Cyber Times International Journal of Technology & Management

The quality of stamped sheet metal parts in sheet metal manufacture is influenced by one of the key factor name as spring-back. To evaluate and or decrease spring-back, the diverse efforts have been taken for a long time. For analyzing parts of two-dimensional or simple three-dimensional geometry, firstly analytical methods have been developed. To apply analytical methods to fully three-dimensional parts in general is almost impossible. Henceforth the numerical methods including the finite element method (FEM) have recently been developed and applied to sheet metal parts of general shape as a result of rapid progress of computing environments. A comprehensive assessment of numerical factors influencing spring-back is required because the results of spring-back simulated by FEM may vary greatly according to how numerical factors are set, for example element size, punch velocity, contact penalty constant, damping ratio. In this work, numerical factors influencing spring-back have been evaluated using the Finite element analysis. The L-draw bending process is chosen as an evaluation problem because of its large spring-back, to clarify the effect of each factor on it. In the analysis, the explicit time integration method is used in the simulation of forming stage, whereas the implicit time integration method is applied to the spring-back stage in order to get the static solution readily. Various combinations of numerical factors are taken in consideration to carried out numerical experimentation. For validation, numerical results were compared with the experimental results. Also the important factors for spring-back have been assessed.