A Method for Evaluating NDT Detectability in Additive Manufacturing Aerospace Parts

Additive manufacturing (AM) offers significant advantages in producing aerospace components, allowing for complex, optimized designs that enhance functionality and reduce weight. However, these designs must adhere to stringent mechanical and physical requirements while considering the limitations of non-destructive testing (NDT) techniques used for inspection. Additionally, managing the costs associated with production, qualification, and deployment is crucial.
One of the primary benefits of AM is its design freedom, which facilitates the creation of intricate geometries. However, this complexity inevitably complicates the inspection process. Given the critical nature of aerospace components, a high level of confidence in detecting flaws defects is essential. Thus, understanding the detectability limits of various NDT techniques is vital for ensuring the dependable inspection and qualification of components prior to their deployment. The effectiveness of these inspections and their cost are defined by the combination of the capabilities of NDT techniques and the specific characteristics of each component, including geometry, material and dimensions.
This project aims to determine the defect detectability limits of three NDT radiography-based techniques (X-ray computed tomography, digital and film X-ray techniques). To this end, a specific aerospace component is produced from Ti-6Al-4V using powder bed laser fusion (PBF-L) technology. Prior to production, defects of varying sizes (100 to 800 µm) and shapes (spheres, half-spheres and discs) are embedded in subsections of interest of the part via CAD modeling. The printed subsections are then used as inserts and assembled with the main component for inspection. Finally, a cost modeling analysis is used to compare the economic relevance of the studied NDT techniques in an industrial setting. This approach establishes an economic and replicable methodology for identifying the detectability limits of various NDT techniques and the selection of an appropriate NDT technique for a specific aerospace AM component.