Development and evaluation of an advanced wire-arc directed energy deposition process with integrated temperature control and in-situ heat treatment

Abstract

The acceptance of Directed Energy Deposition with Arc (DED-Arc) in industrial applications is increasing due to ongoing research and development. A key challenge is maintaining temperature control, which affects process efficiency, sustainability, and the properties of the components. There is a need to actively modify the thermal conditions during the process to flexibly optimize the manufacturing quality and efficiency. This work aims to design and validate an advanced wire-based DED-Arc process with closed-loop temperature control and in-situ heat treatment for various applications. The existing DED-Arc system was enhanced by integrating cobot-guided in-situ cooling with nitrogen, water, and air, as well as an inductor for localized heat input. Different control configurations were applied to enable a fully automated temperature-controlled process. The findings show that the basic in-situ cooling concepts can reduce waiting times by up to 65%. Scaling and integrating these concepts into a control system enabled the production of components using ER100S-G without any cooling pauses, despite an interlayer temperature of ≤ 200 °C. Compared to the reference without thermal management, specific in-situ cooling increased the offset yield strength (Rp0.2) by over 100 MPa, while targeted heat input raised the plastic elongation at fracture to over 40%. It was also possible to precisely demonstrate heat treatment with significantly varying hardness profiles of up to 150 HV and corresponding microstructural and phase changes within a single component. Validation tests showed that temperature control can effectively optimize the DED-Arc process, emphasizing the need for further research on flexible, autonomous thermal management.Projekt DEALTechnische Universität Münche