Friction Stir Clinching (FSC)

In clamping step, a steel holder and a die tightly clamp two metal sheets. In punching step, a rotating tool with a probe indents the upper and lower sheets into the die. When the rotating tool contacts the upper sheet, the downward force is applied. The rotational speed and downward force of the tool are applied through the whole process to generate frictional heat. The heated and softened sheets nearby the tool are deformed plastically as two buttons. Note that the inner and outer buttons are made of the upper and lower sheets, respectively. In interlocking step, when the tool is fed to the given depth, the materials of the inner and outer buttons are squeezed into the groove of the die and then deformed as an undercut. Finally, the tool is drawn out from the sheets and a FSC joint is made as in final step.