CompositesWorld
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CompositesWorld.com 13 OUT OF AUTOCLAVE SUPPLEMENT ยป Automated dry fber placement (DFP) and out-of-autoclave processes are listed as the key parameters that will afect the cost of future aerospace composites in the 2015 report, "Carbon composites are becoming competitive and cost efective," produced by Infosys (Bangalore, India). Dry fber placement removes from the manufacturing equation the additional cost of prepregging, frozen storage and autoclave processing. It also facilitates production of large unitized structures because there are no out-time limita- tions for complex layups as there are with prepreg. Te current maximum out-time for OOA prepreg is 21 days. Tis could present difculties for large, integrated wing structures, like those developed for the Irkut (Moscow, Russia) MS-21. Conversely, without this limit, it is now possible to develop unitized primary structures even further, including the use of novel materials and elements for inte- gration of additional functions (see "Learn More," p. 14). Because the dry fbers are infused or injected with liquid resin after layup, the dry fber tows must be coated with a binder to prevent displacement during automated layup. How does automated fber place- ment (AFP) with dry fber difer from traditional epoxy prepreg tows? "It is less stif, so you must keep the fber tension in the machine very low," replies Coriolis Composites' (Queven, France) chief tech- nology ofcer Alexandre Hamlyn. He notes this makes laying fber at high speeds more challenging than with thermoset materials and that accuracy of fber placement is also demanding. "You must optimize the fber placement to achieve permeability in the preform so that it can be infused reliably," Hamlyn adds. However, he notes that early indica- tions from development work, to date, show dry By Ginger Gardiner / Senior Editor The dry fiber advantage Dry fber placement frees part manufacturers from the necessity to refrigerate prepreg and lay up today's OOA prepregs within the current best 21-day out-time window, permitting designers to more thoroughly integrate structures, reducing the need for fasteners, joints and assembly steps/labor. Source (top photo) | Coriolis Composites / (bottom photo) | Hexcel Dry fiber placement: Surpassing limits Coriolis Composites' automated aerostructures manufacturing using dry materials moves from development projects to production.