Diameter calibration of cylindrical artefacts with nominal diameters of 2.5 mm

Project Description

On two piston-cylinder pressure gauges with 35,3 mm diameter and two sets of fiber connector standards with 2,5 mm diameter, calibrations of internal and external dimensions with uncertainties aimed at 0,1 µm or better have to be made. A total of 16 diameters on the pressure gauges and 8 diameters on the connector standards will be measured. Form measurements will be provided by the proposer at least and the results may be taken into account for diameter uncertainty estimation by other participants.

Planned duration: 18 months.
The number of partners should not be extended, to be able to follow the time schedule of a CCM pressure comparison, the piston-cylinder units are used for.

Final Report 2001-09-26

The measurement results of EUROMET project 369 concerning the part of the external (ferrules) and internal (sleeves) 2,5 mm cylinders show very good agreement. The participating national metrology institutes furnished measurement results with maximum deviations from one another in the range of the uncertainties given by them, if it is taken into account that a given uncertainty of 0,1 μm includes, for example, the deviation in the rounding frame of ± 0,15 μm (here max. dev. -0,143 μm).
The deviations are in the same range as documented for diameter measurements on the small artefacts of EUROMET comparison measurement project 384 (2,5 mm plug and 3 mm ring gauge).
The documentation of the form deviations of the ferrule and sleeve artefacts was made available by the pilot laboratory together with the guidelines.
The documentation of the roundness profiles of the ferrules shows local deviations which must influence a small uncertainty of the diameter calibration. It seems, however, that, for the diameter calibration of the ferrules, neither the form profiles documented by the pilot laboratory nor calibrations of the participants were taken into account.
The results have shown good harmonisation among the participating institutes, incl. the National Institutes for Standardisation and Technology (NIST) of the United States of America. This is one of the first (and already successful)steps towards a harmonisation between the USA and Europe in the field of dimensional calibrations.