Controlling Product Stiffness by an Incremental Sheet Metal Forming Process

Each process and each machine is subject to fluctuations, which lead to deviations in the quality of the components to be manufactured. In order to counter these uncertainties, a flexible incremental sheet forming (ISF) process for the production of truncated cone components is presented. These flexible methods are in contradiction with conventional forming processes, which are mostly designed for steady processes with large batch size. However, with the multi-technology machine 3D Servo Press, such a highly flexible process can be implemented on a forming machine for the first time. Through a determination of influence parameters and derivation of a model by means of simulative and experimental investigations, a closed-loop control for axial stiffness of the part can be realized. The control of the stiffness is not trivial in that, it depends on the geometric features as well as on the material properties, i.e., Young's modulus. The fluctuations are inherently present and can be adjusted by a stiffness correction model as shown in the presented work.