CompositesWorld
Issue link: https://cw.epubxp.com/i/620463
JANUARY 2016 34 CompositesWorld INTEGRATED MANUFACTURING SYSTEMS SIDE STORY Fives Cincinnati (Hebron, KY, US) has announced an integrated system for automotive composites comprising two automated manufacturing cells: a tape layer with integrated ply cutters that provides near net-shaped and kitted material stacks, and a form-and-cure cell in which a conveyor receives and places the kitted stacks into a compression forming press supplied by technology develop- ment partner Continental Structural Plastics (Auburn Hills, MI, US). According to chief technology ofcer Yannick Leprêtre, this thermoforming process is being developed with a US automotive supplier for continuous fber-reinforced composites for structural applications. "We are transferring our aerospace technology into automotive," says Leprêtre. Fives director of product strategy and development Dan Allman details, "The frst step is to make a fat charge using one of our automated tape laying or fber placement machines. Our goal is to go directly from 2D charge to 3D part in one step, but some parts, due to their complex geometry, require preforming frst." The preform is then moved into a curing mold. The system is designed to support thermoset or thermoplastic polymers. "We have demonstrated under 3-minute cycle times to produce a 2D thermoset charge, and are targeting 90 seconds, utilizing an automated fber placement process that minimizes waste to less than 5%," says Allman. He notes the form-and-cure process has a 4-minute cycle time with epoxies, which drops to 90 seconds for some of the new, innovative polymers based on a 1-minute cure. "For thermoplastics, we can easily achieve cycle times under 90 seconds for automotive applications," Allman adds. Demonstrations have primarily used unidirectional tapes and tows in glass and carbon fber but have also used woven materials and non-crimp fabrics. "This is a very fexible system," claims Allman, "and automation is tailored per production volume." He points out that high-volume applications require highly automated systems that provide repeatable, rapid cycle-time capability in order to maximize the output and return on investment of the equipment assets. "We have moved well beyond the semi-automated, labor-intensive and long cycle-time solutions of yesterday," says Allman. Aiming for automotive-industry volume production Automating for the automaker Fives Cincinnati's integrated system for automotive composites comprises two auto- mated manufacturing cells: a tape layer with integrated ply cutters that provides near net-shaped and kitted material stacks (top) and a form-and-cure cell (bottom) where a conveyor receives and places the kitted stacks into a compression forming press. Source | Fives Group Egger admits, however, that thermoset processes like HP-RTM currently produce the most light- weight part solutions. "But the only company that is really using RTM for serious production is BMW," counters Fries. "If you look at the new 7-Series, the cycle time for the composite parts is below 3 minutes. Tis you can't do without a fully automated system." "It's clear that everyone is trying to get something out of thermoplastic composites because it ofers so many advantages, including recyclability," says Egger. "Termoplastic composites will go to the next level to be competitive, but this will take time." He thinks both injection molding and HP-RTM will remain for some time because they ofer diferent advantages in the marketplace. "I think thermoplas- tics will win out eventually, especially if the tech- nology can be developed to achieve lightweight structures like with thermosets, but some manufac- turers will always stay with thermosets, and some will always stay with metals." Egger points out, however, that widespread success with composites in the automotive industry is yet to be seen. "It is still very much in development." Compression molding machine supplier Pinette Emidecau Industries (PEI, Chalon-sur-Saône, France) also sees thermoplastics as more viable long-term vs. RTM, and is pushing development of its new Quilted Stratum Process (QSP) in that direction. "Tere is no cure cycle with thermoplastics," says North America business development manager Andrew Rypkema. "QSP uses automated ply stacking to build preforms and then forms them, but with very efcient patented technology for heating the preform." Rypkema says the transfer operations are also innovative and the forming process enables overmolding in the press for local reinforcement. Indeed, the potential of thermoplastic composites processing has been demonstrated in brake pedals for the Porsche 918 Spyder. Te glass fber/nylon 6 composite with compatible short fber-flled over- molding was made using a two-part process, and it cut part weight by 30% vs. steel while matching metal's functionality after 320,000 cycles at 3,000N load cycling between -35°C and 80°C. Although the program was low volume (a 918-vehicle limited production run), Egger notes, "it is real production and a success." Moreover, it is just one of the many new technologies that have been trialed by Porsche on the 918 for refnement into future vehicles. Tese structural parts are where Engel sees the highest value for composites.