Penetrating High-Resolution Inspection Tool for In-Process Control of Additive Manufacturing

To address the NASA need for reliable in-process sensing and monitoring technologies for additive manufacturing(AM), Physical Optics Corporation (POC) proposes to develop a new Penetrating High-Resolution Inspection Tool (PHRUIT). The PHRUIT, intended primarily for layer-by-layer quality control in the power bed fusion (PBF) process, is based on innovative X-ray Compton backscatter microscopy, which enables single-sided, high-resolution (~50 um), subsurface inspection of PBF parts. Due to the penetrating nature of X-rays, the PHRUIT will be able to inspect not only the surface of the last layer, but also the subsurface features, with typical penetration depths of 1-2 mm, and therefore will reveal voids and defects that are not visible with optical imaging. The PHRUIT will enable a user to "focus" on a particular depth within the part and localize any features or voids in x/y/z with accuracy of ~50 um. The PHRUIT will have a capability to cover arbitrarily complex part profiles with two dimensional translation, with a total inspection time of typical parts of around 1-2 min. In Phase I, POC will demonstrate the feasibility of the PHRUIT high-resolution imaging approach by fabricating and testing a technology readiness level (TRL)-4 preliminary prototype. In Phase II, POC plans to develop a fully functional and integrated TRL-6 prototype and demonstrate its NDE capabilities to NASA by testing it with relevant PBF AM systems. At the end of Phase II, the PHRUIT system prototype will be delivered to NASA for further characterization.