Underwater structures such as offshore wind turbines, bridge piers, or port infrastructure are exposed to extreme conditions. Repairing damage to their steel structures is considered complex and expensive. In the “RoLaKI” project, funded by the Federal Ministry of Research, Technology, and Space (BMFTR) (Robot- and Laser-Based 3D Printing with AI Support for the Sustainable Repair of Underwater Steel Structures), the Laser Zentrum Hannover (LZH), the Institute for Information Processing (TNT) at Leibniz University Hannover, and OFTEC Handelsgesellschaft für Oberflächentechnik mbH are working on a solution: They are developing a process that allows steel structures to be coated over large areas underwater or repaired by “printing” new structures onto them.

At the heart of the project is underwater laser-based 3D printing. The scientists are first investigating how various process parameters influence the layer structure and the processing result. Using this data, they then train an artificial intelligence (AI) system that learns autonomously and predicts optimal parameters for new repair tasks. Additionally, they aim to design an AI-supported path planning system that calculates the best way to repair a damaged area.

For use outside the laboratory, the team is developing special laser processing optics. These are intended to combine the optical components with the wire feed for the coating process. These optics are mounted on a magnetic crawler using a fine-positioning system, which transports the system underwater to the damaged area. This fine-positioning system makes it possible to precisely build weld seams side by side and on top of one another. By the end of the project, the partners aim to be able to carry out the entire process using a demonstrator.