Adaptive clamping method for the realisation of rotary draw bending of thin-walled rectangular tubes

• Applicant: Professor Dr.-Ing. Bernd Engel
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 567602667

Rotary Draw Bending (RDB) is a tool-based bending process that combines bending moment and tensile force, making it particularly suitable for demanding forming operations. The bending moment is transferred frictionally to the semi-finished product via the clamping dies. Unlike round cross-sections, rectangular cross-sections tend to yield under the stresses acting along the circumference of the tube, which means that the force required to transfer the bending moment cannot be applied, particularly in the case of narrow bends and thin wall thicknesses. The aim of the project is to investigate a method for the realisation of RDB of thin-walled rectangular tubes, taking into account the interactions of the force transmission mechanisms and their influencing factors. The influencing factors are derived from clamping concepts. They are systematically analysed under pure tensile loading and under tensile and bending loading. The guiding thesis of this project proposal is concluded as follows: The clamping system in the RDB can be designed with specific tooling geometry, pitch and material to provide the required force transmission. A significant widening of the process window and improve manufacturing accuracy in terms of cross-sectional deformation in the clamping area are envisaged.

• DFG Programme: Research Grants