CompositesWorld
Issue link: https://cw.epubxp.com/i/632301
FEBRUARY 2016 44 CompositesWorld INSIDE MANUFACTURING was used as a base onto which the FPP system placed carbon patches along specifc load paths (Step 2). "Te scrim sheets with patches are very stable, robust and easy to handle," notes Michl (see Steps 3-5). "Tere are 3-6 layers of carbon fber per patch with one layer measuring roughly 0.08 mm in thickness." Te three patch/scrim preforms were then boxed and sent to the Austrian facility that produces North's boards. Tis production facility also manu- factures snowboards, and uses basically the same process for North Kiteboard- ing's products — wet layup with epoxy resin in a steel mold and compaction/ cure in a heated compression press. Te patch/scrims for the prototype boards were unpacked and arranged as part of the kits for each board layup. In this case, each board layup is done upside down, starting with what would be its top layer, a sheet of abuse-resistant polyurethane, which is also used to encapsulate the sides. Next, a scrim layer without patches, and layers of hybrid carbon/glass fber noncrimp fabrics (NCF) from Saertex (Saerbeck, Germany), were wet out with epoxy and hand layed, followed a wood core. Over the wood core, each board's bottom was wet-laid with layers of NCF glass followed by the bottom scrim with the FPP carbon fber patches on it (Step 6, p. 41). Next came board decorations and a fnal (bottom) layer of plastic (Step 7). Te fnished layup was then placed into a 75-120°C press for a 10-minute cure cycle (Step 8). CNC machining was used to trim each demolded board's outline and to drill and countersink inserts for fns (inserts can be seen on the boards in Fig. 1, p. 42). Te fnished boards were shipped for North Kiteboarding testing in Mauritius, an island of Africa's east coast. Potential for product development "Our testing showed exactly what we thought the Cevotec patches would do for us," says Hanel. "We were able to feel the torsion fex we were seeking when riding the boards on the water." Of the three designs, Hanel's team singled out one for further refnement and began working with Cevotec to vary the patch layers, an DeWAL's pressure-sensitive PTFE tapes and flms are known for tightly sealing carbon-fber composites and cleanly releasing parts from molds. Use them to separate epoxy resins from laminates or to seal vacuum bags up to 500°F. DeWAL PTFE tapes and flms offer minimal elongation and temperature-resistant silicone-based adhesion. UL-recognized 204-HD flms are both skived and tensilized for higher tensile strength, lower elongation and higher dielectric strength. 204-HD flms range from 0.5 to 21.5 inches wide and are as long as 108 feet, with tensile strength up to 13,000 psi at 500°F. They are in stock in 2, 3 and 5 mil thicknesses, as are other 36" width DeWAL tapes and flms for composites. Whether you are doing open or closed molding, whether your process is lay-up, compression molding, resin transfer or continuous lamination, DeWAL will share a solution with you. 15 Ray Trainor Drive Narragansett, RI 02882 www.dewal.com usa1@dewal.com 800-366-8356 (International: 001-401-789-9736) Quality of Product...First DeWAL PTFE Tapes & Films — for tighter vacuum seals and cleaner mold separation. Used as an alternative to sanding and painting Used as peel-ply on molds Used between a mold and a carbon-fber composite DW 134 DW 204-HD DW 202 & DW 2000 diferent patch layout designs were developed for North Kiteboarding to test on the bottom sides of prototype boards (see Step 1, p. 40). Te preform patches were then produced using Cevotec's automated FPP equipment. "Te patches were actually layed onto a glass fber scrim that North was using on both sides of its board to increase adhesion between its wood core and reinforcement layers," says Michl. Te scrim material Read this article online | short.compositesworld.com/Kiteboard Read more about the FPP process in "Automated preform process boosts properties while cutting cycle time" online | short.compositesworld.com/CWT-FPP