scope:

This guideline describes one possible procedure for determining the task-specific uncertainty of coordinate measurements. It allows to determine measurement uncertainties of practical workpiece tests, which can then be used for establishing conformance or non-conformance with the specification in accordance with DIN EN ISO 14 253-1, or for assessing the test suitability.

The procedure described can be applied wherever the procedures according to VDI/VDE 2617 Part 7 or Part 8 are not applicable due to possibly unsatisfied requirements (simulation software or calibrated workpiece).

Furthermore, the procedure is suitable for determining contributions from individual influence quantities. Such information is required, e. g., to optimise the measurement strategy in terms of the number and arrangement of the measuring points.

The procedure is suitable for all measurands for which the mean value is the best estimate as per DIN V ENV 13005 (GUM). This holds for all results calculated by means of Gaussian regression, e. g. linear measures such as diameters or distances, but also angles and location errors including position, symmetry and coaxiality as per DIN EN ISO 1101.

In some cases, the measurands are defined as extreme values, e. g. form, orientation and run-out as per DIN EN ISO 1101. The uncertainties, then, can only be determined if the local form errors of the surface were recorded comprehensively during the measurement, using a rather large number of measuring points.