Additive manufacturing of continuous fibre-reinforced polymer parts using the laser-sintering process

• Applicant: Professor Dr.-Ing. Jürgen Fleischer
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing ; Lightweight Construction, Textile Technology ; Production Automation and Assembly Technology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 530064792

The use of continuous fibre-reinforced plastic composites (CFRPC) has enormous potential to significantly reduce the carbon dioxide emissions of current and future mobility applications, both economically and effectively. CFRPC are characterised by their high mechanical properties combined with low mass. By using continuous fibres, CFRPC can be specifically reinforced according to the load path, i.e. in the direction of the load, making CFRPC an essential basis for the research and development of highly stressed products. In addition to the reduction of pollutant emissions through lightweight construction, the trend towards individualisation and shorter availability of products driven by globalisation and digitalisation is a major challenge for the manufacturing industry. In order for companies to be able to adapt to the changing market, new types of production processes are needed that can produce customer-specific solutions from batch size 1. Additive manufacturing offers great potential for solutions. Current research in additive manufacturing shows a clear trend towards the production of CFRPC using extrusion and resin-based processes. However, the processes presented in the state of the art for 2D and 3D fibre reinforcement have considerable disadvantages. Either downstream process steps (e.g. for post-consolidation in the case of 3D extrusion processes) or process-related support structures are required, which have to be removed and disposed of after completion. In addition, the use of support structures means that overhangs, cavities and undercuts are only possible to a limited extent. To avoid the deficits, powder bed-based processes have been able to establish themselves in the industry, especially laser sintering of plastics. Laser sintering enables the production of components in injection moulding quality with a high degree of customisation and high lightweight character, which qualifies the LS process for the production of CFRPC. The layer-related integration of continuous fibres in the laser-sintering process and the associated component-machine interactions could not be investigated so far due to the lack of a machine concept. This considerably limits the application range and the potential of the LS process. With the help of a CFRPC-sintering machine developed at the wbk Institute of Production Science, the technical feasibility for the targeted 2D integration of continuous fibres in the sintering process could be demonstrated. Within the framework of this research project, the influences and interactions existing in this process are to be understood, a comprehensive process understanding for the CFRPC-sintering process is to be developed. The overarching goals of this project are therefore to clarify the process- and material-side interactions and to optimise the mechanical properties of the sintered components through 2D continuous fibre integration.

• DFG Programme: Research Grants