Applications and systematic errors of X-ray computed tomography associated with dimensional metrology

X-ray computed tomography (XCT) is increasingly being used in many industrial quality control applications due to its ability to visualise in three dimensions both the external and internal structure of parts and to detect defects without contact or damage to that part. XCT technology also has the potential to deliver critical dimensional measurements at the micrometre level. However, the quality of these measurements can be limited by a number of systematic errors associated with the technology, for example, beam hardening and cone beam effects. In this paper, beam hardening and cone beam errors associated with the cone beam XCT are described together with their impact on typical dimensional measurements.