Performance Characterization of Process Monitoring Sensors on the NIST Additive Manufacturing Metrology Testbed

Researchers and equipment manufacturers are developing in-situ process monitoring techniques with the goal of qualifying additive manufacturing (AM) parts during a build, thereby accelerating the certification process. Co-axial melt pool monitoring (MPM) is one of the primary in-situ process monitoring methods implemented on laser powder bed fusion (LPBF) machines. A co-axial MPM system is incorporated on the Additive Manufacturing Metrology Testbed (AMMT) at the National Institute of Standards and Technology (NIST); a custom LPBF and thermophysical property research platform where one of many research goals is to advance measurement science of AM process monitoring. This paper presents the methods used to calibrate and characterize the spatial resolution of the melt pool monitoring instrumentation on the AMMT. Results from the measurements are compared to real melt pool images, and analysis is provided comparing the effect on spatial resolution limits on image analysis.