Distinctive headlamp bezels in cost-effective Crastin®
Automotive headlamps – a significant opportunity to add personality to vehicle styling – can now be manufactured more cost-effectively through the “Design-Materials-Processing” solution offered by DuPont. The first tier supplier of exterior automotive lighting – Automotive Lighting of Reutlingen (Germany)– has turned to this solution from DuPont for the development of the headlamp bezels of the new-look Audi A4.
The headlamp is one of the most important design features of any car, with the bezel – the trim ring located between the reflectors and the housing of the headlamp – playing a prominent and highly visible role in its styling. As a consequence, aesthetics and a perfect surface quality, in addition to the more practical requirements of high temperature resistance, ease of metallization, resistance to climatic effects and moisture, dimensional stability and processability, have become key features of this injection-molded part.
Whereas the manufacturers of headlamp bezels may have traditionally relied on high-heat resistant polycarbonate or standard PBT polyester, many have been turning to DuPont for a tailored solution that combines the exceptional properties of DuPont™ Crastin® PBT with innovative manufacturing techniques, design and development for more stylish and cost-effective results. One such company is Automotive Lighting, a global leader in exterior automotive lighting founded in 1999 as a joint venture between Magneti Marelli and Robert Bosch GmbH.
When specifying the material for the bezels of the headlamps (both xenon and halogen) of the new-look Audi A4 and Audi TT, Automotive Lighting chose Crastin® over a range of potentially competitive materials. “The DuPont material provides much higher temperature resistance compared to standard polycarbonate, involves significantly lower cost compared to high-heat resistant polycarbonate and offers much higher temperature resistance (up to 170° C) with less outgassing compared to competitive PBT materials,” states Alexander Müller, development team leader at Automotive Lighting Reutlingen GmbH. Because Crastin® bezel grades are optimized to provide very high stability and very low thermal degradation during the molding process, Automotive Lighting was able to achieve very low reject rates during production. Moreover, DuPont technical specialists in Germany were on hand to define the optimum part design, tooling and machinery to meet all technical requirements, achieve the lowest possible part cost and maximize productivity. “During testing and production start-up for the Audi A4 bezels, Crastin® clearly showed by far the highest productivity compared to other PBT materials available, largely thanks to the quality of the material and the excellence of the local technical support,” confirms Alexander Müller. “Overall we were delighted with the cost-effective performance of the material in what is a demanding and highly-visible application. The quality and appearance of the bezels in the headlamp unit we developed for the A4 was also greatly appreciated by Audi.”
As well as being optimized for flow and stability in a high-temperature environment, Crastin® bezel grades are designed to provide a top quality and class A surface straight from the mold, without hazing or other defects. Although not pertinent to the bezel developed by Automotive Lighting for the Audi A4, Crastin® grades can be used for direct metallization, providing designers with more flexibility and freedom whilst reducing both overall costs and manufacturing costs.
DuPont is working on further performance enhancements for its range of Crastin® grades for bezels, including even higher temperature resistance and part stability, as well as the use of renewably-sourced materials in the same application.