Abstract:

The concept of measurement uncertainty is expended to the compliance uncertainty in the new generation geometrical product specifications (GPS), but the corresponding evaluation methods are not given. In order to fully estimate differences between the measurement result and specifications in product inspection, the evaluation of compliance uncertainty is studied based on the new generation GPS. Based on the definitions in the GPS, evaluation methods are proposed for specification uncertainty, method uncertainty and compliance uncertainty. By the black box model, with the help of the measurement result statistic value characteristic indexes, implementation uncertainty is evaluated. Selecting measurement of roundness in product inspection as an example, the detailed operation process to evaluate the compliance uncertainty is described, and the conformance zone is divided by the compliance uncertainty. Experiment results show that the specification uncertainty and method uncertainty can not be ignored because they are roughly equivalent to the implementation uncertainty. Since compliance uncertainty contains all the differences between the measurement result and the drawing specifications, making decisions for product conformance or non-conformance by the compliance uncertainty is more reliable.

Key words: black box model, compliance uncertainty, product conformity assessment, geometrical product specifications