Micro-screw extrusion 3D printing of multiscale ternary nanocomposite absorbers – Part II: Design and process simulation of the extrusion system

In the context of structural–functional integration, the development of advanced functional resin-based composites using Fused Filament Fabrication (FFF) technology has become a prominent research area. However, conventional FFF methods face limitations. This research explores the melt flow behavior of multiscale ternary nanocomposites via a customized Micro-screw 3D printing system. Using finite element analysis and Computational Fluid Dynamics simulations, the impact of extrusion die geometry on key flow parameters—velocity, viscosity, shear rate, pressure, and temperature—is analyzed. Findings reveal that increasing the compression angle raises both peak pressure and temperature. Additionally, flow parameters exhibit gradient variation across different materials under the same conditions. Optimizing extrusion die geometry significantly improves melt flow performance, enabling the efficient production of functional structural components. 3D printing experiments have proved that the process can achieve stable extrusion of polymer materials with an extremely wide viscosity range, and thanks to the effective pressure gradient and high shear rate, the ternary nanometer composite material finally achieves nanoscale mixing. This work offers a theoretical basis and practical guidance for designing advanced FFF-compatible composites, addressing current limitations, and contributing to the broader application of structural–functional integrated materials in industrial settings.