Audi Q7 with headlight LED/HID module construction in Arnite XL-T. (Photo: DSM Engineering Plastics)
DSM has collaborated with ZKW Group, a provider of light systems for motor vehicles, to produce a new lightweight LED lighting module for the Audi Q7.
The headlight uses DSM’s Arnite XL-T material, chosen for its technical and aesthetic properties, as well as conforming to strict fuel, safety and emissions policies.
Currently LED lighting, with its excellent performance characteristics, is the cutting edge of automotive headlamp design. Headlights are also a safety critical item and must perform to highest international standards. LED, HID and Halogen lighting systems, often combined in one headlight assembly, offer excellent performance but also place more restrictions on the use of materials and design. Sunlight radiated into the multiple LED/HID lenses creates localised increases in thermal loadings in excess of 235 °C.
Such high sun loadings, however, can cause heat distortion and outgassing of both functional and aesthetic components. Components in the headlamp assembly, such as the bezel, lensholders or frames can suffer from outgassing, become distorted, damaged or can even melt under such severe conditions. Aesthetic trim components extend the performance challenge in being able to meet the designer’s requirement for exacting surface appearance in black or dark grey colours that increase the issue of sun load.
DSM says that its Arnite XL-T, with a heat deflection temperature (HDT) of 250 °C, low outgassing and excellent textured surface finish in dark colours, offers both the designer and engineer extended freedom in headlight LED/HID module construction. Arnite has been used successfully for many years in lighting and other automotive electrical and electronic applications that demand high heat performance and low outgassing characteristics. Following research and testing, DSM says it has developed proprietary technology that has extended the thermal conductivity of Arnite XL-T to outperform high heat resistance thermoplastics such as polyether sulfon (PES), polyetherimides (PEI) and polyphthalamides (PPA) without high costs or issues such as critical processing and water absorption. A key benefit of Arnite XL-T, DSM added, is its outstanding surface finish when textured, even in glass fibre reinforced grades/variations/options.
“Innovation is our foundation and we stake our reputation on the pioneering advances we continue to make in headlight systems,” explained Sylvana Wetscher of the ZKW Group. “Arnite XL-T enables us to design LED lighting modules that meet all the design criteria set by our OEM customers who have recognised the advantages it offers for sunload issues.
“Together with our partner DSM, we have achieved the ultimate goal of meeting the functional requirements of the headlamp module as well as conquering the issues of heat distortion and outgassing, without complex and costly redesigns for metal inserts or additional heat shields. This has kept the overall weight to a minimum that contributes to improved fuel economy and reduces the vehicles carbon footprint.”