Decoupling interlayer bonding and fibre orientation in 3D-printed glass fibre reinforced nylon composites

Abstract

This study investigates the tensile behaviour of short-glass-fibre-reinforced polyamide 6 composites produced by fused filament fabrication. A dual L9 Taguchi design was used to evaluate nozzle temperature, infill speed and layer height at raster angles of 0° and 90°, producing 18 parameter groups with 3 specimens each. Tensile testing followed ASTM D638 Type IV on a Shimadzu AGS-X2, with a clip-on extensometer used to determine elastic modulus and Poisson's ratio. UTS values ranged from 78.5 MPa to 90.9 MPa, with the 0° groups averaging 86.4 MPa compared to 84.7 MPa for the 90° groups. The elastic modulus ranged from 5689 MPa to 7930 MPa with no significant difference between raster angles. All specimens exhibited linear elastic behaviour followed by brittle fracture, and the results show that interlayer bonding quality is the dominant factor governing tensile performance across all parameter combinations tested. The strongest parameter combinations were A9 (290 °C, 250 mm/s, 0.15 mm, raster 0°, 90.0 MPa) and B3 (270 °C, 250 mm/s, 0.18 mm, raster 90°, 90.9 MPa). Future research could include microstructural analysis using scanning electron microscopy and a full factorial design to better quantify the individual and interaction effects of each printing parameter.