Experimental study of the mechanical performance of the new high-speed mechanical clinching

Environmental issues have made automotive manufacturers use lightweight materials. Dissimilar material is a new discipline in joining by forming processes that are capable to fulfill the construction of lightweight structures. This paper aims to underline a new joining technique which is called high-speed mechanical clinching (HSMC). The high speed of the punch is provided by the discharge of the electric energy in a fluid like in the electro-hydraulic forming process. A pulse generator discharges the stored electrical energy between two electrodes located in the pressure chamber. This creates a plasma channel between the two electrodes and results in a shock wave. The shock wave is transmitted to the piston and then to the sheets via the punch. The sheets are formed to the die cavity by the punch and are joined to each other. To investigate the proposed method, the AA1050 with a thickness of 1 mm is joined to the AISI1070 with a thickness of 0.5 mm. The mechanical performance of the clinched joints is evaluated in three configurations. Also, the working principle, and neck thickness during high-speed clinching is investigated by metallographic observations of cut clinched sample. In proportion to the achieved results, the usage of this joining technique develops the material flow which results in an improvement in the joint strength and applicability.