Abstract:
X-ray tomography has emerged as a uniquely powerful and non-destructive tool to analyze defects in additive
manufacturing. Defects include unintended porosity, rough surfaces and deviations from design, which can
have different root causes and can vary significantly among samples. Powder material properties, non-uniform
delivery of the powder layer, deformation during manufacturing, deviations from optimal process-parameters
caused by changes in the laser beam, the optical components and the scanning system operation, may result in
lack of fusion pores, metallurgical pores, keyhole pores, etc. These different types of pores have different typical
sizes, shapes and 3D distributions. All types of defects have effects on the mechanical properties of a final part.
The use of X-ray tomography to visualize pores in parts (non-destructively) prior to mechanical testing has
allowed us to improve our understanding of the effect of this porosity on the mechanical properties of the part
(also referred to as “effect of defect”). This can provide the possibility to discriminate critical defects from harmless
ones, and thereby build confidence in additivemanufacturing processes. This paper reviews the current state
of knowledge with regard to the “effect of defect” in metal additivemanufacturing, and highlights some relevant
examples from our recent work.
