Active thermography for in-situ defect detection in laser powder bed fusion of metal

Additive manufacturing (AM) has revolutionized production by offering design flexibility, reducing material waste, and enabling intricate geometries that are often unachievable with traditional methods. As the use of AM for metals continues to expand, it is crucial to ensure the quality and integrity of printed components. Defects can compromise the mechanical properties and performance of the final product. Non-destructive testing (NDT) techniques are necessary to detect and characterize anomalies during or post-manufacturing. Active thermography, a thermal imaging technique that uses an external energy source to induce temperature variations, has emerged as a promising tool in this field. This paper explores the potential of in-situ non-destructive testing using the processing laser of a PBF-LB/M setup as an excitation source for active thermography. With this technological approach, artificially generated internal defects underneath an intact surface can be detected down to a defect size of 350 mu m - 450 mu m.