Material-Efficient Design of 3D-Printed Furniture Connectors: Effects of Perimeter Count and Infill Density

Additive manufacturing offers opportunities to improve material efficiency and support more resource-efficient production of furniture components by reducing material consumption while maintaining sufficient mechanical performance for practical use in wooden structures. This study evaluated the effect of perimeter count and cubic infill density on the mechanical behaviour and material efficiency of FDM-printed dovetail connectors made from recycled PLA+ and used in wooden frame corner joints. Connectors were manufactured with three infill densities (20%, 30%, and 40%) and three perimeter configurations (1P, 3P, and 5P). Mechanical tests were performed on beech wood (Fagus sylvatica L.) corner joints, and maximum bending moment, rotational stiffness, and specific maximum bending moment were evaluated. The experimental results were supported by a homogenized shell–core FEM model used to analyse contact behaviour, load transfer, and critical stress regions. Perimeter count had a statistically significant effect on the maximum bending moment, whereas infill density did not. Among the evaluated configurations, 3P30 exhibited one of the highest mean bending moments (14,998 N·mm) and the highest mean rotational stiffness (6172 N·mm/deg), whereas 3P20 achieved the highest specific maximum bending moment (3903 N·mm/g). Increasing infill density to 40% increased material consumption and printing time without proportional mechanical improvement. FEM analysis showed that configuration 3P30 achieved the highest contact pressure, frictional stress, and reaction force among the analysed 3P variants, whereas increasing infill density from 30% to 40% reduced sliding but did not improve the overall mechanical response of the joint. The results indicate that appropriate selection of perimeter count and infill density can improve material efficiency by reducing material consumption while maintaining the mechanical performance of FDM-printed furniture connectors, thereby supporting more resource-efficient and sustainable furniture manufacturing.