NOV 2018


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NEWS 29 Filament Winding, Reinvented e part's digital design directs placement of the pins and genera- tion of the robotic winder code — the combination, in turn, actu- alizes the part. e entire design process is managed by software developed in cooperation with the Institute of Textile Machinery and High Performance Materials (ITM) at the TU Dresden (Dresden, Germany). "e deviation points (pins) can be made higher or lower to create the 3D depth versus a planar structure," Minsch observes. "Longer deviation points will induce more bending moment, so there is some tradeoff. e structures we are making are more like 2.5D." Minsch explains that because there is no cutting and no waste, the aluminum becomes the cost driver, not the carbon fiber. "We're using 24K tow, which is typical for automotive," he adds. e resin is a room-temperature cure laminating epoxy because there are no high-temperature requirements for the first produc- tion part. "We are also able to integrate metal inserts easily for wear points," says Minsch. "is was necessary when we started with grippers because they need a lot of attachment points — which is also why we don't use composite pultrusions. With our approach, we can match the strength and stiffness of a standard aluminum gripper but at 50% of the weight." If towpreg is typically faster to filament wind, why is wet winding preferred in the FibreTEC3D process? "We tried towpreg," says Minsch, "but it was too sticky and damaged the roving. is doesn't happen with wet winding because the roving is slippery." He notes towpreg also requires compression, post-winding, to compact the separation between plies. "e tension in wet winding compacts the fiber as it is wound," says Minsch. "We're using pretension as well, which is important for final part prop- erties." He concedes that additional compression could increase composite properties by 10-15%, "but it increases cost severely because you then need tooling, vacuum and pressure. is isn't a rocket motor casing. Our approach provides sufficient properties and meets the cost target." at, ultimately, is the driver for and potential disruptive power of the latest filament winding developments: putting fiber where it needs to be with precision, speed and practically zero waste. Read more in the online article | Read about generative design and composites online | CW senior editor Ginger Gardiner has an engineering/materials background and more than 20 years of experience in the composites industry. WHAT YOU VALUE MOST, WE'LL GET YOU MORE OF. LIGHTER. STRONGER. FASTER. TOUGHER. LOWER-COST. Our braiding technologies can produce complex parts to near-net-shape with dramatic improvement in performance measures that mean the most to you. Learn how today at 129 Business Park Drive, Statesville, NC 28677 • 1-704-924-3090

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