TransForm - Controlling the wrinkling of fibre-based materials through adaptive process control and camera-based data acquisition in transparent forming tools

• Applicant: Professor Dr.-Ing. Peter Groche
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 524957871

Both legal framework conditions and a growing consumer need for sustainable packaging require a reduction in the share of plastic-based disposable packaging. An alternative to this is paper-fibre-based packaging. In order to be able to offer a high variety of shapes, three-dimensional forming processes such as deep-drawing are required. The low degree of forming that can be achieved and the defects that occur still pose challenges for a comprehensive substitution of plastic-based packaging with paper as a material. A particularly noticeable defect in deep-drawing paper is the formation of wrinkles in the flange. These basically occur due to tangential compressive stresses as a result of material displacement in the forming process, but their exact local and temporal formation and development are not yet sufficiently understood. This circumstance as well as the development of methods to locally influence the forming process are to be addressed within the scope of the proposed project. The key elements are a transparent die and image-based sensors for the in-situ detection of the material feed and the formation of wrinkles. On the basis of this optical process monitoring, insights into influencing factors on the local material flow can be gained with temporal resolution and a comparison with an analytical prediction of the wrinkle formation can be carried out. On this basis, locally adaptive process control is investigated. Locally adaptive process control is particularly promising for complex forming geometries and due to the strongly anisotropic material properties of the fibre material paper. For this purpose, a locally adaptive blank holder is being developed using additive manufacturing processes. By means of individually controllable elastic pressure pockets, the influence of a locally adapted control and regulation of the blankholder pressure on the wrinkle pattern can be investigated. The aim is thus to maximise the quality of the produced part.

• DFG Programme: Research Grants