In situ 3D X-ray microtomography of laser-based powder-bed fusion (L-PBF)-A feasibility study

X-ray microtomography can be used to characterise objects undergoing fabrication by additive manufacturing. During the layer-by-layer building process, it can provide key information about geometry, roughness and it can even reveal typical defects such as lack-of-fusion porosity, gas pores or cracks. Usually, objects are built with varied processing parameters and then characterised post-mortem. In the present work, we describe our custom-designed additive manufacturing chamber allowing in situ 3D-non-destructive characterisation to be performed during layer-by-layer construction using synchrotron X-ray microtomography. Scans before (subsequently to powder deposition) and after local laser melting are acquired for every layer. A few examples of such a characterisation demonstrate the ability of the set-up to reproduce conditions close to those used in conventional laser powder-bed fusion devices and to reveal key phenomena.