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AUG 2018

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AUGUST 2018 28 CompositesWorld INSIDE MANUFACTURING 3 The MS-21 wing stringers are laid up flat and then press-formed into an L shape. Two L-shaped preforms are placed in the tools pictured here, back-to-back, to create the T-shaped stringers that will be co-infused on the upper and lower wingskins. 2 An AeroComposit technician inspects the fiber-placed wingskin, looking for laps, gaps, wrinkles and foreign object debris in the layup. In the background is the tool used to lay up the spar. 1 The wingskins are laid up via automated fiber placement (AFP) using a Coriolis machine. The material is Solvay's PRISM TX1100, which is comprised of Teijin's IMS65 24K tow UD fiber surrounded on each side by a film layer of Solvay's Cycom 7720 binder, a thermoplastic that offers the tack needed to provide ply-to-ply friction. Source (all step photos) | Alexander Popov 4 Skins and stringers are vacuum bagged, infused with Solvay's PRISM PE2400 one-part epoxy resin, and cured in a standard oven in a process that takes 8-10 hours to complete. The resulting wingskin with co-infused stringers (shown here) undergoes CNC machining operations — trimming, routing, drilling, cutting — in an MTorres gantry-based system. must be modified if they are to be successfully used in automated placement. Sam Hill, applications and research engineer, Solvay Compo- site Materials (Alpharetta, GA, US), who consulted with AeroCom- posit on materials and processes development for MS-21 wing fabrication, says Solvay was tasked with solving that problem and developing the wing's infusion material system. Solvay's PRISM TX 1100 is a slit tape comprising Teijin's (Tokyo, Japan) IMS65 24K tow UD fiber and Solvay's CYCOM 7720 binder, which, when heated, offers the tack needed to provide ply-to-ply friction. Further, topping each tape is a lightweight veil (proprietary Solvay technology) designed to provide weft stability, perme- ability for the infusion process itself and enhanced mechanical performance. For infusion, Solvay developed PRISM EP2400, a single-part 180°C-cure, toughened epoxy with a low-viscosity/ temperature profile that enables injection at temperatures as low as at 70°C. e resin offers a wet T g of 150°C and — designed expressly for use in fabricating primary aerostructures — it has an infusion open time of about 8-10 hours, says Hill. How it's done AeroComposit operates two plants that fabricate composite parts and structures for the MS-21. e first, in Kazan, Russia, does the autoclave-based fabrication, such as ailerons, rudders, flaps, spoilers and air brakes, as well as the nose of the plane and the tail- planes. e other site is in Ulyanovsk, Russia, where the infusion work is done on the wings and wingbox in a 11,000m 2 cleanroom. Irkut's decision to infuse the MS-21 wing and wingbox dates back to the plane's launch in 2009. Irkut could have employed conventional prepreg/autoclave technology, but opted instead to

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