Inspection of Additively Manufactured Aero-engine Parts Using Computed Radiography Technique

The recent advancement and development of fabricating metallic end-use parts by the additive manufacturing (AM) process are targeted for the complex shapes and part consolidation applications of aero-engine systems. Among various AM technologies, laser powder bed fusion (LPBF) is promising for complex geometries with better dimensional accuracy and surface finish. Application of non-destructive testing (NDT) methods to inspect the quality and integrity of LPBF processed parts is inevitable for quantitative assessment of process-related defects like voids and porosities. The LPBF process also tosses inspection and metrological challenges for end-use parts involving the inherent geometric complexity of topology-optimized AM parts and inaccessible internal geometries, primarily for conventional NDT methods. The computed radiography (CR) is a simpler and faster NDT technique employed in the present study to inspect the inaccessible internal geometries in the LPBF parts. CR inspection methodology is established on the different LPBF samples with different internal through-hole of 0.5 and 1.0 mm diameters. The established methodology was employed on the aero-engine parts such as instrument probe, oil injector, and diffusion cooling hole plate. The dimensional analysis demonstrated that the CR results were comparable with the CAD model. In the present study, a reasonable accuracies of 0.6, 0.6, 0.8, 0.85, and 1.24% for thin-walled plate (0.5 mm hole), thin-walled plate (1.0 mm hole), diffusion cooling hole plate, oil injector, and instrument probe, respectively, were arrived. The present study envisages the CR technique as a quicker and cost-effective inspection tool for early-stage detection of unacceptable dimensional deviations and process-induced defects for shortening the lead time of the complex-shaped aero-engine end-use parts.