Directed energy deposition (DED) is a method used for 3D printing and repairing metal parts. Although it provides a very flexible and efficient means for the manufacture and repair of high‑value components, DED often results in surface irregularities called humping, which can lead to cracks and reduce the strength of the printed parts. To better understand this problem and find solutions, researchers from Rolls Royce plc, Queen’s University and University College London, used a combination of two imaging techniques: inline coherent imaging (ICI), and in situ X‑ray imaging at Diamond1.
By aligning the ICI system with the DED system and the I12 beamline, the researchers were able to accurately monitor the surface of the printed parts and detect cracks as small as 7 micrometers. This is important because cracks can significantly weaken the parts and reduce their lifespan. The researchers also found that the humping on the surface of the parts increased the likelihood of crack formation.
Thin‑walled structures, which are commonly used in industries like aerospace and automotive, are particularly prone to humping and cracking. The use of X‑ray imaging and ICI will provide valuable insight into the formation and growth of cracks during the DED process. This knowledge can be used to improve the quality and reliability of 3D‑printed metal parts, especially in industries where thin‑walled structures are used.