Extrusion optimization and advanced mechanical characterization of fibre-reinforced polycarbonate filaments: Improving performance for fused filament fabrication

This study explores the optimization of extrusion process parameters for fabrication of short glass fibre-reinforced polycarbonate filaments suitable for Fused Filament Fabrication. Employing Response Surface Methodology, the effects of fibre content, screw speed, and die temperature on mechanical properties and dimensional stability of filaments were investigated. This work introduces the application of Digital Image Correlation directly on filaments during tensile testing, contributing to the development of advanced filament characterization techniques. The optimal parameters—10 wt% fibre content, 40 rpm screw speed, and 239.9 °C die temperature—achieved a balance between high tensile modulus, high tensile strength, and minimal diameter deviation. The optimal processing condition led to a 148 % increase in tensile modulus, while maintaining good tensile strength and acceptable diameter deviation. Overall, fibre content had the most significant impact on filament properties, followed by screw speed. Fracture surface analysis provided valuable insights about the effects of process parameters on microstructure of the composites.