The comparison has been proposed and is organised by CEM (ES) as a continuation of the EURAMET comparison L-S23.(2013). The aim is to solve difficulties found by some participants in the previous comparison due to the lack of metrological quality of the circulating sphere. CEM, after locating high quality standard spheres, proposes this new comparison in order to know the real capabilities of measuring roundness in spherical standards by applying error separation techniques to seek the lowest uncertainty. The comparison is ready to start after consultation with some participants, most of whom were also involved in the previous comparison.
Progress Report 2020-10-21
Artefacts selected were 2 ceramic spheres of 20 mm and 25 mm. The comparison started in February 2020 as scheduled. On the date of this progress report, the results from all participants, VSL, DTI, INRIM and LNE have been already received. So, only final measurements of CEM are needed to close the circulation. The finalisation of the comparison is expected by December 2020.