Utilization of additively manufactured lattice structures for increasing adhesive bonding using material extrusion

Additive manufacturing (AM) typically is more costly than traditional manufacturing processes, but it opens new opportunities for design that are often not fully utilized because of its price. Bonding complex additively manufactured structures to conventional parts is a way of reducing cost, while maintaining design freedom. However, not all polymers used in AM are easily bondable. These materials are typically pre-treated with plasma in order to increase adhesion at the interface. By utilizing the design freedom of AM, it becomes possible to omit this pre-treatment step by producing undercut areas that can be filled by the adhesive during bonding. Instead of adhesive bonding, forces are transmitted by positive fit of the adhesive and the AM part. By producing complex lattice structures with AM that are surrounded completely by adhesive, the strength of these bonds can further be increased. The design of such structures is highly complex, however. This publication shows that AM lattice structures can greatly improve bonding strength of low adhesive polymers and suggest a way of characterizing such structures in lap shear tests in order to separate design influence on such bonds. It could be shown that resulting shear strength is comparable to bonding after plasma pre-treatment.