Projectname:
X-ray system for measuring the local material structure of fiber-based materials
Workgroup: Packaging materials
Research Partner and Scientific Guidance: Fraunhofer-Institut für Verfahrenstechnik und Verpackung IVV, Dresden, Cedric Sanjon
Financing: IVLV
Duration: 2023 – 2024
The acceptance of packaging made from oil-based plastics is decreasing due to the problems regarding recycling. Consequently, the pressure on industry and science to develop and implement sustainable packaging solutions with packaging materials made from renewable raw materials is increasing. Due to these developments, the limitations for the use of fiber-based materials, such as paper and paperboard, in advanced packaging solutions, would be reconsidered. Currently, there is often insufficient knowledge about the present properties of the material structure in the industrial processing of fiber-based materials. For this reason, the influence of material structure on formability was investigated as part of a DFG project 415796511 "Improved process stability in three-dimensional paper forming by numerical mapping of material inhomogeneity". The results have shown that the inhomogeneous thickness or density and fiber orientation distribution or the combination of the respective material structure have an influence on the elongability and due to the inhomogeneous distribution of the material structure arise a local elongation concentration, which leads to premature fracture.
The approach of the Fraunhofer IVV is to measure and monitor the local thickness, mass and fiber orientation of fiber-based materials using a transmitted light system. Based on the material transmission as a function of the light intensity, the transmitted light of the specimen enables the local physical material structure such as the thickness, density and fiber orientation distribution to be recorded. The fiber-based material is penetrated by a light source of defined wavelength from one side. From the other side of the fiber-based material there is a capturing device, e.g. a camera, which measures the light intensity. The measuring method is based on the assumption that there is a defined relationship between transmitted light and material structure. This measurement method is particularly suitable for opaque materials. The specific relationship between the opacity of the measured material and the physical structure must be determined before the measurement. This process is part of the necessary calibration method.
The results from the project will be used as the basis for a research proposal relating to the development of a method for adaptive adjustment of the forming parameters as a function of the inline material structure and for predicting the manufacturability of packaging and the packaging quality.