SEP 2018


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SEPTEMBER 2018 56 CompositesWorld FEATURE / Welding Thermoplastic Composites need a specific coil — in this case, a multi-coil." Founded as Pôle de Plasturgie de l'Est (PPE) 25 years ago, Composite Integrity is a leader in resin transfer molding (RTM) and epoxy resin-infused aircraft structures with French aero- space companies. Incorporated into the IS Groupe in 2016, it has worked with Aviacomp (Launaguet, France) to develop co-consolidation welding technology used in TPC fuel access doors for the Airbus A350 aircraft. "Resistive components on the surface of the molded inner and outer composite parts put heat into the weldline," says Raynal. Composite Integrity began working on the STELIA Arches TP project in 2015, enabling induction welding of fuse- lage-sized, curved parts. e process is described as "dynamic" because the robot welds the stringers down the length of the fuselage and accommodates 3D shapes, including movement in the z-direction during welding. "Both the stringers and skin in the STELIA demonstrator have a change in thickness," Raynal explains. An aluminum rail serves as fixation jig to prevent movement of the stringer on the skin as it is welded. For the demonstrator, pressure was applied via two rollers in the welding head. ese sit above the coil. During welding, the rollers run along the stringer, next to the fixation rail while the coil is traveling over the weldline. "We have now developed a new, patent-pending welding head, which uses a single roller and increases the weldline mechanical properties," Raynal notes. "We also have a cooling device blowing air on the welding surface in pressure to be sure we are below the crystalliza- tion temperature, so there is no risk of de-compaction once pressure is released." Provision for cooling also affects the crystallinity of the thermoplastic matrix at the weldline. "We test to measure that crystallinity meets the aerospace standards and then establish the corre- sponding parameters for the welding process," Raynal explains. Speed is also a factor. "For the demonstrator, the speed was 2 m/min, but our target now is 5 m/ min," he says. "Managing the cooldown and crystallinity of PEEK and PEKK are more complicated, which affects the global speed of welding, but we have good results with both, using conven- tional organosheet qualified by Airbus." e maximum thickness of parts welded France) Arches TP structure demonstration project, unveiled at the 2017 Paris Air Show (Fig. 5). Composite Integrity is the composites division within the Institut de Soudure (IS Groupe, Villepinte, France). "We draw off more than 100 years of IS Groupe experience in welding metals to design and build our own induction coils optimized for each material, thickness and part shape, including specific coils for woven fabric, noncrimp fabric and UD," explains Composite Integrity business development manager Jérôme Raynal. "e major problem with UD is that there are no welding nodes to generate induction current, so we Verisurf Software lets you see the difference between the nominal CAD design and finished machined part, in real-time. Perfect for in-process, first article and automated production inspection. Verisurf works with ALL CAD software and ALL measurement hardware devices, including portable, fixed or programmable CMMs, trackers, and scanners, new or existing, to provide flexible inspection and reporting solutions, in the quality lab or on the shop floor. See the difference Verisurf can make in your business by reducing training costs, increasing efficiency, reducing scrap and improving overall quality. Let us show you the difference, in your shop, with your parts. Contact us, today. Dealer inquiries invited. Educators, ask about our education program. See the Difference • 866-340-5551 Inspection Software

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