Optimization of FDM printing parameters for high-speed fabrication of PLA-ABS Bi-layer laminate structures

The present study investigates the influence of Fused Deposition Modelling (FDM) process parameters on the mechanical properties and surface quality of multi-material PLA-ABS Bi-layer Laminate Structures fabricated at elevated printing speeds. A Taguchi L9 orthogonal array was used to evaluate the effects of printing speed (150–250 mm/s), layer height (0.1–0.3 mm), and infill pattern (concentric, octagram spiral, and Hilbert curve) on tensile properties and surface roughness. The results show that a printing speed of 150 mm/s, a layer height of 0.1 mm, and concentric infill provided optimal mechanical performance, yielding a Young’s modulus of 1252.29 MPa, an ultimate tensile strength of 42.17 MPa, and an elongation at break of 5.79%. Surface roughness analysis indicated the minimum roughness (R a = 3.4 µm) at a printing speed of 250 mm/s and a layer height of 0.2 mm using concentric infill. Statistical evaluation using mean effect plots, signal-to-noise ratios, and ANOVA revealed that layer height predominantly governs surface quality, while infill pattern and printing speed significantly influence tensile behaviour. Optical fractography and scanning electron microscopy showed that fracture initiation occurred at interlayer interfaces and inter-raster voids. Well-bonded specimens exhibited ductile micro-void coalescence, whereas poorly bonded samples failed by interlayer separation and brittle fracture propagation. These findings demonstrate that appropriate selection of layer height and infill pattern enables rapid fabrication of PLA-ABS Bi-layer Laminate components with improved mechanical performance and surface finish.