Measurement uncertainty analysis on a five-axis nano coordinate measuring machine NMM-5D following a vectorial approach :
Messunsicherheitsbetrachtungen an einem fünfachsigen Nano-Koordinatenmessgerät NMM-5D nach einem vektoriellen Ansatz. - In: Technisches Messen, ISSN 2196-7113, Bd. 88 (2021), 2, S. 61-70
Dieser Beitrag zeigt ein Konzept für eine fünfachsige Nano-Koordinatenmessmaschine zur Messung auf stark gekrümmten asphärischen und frei geformten optischen Oberflächen in einem Messvolumen von 25mm × 25mm × 5mm mit einem maximal möglichen Neigungswinkel von bis zu 60˚ zur Hochachse und einer maximalen Rotation von 360˚ um die Hochachse. Dabei wird die Probe translatorisch bewegt und der Sensor in seiner Orientierung verändert. Unter Einhaltung des Abbe-Komparatorprinzips für alle Messachsen wird die Bewegungsabweichung des Sensors bei der Rotation durch ein in-situ-Referenzmesssystem erfasst. Dieses besteht aus drei kartesisch angeordneten Fabry-Pérot-Interferometern mit dem Ursprung im Antastpunktes des Sensors, die den Abstand zu einer hemisphärischen Referenzfläche messen. Die Messunsicherheitsbetrachtung des Gesamtsystems erfolgt nach dem guide to the expression of uncertainty in measurement in einem vektoriellen Ansatz und liefert unter konservativen Annahmen eine Unsicherheit des Antastpunktes von maximal 72 nm (k=1).
https://doi.org/10.1515/teme-2020-0092
Suppression of free convection effects for spherical 1 kg mass prototype. - In: International journal of heat and mass transfer, ISSN 1879-2189, Bd. 170 (2021), 121037, insges. 13 S.
We investigate the free convection processes in the vicinity of a spherical 1 kg mass standard by two- and three-dimensional direct numerical simulations using a spectral element method. Our focus is on the determination and suppression of updraft forces in a high-precision mass comparator which are caused by temperature differences between mass standard and its environment in the millikelvin range - a source of systematic uncertainties in the high-precison mass determination. A two-dimensional model is presented first, which obtains a good agreement with previous laboratory measurements for the smaller temperature differences up to 15 mK. The influence of different boundary conditions and side lengths of the square domain is discussed for the mass standard positioned in the center of the chamber. The complexity is increased subsequently in configurations with additional built-ins for counter heating in form of planar plates or hemispherical shells above the mass standard. The latter ones lead to a full compensation of the updraft force. Three-dimensional simulations in a closed cubic chamber confirm the two-dimensional findings and additionally reveal complex secondary flow patterns in the vicinity of the mass standard. The reduction of the heat transfer due to the built-ins is also demonstrated by a comparison of the Nusselt numbers as a function of the Rayleigh number in the chosen parameter range. Our simulations suggest that such additional constructive measures can enhance the precision of the mass determination by suppression of free convection and related systematic uncertainties.
https://doi.org/10.1016/j.ijheatmasstransfer.2021.121037
Nanopositioning and -fabrication using the Nano Fabrication Machine with a positioning range up to Ø 100 mm. - In: Novel Patterning Technologies 2021, (2021), S. 1161016-1-1161016-10
This paper focuses on a new Nano Fabrication Machine 100 (NFM-100) with a working range up to 100 mm in diameter and its integrated tip-based system, which can be used as an Atomic Force Microscope (AFM) as well as for Field-Emission-Scanning-Probe-Lithography (FESPL). The combination of both systems offers the possibility to fabricate and analyze micro- and nanostructures with high resolution and precision down to a single nanometer over a large area in one single configuration without tool or sensor change. After the description of the basic machine structure of the NFM-100, the demonstration of long range and large area AFM scans in combination with the NFM-100 will be shown. Additionally, the basic functionality of the FESPL manufacturing process is presented.
https://doi.org/10.1117/12.2583703
A novel approach to generate a static torque in the range from 1 mN&hahog;m to 1 N&hahog;m :
Ein neuartiger Ansatz zur Erzeugung eines statischen Drehmoments im Bereich von 1 mN&hahog;m bis 1 N&hahog;m. - In: Technisches Messen, ISSN 2196-7113, Bd. 88 (2021), 2, S. 103-113
Drehmomentsensoren mit einem kleinen Messbereich bis zu 1 N&hahog;m sind Teil verschiedener Präzisionsgeräte, wie beispielsweise Roboter oder Werkzeuge für medizinische Operationen und Nanofabrikationsgeräte. Die Drehmomentsensoren benötigen häufig eine Kalibrierung, für die eine Rückführbarkeit nachgewiesen werden muss. Gemäß gesetzlichem Auftrag haben die nationalen metrologischen Institute die Aufgabe, die Drehmomenteinheiten zu realisieren und die geforderte Rückführbarkeit zu ermöglichen. Dieser Artikel zeigt, wie nach einem neuen Prinzip statische Drehmomente im Bereich von 1 mN&hahog;m bis 1 N&hahog;m erzeugt werden können. Ziel der laufenden Arbeiten war die Umsetzung dieser neuen Idee der Drehmomenterzeugung zur Schaffung einer neuen, präziseren Drehmoment-Normalmesseinrichtung. Die Leistungsfähigkeit der neuen Methode wurde mit der Erzeugung von statischen Drehmomenten nach dem Stand der Technik (PTB-Drehmoment-Normalmesseinrichtung) verglichen.
https://doi.org/10.1515/teme-2020-0090
Revisiting the limits of photon momentum based optical power measurement method, employing the case of multi-reflected laser beam. - In: Metrologia, ISSN 1681-7575, Bd. 58 (2021), 1, 015006, insges. 13 S.
