Metrological industrial x-ray computed tomography system
The ability to holistically and accurately measure the external and internal dimensions of an object is a Holy Grail that has now become a reality. Traditionally, manufactured components have been measured using contact or optical measurement systems. However, such systems can be slow when taking a high-density point cloud of information and cannot access internal features.
X-ray computed tomography (XCT) is widely known for its use in medical scanning but, with the development of compact, high-energy x-ray sources, XCT is now being used to measure engineering components. However, most XCT systems have been designed for detecting defects and to essentially image an object, not necessarily to extract accurate dimensional information.
Recently, a number of XCT manufacturers have developed metrological XCT systems – these are designed to be highly stable and allow the extraction of dimensional information from the XCT image data. This stability and accuracy is essential when using XCT to assess tolerances and dimensional information during manufacture.
Currently, there is a metrological XCT at the National Physical Laboratory, where they are carrying out the research necessary to achieve measurement traceability for industrial XCT. The system is based in the Institute for Advanced Manufacturing at The University of Nottingham and is focused on manufacturing research.
The XCT system is accessible by academia and industry, but is not primarily to be for service provision. Priority will be given to innovative research; both in how to make use of the system in a manufacturing environment and how to improve the metrological performance of the instrument. There is scope to use the large amount of information that is available from the design stage (e.g. CAD data) to significantly enhance the dimensional metrology capability in terms of both spatial (more information) and temporal bandwidth (less time for measurement).
XCT is a revolutionary tool for manufacturing research and, with the inclusion of metrological principles into its design, will lead to a step-change in both how we make things and what we make.