra-precision devices. - In: EASS, (2022), insges. 3 S.

Ultra-precision devices are often operated in hermetically sealed chambers to avoid external disturbances and maximize their performance. The remaining disturbing effects are mitigated through compensation or corrective methods. Compensation is frequently done in form of in-situ fine mechanical adjustments of highly sensitive units. Such adjustment systems utilize electromechanical drives to transform electrical energy into an intended motion. Electric cables are used as energy and signal carriers from an external control unit. The associated disturbing effects limit the adjustability. In particular, cable connections act as mechanical coupling elements, introducing indeterminate and time-varying forces. This paper deals with the conceptual design of a fine adjustment system for ultra-precision devices with an integrated energy storage. A spring-based mechanical energy storage system controlled by an optical signal is found to be the most suitable solution for the targeted field of application. The integration of an energy storage in the adjustment system to avoid electric cables and their disturbance effects will significantly improve the quality and stability of the adjustment and further increase the performance of precision devices.

Leineweber, Johannes; Meyer, Christoph; Füßl, Roland; Theska, René; Manske, Eberhard
A novel concept for 5D nanopositioning, nanomeasuring and nanofabrication machines :
Ein neuartiges Konzept für 5D Nanopositionier-, Nanomess-, und Nanofabrikationsmaschinen. - In: Technisches Messen, ISSN 2196-7113, Bd. 89 (2022), 9, S. 634-643

In den vergangenen Jahren wurden an der TU-Ilmenau zahlreiche Entwicklungen im Bereich der Nanopositionier- und Nanomesstechnik realisiert. Insbesondere die NMM-1 [Gerd Jäger, Eberhard Manske, Tino Hausotte, Jans-Joachim Büchner, Nanomessmaschine zur abbefehlerfreien Koordinatenmessung, tm - Technisches Messen, 67(7-8), 2000] sowie die NPMM-200 [Eberhard Manske, Gerd Jäger, Tino Hausotte, Felix Balzer, Nanopositioning and Nanomeasuring Machine NPMM-200 - sub-nanometre resolution and highest accuracy in extended macroscopic working areas, euspen’s 17th International Conference, 2017] stellen ein Novum auf dem Gebiet der Koordinatenmesstechnik mit Nanometerpräzision unter Einhaltung des Abbe-Komparatorprinzips [Ernst Abbe, Messaparate für Physiker, Zeitschrift für Instrumentenkunde, 10:446-448, 1890] dar. Ausgehend von diesen Errungenschaften besteht ein nächster Schritt im Messen und Fabrizieren auf stark gekrümmten, asphärischen, oder freigeformten Oberflächen. Vor jenem Hintergrund wird im folgenden Artikel ein Konzept für ein zweiachsiges Rotationsmodul vorgestellt. Dieses dient als Erweiterung für die NMM-1 und ermöglicht über das kartesische Messvolumen von hinaus zusätzlich eine Rotation des Tools über 360 ˚ um die Hochachse sowie 60 ˚ Neigung. Die Umsetzung erfolgt über eine neuartige sphärische Parallelkinematik. Mit Hilfe eines interferometrischen In-Situ-Referenzmesssystems können die während der Rotationsbewegungen auftretenden translatorischen Positionsabweichungen detektiert werden. Erste Untersuchungen an einem Prototypenaufbau erbringen den Funktionsnachweis des Referenzmesssystems über den gesamten adressierbaren Winkelbereich.
Keck, Lorenz; Seifert, Frank; Newell, David; Schlamminger, Stephan; Theska, René; Haddad, Darine
Design of an enhanced mechanism for a new Kibble balance directly traceable to the quantum SI. - In: EPJ Techniques and Instrumentation, ISSN 2195-7045, Bd. 9 (2022), 1, 7, S. 1-18

The "Quantum Electro-Mechanical Metrology Suite" (QEMMS) is being designed and built at the National Institute of Standards and Technology. It includes a Kibble balance, a graphene quantum Hall resistance array and a Josephson voltage system, so that it is a new primary standard for the unit of mass, the kilogram, directly traceable to the International System of Units (SI) based on quantum constants. We are targeting a measurement range of 10 g to 200 g and optimize the design for a relative combined uncertainty of for masses of 100 g. QEMMS will be developed as an open hardware and software design. In this article, we focus on the design of an enhanced moving and weighing mechanism for the QEMMS based on flexure pivots.
Schulze, Sven; Arumugam, Kumar; Theska, René; Shaw, Gordon
Development of a high precision balance for measuring quantity of dispensed fluid as a new calibration reference for the becquerel. - In: Proceedings of the 22nd International Conference of the European Society for Precision Engineering and Nanotechnology, (2022), S. 337-340

Hebenstreit, Roman; Wedrich, Karin; Strehle, Steffen; Manske, Eberhard; Theska, René
First prototype of a positioning device with subatomic resolution. - In: Proceedings of the 22nd International Conference of the European Society for Precision Engineering and Nanotechnology, (2022), S. 97-100

In the forthgoing work on a device that enables subatomic resolved highly reproducible positioning, a first prototype is here presented. The entire positioning system including the actuator, sensor and guiding mechanism, is realized as a micro-electro-mechanical system (MEMS) on chip level, based on silicon-on-insulator (SOI) technology. A modular printed circuit board acts as the mechanical as well as the electrical contacting interface for the silicon chip. First variants of a linear positioning system comprising axisymmetric double parallel crank structure are investigated. Pivot joints as flexure hinges with concentrated compliance are deployed. These hinges show minimal rotational axis displacement for small angles of deflection, thus ensuring smallest deviations to a straight-line path of the linear guiding mechanism. An electrostatic comb actuator transmits forces contactless to minimize over constraints. A measuring bridge in differential mode utilizes the same comb structures to measure the table position based on the capacitance change. Estimating the position resolution, limited by the resolution of the capacitive sensor, a measurable step width below 50 pm can be expected. In further steps, the device will be a platform to be equipped with a lattice-scale-based position measurement system according to achieve an even higher resolution and reproducibility.