Physikalisch-Technische Bundesanstalt (PTB)

The Physikalisch-Technische Bundesanstalt (PTB) is the national metrology institute of Germany providing scientific and technical services. PTB measures with the highest accuracy and reliability – metrology as the core competence.

PTB has worked for over 25 years on coordinate metrology and is the leading partner in a large number of international and national projects for developing procedures and standards to improve the accuracy of CMMs to the limits. Hence PTB is a member of many national and international standardisation committees (e.g. ISO TC 213 WG10). Several ISO standards in coordinate metrology (especially standards of the ISO 10360-series) were predominantly drafted by PTB experts.

PTB has long experience in the operation of different types of coordinate measuring machines featuring different sensor types (tactile, tactile-optical, several optical). These CMMs have been used for calibration purposes and for research activities in the field of coordinate metrology. This work leads to error modelling for several types of CMMs.

In the last few years the work on micro-scale measurements was intensified. For example the principle of the tactile-optical probing realising very small probing elements and very low probing forces was invented, patented and has been successfully transferred to industry. This measurement principle and others are under on-going study and development by PTB to further enhance resolution and to decrease measurement uncertainty. Also the development and fabrication of tactile sensors based on micro-machined silicon was performed at PTB in the last ten years. The latest result of this work is a piezoresistive, isotropic tactile micro-probe with nanometre resolution.

In the field of dimensional CT measurements PTB has leading expertise (PTB was the first NMI using his own industrial CT system). PTB plays an active role in the standardisation activities in the field of dimensional CT.

In the field of micro-CMMs, first artefacts have been evaluated which facilitate for the first time tests similar to the standardised test for macro-CMM. Furthermore, in recent years various approaches have been undertaken by PTB in the development and fabrication of dimensional artefacts based on micro-machined silicon using photolithography, wet etching and silicon direct bonding technologies.

PTB will coordinate the project.

Website: www.ptb.de