Although the smart fortwo vehicle, which will be available in the U.S. early in ’08, is a comparatively small car—wheelbase: 73.5 in.; length: 106.1 in.; width: 61.4 in.; height: 60.7 in.—it has something that not even the biggest Maybach offers. “With an area of around 1.2 square meters, this is to date the largest polycarbonate roof module fitted in a production-line vehicle anywhere in the world,” claims Dr. Sven Gestermann, key account manager, Automotive Glazing for Europe, Bayer MaterialScience AG (www.bayerbms.com; Leverkusen, Germany). The roof module is made by Webasto AG (www.webasto.com) at a facility in Stockdorf, Germany.
The module is produced with two-component injection-compression molding: (1) the transparent outsider skin is made with a polycarbonate, Makrolon AG2677; (2) the large area frame is then produced with Bayblend DP T95 MF.
Although it is a large component, it is estimated to weigh 40% less than a comparable glass module.
And apparently while big, there could be bigger roof modules to come: “Tests at our company have shown that, with present-day materials and modern injection-compression molding tools and machinery, low-stress roofs with an area of up to 1.7 square meters are quite feasible,” according to Gestermann.