CompositesWorld
Issue link: https://cw.epubxp.com/i/866813
SEPTEMBER 2017 64 CompositesWorld PLANT TOUR FIG. 3 Adding foam in-mold to beat NVH This CFRP spare wheel well is formed using one-shot RTM and foam core to reduce noise, vibration and harshness (NVH) vs. previous SMC design. FIG. 2 History of high-volume success BENTELER SGL's gallery of complex CFRP structures and assemblies includes the Porsche 911 GT3 rear decklid (top), which integrates spoiler and >10 major components into a Class A-painted module, and the Lamborghini Aventador rocker/A-pillar (above), comprising an upper and lower structure, including RTM hollow structures made with braided reinforcement. Despite the SGL connection, however, not all production at BENTELER SGL involves carbon fiber reinforcement. One of its signature products, in fact, automotive leaf springs, are reinforced with glass fiber. "We always look to select the right technology, which fits best with respect to targeted properties, production volume and cost," says Ernst-Siebert. is applies not only to reinforcements but processes as well. BENTELER SGL production has used woven and noncrimp fabrics (NCF), tailored fiber placement preforms (see Learn More), braiding and filament winding. Automating and scaling manufacturing to fit parts and programs is really the essence of BENTELER SGL. "Our core competencies include product and process development and automated preforming," notes Ascher. "We are also a leader in RTM and wet pressing, enabling us to produce high volumes with short cycle times." Additional areas of expertise include prepreg pressing, sheet molding compound (SMC), adhesives technology, CNC machining and assembly. Gallery of structures From upstairs, the tour heads downstairs and through a composite parts gallery on display in the building lobby. A CFRP seat for the BMW M3 CRT features two preforms that use recycled carbon fiber and a paper honeycomb core. A rear decklid for the Porsche 911 GT3 integrates a rear spoiler/wing and at least 10 other major components into a fully finished, Class A painted part delivered to the OEM production line (Fig. 2, at left). Next is a CFRP-reinforced steel B-pillar, part of a proto- type qualification program with an OEM, which developed BENTELER SGL's Hybrid Patch Process. Capable of producing A- and B-pillars, front walls, door trunk beams and sills, this process uses an automated preforming-and-cutting cell to build tailored prepreg patches — from both glass and carbon rein- forcements — which are then pressed and cured onto prefin- ished steel parts. Adjacent is a U-shaped CFRP front-end strut brace developed with BMW. e brace features structural sandwich construc- tion, produced using RTM and polyurethane resin. Another strut brace BENTELER SGL developed for this customer also uses a braided preform and delivers high strength and stiffness, but features epoxy resin, a Class A "clear carbon" surface and hybrid construction — bonded to aluminum. "We have more than several parts in production for the BMW i3 and i8 models," says Ascher, "for structural components." is theme of complex, multi-material assemblies is illus- trated again in a chassis module for a major OEM, which replaces steel with glass fiber-reinforced plastic (GFRP) for weight savings. "BENTELER can make the whole assembly, including the GFRP leaf springs," Ascher notes. A rocker/A-pillar for Lamborghini (Saint'Agata Bolognese, Italy) comprises an upper and lower structure, the latter inte- grating two CFRP parts made with braided carbon reinforce- ments and a meltable wax core to create hollow parts that are light yet able to withstand impact and deliver key performance