Digital Twin for Region-of-Interest Computed Tomography of Additive Manufactured Components using an Industrial Robot

摘要

Computed tomography (CT) is often used as a non-destructive testing (NDT) method to analyze the internal structure of safetycritical parts, e.g. in the automotive or aerospace industries. Additively manufactured (AM) components in particular often result in very complex structured parts due to their bionic design, which are lightweight and thus reduce the CO2 emissions of cars or aircrafts. For metallic AM components produced in a powder bed fusion process pores, inclusions or lack-of-fusion errors (LoF) may occur typically. The latter one arises if powder could not be melted properly, i.e., it is an inclusion of loose powder inside the part. Such LoF are very low in contrast compared to the surrounding solid material and therefore harder to detect the smaller they are and the thicker the penetrated material is. Monitoring systems integrated in the 3D-Printer help to detect indications of where a defect could have occurred. Exactly on each of these predefined positions the CT-System will do a region-of-interest scan (ROI scan). In this study we are using an industrial robot as manipulator of the component to overcome the limitations of traditional CT setups. Its dedicated trajectory using only the optimal projection directions of the current ROI is derived by using our newly developed Digital Twin containing the robot, the AM component and the X-Ray imaging chain. In this study we will show how the simulation is used to find optimal projection directions and a first CT scan of the robot will be demonstrated.