Form and dimension measurements using X-ray computed tomography (X-ray CT) are useful in product development, reverse engineering, production control and quality certification. This is because X-ray CT systems can get three-dimensional 3D volumetric data on the full body of the target object all at once. The measurement space of 3D coordinate measuring systems (CMSs), which include X-ray CTs, are distorted by kinematic and other factors. This means that measurement space deformation should be compensated for precise dimensional measurement. The compensation function should also be occasionally checked. For the widely-used coordinate measuring machine (CMM), the mobile frame is stable over a long period, making it unnecessary to check whether the compensation function works well or not on the CMM. The mobile frame of the X-ray CT is less stable than that of a CMM, so the space deformation compensation function on X-ray CTs should be checked more often than that on CMMs to perform precise dimensional measurement using X-ray CTs. We propose a simple interim check method for an X-ray CT that is through repeated checking, assesses the long-term stability of the mobile frame of the X-ray CT.
Enhanced dimensional measurement by fast determination and compensation of geometrical misalignments of X-ray computed tomography instruments