In recent years, the use industrial X-ray computed tomography (XCT) in industrial inspection has greatly increased as it allows contact-free measurements of the geometry and dimensions of complex 3D objects. The ability to measure complex geometries allows, e.g., nondestructive testing (NDT) of samples ranging from simple welded structures to complex electronic or mechanic devices and 3D-printed samples.
A typical XCT device can measure through few centimeters of steel and longer distances through less dense materials. The best achievable accuracy of geometric measurements is in the range of 1/2000 of the sample size. The XCT measurement data can be used to determine the external and internal dimensions as well as surface geometry of the sample, which can then be compared to a CAD model.
VTT MIKES has recently started x-ray computer tomography research and measurement services for industrial customers. Our service offers possibilities for comparing measured component geometry to CAD models, identifying and locating defects, and for quality control of mechanical assemblies, among others. In our research on XCT, we focus on developing traceable industrial XCT measurements, better understanding of measurement errors and improving the measurement uncertainty. Key features of the industrial XCT system (GE phoenix v|tome|x s240) on which our services are based
- Microfocus: maximum voltage 240 kV, minimum spot size 5 µm
- Nanofocus: maximum voltage 180 kV, minimum spot size 0.9 µm
- Maximum sample size: ~0.3 m (one dimension can be longer)
- Maximum sample weight: 10 kg
The images below illustrate what kind of measurements the XCT system can be used for. Upper left image is a density map of a welded seam, upper right is 3D profile of a needle, lower image shows how dimensions in a sample can be determined from a measured surface.