X-ray tomography and coordinate metrology benchmark for internal cavities in additively manufactured alloys

Abstract X-ray computed tomography (CT) is widely used for dimensional inspection of inaccessible internal geometry, but multi-modal public benchmark datasets with reference metrology remain scarce, particularly for internal cavities. This paper releases a CT--coordinate measuring machine (CMM) benchmark for wall-thickness measurements using CT surface extraction of an artefact with a complex internal cavity that is disassembled for tactile probing. Four cases span Ti-6Al-4V and Inconel 625 in rough and chemically milled states. Each case includes nominal computer-aided design (CAD) geometry aligned to the CT reconstruction, CT projections, reconstructed volumes, CT surface segmentations, CMM point clouds with predefined thickness-pair vectors, and derived surface- and thickness-deviation labels. The paper defines the benchmark tasks and reporting convention and reports baseline results for reconstruction-based and CAD-informed routes. The benchmark permits validation of CT-based dimensional metrology in noisy and clean environments, including CAD-constrained surface reconstruction approaches that work entirely in projection space, such as elastic registration.