Statistical analysis of spatter velocity with high-speed stereovision in laser powder bed fusion

As unprecedented design freedom is realized through additive manufacturing and simultaneously as the diversity of materials improves to include high-performance metals, aerospace and biomedical applications demand improved quality control measures. In the context of additive manufacturing, new opportunities for in situ monitoring are now possible with a qualify-as-you-go layer-by-layer methodology. In this study, a pair of low-cost, high-speed cameras recording the selective laser melting of maraging steel was synchronized to measure stereoscopic features of the resulting spatter. Through epipolar geometry, accurate measurements were calculated of the age, speed and direction of thousands of spatter events. Statistical analysis was performed focusing on spatter velocity with the driving hypothesis that velocity can be correlated to the weld quality and eventually leveraged in real-time process control. Opportunities, future work, and challenges are discussed.