Injection Moulding
Injection Moulding Injection moulded NFC Simulation vs. Experiment Figure 1: SEM pictures of sisal fibre bundles before (left) und after compounding (right). A: Fibre bundle breakage. B: Start of fibre bundle splitting. C: Peeling behaviour of sisal. [2] Figure 2: Distribution of the length (left) and width (right) for sisal before processing (Original), after compounding (Granules) and after injection moulding (Plate). The results are shown as box-and-whisker plots (whiskers with a maximum of 1.5 x IQR, outliers shown as circles). Boxplots with * represent not normally distributed samples and different capitals represent significant differences. [2] Due to growing environmental concerns, the interest for renewable resources increases drastically nowadays. Natural fibre-reinforced composites (NFC) are an interesting prospect to combine light weight constructions with renewable resources. Natural fibre-reinforced form-pressed composites have been used for interior panels since 1954 [1]. A new interest increases using natural fibre-reinforced, injection moulded components for largescale production in the automotive industry. As engineers only consider predictable compounds in component development processes, models to simulate natural fibre-reinforced compounds need to be developed. Common software programs for injection moulding simulation already include models to simulate glass fibre-reinforced polymers, but not yet NFC. To close this gap the project “Material and Flow Models for Natural Fibre-Reinforced Injection Moulding Materials for Practical Use in the Automotive Industry” (NFC-Simulation) was created. Besides others, two main aspects of the simulation are the prediction of the fibre orientation and the final fibre morphology (fibre length and width) in the component part. The fibre orientation and fibre morphology influence the mechanical properties of the component. For the analyses of the fibre orientation and fibre morphology in a component, plates were injection moulded with 30 mass% sisal/PP. Sisal fibres are leaf fibres from the plant Agave sisalana P.. The fibre morphology was determined before compounding, after compounding and after injection moulding via scanning electron microscopy (SEM) and via FibreShape 5.1.1 (IST AG, Vilters, Switzerland), an image analysis software. The SEM pictures show that the sisal fibre bundles split and break during compounding (figure 1). In figure 2, it is shown that the length is significantly reduced during compounding, while no further reduction could be observed during injection moulding. The simulation also showed correlating results: no fibre breakage during injection moulding [2]. For the fibre orientation measurements, the µ-CT analysis was found to be the most promising experimental method to validate the fibre orientation results of the injection moulding simulation [3]. The fibre orientation results of the µ-CT analysis showed good correlation with the injection moulding simulation via Cadmould at different measuring points on the injection moulded plate (see figure 3). Finally, glove boxes of the Ford B-Max (figure 4) were injection moulded by IAC Group and crash tests were performed experimentally and simulatively. The experiments and crash simulation correlated well [4,5]. A first closed development cycle for a sisal-reinforced component could be realised from the process simulation, over the component manufacturing and component test to the crash-simulation in the project NFC-Simulation. 16 bioplastics MAGAZINE [03/18] Vol. 13
Injection Moulding By: Katharina Albrecht, HSB – City University of Applied Sciences Bremen, Germany Tim Osswald, University of Wisconsin - Madison, USA Erwin Baur, M-Base Engineering + Software GmbH, Aachen, Germany Maira Magnani, Ford Forschungszentrum Aachen, Aachen, Germany Jörg Müssig, HSB – City University of Applied Sciences Bremen, Germany Natural fibres used to reinforce polymers in the automotive industry instead of glass fibres can provide the advantage of reduced carbon footprints [6]. The implementation of material models of NF-reinforced polymers in software programs opens the market for sustainable, bio-based compounds in various automotive components. References [1] Prömper E. (2010): Natural Fibre-Reinforced Polymers in Automotive Interior Applications. In: Müssig J., (editor): Industrial application of natural fibres: Structures, properties and technical applications. Ed. John Wiley & Sons, Ltd, 2010, 423-437. [2] Albrecht, K., Osswald, T., Baur, E., Meier, T., Wartzack, S. & Müssig, J. (2018): Fibre length reduction in natural fibre-reinforced polymers during compounding and injection moulding - Experiments versus numerical prediction of fibre breakage. Journal of Composites Science 2, 20. [3] Albrecht, K., Baur, E., Endres, H.-J., Gente, R., Graupner, N., Koch, M., Neudecker, M., Osswald, T., Schmidtke, P., Wartzack, S., Webelhaus, K. & Müssig, J. (2017): Measuring fibre orientation in sisal fibre-reinforced, injection moulded polypropylene - Pros and cons of the experimental methods to validate injection moulding simulation. Composites Part A: Applied Science and Manufacturing 95, 54–64. [4] Ford Forschungszentrum Aachen GmbH, IAC Group GmbH, LyondellBasell, Kunststoffwerk Voerde, Simcon Kunststofftechnische Software GmbH, M-Base Engineering und Software GmbH, Hochschule Hannover, Hochschule Bremen, TU Clausthal, Fraunhofer LBF, University of Wisconsin-Madison (2014): Werkstoff- und Fließmodelle für naturfaserverstärkte Spritzgießmaterialien für den praktischen Einsatz in der Automobilindustrie. Final report of the project “NFC-Simulation”, 2014. < http://www.fnr-server.de/ftp/pdf/ berichte/22005511.pdf > (2018-04-27). – in German [5] Franzen, M., Magnani, M. & T. Baranowski (2014): Advanced Crash Simulation of Natural Fiber Reinforced Thermoplastics with MF- GenYld+CrachFEM. 3rd MATFEM Conference, 21st October 2014 Schloss Hohenkammer, Hohenkammer, DE. [6] Markarian J. (2015): Renewable reinforcements hit the road. Compounding World 2015, Vol. March 2015, 57-64. www.bionik-bremen.de Figure 3: Comparison of results of the µ-CT measurements and the IM simulation determing the fibre orientation at six measuring points in the IM plate. Left: Main fibre orientation angles in the shell layer. Right: Main fibre orientation angles in the core layer. Positions without any bar refer to an angle of 0°. Results are shown in a mathematical positive sense. [3] The project NFC-Simulation was funded by the German Federal Ministry of Food, Agriculture and Consumer Protection (BMELV) through the Fachagentur Nachwachsende Rohstoffe e.V. (FNR, Gülzow, Germany). Project partners were: Ford Forschungszentrum Aachen GmbH, Aachen, DE; IAC (International Automotive Components), Ebersberg, DE; LyondellBasell, Frankfurt, Germany; Kunststoffwerk Voerde Hueck & Schade GmbH & Co. KG, Ennepetal, DE; Simcon Kunststofftechnische Software GmbH, Würselen, DE; M-Base Engineering + Software GmbH, Aachen, DE; University of Wisconsin-Madison, Madison, USA; University of Applied Sciences and Arts Hannover, IfBB (Institute for Bioplastics and Biocomposites), Hannover, DE; HSB - City University of Applied Sciences Bremen, Bremen, De; Clausthal University of Technology, Institute of Polymer Materials and Plastic Engineering, Clausthal, DE, and Fraunhofer LBF, Darmstadt, DE. Figure 4: Injection moulded glove box with 30 % sisal/PP. [4] (Foto: Frank Schumann, IAC) bioplastics MAGAZINE [03/18] Vol. 13 17
