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Aluminum extruded materials have been mostly used only a few automotive parts until now, such as roof rail, sunroof frame and bumper beams. However, aluminum extruded materials have been being increased in suspension parts, especially, lower control arm. Most of aluminum suspension parts could be obtained by straight profile extrusion and stretch bending and forming technology but the cost of production is a little bit high due to complex forming process. In this paper, curved profile extrusion technology was applied for cost reduction and higher quality guarantee by removing forming process. It has been fabricated curved extruded profile used by curved profile extrusion equipment for removing bending process and designed control arm with optimized profile for taking off forming process. For curved profile extrusion and excellent quality, it has been optimized extrusion condition by controlling and combining extrusion speed and traverse moving speed and distance.

The gel fraction and the curing rate of the silver mirror protective film according to the curing condition were investigated. Two-packaged polyurethane dry film made from acryl polyol and three different isocyanate curing agents (HDI-biuret, HDI-trimer and IPDI trimer) were built on the silver mirror layer in order to protect the layer. FTIR/ATR spectra showed the isocyanate content was clearly decreased and the gel fraction was increased as curing temperature and time were increased. The optimum curing condition of the silver mirror protective film was 80□ and 30 minutes. The dry film prepared with the optimum condition satisfied all tests in our materials specification for automotive interior parts. Moreover, the pencil hardness of the film containing dibutyltin dilaurate was stronger than the film without catalyst.