A feasibility study of various joining techniques for three-dimensional printed polylactic acid and wood-reinforced polylactic acid biocomposite

The current research assesses various joining techniques such as an adhesive bond, direct three-dimensional printing, and ultrasonic welding for dissimilar three-dimensional printed thermoplastics such as polylactic acid and wood-reinforced polylactic acid biocomposite. This study is the first of its kind to determine an effective technique for joining three-dimensional printed polylactic acid/wood-polylactic acid profiles. Mechanical responses such as lap shear strength and shore D hardness of the various joints are investigated and compared experimentally. The results highlight that 15%–17% higher shear strength can be obtained for ultrasonically welded joints compared with direct three-dimensional printing of polylactic acid and wood polylactic acid lap joints. The macroscopic investigation of the ultrasonic welded polymeric joint exhibits a good level of melting of polymers and wetting in the interface. This results in an inter-molecular diffusion of polymeric chains and entanglement of polymers under respective conditions.