X-Ray CT Proposed Measurement Study

Publication Details

Abstract

World-class manufacturers have many metrology solutions at hand to help them ensure the quality of their parts and finished products. For many decades, the “gold standard” for accuracy have been coordinate measuring machines (CMMs). Increasingly, however, alternative options have established niches within dimensional measurement applications based on the unique qualities of their specific technologies. For metrologists seeking to match the right technology to the right application, it is important to understand the relative accuracies and other performance profiles of these discrete technologies, some of which can approach, equal, and even exceed the performance of CMMs for dimensional measurement and/or inspection.
An option for an increasing number of manufacturers is X-ray computed tomography (CT), which uses penetrating radiation to provide three-dimensional images of an object These systems can help engineers acquire data about parts and other objects in unique ways—by, for example, peering inside the object o analyze porosity, connection issues, or even the material layers in parts or models created through additive manufacturing processes. Traditional CMMs are often limited by certain limitations of tactile probes. Even when used with noncontact optical systems, such as when laser scanners are swapped out for tactile probes, CMMs cannot see inside parts to obtain critical data on interior contours and structures.
In this paper, we will review the current state-of-the-art for X-ray CT, investigate the environmental and application factors that can affect measurement results, and consider some possible experiments that might reveal the performance and accuracy of CMMs vs. X-ray CT in a variety of settings and for different applications. In this endeavor the author will humbly accept suggestions from the members of the Coordinate Metrology Society regarding the scope and setup of potential experiments
going forward to reveal the relative strengths and weaknesses of X-ray CT, CMMs, and other dimensional measurement systems.