Creating a Multi-material Probing Error Test for the Acceptance Testing of Dimensional Computed Tomography Systems

The requirement of quality assurance of inner and outer structures in complex multi-material assemblies is one important factor that has encouraged the use of industrial X-ray computed tomography (CT). The application of CT as a coordinate measurement system (CMS) has opened up new challenges, typically associated with performance verification, specification definition and thus standardization. Especially when performing multi-material measurements, further, new, challenging effects are included in dimensional CT measurements, e.g. the influence of material A on material B in multi-material scenarios and the appropriate parameters for surface determination in a multi-surface setting. Thus, this paper presents – as part of a multi-material acceptance test and to create trust in multi-material CT measurement – a new concept for multi-material probing error testing (P-test) and discusses the test design and the first experimental results. This paper also attempts to perform a critical analysis of this new concept ̶ featuring a compound sphere made of two half spheres of different materials ̶ and tries to perform analyses of geometrical features of the new standard.