Evaluation and management procedure of measurement uncertainty in new generation geometrical product specification (GPS)

Abstract

Because of measurement errors objectively existing, measurement results always deviate from the “true value” of the measurand. Measurement uncertainty, as a quality index characterizing measurement results, attracts wide attention in the world. Unifying the evaluation of uncertainty and its expression will help understand measurement results, and promote international technical and commercial communication. According to the International Organization for Standardization ISO/BIPM “Guide to the Expression of Uncertainty in Measurement” – usually referred to as the GUM, which was published in 1993, this paper deals systematically with the way of evaluation and expression of measurement uncertainties. It expands the concept and meaning of measurement uncertainties, and normalizes the Procedure for Uncertainty of Measurement MAnagement (PUMA) by using new thoughts based on the GUM and the systematic quantifying-unifying in the new generation Geometrical Product Specification (GPS). Furthermore, the concept of uncertainty has been expanded to the whole GPS system beyond just measurement uncertainty, and the functions, specifications and measurement verification of workpieces are quantified and integrated by using the statistic and quantificational characteristic of expanded uncertainty. The optimum allocation of resources amongst specification, manufacturing and verification is realized, the total efficiency of products is increased by the adjustment function of uncertainty as an economic tool.