Performance Comparison of Surface Sensitizers for Diode Laser Powder Bed Fusion of Polyamide 12

The efficient processing of polyamide 12 (PA12) in laser‐based additive manufacturing with near‐infrared (NIR) diode lasers requires modification with NIR‐absorbing additives. This study presents the absorbance‐normalized investigation, where the loading of copper sulfide (CuS), lanthanum hexaboride (LaB₆), and carbon black (CB) on PA12 is adjusted to achieve identical absorbance at the diode laser printing wavelength of 808 nm. This approach enables a direct comparison of their effects on the processability, mechanical properties, and thermal stability, independent of the energy input. Interestingly, sub‐vol% sensitizer amounts are sufficient for processing. CuS, at only 0.04 vol%, achieves the highest mechanical strength (≈41 MPa) of the printed parts, good powder flowability, and thermal stability. LaB₆ achieves the best flowability, but requires three times higher loading, affecting fusion behavior, while CB needs increased amounts due to its low density. All nanoparticle‐modified powders maintain stable optical properties during laser powder bed fusion processing, which is a basic requirement for a refresh rate of 0%, outperforming conventional organic dyes in thermal stability. These findings pave the way for high‐performance polymer feedstocks in diode laser‐based additive manufacturing.