Control of the forming zone by varying the surface pressure in the clamping surfaces during incremental swing bending

Incremental swivel bending (ISB) is a flexible forming process for producing a wide variety of profile geometries. The formation of the forming zone—and thus the achievable component geometries—is significantly influenced by the clamping force, the contact normal stress, and the friction between the die and the blank. To date, rigid clamping surfaces have predominantly been used, which limits the ability to specifically control the forming zone during the process.

The goal of this research project is to fundamentally investigate the relationship between locally adjustable contact normal stresses and the formation of the forming zone. To this end, the clamping surfaces of the ISB die are segmented, and individual areas are dynamically loaded and unloaded during the bending process. This is intended to specifically influence the forming zone in terms of its size, geometry, and the resulting strain gradients.

The investigations combine numerical simulations, fundamental material and tribological tests, and experimental bending tests. Based on the findings, a tool module with controllable functional surfaces will be developed, and an existing process model will be expanded. In the long term, the targeted control of the forming zone is expected to help more efficiently utilize local formability, enable smaller bending radii, and expand the process window for incremental swing bending.

Key Focus Areas of the Project

• Control of the forming zone through locally variable contact normal stresses
• Segmentation of the die functional surfaces for targeted adjustment of the clamping force distribution
• Dynamic control of individual clamping surface segments
• Extension of the process model and the process window

The research project is supported by various funding agencies and carried out in collaboration with a range of partners. The German Research Foundation (DFG) supports the project through in-kind grants. This close collaboration facilitates regular professional exchange and supports the project throughout all phases—from planning and implementation to the final evaluation of the results.