Hybrid deep drawing tools for high strength steels

Abstract

In automotive industry the variants of models increase so that the batch size for parts decreases simultaneously. With increasing number of parts and tools, the time for design and try out processes becomes less. Therefore, there is a need for tools which withstand just a low amount of parts and which can be produced in an easy and cheap way. In this case, the use of polymer tools can replace conventional steel and cast iron tools. For forming processes of high strength steels, the polymer tools arereinforced by fiber reinforced plastics. To avoid wear on such a tool, metallic protective coating is applied on the surface. Investigations of forming high strength steel blanks in hybrid tools show that the geometry accuracy is high and the wear is as less as in conventional steel tools. One of the main benefits is the uniform distribution of the contact pressure due to the lower Young's Modulus of polymer compared to steel. Furthermore, the hybrid tools enable to vary the stiffness locally and temporally without the use several tool inserts, which is helpful for the minimisation of springback.