Reference standards for XCT measurements of additively manufactured parts – A Obation et al.

X Ray CT/11

Abstract

An increasing number of industrial sectors are considering the potential of additive manufacturing as an asset to improve their
production. Indeed, additive manufacturing enables the fabrication of very complex geometries and inner cavities that cannot be
manufactured with conventional techniques. However, in critical sectors such as aerospace, defence and medical, the parts need
to be certified, which requires parts to be non-destructively characterised in terms of flaws, geometry and dimensional accuracy.
X-ray computed tomography is the only current 3D volumetric technique, which is suited for the non-destructive analysis of
internal flaws, geometry and measurements of internal dimensions and roughness. However, regardless of its huge potential, Xray
computed tomography is not as mature a technology for dimensional metrology as compared to conventional tactile
coordinate measuring machines. In most cases there is no traceability to SI units in the dimensional domain. Recently, numerous
reference standards (i.e. physical artefacts) addressing X-ray computed tomography dimensional accuracy have been published,
but they do not necessarily address the calibration of XCT system in connection with AM parts. In this work, a new and improved
standard in three different materials has been designed with a dual purpose: Fully calibrating X-ray computed tomography for
dimensional measurements while being representative of additively manufactured parts in terms of flaws and material, meeting
the needs of the industry. These standards will be used to metrologically validate X-ray computed tomography for the inspection
of additively manufactured parts.