Investigation of Microscale Laser Shock Flat Hole Clinching

This paper proposes an improved laser shock flat hole clinching process for joining ductile and brittle materials to obtain single-sided flat joints in microscale. A copper foil is clinched with a perforated sheet and a mechanical joining is achieved by this process. Experiments and numerical simulations are conducted for three thickness combinations of 50 μm/50 μm, 30 μm/50 μm and 20 μm/100 μm to investigate the joinability of this process. The results show that a step-by-step laser shock process with a low-energy pre-shock and a high-energy secondary shock can effectively join the copper foil and the perforated sheet. The three thickness combinations of the upper and lower sheets result in three clinching structures, namely stacked, intermediate and thinning joints. And the joint strength mainly depends on the thinner sheet in a successful joining even for the single joint or the double-joint.