Laser powder bed fusion of metals (PBF-LB/M) is an established AM technique that enables efficient net-shape fabrication with enhanced resource utilization compared to traditional methods.[1] Despite the recognized advantages of in-situ quality tracing and control instrumentation over post-processing measures, the current landscape of PBF-LB machine upgrades primarily features cameras or pyrometers, which fail to provide insights into the chemical composition.[2,3] Acknowledging this gap, our exploration into voxel-wise tracking of chemical composition during PBF-LB/M emerges as a pivotal endeavour. Our approach seeks to establish meaningful correlations between compositional alterations and resultant material properties, thereby enhancing manufactured components' overarching quality control capability.

Delving into elemental composition analysis through in-situ optical emission spectroscopy (OES) during the PBF-LB/M process, our study draws inspiration from the successful application of OES in laser welding for in-situ metal vapor plume analysis [4,5]. Focusing on initial investigations, we explore the elemental analysis of metallic samples, exemplified by an Nd-Fe-B-based alloy [6]. For direct comparison, the established technique of ex-situ inductively coupled plasma OES (ICP-OES) has been applied, revealing a commendable correlation. Notably, our findings underscore 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 the in-situ OES analysis of PBF-LB/M and expands the quality tracing by information on the local composition of the produced parts.