3D-characterization of micro balls with nanometer precision
Final Report Abstract
Nano and micro coordinate measuring machines (CMMs) have been developed for the precise and traceable measurement of small complex parts. The achievable uncertainty of these machines is mainly limited by the shape of the probing sphere, which needs to be well characterized. However, there is currently no established technique for the characterization of such spheres. It was, therefore, the objective of this project to investigate, develop and compare procedures for the characterization of micro spheres with radii of 150 µm or less and with an uncertainty of 10 nm. In order to reduce the complexity, the investigations were initially limited to the measurement of one great circle. These investigations led to the development of a new strategy, which enables the characterization of such spheres with a high lateral and vertical resolution. It is based on a set of atomic force microscope (AFM) surface scans in conjunction with a stitching algorithm. The strategy has been tested on spheres with nominal radii ranging from 61 µm until 150 µm. We were able to achieve repeatabilities of up to 2.5 nm. Reducing the complexity to equatorial measurements was a conscious decision to enable extensive experiments to be carried out at an early stage of the project. The knowledge, thus, gained should be transferable to the characterisation of the entire sphere. This case was investigated in the second half of the project. The sampling of a full sphere through a set of AFM surface scans could be demonstrated. Nevertheless, this case requires further research efforts. That applies in particular to the dynamics of the scanning process and the speed of data processing techniques.
Publications
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Radius and roundness measurement of micro spheres based on a set of AFM surface scans. Measurement Science and Technology, 32(4), 044005.
Oertel, Erik & Manske, Eberhard
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Unsicherheitsbetrachtungen zur Charakterisierung von Mikrokugeln auf Basis von AFM-Oberflächenscans. Messunsicherheit praxisgerecht bestimmen – Prüfprozesse in der industriellen Praxis 2021, 121-132. VDI Verlag.
Oertel, E. & Manske, E.
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Ein Bottom-up Ansatz für die Radius- und Rundheitsmessung von Mikrokugeln. tm - Technisches Messen, 89(s1), 101-106.
Oertel, Erik & Manske, Eberhard
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Influence of form deviations on the radius and roundness measurement of micro spheres. tm - Technisches Messen, 89(10), 704-713.
Oertel, Erik & Manske, Eberhard
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Influence of the reference surface and AFM tip on the radius and roundness measurement of micro spheres. Measurement Science and Technology, 35(2), 025010.
Oertel, Erik & Manske, Eberhard
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“Characterization of micro spheres through AFM surface scans”. In: euspen’s 23rd International Conference and Exhibition. (2023)
Erik Oertel & Eberhard Manske
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„Modelling the measurement process for the radius and roundness measurement of micro spheres”. In: NanoScale
Erik Oertel & Eberhard Manske
