Optimization of FDM Printing Parameters for Enhanced Compressive Performance of 3D-Printed PLA/CF Composite Lattice...

This study statistically examines how fused deposition modeling (FDM) parameters influence the mechanical behavior of FDM-printed lattice structures. Diamond triply periodic minimal surface (D-TPMS) lattice structures were 3D-printed using carbon fiber-reinforced polylactic acid (PLA/CFs) composites. The effects of FDM parameters, including extruder temperature (ET), printing speed (PS), and layer thickness (LT), on the mechanical behavior of D-TPMS structures were investigated using response surface methodology (RSM). Uniaxial compression testing was performed to evaluate the mechanical properties of the 3D-printed samples, including compressive modulus (E), peak strength (σ_peak), and specific energy absorption (SEA). The optimal FDM parameter settings for maximizing E, σ_peak, and SEA were determined using multi-objective optimization via the desirability function. A deformation analysis was further conducted. The as-built D-TPMS samples generally matched the design relative density (44%), with absolute errors of 0.3-4.5%, while the largest deviation (~4.5% below the design value) occurred at low-ET and high-LT combinations. The results showed that LT was the dominant factor affecting E and σ_peak, accounting for 77.45% and 89.25% of the total variation, respectively, whereas ET had the most significant influence on SEA, accounting for 55.76% of its total variation. In addition, increasing ET improved interfacial bonding and shifted the failure mode from early wall and layer fracturing to predominantly wall yielding, thereby enhancing structural integrity during compression. Higher LT deteriorated the mechanical properties (E, σ_peak, and SEA) and promoted a progressive failure mode characterized by gradual interlayer separation. The findings revealed that the optimal settings (60 mm/s PS, 232 °C ET, and 0.2 mm LT) simultaneously maximized E (0.567 GPa), σ_peak (15.937 MPa), and SEA (15.510 J/g), with high predictive accuracy (maximum % error ~±1.41%). Correlation analysis further revealed significant relationships between as-built relative density and the compression responses E, σ_peak and SEA, with correlation coefficients exceeding 0.8. Overall, this study advances the understanding of how FDM printing parameters govern the mechanical behavior of PLA/CFs D-TPMS lattice structures and highlights the potential for predicting their mechanical performance.