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Roller clinching combines the advantages of translational clinching with a continuous feed of the parts to be joined. Challenging tasks are the non-perpendicular impact and retraction of the tools leading to anisotropic joint properties. These effects are strongly influenced by scaling the setup. Reducing the size of roller clinching machines increases the impact angle of the tools on the sheets. This paper focuses on the kinematic description of the tool movement as well as the joint formation depending on different setup sizes. Process limits for different setups are investigated.

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The forming history influences the mechanical properties and the formability of sheet metals. Numerous models and approaches have been published to implement this influence into FE-tools, based on isotropic damage or failure criterions. In this paper, the influence of a uniaxial pre-forming and a change in loading direction on the material parameters is investigated for two different steel grades in tensile tests. It was found, that a change in loading direction significantly affects the mechanical properties of the material. The force–displacement curves obtained from nanoindentation experiments were utilized to determine the flow curves for single grains as well as grain boundaries of the pre-formed materials. This was done by inverse parameter identification using finite element analysis.

To evaluate the prediction accuracy of the anisotropic yield function, we propose an original cruciform hole expansion test. Displacements on two axes were applied to the cruciform specimens with a hole in the center. The thickness strain in the region near the hole was compared to the simulation results. Because this forming test is free of friction and bending, it is an appropriate method to assess the anisotropic yield function without the influences of friction or the Bauschinger effect, or the need to consider the stress-strain curve in high-strain region. Hill1948, YLD2000-2D, and spline yield function which is an improved version of the Vegter model were selected, and 6000 series aluminum alloy sheets (A6116-T4) were used in this study. The parameter identification method of the spline yield function also proposed in this paper using the pseudo plane strain tensile test and optimization software. As a result, the spline yield function has better predictive accuracy than the conventional anisotropic yield functions Hill1948 and YLD2000-2D.