In the Henry Moseley X-ray Imaging Facility at The University of Manchester, which was established in 2003, the versatility of Nikon Metrology computed tomography (CT) systems enable staff members to take on commercial projects as well as academic research. The first system to be installed at the university in 2000 was an XT H 225, which has since been joined by a custom built, large-envelope system with exchangeable 225/320 kV micro-focus sources and an XT H 320 large-envelope system complete with 16-bit detector. Of the 11 imaging systems in the X-ray facility, the three Nikon Metrology systems perform the majority of inspection projects.
Both large-envelope installations have the capacity to hold specimens up to one metre across and weighing up to 100 kg and the high-flux X-ray targets enable fast scanning. The original XT H 225 is used for inspecting much smaller samples. All systems are used more or less 24/7.
Tim Burnett, Deputy Director of the Henry Moseley X-ray Imaging Facility explained, “All the Nikon CT systems are perfect for exploratory work, even by first-time users, because they are quick and versatile. With interchangeable sources and a large range of energies, they allow a lot of different sizes and densities of samples to be studied. Components can be scanned in less than an hour and reconstructed to take a closer look.”
The imaging facility was initially opened for internal research, but is also used by other academic establishments and for sub-contract inspection in industrial applications as well. One member of staff is currently working full-time with industrial customers who come in to the facility, which accounts for approximately 20 per cent of the activities. Projects involve investigative analysis of composites, failures in metals and defects in additively manufactured components. The facility also works closely with museums to scan artefacts and even mummies. It also helped to check the authenticity of the Jules Rimet football world cup trophy.
There has recently been an increase in additive manufacturing (AM) research projects, in collaboration with the University of Sheffield. One purpose is to evaluate how well the shape of a final component correlates with that of the design, looking at the tolerances and any distortions during manufacture. Another involves observing internal defects and voids in AM products. Some are large inter-particle voids caused by incomplete sintering, while other, often much smaller voids could have been present in the original powder. Nikon Metrology CT is also the optimal solution for measuring internal and external geometry and for revealing internal defects.
Additionally, the CT equipment is employed to scan biological specimens or moving systems intermittently in what amounts to 4D time-lapse CT. 3D scans are taken at intervals and the motion can be illustrated in a video made from the individual images.