thermoplastic composites | Innovation Right: A prototype
automotive oil pan designed by Nifco in
DuPont’s Vizilon TPC material
Laminates (now part of Lanxess). Vizilon TPC marks the company’s return to this sector. The product family currently comprises continuous-glass fibre woven reinforced consolidated sheets based on polyamide 66/6 blends. The sheets can be stamped or thermoformed into various shapes, which can then be over-moulded. In addition, the company
offers various specific over-moulding resins based on PA 6 and 66, as well as PPA. DuPont is also considering production of UD tapes, but has no commercial offering yet. Craig Norrey, TPC Global Technical Service Manager, says the company has been approached about developing UD tapes and admits that unit costs of tapes are lower than fabric sheets. However, he points to extra challenges in terms of placing tapes in moulds and holding them in position during over-moulding unless they are converted into preforms first in a separate process. DuPont highlights not only the weight saving virtues
Below: A TPC production cell developed by DuPont for hybrid
moulding applications
of Vizilon TPC but also its crash absorption potential. It absorbs more energy than metal and also performs better in crash applications than other thermoplastics. “In tests, a beam made of Vizilon TPC delivered 5.4 times more energy absorption than a short-glass fibre polymer beam,” the company claims. It also sees potential in large structural items such as floor pans that require lightness and stiffness. Norrey says that adoption of TPCs in place of metals
is going to take time, particularly with safety-critical components. “We have to jump through a lot of hoops at
automotive OEMs,” he says. “They won’t adopt a new material or technology without having fully proved it out first, in terms of design, manufacturing, assembly and so on. And of course they are very concerned about costs.” The latter is one of the reasons
that DuPont is concentrat- ing on glass reinforcement rather than carbon fibre. “But the big thing is the upcoming CO2 emission
norms. The closer we get to their implementation, the greater is going to be the pressure to lose weight,” Norrey says. “So things will happen in the next one or two years. I think at the moment the major OEMs are all looking at each other [over largescale adoption of TPCs], and when one moves it could trigger a snowball effect. And when it happens, it will be in Europe first.”
In Europe, by 2021, fleet average CO2 emissions by new cars will be 95 g/km, which is 40% less than the 2007 fleet average of 158.7g/km.
Design matters
Realising the full benefits of lightweighting technology isn’t a simple matter of swapping out steel parts for composites: it requires a fundamental shift in the way vehicles are designed. “The most effective way to reduce weight is to design for composites first, rather than using composites in parts that are designed for metal,” Norrey adds. “Designing for TPCs requires a different approach in order to capture all the light- weighting, strength, and functional benefits.” As with several other polymer majors active in thermoplastic composites, DuPont is deploying advanced FEA (finite element analysis) technology for more accurate design and performance prediction, and has installed manufacturing capabilities for better process development, prototyping, and demonstration. Several years ago, working with PSA Peugeot
Citroën, DuPont tested a prototype side-impact beam made in over-moulded Vizilon TPC. The beam was 40% lighter than one in ultra-high strength (UHHS) steel, while absorbing more energy than both metal and short glass-fibre polymer beams. It also showed very good stiffness, “responding favourably in temperatures from -40°C to +90°C, and being fully compatible to the e-coat process,” according to DuPont. Norrey says PSA is now considering Vizilon TPC as a serious lightweighting option. More recently, car parts manufacturer Nifco UK used Vizilon TPC in an oil pan designed as part of the UK
18 INJECTION WORLD | January/February 2017
www.injectionworld.com
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