An experimental study on the compressing process for joining Al6061 sheets

Mechanical clinching is suitable for joining lightweight sheet materials. However, the use of mechanical clinching may be restricted because of the exterior protrusion. In order to reduce the protrusion height, a compressing technology was investigated with experimental method in this paper. A pair of dies was used to compress the protrusion in a single stroke. The average tension-shearing strength of the compressed joint with a compressing force of 28kN was increased from 1231 to 1654N, and the average cross-tensile strength was increased from 953 to 1102N. As for the compressed joints, the main failure mode is neck fracture mode. The energy absorption values of the compressed joints with different compressing forces are all higher than those of the clinched joint in the failure process. Geometric characterization of the joint profile was analyzed in terms of interlock, neck thickness and protrusion height. The interlock and neck thickness were enlarged with the decrease of the protrusion height in the compressing process. The protrusion height of the compressed joint with a compressing force of 28kN was reduced from 1.62 to 0.94mm. The compressed joint can be used in the visible areas where a higher strength and a lower protrusion are needed. •The strength of the joint can be increased by the compressing method.•The compressed joints have higher energy absorption than the clinched joints.•All the clinched joints failed as the neck fracture mode in the strength tests.•The compressed joint has larger neck thickness than the clinched joint.•The protrusion of the clinched joint can be reduced by the compressing method.