A flexible tool for joining dissimilar materials by the novel hole hemming process

This research work presents the development of a flexible tool for performing the new joining process, called hole hemming, between dissimilar materials with very different mechanical properties. This work includes the design, fabrication, and assembly of the structural, active and passive components of the hole hemming tool and the evaluation of their performance. The tool is designed to have adjustable structural and passive tool components as well as easily interchangeable active tool components. The tool is evaluated for joining the AA6082-T4 aluminum sheet with 2 mm thickness to the AZ31 magnesium sheet with 0.9 mm thickness by experimental tests. The maximum force measured during the hole flanging and hemming stages is about 55 kN and 70 kN, respectively. The experimental data is also compared to the numerical results obtained from the finite element analysis of an ideal design. The results in both stages allow concluding the developed tool meets the considered requirements and can be efficiently used for creating hole-hemmed joints between dissimilar materials.