Technology of Clinch–Adhesive Joints

The technology of clinching is rather old. The first patent for clinching was granted in Germany in 1897. However, pure clinching was not used on an industrial scale until the 80s of the twentieth century. Shortage of this cold-formed mechanical fastening can be removed by hybrid joining involving clinching and adhesion techniques. It is a modern and innovative technology allowing connection of different types of materials to create durable and reliable light constructions. However, its practical implementation is still very limited. Aspects associated with the automotive, aeronautical and aerospace industries which could benefit from this technique are described in this chapter. The application of clinching together with adhesive joining leads to an improvement (in comparison to a simple joint): of the quality, rigidity and the load capacity, dumping of noise and vibration, pressure tightness and corrosion protection. This entails a significant increase of: long-term static strength; the amplitude of force under fatigue test; the energy required to the rupture of the hybrid joint under static, dynamic and impact loading. This chapter aims to describe the basic technological aspect of the creation of clinch–adhesive joints and different types of joining. Basic parameters that need to be taken into account in the designing process are also presented. A comparison of experimental testing of the hybrid joint with simple clinching for a combination of different joining materials underlines the advantages of the application of hybrid joints. The formulated conclusions can be useful for the application of this new fastening technology in practice.