Interlayer adhesion and mechanical properties of wood-based multilayer composites fabricated by fused deposition modeling

In recent years, studies on producing high-strength, lightweight, and sustainable components through additive manufacturing (AM) have been on the rise. The aim is to explore how material combinations and process parameters influence interlayer adhesion and mechanical behavior, providing insights for advanced structural and eco-friendly applications. In this study, multilayer plates consisting of two and three layers were made with polylactic acid (PLA), wood-reinforced polylactic acid (wood-PLA containing 30% wood flour), and high-impact polystyrene (HIPS) filaments using fused deposition modeling (FDM). An experimental design was employed to assess the effects of filament type and layer configuration on tensile, bending, and impact strengths. The mechanical strengths (tensile, bending, and impact) of the samples produced in accordance with this design were experimentally investigated, and the deformation modes occurring in the samples were determined. ANOVA (analysis of variance) showed that filament type was the most influential parameter on mechanical properties, with the contribution ratio of this parameter being 87.40% for tensile strength, 40.83% for bending strength, and 31.54% for impact strength. Experimental test results were optimized using the response surface methodology (RSM) to determine the plate design that would provide the best mechanical performance. As a result of the RSM optimization used a multiple response approach to obtain the optimum parameter combination for a 0.60 mm nozzle diameter, PLA/Wood-PLA material, and a three-layer structure. The composite desirability value of 0.712 indicates balanced optimization of mechanical properties, making layered structures a promising alternative for enhanced performance.