An Original Investigation into the Rheo-Mechanical Behaviour of Polymeric Suspensions During High-Throughput Additive Manufacturing for Custom Textile Components

Additive manufacturing of polymeric textile components enables production of custom structural geometries and integrated functional features impossible with conventional textile processing, but the relationship between the complex rheo-mechanical behaviour of polymer suspensions during extrusion-based printing and the resultant textile component structure and properties is inadequately understood. This research conducts an original investigation into the rheo-mechanical behaviour of polymeric suspensions during fused deposition modelling additive manufacturing of textile-structured components, establishing a predictive framework for process-structure-property relationships relevant to custom technical textile applications. Thermoplastic polyurethane, polylactic acid, and polyamide-12 suspensions with varying fibre, platelet, and particle fillers at 0 to 20 percent volume fraction were characterised by oscillatory and steady shear rheometry across shear rate ranges representative of additive manufacturing extrusion conditions. A computational fluid dynamics model of the heated nozzle extrusion zone was developed, incorporating non-Newtonian viscosity and filler orientation dynamics to predict pressure drop, melt temperature distribution, and fibre orientation at deposition. Textile-structured specimens with lattice, auxetic, and woven-inspired geometries were printed and characterised for tensile properties, anisotropy ratio, inter-bead adhesion strength, and surface roughness. X-ray microtomography revealed internal void content, fibre orientation distribution, and inter-layer bonding quality. The effect of printing speed, layer height, nozzle temperature, and raster angle on structure and properties was systematically investigated at a digital manufacturing facility in Abuja, North Central Nigeria. Results demonstrate that filler-reinforced polyurethane with auxetic geometry achieved tensile elongation of 280 percent with energy absorption 3.4 times that of conventional geometry controls. Computational fluid dynamics predictions of fibre orientation agreed with microtomography measurements within 12 degrees mean error. The research provides a validated design and process optimisation framework for additive manufacturing of functional polymeric textile components in the emerging Nigerian digital manufacturing sector. Keywords: additive manufacturing, polymeric suspension, textile component, rheo-mechanical behaviour, fused deposition modelling