Analytical estimation of coordinate measurement uncertainty

Abstract The paper presents the assumptions and theoretical background of analytical method of estimation the coordinate measurement uncertainty. The uncertainty for each characteristic is estimated separately. Mathematical model for each characteristic uses the minimal number of so-called “characteristic points” of the measured workpiece. Each characteristic is defined by a formula presented in a form where it is a function of coordinates’ differences’ of characteristic points. The uncertainty budget for the coordinates’ differences includes influences of particular geometrical errors of CMM, probing system errors, as well as temperature errors. The applied algorithms of uncertainty estimation use the type B method according to the rules of GUM. The paper presents also the operational rules of software for the estimation of coordinate measurements uncertainty. The software covers 48 measurement models. The software is oriented on the ease of use. All necessary information concerning the accuracy of the used CMM are implemented by software provider. The basic version of the software includes the minimal database of the styli, but on demand the styli of particular customer can be implemented.