Progressive Forming Tailor-Welded Automotive Bulb Shield and Vibration Test 2008-01-1444

The automotive bulb shield is a major sheet metal component in the vehicle lighting system, which helps to generate desirable photometric and beam pattern. Due to the complex geometry, bulb shields are primarily manufactured by progressive drawing processes. Similar to any other automotive cosmetic stamping, bulb shields are required to possess both vibration durability and fashionable styling design. However, high rigidity requires high strength and complex styling design, which requires better formability. These two contradicting requirements can now be satisfied by newly emerged tailor-welded strip materials, which are welded from tailored coils with different material properties. A bulb shield, which is originally made from expansive stainless steel, is formed from Tailor-welded strips of four combinations. Vibration testing is conducted and 40% endurance improvement is observed. Since expensive and thicker stainless steel is substituted by thinner and economic cold rolled steel (CRS), the technology also provides a potential reduction on both cost and mass of bulb shield.