CompositesWorld

OCT 2017

CompositesWorld

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OCTOBER 2017 36 CompositesWorld PLANT TOUR composite parts made from bio-resins as well as bio-based fibers, and complex ribbed parts made using Dieffenbacher's RELAY technology (developed originally by FiberForge, see Learn More) that have been subsequently overmolded via injection molding. Roch shows parts made in a process that he has helped pioneer, as reported by CW: A thermoplastic in-mold foaming tech- nology, combined with a controlled mold-opening technique called "breathing mold," produces a foamed core between solid faceskins — both reinforced with chopped glass fibers. e part is formed in a single shot (see Learn More). Roch then leads the way to ICT's variety of laboratories and work areas to show how these innovative materials and processes are realized. An array of polymer processes e first stop, only steps away from the atrium, is the compounding and foam shop. Here, workers are experimenting with extru- sion of foam profiles and shapes, derived from neat resin pellets. "We're researching materials from commodity plastics through engineering resins to high-performance plastics, as well as the process itself, using a twin-screw extruder," says Roch. "In particular, we're looking at a range of particle foams, including bio-based foams, and experimenting with beads with tailored properties and sizes, and better ways of molding." e polymer beads undergo pre-treatment, including pressure loading and prefoaming, then are processed in a laboratory-scale "steam chest" molding machine that welds the foamed beads together — the most common example of such a process is the Styrofoam cup. Roch says the lab-scale machine allows produc- tion of samples with precise densities for testing, for example, mechanical and thermal properties or weldability, for industrial and consumer applications. A larger steam chest molding machine from Erlenbach Gmbh (Lautert, Germany) is used for part production. He shows two examples: A molded particle bio-based foam bicycle helmet prototype and a shape that could be used for an automotive visor application. Many market-oriented particle foam projects are ongoing, including creating tailored polymer combinations in a single part, dosing to create larger foam particles, as well as combinations of polymers with metal foams. Additionally, foamed profiles are being extruded as part of a study for a confidential client. ey will be trialed as insula- tion panels for the construction industry. e adjacent, spacious work area is dedi- cated to research and optimization of injection molding processes, and partic- ularly, long-fiber injection molding (long fiber-reinforced thermoplastics or LFRT), foam injection molding (FIM) as well as thermoset injection molding using thermoset granules. Roch shows ICT's newest machine from KraussMaffei, a multifunctional GX Series machine capable of all three Thermoplastic overmolding A process called Tailored Continuous Fiber Reinforcement incorporates continuous fibers wound around metallic anchor points, in areas of highest load, which are subsequently overmolded or encapsulated by a (typically fiber-reinforced) thermo- plastic resin, in the molding machine shown here. The metallic anchor points for the continuous fibers can be seen as bright silver, within the black thermoplastic part. Source | Fraunhofer ICT Glass/phenolic engine cylinder housing One remarkable result of ICT research is the cylinder housing for this small engine (the black portion of the assembly), which is injection molded using thermoset material made by SBHPP, the high-performance business unit of Sumitomo Bakelite Co. Ltd. (Tokyo, Japan). The glass fiber-reinforced phenolic (55 wt-% fiber content) pourable granules can be molded in a cycle time as short as 45 seconds. Source | Fraunhofer ICT

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