ENGINEERING THERMOPLASTICS | MATERIALS
Left: Covestro showed this headlamp concept made in PC and PC/ ABS at K2019
Covestro demonstrated a beautiful concept
headlight made completely in different types of polycarbonate or PC/ABS (apart from a siloxane scratch-resistant coating), comprising three primary components and two secondary ones. Paul Platte, Senior Marketing Manager, Automotive, with Covestro in the USA, says the headlight incorpo- rates no fewer than nine novel technologies in materials, processing, and design. The concept facilitates assembly and also disassembly, since only the electronics need to be removed before the thermoplastics can be recycled all together into new PC-based blends. The outer lens in polycarbonate is laser welded to
a frame in a Bayblend PC/ABS blend (thus eliminat- ing any adhesive bonding) that is part of a two-com- ponent moulding, the other component being the housing/reflector in a thermally conductive com- pound. All electronics are placed either in or on the housing/reflector, Platte says, so heat is conducted directly into the conductive material, eliminating aluminium heat sinks. One LED chip is for example insert moulded into place. “The compound is not as conductive as aluminium, but we can keep the LEDS at within two degrees of where it would be with aluminium,” say Platte. This leads to a reduction of 40% in weight and a 20% cost reduction. A new material used in the headlamp is Makro- lon DS 801, which has particularly high dimensional stability. This is a filled material, but by using variotherm mould temperature control technology, it is possible to achieve surface roughness the same as with an unfilled material. The headlamp bezel provides aesthetics and performance. Lidar and radar are both incorpo- rated into the total assembly, which means that the material used for the bezel has to be transparent to lidar and radar, but opaque to visible light. This is achieved with Makrolon LED 2245 ST. A further
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polycarbonate used is a diffusion grade that forms part of another two-component moulding to evenly spread out light from a strip of LEDs. The use of novel moulding technologies means
that far fewer assembly stages are required than in current head lamps. The headlamp incorporates around 70 small LEDs, not counting the larger LEDs used for the main beam. A new grade in SABIC’s Xenoy range of polycar-
bonate-based blends, Xenoy HTX, is aimed at crash absorbers, body-in-white components and struc- tural reinforcements. The company says it has just closed its first application. This PC/PBT is ductile down to -30°C and also resistant to e-coat oven temperatures. Xenoy HTX is available in unfilled and glass-
filled grades and offers significant weight savings compared to steel and aluminium, SABIC says. It also says the new family provides a drop-in alternative for PA 66 compounds and alloys. The unfilled resin is modified to absorb signifi- cant energy and withstand plastic deformation in the event of a crash. SABIC is targeting the material for use as a lightweight metal replacement solution in new safety applications, including side rockers designed to offer protection for battery modules mounted to the floor of EVs. At K2019, SABIC displayed the structural lightweighting capabilities of the new technology with a 3D printed prototype of a rocker panel reinforcement incorporating a honeycomb structure designed for EV battery side protection. The company says hybrid honeycomb designs with Xenoy HTX have the potential to save up to 60% of the weight normally associated with traditional all-metal based, multi-piece steel or extruded aluminium crash countermeasures, without compromising on dimensional stability, rigidity and mechanical strength.
� November/December 2019 | INJECTION WORLD 55
PHOTO: PETER MAPLESTON
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