Spectral emission characteristics of single point exposure LPBF process

Despite the advantages of laser powder bed fusion (LPBF), part defects may arise from inaccurately chosen process parameters or heat accumulation during the scanning of complex geometries. Amongst different monitored entities the chemistry or the process fingerprints related to the material requires further attention. Monitoring the spectral content of light emitted from the laser-material interaction provides insight into thermal conditions and chemical composition of the processed material. This work implements an off-Axial spectral monitoring setup for Optical Emission Spectroscopy (OES) in LPBF. Single-point experiment was conducted on AISI316L and Ti-6Al-4V. The study showed that the variation of laser energy input causes consequent variation of spectral emission intensity, as well as that the developed setup successfully captures spectral peaks of alloying elements. Principal Component Analysis demonstrated clear differentiation between the two materials. These findings prove the potential of OES for monitoring alloying elements of processed material and processing conditions in LPBF.