NOV 2018


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NEWS 23 Composites Gliding into Competition mold for an aircraft wing panel and then becomes the outer layer of the wing after cure of the additional laminate plies: "ere are only two resin infusions on a flat surface, the first one to produce the flexible mold sheet, the second one to complete the part laminate." e thin composite laminate that will double as the mold is made on a flat or otherwise formed surface and cured until hard. is gives the molder a flexible but, if bent, stiff composite sheet. "e flat working surface defines the structure and quality of the laminate lower, or outer, side." One or more plies of reinforcing fibers (glass, carbon, aramid, etc.), or one or more layers combined with foam or honeycomb cores or other materials, are added on top of this sheet and impreg- nated with resin. is still flexible but lengthwise-stiff ensemble, the lower side being the cured flexible shell and the upper side consisting of the additional wet layers, is then placed over appropri- ately positioned templates, frames or ribs, giving the assembly its specific designated shape, at which point the flexible lower shell takes final part shape (after having served as the mold for the wet layers on the upper side). At cure, the mold thus becomes a member of the part (e.g., the wing surface) and, together with all the added layers, forms the complete wing panel. For example, the bi-functional flexible mold process allows the molder to produce wingskins as seamless shells from trailing edge to trailing edge, without a splice at the airfoil nose. e trailing edges are joined, wet in wet, and co-cured. is process can be used at room temperature or at elevated temperature. "It's an ideal method for resin infusion processes. A panel is produced with two single infu- sions on a flat plate and there is no need for work in a 3D mold," Wehren sums up. Concludes Wehren: "e xxtherm2 Read this article online | See an xxtherm prototype's launch and flight videos on Helmet Wehren's YouTube channel | was designed inversely, beginning with simplicity, manufacturability, reliability, safety, quality. is led to structures, ways of construction, choice of materials, jigs and tools, ways of working, balance of external labor and personal contribution, and a balance of material vs. labor costs. And we allowed ourselves enough time to walk the road without detours." e actual xxtherm2 is in a prototype stage, and first test flights will commence before the end of 2018. Sara Black is a CW senior editor and has served on the CW staff for 19 years. VISIT US AT FABTECH IN BOOTH B6951 OMAX abrasive waterjets can cut a wide range of materials and do more thanks to advanced technology and accessories. Get the whole story at

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