Laser powder bed fusion of metals (PBF-LB/M) is a well-established additive manufacturing technique that enables efficient net-shape fabrication with better resource utilization compared to traditional methods.[1] While in-situ quality monitoring and control instrumentation offer significant advantages over post-processing measures, current PBF-LB/M machine upgrades predominantly feature cameras or pyrometers, which do not provide chemical composition insights.[2,3] Recognizing this gap, our research into tracking chemical composition during PBF-LB/M is a crucial step forward. We aim to establish meaningful correlations between compositional changes and material properties, thereby improving the overall quality control of manufactured components.

Our study investigates elemental composition analysis through in-situ optical emission spectroscopy (OES) during the PBF-LB/M process, inspired by its successful use in laser welding for in-situ metal vapor plume analysis.[4,5] Focusing on preliminary investigations, we analyze metallic samples, such as an Nd-Fe-B-based alloy.[6] For comparison, we applied ex-situ inductively coupled plasma OES (ICP-OES), which showed a commendable correlation. Our findings highlight the potential of local emissivity within Fe and Nd lines as reliable indicators for determining plasma temperature and elemental concentration. Overall, our study provides valuable insights into in-situ OES analysis of PBF-LB/M, enhancing quality tracing by including local composition information of the produced parts.

References

[1] S.R. Narasimharaju, W. Zeng, T.L. See, Z. Zhu, P. Scott, X. Jiang et al, J. Manuf. Process., 2022, 75, pp. 375

[2] Deutsche Akademie der Naturforscher Leopoldina e.V., Nationale Akademie der Wissenschaften, Schriftenreihe zur wissenschaftsbasierten Politikberatung, 2020

[3] A. Molotnikov, A. Kingsbury and M. Brandt, J. Fundamentals of LPBF of Metals, 2021, 23, pp. 621

[4] L. Zhou, M. Zhang, X. Jin, H. Zhang and C. Mao, Int. J. Adv. Manuf. Technol., 2017, 88, pp. 1373

[5] B. Ribic, P. Burgardt and T. DebRov, J. Appl. Phys. (2011), 109, pp. 083301

[6] A.R. Ziefuß, R. Streubel, P. Gabriel, F. Eibl, S. Barcikowski, ChemRxiv., 2023