Theoretical Analysis of Measuring Accuracy of Three Linear Axis CMMs from Position Errors

Abstract

The measuring accuracy of coordinate measuring machines (CMMs) depends on different factors such as the errors associated to the CMM axis movement, the working table and other CMM elements. In order to estimate the measuring errors that can be present during the dimensional evaluation of mechanical components, the nature and relevance of the distinct factors involved in the inspection process should be properly identified, such as the position errors, straightness errors, part errors and other geometrical and dynamic deviations. The knowledge about the influence of the main errors related to the elements integrated in the CMM, can serve to estimate the expected accuracy during the geometrical evaluation of manufactured products or machinery components. In this work, the effect of position errors will be evaluated by separate in order to deduce the contribution of this factor to the resultant measuring accuracy. This study is oriented to the analysis of three-axis coordinate measuring machines, and distinct types of CMM axis errors will be discussed. The results shown in this work are focused on CMMs type FXYZ, although similar studies could be developed for other structural configurations.