Printability and mechanical properties of wood resin polymer composites manufactured using stereolithography

Wood polymer composites (WPC) fabrication using stereolithography has received little attention. WPC research has been mostly directed to traditional manufacturing methods and fused deposition modeling. Stereolithography offers better print precision, structural accuracy, and ease of production than other 3D printing methods and directly creates the final wood polymer composite. Typically, WPCs fabricated using traditional methods used 40-60% wood in the mixture; however, the highest ratio used with stereolithography has been 10%. Increased wood content reduces costs and creates a product that more closely resembles the mechanical properties of wood. This study focused on increasing the wood flour ratio of WPC printed using stereolithography beyond 10% while studying the factors influencing printability and the mechanical properties of the printed materials. A blend of maple and oak wood flour was combined with methacrylate-based resin at wood levels of 2.5, 5, 7.5, 10, 12.5, 15, and 17.5 wt. % to fabricate the wood polymer composite. The highest ratio of wood flour successfully printed in this study was 17.5 wt.%. This paper discusses the tensile and compressive behaviors of the WPC, as well as the dimensional accuracy of the stereolithography process for higher wood ratio WPC fabrication. The process of fabrication, post processing, success and failure in printing, and characterization of print defects were also studied. Stereolithography can be used to manufacture wood polymer composites in a direct production method at higher wood flour ratios, and improving the capability of the method holds the potential to increase access to a sustainable substitute for conventional wood for various uses.