Structural behaviour of adhesive bonds in 3D printed adherends

Additive manufacturing (AM) processes, also known as 3D printing, are experiencing growth and more industries are seeking solutions in these types of processes due to their advantages, including reducing the manufacturing time, sustainability, and the freedom to execute complex geometries. However, the dimensions of components are still quite small. Thus, it is necessary to find solutions for cases where assembly and joining of manufactured components are necessary. This work studies the tensile performance of adhesively bonded single-lap joints (SLJ) between AM adherends of polylactic acid (PLA), Polyethylene Terephthalate Glycol-modified (PETG), and Acrylonitrile Butadiene Styrene (ABS), bonded with the adhesives Araldite® 2015 and Sikaforce® 7752. The adherends' mechanical elastic, plastic and fracture properties are determined prior to the assessment of the adhesive performance in SLJ. Failure modes, joint strength, assembly stiffness, and failure energy are obtained experimentally and compared to Cohesive Zone Model (CZM) predictions, aiming to provide the best material/adhesive combination that maximises the joint performance. In terms of strength and stiffness, PLA joints bonded with the Araldite® 2015 provided the best results, although the behaviour was different for the dissipated energy. The CZM approach showed to be a reliable design approach for bonded AM joints.