CT Measurement Realization Process: The Need for Advanced Correction Methods

Computed tomography use as a dimensional metrology technique has increased steadily, despite the fact that the uncertainty has been rarely determined and expressed in measurements of production parts. This perception may be attributed in part to a limited way of employing the uncertainty concept. From this perspective, the conceptual integration of the product (and measurement) realization process with the uncertainty approach is first emphazised in this paper. The reasoning behind it is to employ different methods for uncertainty evaluation in a rational sense, where the accuracy required to the uncertainty evaluation process drives the method selection. For critical measurement cases, which can be identified in the proposed concept, the need for advanced correction methods, using master part reference measurements for point-based compensation, is presented, tested and justified for GD&T characteristics.