Fully automatic optical system for gauge block calibration

This paper presents a novel principle for a contactless gauge block measurement using a combination of low-coherence interferometry and laser interferometry. The designed optical system combines a Dowell interferometer and a Michelson interferometer to ensure the gauge block length measurement with direct traceability to the primary length standard. The key advantage of the presented optical setup is its contactless measurement of the absolute gauge block length done as a single-step measurement giving complete information of the gauge block length, without any additional gauge block manipulation or any length comparison with a reference dimension. The measurement is fully automatic, with no operator influence. The designed setup is supplemented by an automatic handling system designed for a set of 126 gauge blocks (up to 100 mm) to allow the automatic contactless calibration without a human operator. Acknowledgements: The research was supported by Technology Agency of CR, project no. TA03010663. The research infrastructure was funded by the Ministry of Education, Youth and Sports CR, projects LO1212, CZ.1.05/2.1.00/01.0017, and by Academy of Sciences CR, project RVO: 68081731.