In this work, we review the viability and precision of the photon-momentum-based optical power measurement method that employs an amplification effect caused by a multi-reflected laser beam trapped in an optical cavity. Measuring the total momentum transfer of the absorbed and re-emitted photons from a highly reflective surface (reflection of the laser beam from an optical mirror) as a force provides the possibility of measuring the optical power with direct traceability to SI units. Trial measurements were performed at two different metrology laboratories: the laboratory for mass/force at the Technical University of Ilmenau, and the clean room laser radiometry laboratory at PTB, with a portable force measurement setup consisting of two electromagnetic force compensation balances. We compared the results of the optical power measurements performed with the force measurement setup, via the photon-momentum-based method, with those performed using a calibrated reference standard detector traceable to PTB's primary standard for optical power, the cryogenic radiometer. The comparison was carried out for an optical power range between 1 W and 10 W at a wavelength of 532 nm, which corresponds to a force of approximately 2000 nN at the upper limit, yielding approximately 2.3% relative standard uncertainty in the case of 33 reflections. Thus, conflating the high-precision force metrology technique at [my]N to nN levels with the optical setup required to achieve specular multi-reflection configuration of the laser beam, where a macroscopic optical cavity with ultra-high reflective mirrors (>99.995%) can adjustably be suspended from the force sensors, depending on required geometry of reflections, we show that the uncertainty of the optical power measurements upon further increase of the nominally applied optical power, the number of laser beam reflections, or the reflectivity coefficient of the mirrors can be markedly reduced.
https://doi.org/10.1088/1681-7575/abc86e
Conceptual design of a microscale balance based on force compensation. - In: Microactuators, microsensors and micromechanisms, (2021), S. 103-114
Macroscopic electromagnetic force compensation (EMFC) balances are well established but were not yet demonstrated within microsystems. Hence, in this paper, the concept and the design of a micro fabricated force compensation balance is presented. The implemented concentrated compliance mechanism in form of flexure hinges enables motion with high precision, which is combined with a force compensation mechanism. The concept of force compensation promises a high measurement range, which is expected to be up to 0.5 mN, while still enabling a high resolution of less than 8 nN. The developed dynamic model of the miniaturized balance is used for the design of a PID-controller strategy. Here, continuous and time-discrete controller approaches are compared. The time-discrete controller with realistic delay times, leads to an accuracy of the controller, which is better than the expected accuracy of the integrated capacitive position sensor.
https://doi.org/10.1007/978-3-030-61652-6_9
Radius and roundness measurement of micro spheres based on a set of AFM surface scans. - In: Measurement science and technology, ISSN 1361-6501, Bd. 32 (2021), 4, 044005, S. 1-11
Micro coordinate measuring machines have been developed for the traceable characterisation of small complex parts, due to the demand in research and industry. These machines require geometrically well characterised probing spheres of ever smaller radii. Currently, there is no established procedure for the measurement of such spheres below radii of 500 [my]m. In this paper we, therefore, propose and investigate an approach which is based on a set of AFM surface scans in conjunction with a stitching algorithm. The strategy was implemented on a nano measuring machine and investigated on a ruby sphere with a radius of 150 [my]m. Although the strategy can generally be applied to the characterisation of a full sphere, we limit ourselves to the measurement of one greate circle (equator). The technique enables the measurement of micro spheres with a high lateral and vertical resolution. The mean radius of the ruby sphere was measured with a standard deviation of 3.7 nm over 6 repetitions. As our experiments have shown, the measurement procedure is at the moment mainly influenced by the shape of the AFM tip which requires further attention.
https://doi.org/10.1088/1361-6501/abcff4
Coordinate transformation and its uncertainty under consideration of a non-orthogonal coordinate base. - In: Measurement science and technology, ISSN 1361-6501, Bd. 32 (2021), 4, 045001, insges. 6 S.
Nanopositioning and nanomeasuring machines are 3D coordinate measuring systems with nanometer precision at measurement volumes in the cubic centimeter range. The coordinate base is formed by an interferometer system with a common mirror corner. The orthogonality deviations of the mirror corner require a coordinate transformation of the measuring axes. The uncertainty of the coordinate transformation must be taken into account in the overall measurement uncertainty budget. Starting from a complete transformation model, the result of model simplications on the transformation behaviour is analysed and discussed.
https://doi.org/10.1088/1361-6501/aba3f5
An electrothermally actuated membrane as oscillating pinhole for the high-frequent modulation of light. - In: DGaO-Proceedings, ISSN 1614-8436, Bd. 121 (2020), B37, insges. 2 S.
We present theory, processing steps and first results for a thermally actuated Aluminiumnitride-Platinum membrane with a resonant frequency of the first mode at around 100 kHz and resonant displacements at its center of around 30 µm. The radial-symmetric membrane is broadband opaque for wavelengths from visual light and beyond. An exception is a small pinhole of various diameters below 3 µm in its center. Through thermally induced asymmetric stress inside the multilayer, the clamped membrane bends out. The pinhole in its center will be displaced parallel to the optical axis.The intended use for such a membrane is to replace the traditional confocal pinhole in the detection path of a microscope. Applying a stable known resonant modulation on an acquired signal enables a lock-in principle for a differential confocal depth sensing as shown in [1]. The advantage over the employed tunable acoustic gradient lens (TAG lens) there, is the reduced size, the simplicity of the arrangement and constant illumination properties on the sample.
https://nbn-resolving.org/urn:nbn:de:0287-2020-B037-6
Grundlegende Untersuchungen zur Entwicklung von fünfachsigen Nanopositioniermaschinen für Mess- und Fertigungszwecke. - In: Jahrbuch Optik und Feinmechanik, ISSN 0075-272X, Bd. 66 (2020), S. 67-92