Geometric size and forming force prediction in incremental flanging: A new analytical model

A new analytical model for geometric size and forming force prediction in incremental flanging (IF) is presented in this work. The complex deformation characteristics of IF are considered in the modeling process, which can accurately describe the strain and stress states in IF. Based on strain analysis, the model can predict the material thickness distribution and neck height after IF. By considering contact area, strain characteristics, material thickness changes, and friction, the model can predict specific moments and corresponding values of maximum axial forming force and maximum horizontal forming force during IF. In addition, an IF experiment involving different tool diameters, flanging diameters, and opening hole diameters is conducted. On the basis of the experimental strain paths, the strain characteristics of different deformation zones are studied, and the stable strain ratio is quantitatively described through two dimensionless parameters: relative tool diameter and relative hole diameter. Then, the changing of material thickness and forming force in IF, and the variation of minimum material thickness, neck height, maximum axial forming force, and maximum horizontal forming force with flanging parameters are studied, and the reliability of the analytical model is verified in this process. Finally, the influence of the horizontal forming force on the tool design and the fluctuation of the forming force are explained.