CompositesWorld
Issue link: https://cw.epubxp.com/i/891910
NOVEMBER 2017 32 CompositesWorld FEATURE / Reconfigurable Tooling Roundup aluminum and steel," says Geuskens, "but with composites, you instead must build a plug, make the mold and then laminate the whole hull and deck, so there is a long lead time." And a large capital investment. After designing and developing composite structures for Airbus Defense & Space (Toulouse, France), Geuskens founded Curve Works in 2016. "Multipoint forming is very old technology, with patents from 100 years ago," Geuskens points out, but notes, "What makes ADAPA unique is they have integrated pin beds with very nice 3D software." e Curve Works mold has 528 pins (Fig. 1, p. 31). "So it must be automated digitally," Geuskens explains, "and the pins need to smoothly transform from one shape to another. ADAPA did an excellent job in the electromechanical design of these molds." ere is also an interpolation layer, which makes it possible to pull vacuum and have a smooth surface for molding compos- ites. "is top layer must support the material, but also be flexible and stretch to form 3D shapes," says Jepsen. e typical silicone forming layer enables temperatures up to 200°C. Jepsen points out that the technology developed by North Sails (Milford, CT, US) for its 3D molded sails is generally the same concept, "just a larger scale vs. our machines." Companies see the utility of this technology, he explains, "but don't have the ability to develop and apply it like North Sails. So this is our niche — we customize our adaptive molds to fit our customers' specific appli- cations, including thermoforming glass, plastic, concrete and composites." Adaptive molds, affordable products Curve Works uses an infrared heater mounted above its mold to thermoform materials onto the curved mold surface, but has also built a 30-kW convection oven around the mold and can use stretchable heating blankets capable of 200°C. It also has used ultraviolet light for special fast-cure resins. "For thermoforming plastic, we place a panel on the mold, hold it with vacuum and then preheat," says Geuskens. With the push of a button, the mold starts to shape the plastic. "It reaches shape within 3 minutes," he adds, "so you are done very quickly." "Cycle times can be quite low with our technology," agrees Jepsen. "If you have lower-cost, reusable tooling and low cycle times, you can have a competitive product." Curve Works has made a composite architectural façade panel, using Parabeam 3D (Parabeam BV, Helmond, e Neth- erlands) textile hand-laminated with polyester resin. "With vacuum infusion, we use a different surface because silicone rubber doesn't do well with polyester and epoxy resins," Geuskens explains. "We apply a foil/film release, shape the mold, lay fabrics, vacuum bag and then infuse. e same process can be used for prepreg. You can also put a rubber profile on the mold to produce a groove or slot, but this mold is best for smooth profiles and less- complex geometry." "Our typical customer starts with a minimum radius of 400 mm," says Jepsen, "but we're doing a project now for forming down to 200-mm radius." FIG. 2 One adaptive mold, myriad curved panels ADAPA's adaptive molds are used to produce fiber-reinforced concrete panels, such as the 80 molds used to construct 40,000 unique curved panels that comprise Kuwait International Airport's new interna- tional terminal (top). Curve Works has used an ADAPA mold to produce curved composite panels using wet layup, prepreg and resin infusion for applications including architectural façades, boats and airship gondolas. Source | Foster + Partners Source | Curve Works