CompositesWorld
Issue link: https://cw.epubxp.com/i/841219
NEWS 37 CompositesWorld.com Klausen explains that the T g of the PU resin is slightly higher than epoxy, but the cure temperature is very similar, at 80°C. is was achieved using heated molds, a standard practice in blademaking. Once infusion was complete, insulation blankets were placed over the infusion setup, per standard blade manufacturing practice, to reduce heat loss for a more efficient heating and cure cycle (Step 6, p. 35). A video of the spar cap infusion (see Learn More) shows the wind blade mold closing (also shown in Fig. 7, p. 35), but Klausen says this was not necessary for curing just the spar cap, but was done more as a demonstration of the process necessary to mold a complete blade. Four hours at 80°C is enough to cure the polyurethane resin, but Klausen believes his team can reduce the cure duration significantly. Capturing savings in cost and time "We were able to cut both infusion time and cure time compared to epoxy," says Klausen of the spar infusion, who esti- mates that overall blade production time could be cut by >10%. "e price of this polyurethane is competitive with epoxy," he explains, "but the process savings would then give an overall advantage." Is this possible for all resin-infused blades? "You can never state that it is possible for all blade types or designs," replies Klausen, "because there are so many different solu- tions and production methods, which create individual challenges. However, the lower viscosity and curing time of our resin can save time." He estimates that most parts can be produced 10-20% faster with this PU system vs. epoxy, adding that "It will probably be necessary to adapt the injection equipment and flowlines to make use of the higher infusion speed." is single PU resin can be used for all blade components, Klausen points out, including root, spar cap, spar web and shell, as has been demonstrated in the 37.5m long blade in China. "It is also possible to use it only for one of these components while maintaining the others in vinyl ester or epoxy," he notes. "is resin is compatible with vinyl ester PU-infused Wind Blades WE FOUND THE ONLY MISSING PIECE OF THE PUZZLE! Now we're making AIREX® T92 in the U.S.A. It's extruded and processed in Kentucky and North Carolina with all of the AIREX® product quality that the worldwide composites market has come to know and trust: • Universal resin compatibility. • Reliable and consistent physical properties. • Easily machined and thermoformed. AIREX® T92 STRUCTURAL CORE... THE FITTING PIECE FOR ALL COMPOSITES ENGINEERING CHALLENGES. www.airexbaltekbanova.com North America I South America Baltek Inc. I High Point, NC 27261, USA T +1 336 398 1900 I F +1 336 398 1901 corematerials.americas@3AComposites.com Europe I Middle East I India I Africa Airex AG I 5643 Sins, Switzerland T +41 41 789 66 00 I F +41 41 789 66 60 corematerials@3AComposites.com Asia I Australia I New Zealand 3A Composites (China) Ltd. I 201201 Shanghai, China T +86 21 585 86 006 I F +86 21 338 27 298 corematerials.asia@3AComposites.com See us at CAMX 2017, Orlando, FL, Sept. 12-14, Booth #L52. and epoxy, so you can achieve good adhesion." Because the wind blade industry is conservative, Klausen acknowledges that blade manufacturers may want to switch over one structure at a time, to build experience and confidence. He notes that blade designers can simply drop in the PU system to replace the current infusion resin, "but if you really want the full savings possible, then you look at your design and how to exploit the higher resin properties." Because of the resin's higher strength — including higher compression vs. epoxy — designers can either cut weight out of the blade or use these advantages to achieve, longer, slimmer blades for bigger turbines and/or more power. "We are working with a well-known wind