Dimensional Measurement of Internal Features in Complex Castings

Abstract

X-ray computed tomography (CT) provides a powerful capability of visualizing the internal characteristics of an object. The technique has been well proven as a diagnostic tool in medical applications since the introduction of the first CT system in 1971 [1–3]. The use of CT as a tool for industry has not matured in the same way; many unique capabilities of this NDE modality are not being utilized. The Materials Directorate of the Wright Laboratory at Wright-Patterson Air Force Base sponsored the program ``Computed Tomography Applications Development'' to assess a variety of applications for CT as a nondestructive test and measurement technique. Several applications of CT for castings were identified as some of the most promising [4–6]. These applications include locating and characterizing porosity and other flaws, comparing as-cast part dimensions with design dimensions, and providing dimensional measurements for reverse engineering. This paper examines the application of CT to the problem of comparing internal dimensional measurements with critical design dimensions.