In-line monitoring of the material extrusion additive manufacturing process by non-destructive methodologies

This work involves the monitoring of the Material Extrusion (MEX) additive manufacturing process (also known as Fused Filament Fabrication, FFF) for polymeric materials through the combined application of Infrared Thermography (IrT) and Acoustic Emission (AE) methodologies. An innovative methodology has been developed for in-line monitoring of the additive manufacturing (AM) process, enabling the early identification of process-induced defects and manufacturing anomalies in additively manufactured polylactic acid (PLA) parts. The thermal distribution during material solidification and the acoustic activity of the additive manufacturing machine deposition system were recorded concurrently during the build and directly correlated with the resulting part quality. X-ray micro-computed tomography (micro-CT) was employed to benchmark the in-line monitoring results with respect to internal material defects. Furthermore, the mechanical behaviour of the additively manufactured parts was evaluated to establish a relationship between additive manufacturing process quality and structural integrity. The findings demonstrate that the developed in-line monitoring methodology enables the early detection of defects, which in turn can lead to improved additive manufacturing quality and enhanced mechanical performance of additively manufactured parts.