Control and Optimization of Strains Developed in Cup Forming

An analytical evaluation, control and optimization of the strains developed during Cup Drawing using various blankholder forces was performed on a sheet of mild steel used as the blank. It is ensured that the finite element model used consists of the blank holder forces uniformly applied over the blank. Strain formation was evaluated as a function of punch displacement and blank holding forces applied. The study reveals the impact of the varying blank holder forces on the drawn cup. Mathematical expressions of corrected blank holder force were developed in terms of the old blank holder force, and strain data. The draw depth at which wrinkling and tearing occurred was used to define the operational envelop of the die. The strains once controlled were also optimized using a mathematical algorithm to minimize the strains to their least possible values. The major and minor strains of the finite element model proved to be in concordance with the experimental data obtained.