CompositesWorld
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OCTOBER 2015 100 CompositesWorld PLANT TOUR If you could restore your plant infrastructure to stronger than new in a fraction of the time and total cost of traditional repair or replacement – why wouldn't you? You can, with the DowAksa CarbonWrap ® System. This simple, proven method of rescuing degraded concrete, steel or masonry structures not only saves you signifi cantly in terms of repair time and money; it also minimizes operational downtime, saving you even more. This engineered carbon-fi ber solution: • Is corrosion-resistant • Can conform to almost any shape • Requires no demolition and reconstruction Learn more at www.dowaksausa.com/cwoct Don't Replace Your Infrastructure RESTORE IT parts for the Gulfstream 6 and Dassault Falcon 5X via induction welding repre- sents the very latest developmental step that is already delivering on its very great promise. Tis work is done at the next stop on CW's tour, the Marconi Street Building, a short drive from Fokker's main facility in Hoogeveen. Here, we see a jig design and automated process that has evolved beyond that used for the A380 wing leading edge confguration. Te advantage of induction over resis- tance welding, says Ofringa, is that it does not require use of a metal strip or other conductor, thus there is no weight penalty for the weldment. Fokker's induc- tion method was developed and provided by KVE Composites Group (Te Hague, Te Netherlands). Dubbed Induct, it generates eddy currents in the electri- cally conductive carbon fber reinforce- ment within the thermoplastic laminate. Te currents are generated by moving an induction coil over the weld line; the eddy currents it generates then heat the laminate from the inside. Te parts that are being welded must be posi- tioned, says KVE, in a proprietary tooling material (steel, with a "special" ingre- dient) that is transparent to the electro- magnetic feld and has good thermal conductivity. Te coil motion at Fokker is actuated robotically. Ofringa frst shows CW the assembly jig for the Gulfstream 6 rudder, which consists of two spars with supporting ribs. All are fabricated from carbon fber/ PPS via compression molding. As with the A380 wing leading edge assembly, the Gulfstream 6 rudder jigs (there are six, total) are oriented horizontally and elevated about waist high. A jig is 4 to 6m long and features horizontal slots to hold the spars and vertical slots to position the ribs against the spars. With all parts in place, a robot equipped with a KVE induction coil moves into various slots along the jig, welding each rib to the spars. For the Dassault Falcon 5X elevator, Fokker has three jigs, similar to the Gulf- stream jig system but improved in the sense that the six jigs are now replaced by only three, using the same induction technology (see Fig. 9, p. 97). On these the PPS around the mesh and creates a bond with the skin. Te mesh remains in place and becomes a permanent part of the weldment. After all ribs are bonded, the spar is attached and held in place with stifeners, which also are welded (Fig. 7, p. 97). Much of this assembly, says Ofringa, is automated, but some manual labor is required to attach holding fxtures. Te welding itself, however, relies on automation for both speed and consistency. "An electronic ruler on each jig tells the machine which rib it's on," says Ofringa (Fig. 8, p. 97). Advancements in induction welding Although the resistance welding regimen employed on the A380 wing leading edge assembly is an efective and now relatively mature Fokker technology, the assembly of