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Technologies promote all-round reductions

Bayer MaterialScicene also showed a new tailgate design. Unlike the conventional design involving a metal carrier and a glass window inserted in it, the prototype involves plastic/metal hybrid technology. The single part is integrated with a back light, with a seamless outer skin consisting of coated Makrolon PC, which is reinforced with ribs. Strips of sheet metal are inserted in the grooves between the ribs and bonded with an elastic adhesive, which evens out heat expansion differences between the metal and the amorphous plastic. The reinforcements can be positioned exactly and, the company says, only a few metal inserts are required to achieve a high level of stiffness. Non-transparent areas are either back-printed or back-injected with a black frame material using twocomponent injection moulding. The company says besides the weight saving of up to 40%, the integration of functions cuts costs

New automotive technologies shown at the K are aimed at reducing processing costs and the weight of vehicles, as well as keeping to the sustainable theme. What better way to show the use of materials on multiple applications than to bring the product to the show? Sabic Innovative Plastics did just that when it showcased Chery Automobile’s soon to be launched A3CC sports coupe at its booth. Chery is the first Chinese OEM to use Sabic’s Noryl GTX resin for a massproduced fender, replacing steel and cutting weight by 50%. The resin can also be painted on-line along with the metal Body-In-White (BIW), doing away with secondary operations. The The stylish Chinese-made car that uses Sabic’s fuel filler doors are resins also made from the resin. Traditionally, moulded and painted by the component supplier, now colour mismatches can be avoided. Other components like the front and rear energy absorbers are made from Sabic’s Xenoy resin and an under-tray is moulded from Stamax long glass-filled polypropylene (LGFPP) compound, meeting European standards. For weight reduction, Bayer MaterialScience was promoting a customised polycarbonate developed for low-beam and full-beam headlights and fibre optics for daytime running lights in the front headlamps of the new Audi A8. Developed in collaboration with Audi and Hella, the ten plastic lenses used in the headlamp are made from Makrolon LED 2245, which offers high transmission for long light paths, high thermal resistance and yellowing stability to LED light. Weighing 50% lighter, the headlamps are expected to be particularly attractive to manufacturers of electric vehicles. The rectangular, slightly curved headlamps are 4 cm long, 2 cm wide and 1 cm thick. A hybrid configuration of a brake pedal developed by Germany-based Trelleborg Automotive is said to offer cost savings and lightweighting. The design combines metal with glass fibre-reinforced plastic, which is overmoulded using a water injection technique to create a tubular body,

with final assembly in a single step. The part realises weight savings of up to 50%, compared to metal brake pedals that also require stamping and welding operations. Organic sheet hybrid technology Another new hybrid technology for the automotive sector involves preforming and overmoulding resin-impregnated continuous-fibre sheets instead of overmoulding preformed metal sheets to add on ribs and other structures. By replacing metals, it shortens the process and reduces component weight. Lanxess displayed the front end of the Audi A8, produced by Magna Decoma Exterior System using organic sheets and aluminium, allowing for 20% lower weight. The semi-finished sheet is preformed, then inserted in a mould along with three aluminium sheets and overmoulded with reinforcements and ribbing with Lanxess’s 30% glass fibre-reinforced PA6. Another German supplier BASF showcased an all-plastic seat back, developed in cooperation with France-based Faurecia, replacing the existing metal structure. The one-piece part minimises foam and trim, weighs 20% less and is 30 mm thinner. Layers of continuous fibre-reinforced sheets from US company Performance Materials are overmoulded with a new 35% glass fibre PA6 grade from BASF in a second step. Meanwhile, machinery suppliers Engel and KraussMaffei both showed the process using composite sheets from German company Bond-Laminates. KraussMaffei used a 300 tonne CX injection moulding compounder and a KM Berstorff twin-screw compounder for the process. BASF showed an all-plastic seat back developed from the new organic hybrid sheet technology

5 I n j e c t i o n M o u l d i n g A s ia • D E C E M B E R 2 0 1 0

Automotive Engel was demonstrating the production of a steering column made of 40% glass-filled PA and reinforced with a four-layer organic sheet in a process it calls Organomelt. The manufacturing cell comprised a 500tonne machine and three robots. The sheet is preheated and preformed with nylon injected over it and after that it is laser trimmed. Engel says the technology can also be used to make frame components for panoramic roofs and for reinforcing functional modules for doors and hatches. Sustainable solutions The downsizing of engines to meet fuel economy and CO2 reduction while still delivering engine performance is leading to hotter temperatures; harsher chemicals; and, tighter under-the-hood constraints. Since metals are not a long-term and sustainable answer, US supplier DuPont Performance Polymers has introduced Zytel PLUS nylon for transmissions and exhaust systems. The company says it has tests to prove that whether exposed to calcium chloride or to 3,000 or more hours of hot air, hot oil, water, and long-life coolant the nylon outperforms traditional ones. This can allow the automotive industry to more than double the lifetime of certain engine parts, compared to those made of standard, heat-stabilised nylon. In another example of sustainability, DuPont worked with German Takata Petri to introduce a new grade of Hytrel RS, said to be the industry’s first renewablysourced thermoplastic elastomer, for use in airbag systems. Previously, Takata was using a petroleumbased Hytrel for the airbag. The airbag covers that are moulded from DuPont’s Hytrel RS comply with the standard requirements such as paint adhesion, longterm ageing performance, and low temperature ductility

The new grade is based on a thermoplastic etherester elastomer (TPC-ET) with hard segments of PBT and soft segments that contain a polyether derived from non-food biomass. The compound used in the airbags has 35% by weight of bio-content. The company says it replicates the technical properties of standard grades, including consistent physical properties over a wide range of temperatures. Furthermore, based on an internal cradle-to-gate life cycle assessment, DuPont says the grade has a smaller environmental footprint, compared to a petroleum-based TPC-ET. â—†


IMA issue features December 2010

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