Nondestructive evaluation of material properties in polymer additive manufacturing processes: moving towards process-agnostic qualification

Polymer additive manufacturing (AM) is critical for the production of products for many applications. However, qualification of polymer AM products requires following standards that are specific to an AM process and documenting process-centric print parameters. However, this qualification approach is tedious and does not address the problem, which is to understand the properties of the printed part. One way to avoid developing extensive qualification standards for each AM process is to characterise the polymer itself. However, the path towards process-agnostic qualification requires process monitoring and nondestructive characterisation techniques to measure local and bulk polymer properties. To expedite polymer-centric qualification of AM products, this review highlights nondestructive evaluation and monitoring techniques in-situ and ex-situ to offer a promising path to evaluate polymer relevant properties. Furthermore, this paper proposes a path to create a unifying framework that is polymer-centric, rather than process-centric, for future standard development and model validation.