Improvement of the geometrical accuracy of parts by material flow-optimized coil layouts when extruding functional components

• Applicant: Professorin Dr.-Ing. Marion Merklein
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: from 2022 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 492930781

The increased demand for lightweight construction requires functionally integrated components. This in turn leads to an increase in the geometrical complexity of components and thus poses challenges to conventional forming processes. In this context, sheet-bulk metal forming which is defined as the application of bulk forming operations to sheet metal, often in combination with sheet metal forming, extends the range of parts that can be produced by forming technology to flat and functionally integrated lightweight components. Such parts are applied, for example, in the powertrain of vehicles and are therefore required in high quantities. Currently, the majority of the research regarding sheet-bulk metal forming is focusing on the processing of pre-cut blanks. Production from coil, in contrast, has the potential to increase the output quantity due to the part transport in the coil and the associated elimination of cycle-time-limiting handling systems. The central challenge of sheet-bulk metal forming is a limited geometrical accuracy of the components due to a material flow out of the functional elements. In the preparatory investigations, it was identified that additionally an anisotropic material flow occurs in the case of a production from the coil. This additionally limits the geometrical accuracy of the component and prevents the transferability of the findings from sheet-bulk metal forming from blanks to coil.In this context, the present research project aims at investigating the influence of component design on sheet-bulk metal forming processes from coil by numerical and experimental analyses. For this purpose, two multi-stage forward extrusion processes will be developed. On these, knowledge regarding the production of a wide range of parts from coil will be elaborated by analyzing the interactions between the process boundaries (geometrical part accuracy and tool load) as well as the functional element geometry, arrangement of the functional elements, orientation of the parts in the coil and workpiece material. A further objective is to extend the identified process limits by material flow optimized coil layouts. For this purpose, a combined numerical-experimental approach will be applied to investigate how the material flow can be controlled by adapting the inner and outer cutting of the coil, a non-circular cutting and an adjustment of the stage sequence. These measures are intended to counteract the coil-specific anisotropic material flow in order to increase the geometrical accuracy of the components manufactured from coil. This will improve the resource efficiency of the processes by eliminating the demand for reworking to achieve the required geometrical component accuracy. By combining the findings of the research project, knowledge about the design of the coil layout will be gained to replace the previous experience-based approach.

• DFG Programme: Research Grants