Fused deposition modeling (FDM) has gained popularity as one of the polymer additive manufacturing techniques. This is due to the minimization of material waste, cost effectiveness, simplicity, and rapid fabrication of complex objects in diverse fields. In recent years, wood/PLA has been widely used as filament for fabricating FDM 3D printed parts for its certain features, e.g., biodegradability, low density, and improved environmental compatibility. However, the influence of various process parameters on the mechanical properties of the printed polymer composite parts needs to be clearly understood so that the fabricated parts can be reliably used. In this study, the influences of four process parameters, i.e., nozzle temperature (NT), raster angle (RA), infill density (ID), and layer thickness (LT), on flexural properties of the 3D printed parts were evaluated. A response surface methodology (RSM) with central composite design (CCD) was used to conduct experimental analysis. Three-point bending tests were performed to obtain values of flexural strength and flexural modulus. ANOVA was used to determine the statistical significance of process parameters and validate the regression models, which is standard practice in RSM-based experimental studies. Statistical analysis showed that ID was the main factor that affected flexural strength, while LT was the main factor that affected flexural modulus. The obtained models for both responses were statistically significant with R² values of 98.68% for flexural strength and 90.64% for flexural modulus. Contour plots also demonstrated that higher flexural properties came from a high infill density, a low layer thickness, and a raster orientation that was near 45°. The study provides a comprehensive multi-parameter analysis, offering practical guidelines for optimizing FDM process settings for biodegradable composites.

Keywords

Additive manufacturing, Fused deposition modeling (FDM), Wood/PLA, Flexural properties.