In-line monitoring of the Fused Filament Fabrication additive manufacturing process by non-destructive methodologies.

This work involves the monitoring of the Fused Filament Fabrication (FFF) additive manufacturing process of polymers by combining Infrared Thermography and Acoustic Emissions methodologies. Specifically, an innovative methodology has been developed for the in-line monitoring of the additive manufacturing process enabling the early identification of defects and manufacturing anomalies of 3D printed Polylactic Acid (PLA) materials. Heat distribution during materials solidification and acoustic activity of the 3D printing head were recorded concurrently during the printing process and directly linked to the quality of the printed material. X-ray micro-Computed Tomography (µCT) was also employed to benchmark the findings of the in-line monitoring in terms of inherent material defects. Furthermore, the materials’ mechanical behaviour was assessed, to enable the correlation between the printing quality and their structural integrity. It was successfully determined that the in-line monitoring methodology developed in this research has the efficiency of the early identification of printing defects leading to improved printing quality. This work presents a new and effective in-line monitoring methodology for early identification of printing defects, which can be employed to successfully optimise printing quality, ultimately leading to improved mechanical properties.