Product property controlled multi-stage hot sheet metal forming

• Applicants: Professor Dr.-Ing. Thomas Meurer; Professor Dr.-Ing. A. Erman Tekkaya
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing ; Automation, Mechatronics, Control Systems, Intelligent Technical Systems, Robotics
• Term: since 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 424334660

Multi-stage hot sheet metal forming enables the production of hardened geometrically complex components. However, this process involves time-varying interactions between the blank and the tools, which are difficult to estimate and have an effect on the thermo-mechanical history. These interactions ultimately influence the resulting product properties, which are therefore subject to undesirable fluctuations. In order to achieve a robust, efficient, and versatile production, this project aims to sensorially capture the interactions in multi-stage hot sheet metal forming, compensate them with suitable actuator technologies, and to closed-loop control the product properties accordingly. In this 3rd phase, the closed-loop control of the hardness distribution coupled with the thinning distribution for different areas of a press-hardened hat-shaped profile with one bent frame will be implemented in a progressive die with extended actuator technology under near-process conditions. The developed concept for controlling the product properties in multi-stage hot sheet metal forming will be validated and its transferability demonstrated based on this setup. It should be noted that the fundamental control concept of the third phase corresponds to the hierarchical optimization-based concept developed in the second project phase, with various extensions aimed at adapting to near-process conditions. Firstly, the tool and actuator technology as well as the implemented sensors must meet the requirements of a high-volume production. Moreover, the hardware and the software (soft sensors, estimators, control) must exhibit the necessary robustness and real-time capability. Therefore, in order to fulfill the mentioned requirements, the temperature measurement will first be robustified, expanded across the component width, and the temperature and forming modeling will be adapted. Additionally, the improvement of robustness and accuracy will be investigated through expanded disturbance estimation and compensation, with the implementation of a thermal imaging camera, a 3D laser sensor, and the 3MA system. To quantify the improvement of the resulting product properties by the developed closed-loop control, the product properties of manufactured components from experimental series with an activated closed-loop control will be compared to those without active control experiments. In parallel with the investigations, transferable design guidelines will be determined from the perspective of forming and control engineering.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2183: Property-controlled metal forming processes
• Co-Investigators: Dr.-Ing. Marlon Hahn; Dr.-Ing. Heinrich Traphöner