While digital twins of individual machines and systems already lead to significant increases in efficiency in industrial production and continuous operation, e.g. through improved production control and machine maintenance, their potential for value-added and material-triggered process control is still largely untapped. This applies in particular to the increasing series production of plastic-based composite structures.
The digital twin for thermoplastic composites (digitalTPC) is intended to demonstrate this potential by means of the hybrid injection moulding technology, which is currently establishing itself on the market and is capable of large series production, in which fibre-reinforced thermoplastic composite (TPC) semi-finished products are continuously formed and back-injected. In particular, the complex and heterogeneous microstructure of the composite material itself and its influence by the manufacturing process in the manufacture of semi-finished products and structural components poses an enormous challenge for process control and quality assurance and requires the complete digitalization of the entire production process.
The project digitalTPC aims at the comprehensive and holistic consideration of all sub-process steps, partly taking place at different locations, from the semi-finished product to the component production.
- With the help of suitable process-integrated and cognitive sensor technology, selected relevant material, process and component characteristics (e.g. fiber orientation, pore content, semi-finished product thickness) are to be measured and recorded by the Fraunhofer Institute IZFP, if possible in local resolution throughout the entire real value-added chain.
- Fraunhofer SCAI will then analyze the measured sensor data, link it to a continuous simulation chain across all process stages and provide feedback to processes and machines as part of the digital twin.
- In addition to material know-how, the necessary production plant technology and tools for demonstrator structures are available at the Fraunhofer Institutes IMWS (tape semi-finished product production) and ICT (tape laying, consolidation and injection moulding technology) on an industry-relevant scale. The division of the value chain between these two institutes also reflects the industry-typical relationship between material/semi-finished product manufacturers and component manufacturers.
An essential innovation is the comprehensive consideration in the real and virtual process chain, which enables, among other things, the individualization of the relevant characteristics of material, process and component. At present, tolerance limits are used, which multiplicatively link imperfections in every process step along the chain, leading to losses in material and cost efficiency. The concept of real-time-capable digital twins leads to individualized features and an optimized response to varying input variables. Thus the optimal value does not have to be regulated multiplicatively in each stage but integratively on the basis of the virtual prognosis only at the end of the chain in the component.
digitalTPC is funded by the Fraunhofer program for market-driven prospective research (MAVO).