The Resin Transfer Molding (RTM) process is already widely used for manufacuring structural components for the aviation industry. It offers a high potential for automation, with the components exhibiting very good laminate qualities and consequently excellent mechanical properties. Before the components produced using the RTM method are installed in aircraft, they must first pass through a time-consuming and cost-intensive quality assurance process.
Gurten, 12 January 2017 – In order to shorten this process, forming tools are now equipped with sensors, thereby allowing the quality assurance measures to be redeployed in-line into the production process. The Institute for Plastics Processing (IKV) in Industry and the Skilled Crafts at RWTH Aachen University has cooperated with industry partners Airbus and Fill Machine Engineering in developing an innovative approach which integrates these sensors into injection technology for the first time. This approach dispenses with the need to equip every single forming tool with the costly sensor technology. At the same time, the measuring data recorded during the injection process can enable on-line control of the process in future.
The innovative adaptive injection unit injects the resin using non-refillable cartridges in the same way as a piston injection system. The injection unit is connected to the forming tool with a toggle clamping mechanism. A sensor box for in-line measurement of quality and process-relevant parameters is installed between the forming tool and the injector piston. Temperature, pressure, the viscosity of the resin system, the cross-link density of the resin system, and the glass transition temperature are measured.
Integration of the Injection
It should subsequently also be possible to transfer the principle of the implemented sensor box to conventional injection techniques. Moreover, the modular design facilitates combination with current multi-component injection systems. This means that the field of application for the technology can be extended to other industries, such as automotive manufacture.
IKV has implemented the presented approach in cooperation with Airbus Operations GmbH, Stade, and the specialist machine builder Fill Gesellschaft m.b.H. in Gurten, Austria. The system technology is available from IKV and manufactured by Fill Machine Engineering on request. The knowledge transfer project sponsored by the German Research Foundation (DFG) was recently concluded.