Investigating gradient temperature control for enhanced interfacial bonding behavior in material extrusion 3D printing continuous fiber reinforced polymer composites

Interlayer delamination is a significant concern for composites manufactured by fused filament fabrication (FFF) process. To address the problem of interlayer delamination and enhance the macro-mechanical properties of FFF fiber composites, it is necessary to improve the adhesive bonding in the manufacturing process. Therefore, a novel method is provided to improve the interfacial bonding behavior of composites by controlling the nozzle temperature gradients in FFF composites along the build directions during the process. Results showed that the value of the first reheating peaks, in thermal history curves under gradient nozzle temperature settings, reached the effective temperature ranges (between melting temperatures and crystallization temperature). This enhanced the adhesive bonding between each layer. Finally, both experimental and theoretical approaches confirmed that the proposed method could enhance the interfacial behavior of FFF continuous fiber filled composites.