In-line Process Monitoring of Extrusion-Based Bioprinting Using In-Situ Thermal Imaging

In-situ monitoring is crucial in facilitating the industrial expansion of extrusion additive manufacturing by enabling the early detection of defects in a non-destructive manner and at a low cost. This study introduces a technique for assessing the geometric accuracy of extrusion additive manufacturing using a thermal camera as a sensor to monitor the extrusion-based bioprinting process in situ. The geometry of the extruded material is continuously detected during deposition, allowing for a real-time comparison with the corresponding nominal shape, which is extracted from the G-code and registered on the acquired thermal image sequences. The study demonstrates the effectiveness of the proposed in-line monitoring technique in identifying the correctly deposited material, the regions of under-extrusion and the regions of over-extrusion when printing with a transparent biomaterial.