Braided carbon fiber chair a practical, affordable alternative
In the furniture world, carbon fiber is still associated with few-of-a-kind "art pieces" - items that cost thousands of dollars and find their way into museums or the drawing rooms of the rich, but rarely get much use. Talon Technology (Pty.) Ltd. (Brookvale, New South Wales, Australia) and Bang Design (Balmain, New South Wales) set out to change all that with the Talon chair, developed for the contract furniture market. Priced at $450 (USD), the 780-mm high by 480-mm wide by 510-mm deep (30.7-inch by 18.9-inch by 20-inch) stackable chair weighs 2.4 kg/5.3 lb, half that of a comparable metal chair. The chair's right and left side frames, seat and back are molded separately in matched metal tooling. Preforms are made from rigid foam core and uni tape underlayers, over which is drawn several types of custom braid from A&P Technology (Cleveland, Ohio, U.S.A.). "The core is polyurethane foam molded in-house in tooling derived from the original CAD data," says Talon's James Birrell-Gray. Pulling the braid over the foam forces it into tight radii with tight tolerance between the core and the mold surface, enabling complex contours similar to die-cast aluminum.
During development, a strong joint where the braided back and front legs intersect was a challenge. "While the joint design is not that complex," he explains, "the loading method and the way the tool is articulated so that the separate sections can be positioned correctly took considerable trial and error." Talon engineers initially CNC-machined clear acrylic tooling, which allowed them to visually gauge mold flow. "This saves time and stops you from guessing where the injection and vent ports should be placed," says Birrell-Gray. "We ran the same toolpath in the metal production tooling and kept all the other parameters the same, as well." In production, SP115 epoxy resin from SP (Sydney, Australia) is introduced using Talon's Liquid Infusion Technology (LIT), which begins as vacuum infusion but, as the fill cycle nears completion, subjects the resin to positive pressure (4.14 bar/60 psi) to ensure wetout. Talon's Internalized Color System (ICS) enables coloration of the braid inside the transparent resin matrix, using paint (green, denim, gold, silver and red) from DuPont (Sydney, Australia). Logos or insignias may be incorporated into the back or seat laminate. Production time for a single chair is 45 minutes. Demolded parts can be drilled and assembled with bolts (enabling flat-pack shipping) or adhesively bonded. Talon is now at work on a companion round table.