Active thermography in PBF-LB/M with the synchronized path infrared thermography

This contribution presents a new technique for active thermography in laser powder bed fusion of metals (PBF-LB/M), utilizing the Synchronized Path Infrared Thermography (SPIT) setup. The approach uses the processing laser to thermally excite the surface of a stainless steel specimen allowing for in-situ non destructive testing. A secondary galvanometer scanner, optimized for MWIR radiation, in combination with a high-speed thermography system, is capable of conducting detailed subsurface defect analysis. The tests are carried out with artificially induced defects of varying sizes, the method uses temperature gradient analysis and higher order derivatives of the temperature profile along the laser path to identify undesirable thermal behavior. The findings highlight the potential of SPIT as a non-destructive and efficient tool for enhancing PBF-LB/M process monitoring, with implications for improved manufacturing quality and safety.