Metal Additive Manufacturing Conference 2018

Additive Manufacturing (AM) is becoming more and more relevant in industrial small-batch manufacturing though it is still on the verge of being a widely spread manufacturing technology. The lack of holistic quality assurance and process monitoring during Laser-based Powder Bed Fusion of metals (PBF-LB/M), also referred to as Laser Beam Melting (LBM), as well as costly and time-consuming post-process quality inspection prevent the industry from a wider implementation. To meet the quality criteria for applications in the scope of high-grade products the comprehension of how process deviations within the AM process influence the quality of the resulting AM component is crucial. This paper addresses a signal sensitivity study of photodiode signals during PBF-LB/M and discusses the correlation to the quality of AlSi10Mg-parts. The variations in the signal characteristics result from changes of process parameters including laser power, layer thickness, scan velocity and hatch distance. The influence of different process features such as rotation angle and scan vector length on the photodiode signal are discussed. Furthermore, image analysis of microsections is used to classify defect types and their correlation with the signal characteristics is considered. This approach outlines the basis for future research on online process monitoring with respect to quality assurance in AM.