Influencing the Forming Limits in Air Bending Using Incremental Stress Superposition

Abstract

High springback and limited forming limits of modern high strength steels are a big challenge in manufacturing engineering. Both aspects are crucial in sheet metal bending processes. Different modifications of the air bending process have already been developed in order to reduce springback and also to increase the forming limits of materials. The innovative process of incremental stress superposition on air bending, developed at the IUL, is an alternative to conventional processes. Studies of this new process alternative show a positive effect on the considerable reduction of the sheet metal springback and extension of forming limits. Using the principle of incremental stress superposition leads to several advantages compared to conventional bending processes like die bending, bending with an elastomer tool, or three point bending. The bending force and, therefore, the consumed energy during air bending with incremental stress superposition are much lower. This paper presents the new process alternative and shows the latest investigation results.