Mechanical interlocking in materials joining by additive manufacturing: A short review

The joining of materials has been a key driver of engineering and manufacturing advancements throughout history. From early fibre-based bindings to modern welding and chemical adhesion techniques, the evolution of joining methods reflects technological progress. Today, the integration of dissimilar materials, such as metals and polymers, remains a challenge due to their inherent differences in physical and chemical properties. Additive manufacturing (AM) has emerged as a promising solution for producing complex geometries. However, material compatibility remains a significant limitation. In this context, interlocking mechanisms provide an effective alternative by enabling strong mechanical connections without the need for adhesives or thermal treatments. This study examines the evolution of joining techniques, highlighting the advantages of adding an interlocking mechanism. A classification of interlocking strategies is proposed, encompassing geometric, frictional, hybrid, and material-based approaches. By mitigating the challenges of AM in joining dissimilar materials, interlocking mechanisms provide new opportunities for engineering applications, enhancing both mechanical performance and design flexibility.