Comparative Analysis of Process Stability in PBF-LB/M: (Thermal) Highspeed Imaging vs. Melt Pool Monitoring using Novel Gas Mixtures

Powder bed fusion of metals using a laser beam (PBF-LB/M) is increasingly gaining popularity in the industry. However, ensuring a consistent quality of parts processed by PBF-LB/M is crucial to compete with established manufacturing processes. In-situ process monitoring systems, such as coaxial melt pool monitoring (MPM), can contribute to this goal by minimizing post-process quality control. Three monitoring systems, a commercially available MPM system, an optical high-speed camera, and a thermal high-speed camera, were compared to identify process phenomena. Secondly, the suitability of the MPM system for in-situ quality control was tested by employing novel gas mixtures in the process. The mixtures include argon (Ar) with hydrogen (H2), helium (He), and carbon dioxide (CO2). The first results showed the capabilities of the MPM system to monitor relevant process anomalies. Also, the addition of He and H2 to the process gas resulted in an improvement in the melt pool stability and a reduction of process by-products compared to Ar.