Detecting microscale impurities on additive surfaces using light scattering

Additive manufacturing (AM) is a fast-growing method that allows the production of complex geometries by reducing the need for traditional cutting tools and fixtures. A common metal AM technique, known as laser-based powder bed fusion (PBF-LB), uses laser beams to melt and fuse powder layer-by-layer into 3D parts. Despite efforts to improve the process, achieving consistency and reliability in PBF-LB remains a challenge, necessitating the development of comprehensive quality assessment systems tailored to PBF-LB. Microscale impurities that are formed on individual layers can significantly impact the overall part quality, and are the most common features across various materials. Hence, there is a need to establish a measurement system for their detection to create a quality assessment method for PBF-LB. This research introduces a light scattering technique designed for the detection of microscale surface impurities on PBF-LB components. Following the design of the experimental setup, a corresponding scattering simulation model, which is based on the Beckman-Kirchhoff approximation, has been developed to simulate the experimental conditions. This simulation model can be utilised for future use in generating scattering data faster and simpler than through experimentation. The paper presents preliminary results of both the experimental setup and simulation model. Our findings affirm that the proposed methodology, utilising both experimental and simulated approaches, can be used to detect microscale surface impurities. This advancement contributes to the establishment of a quality inspection system for the overall part assessment of PBF-LB.