Optimization of Superplastic Forming Processes for High Volume Production in Aeronautics

Superplastic forming (SPF) is a well-known and widely used sheet metal forming process especially useful for the production of very complex and light thin sheet metal components. The superplastic behavior of a material is highly dependent on the temperature and occurs only at a narrow range of strain rates with an optimum value that is unique for each material. Within the aeronautic industry, this process is mainly used to form complex sheet metal parts made of the titanium alloy Ti6Al4V in heat affected areas and areas where corrosion resistance plays an important role. Even though the process times of SPF are often in the range of hours and therefore recurring costs are very high, the process is sometimes still the only choice when it comes to the forming of Ti6Al4V sheet metal parts for aeronautic or aerospace applications. To overcome the problem of long process times and high costs, in recent years, a lot of research did happen with the goal of temperature reduction during forming or forming at higher strain rates. Especially the change in the aeronautic industry towards high volume production is increasing the competition between suitable forming technologies and the SPF technology can only persist if both goals, reduction of process time and recurring costs are reachable. In this paper we will address those goals and show highly useful numerical procedures to make the SPF process ready for the next generation of aerospace manufacturing.