Laser beam joint welding of complex powder bed based additive manufactured components

• Applicants: Dr.-Ing. Kai Hilgenberg; Professor Dr.-Ing. Michael Rethmeier, since 12/2020
• Subject Area: Production Automation and Assembly Technology
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 429808811

Components can be manufactured close to their final dimensions using additive manufacturing processes such as LBM for Laser Beam Melting (also known as Selective Laser Melting, SLM). A major advantage of these manufacturing processes is that filigree and highly complex structures can be realized that cannot be produced using conventional methods or can only be produced at great expense. The aim of the research proposal is to investigate the application of laser beam welding of LBM-manufactured components made of AISI 316L and Inconel 718.Findings on material and structure-specific properties of laser beam welded joints between additive manufactured components are to be developed in a three-stage approach. The three stages represent three different degrees of complexity of the additively produced components. Welding strategies are to be developed which can guarantee safe joints and the welding suitability of simple to complex component geometries (e.g. lattice structures).Within this framework, basic knowledge for the safe joining of complex LBM-manufactured components is to be developed. In a subsequent step, the material aspect of a precipitation-hardening nickel-based alloy will also be examined with the aim of investigating the microstructure of the joint and its influenceability. At the same time, an understanding of the influence of the LBM-typical microstructure on the welding process will be created. Finally, the findings will be transferred into general welding strategies and models. In analogy to existing approaches regarding the determination of t8/5 cooling times, approaches for the case of additive components will be developed, taking into account the thermal conductivity, density and complexity of the LBM component. The results of the project applied for can provide a basic understanding of the influence of LBM-typical microstructures and defects on the thermal conductivity of the materials and the effect on the welding process. This will provide the basis for the reliable joining of complex LBM-manufactured components and the influence of the joining process on the material properties will be developed primarily on a representative, precipitation-hardening alloy (Inconel 718).

• DFG Programme: Research Grants
• Ehemaliger Antragsteller: Dr.-Ing. Benjamin Graf, until 12/2020