Evaluation measurement of accuracy of industrial Computed Tomography

In order to verify the measurement accuracy of industrial Computed Tomography (ICT), Calibrated test pieces are designed and the technical procedures are established. The experiment is accomplished on the 9Mev high-energy industrial CT system which is produced by the National X-ray Instrument & Equipment Center. Liner dimensions, sphere diameters, angle values, apertures and positioning dimensions are measured. After data analysis, different errors for these dimensions are acquired. The relative error of liner dimensions and angle values are smallest, under 0.4%. The apertures and sphere diameters have a moderate relative error almost 1.2%~1.8%. The positioning dimensions have a highest relative error, up to 2.85%. For the different materials of aluminum, nylon and stainless steel, higher density material with higher density has less measure error without considering the effect of the dimension type. A special standard piece is designed and used for the error of reverse reconstruction process based on CT image. These results compare well to the results attained by CMM (Coordinate Measuring Machining) and validate the ability of industrial CT system as a dimension measuring machine for nondestructive examination.