Method Development and Validation of In-situ Optical Emission Spectroscopy During Laser Powder Bed Fusion for 3D Reconstruction of Chemical Composition of Additively Manufactured Metal Parts (T01#)

• Subject Area: Technical Chemistry
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 405553726

Understanding the elemental distribution in metal parts generated by additive manufacturing is fundamental and indispensable for almost all applications. Given the frequently customized nature of AM processes, it is imperative to document the additive manufacturing procedures, with particular emphasis on analyzing and documenting the locally resolved material composition, to enable effective traceability and quality control of production. Tracking the chemical composition during powder bed fusion of metals using a laser beam (PBF-LB/M) and 3D-composition reconstruction is crucial to correlate the compositional changes in structure formation and to generate a high-quality control ability of the as-built parts. Here, in-situ spectroscopic measurements using optical emission spectroscopy (OES) can contribute to the compositional tracking and documentation of the process behavior and, with this, a much beQer understanding of the material behavior. However, such advanced in-situ techniques for PBF-LB/M are currently not available. A substantial understanding of the material behavior, the process conditions, the reproducibility, and thus the properties of manufactured parts require developing and validating a PBF-LB/M-integrated OES method. This shall be achieved through the collaborative work of material scientists of the University partner (UDE) synergisically combined with the application partner (Aconity) with expertise in machine development and machine component integration. Consequently, this knowledge transfer project aims to jointly develop an in-situ analysis method that analyzes the composition of a PBF-LB/M manufactured as-build part in the 3 construction dimensions. With a high application relevance, T1 will orient on structural (Scalmalloy) and functional (NdFeB) materials suitable as model materials. The overarching goal is to develop a method that enables the machine-integrated analysis and recording of quality control-relevant information in 5 dimensions (space (x,y,z), element emission wavelength, and intensity) and thus the 3D reconstruction of the composition of components in the actual state, validated by ex-situ compositional analyses. The project's core is a joint work program focusing on the intensive mutual exchange of scientific knowledge and corresponding application issues. Our project expands the knowledge on LBF-LB/M of permanent magnets generated in the first funding period of the CRC/TRR270 to a broader material and application range, investigating materialrelated and process-related factors during PBF-LB to pave the way for an in-situ quality control system in PBF-LB/M.

• DFG Programme: CRC/Transregios (Transfer Project)
• Subproject of: TRR 270: Hysteresis Design of Magnetic Materials for Efficient Energy Conversion: HoMMage
• Applicant Institution: Technische Universität Darmstadt
• Business and Industry: Aconity GmbH
• Project Head: Professor Dr.-Ing. Stephan Barcikowski