Shear resistance and surface design of 3D printed dowels made from different materials in glued Scots pine furniture joints

The shear resistance was measured for Scots pine (Pinus sylvestris) furniture joints assembled using straight, cross, and grooved-patterned dowels fabricated via 3D printing with Poly Lactic Acid (PLA), tough PLA, Poly Amide (PA), and tough resin. Results indicated that the highest shear value was given by the straight dowels joints produced from tough resin with an average value of 2845 N. This was followed by the shear resistance values ​​of grooved dowels with 2819 N and cross dowels with 2725 N. The shear performances of the Scots pine joints produced from tough resin dowels were followed by the shear performances of the joints with different patterns produced from tough PLA, PLA, and PA, respectively. No statistical difference was observed in the shear resistances of the joints produced from dowels with different surface patterns. The shear performance of the tough resin dowels joints was higher than those of the solid wood and PA dowels used in the market. Joints with tough resin and tough PLA dowels exhibited both glue line separation and wood rupture near the dowel edge, whereas PA and PLA dowels primarily failed due to glue line separation.