CompositesWorld

OCT 2017

CompositesWorld

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NEWS CompositesWorld.com 33 they dissolved in 15 minutes. Although they haven't tested solubility at higher tempera- tures yet (that's a future research project), stopping at 80°C makes sense, because any customer with an RTM heating system will have water available at that temperature. Ori adds that certain thermoplastic core types can be removed via mechanical or thermal means — via side-access openings, with or without pre-softening and folding the core — although such actions carry the risk of damaging the part. at's why the team is encouraged by how well PET cores adhere to carbon composite. He also says that thin and flexible PET cores produced via rotomolding or blowmolding are another alternative they will explore in the near term. is past year, autoclave-cured carbon fiber/epoxy prepreg-wrapped cores survived 5-bar molding pressures. More recent testing of PVOH-PVA cuboid cores draped with dry carbon materials and resin injected in HP-RTM withstood 10-bar pressure without collapsing. e team is continuing to explore the forming pressure limitations of the hollow cores. What's ahead Persico has ambitions to explore other options. For example, in-mold chemical foaming is often used with rotomolded olefin polymers. is creates a solid outer skin, while the center and inner skin of the hollow parts are foamed, offering opportu- nities for modest weight and cost savings, albeit at cycle times two-times longer than normal. Researchers think foaming could be used to produce olefin or polyurethane structural cores with novel thermal and acoustical damping properties. Another area of interest is use of chopped glass fiber reinforcement for PA6 cores. "Rotomolding ... doesn't suffer severe limitations in terms of size or geometric complexity," adds Carrara. "However, for small components, there are some constraints in terms of using sharp edges/ corners where powdered materials can stick and prevent correct filling of the tool. Also, for large cores, our SMART machines currently have a physical limitation of 2,800-mm diameter for the machine table." How will the company bring the technology to market? Ori says Persico is open to all options. e initial approach will be to co-design parts, build tools and test prototypes with a supplier or OEM partner, who eventually would purchase a SMART machine and produce parts. When the technology matures, Persico will make its know-how available and possibly retain responsibility to co-design and produce tools for the process. Rotomolded Cores Contributing writer Peggy Malnati covers the automo- tive and infrastructure beats for CW and provides communications services for plastics- and composites- industry clients. peggy@compositesworld.com DeWAL's pressure-sensitive PTFE tapes and films are known for tightly sealing carbon-fiber 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 films offer minimal elongation and temperature-resistant silicone-based adhesion. UL-recognized 204-HD films are both skived and tensilized for higher tensile strength, lower elongation and higher dielectric strength. 204-HD films 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 films 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. 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-fiber composite DW 134 DW 204-HD DW 202 & DW 2000 15 Ray Trainor Drive Narragansett, RI 02882 usa1@rogerscorporation.com 800-366-8356 International: 001-401-789-9736 dewal.com

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