Scanner position accuracy, repeatability, and process anomalies correlation in PBF-LB/M

• The scanner accuracy under fixed production-representative parameters showed a build mean deviation of 0.014 mm and 0.029 mm at the 95th percentile, however, deviation up to 0.100 mm can be found in corners and complex paths. • The layers with more scanning inaccuracies (commanded versus actual) showed up to 10× more porosity suggesting a correlation between scan accuracy and defect formation. • Scan path repeatability between two builds under same process conditions showed a mean of 0.004 mm, yet only ∼30% of pores appeared in consistent locations which indicate scan data repeatability alone can’t explain final pore locations. This study investigates position accuracy, repeatability, and reproducibility of the scanning system in a metal laser powder bed fusion (PBF-LB/M) process using a novel data collection method. Deviations between Commanded and Actual scanning positions were quantified using Euclidean distance metrics across a series of builds and geometries. Results showed a build mean accuracy of 0.014 mm, increasing to 0.029 mm at the 95th percentile, with deviations reaching more than 0.100 mm at complex geometric paths and corners. Layers containing high scanning path deviations, showed up to 10 times more porosity than other areas, underscoring a strong correlation between scan accuracy and defect formation. Reproducibility testing across multiple build plate locations showed a 95th percentile deviation of 0.042 mm, with maximum deviations up to 0.080 mm. Scanning accuracy defects that can alter local energy density such as missing or additional hatch sections were found as a function of the build plate location, suggesting a root cause of part variability in addition to other process conditions such as gas flow. Despite high repeatability (0.004 mm mean deviation) of the scanning path, only ∼30% of pores appeared in consistent locations, suggesting that scanner qualification alone is insufficient to explain pore final location. The study also highlighted the influence of geometry, speed, and scanning parameters in the scanning system accuracy. These findings provide new insights into how scanning system performance affects part quality and repeatability and provide a framework for incorporating scanning data metrics into future qualification protocols.