Study On Springback Control And Process Optimization During Sheet Metal Forming

Springback usually happens during the sheet metal forming. It influences the dimension precision and the manufacturing efficiency greatly. It is necessary to predict the springback exactly and to control it effectively in order to improve the products quality and shorten the developing cycle. Reducing the springback based on experience or trial and error expends costly. The Finite Element Method has been used in the springback simulation since the 1990's. It is economical to use the FEM simulation technology to predict the springback during sheet metal forming and modify the die shape in order to obtain the desired part.This paper introduces the development of springback prediction, review the history of analytic method, experimentation and FEM and the achievements. It is obvious that the FEM is an effective and powerful tool to predict the springback at present.Using the mechanics principle, taking the sheet metal bending as an example, the springback mechanics theory is described in detail by analyzing the stress and strain distributions, material flow in the deformation and undeformation zones. The development of springback control method is introduced and analyzed detailedly.The FEM simulation process is studied, and the pre-process, FEM analysis, post-process and their key technologies are described respectively. The influence of simulation parameters on the springback simulation precision, such as material types, element types, element sizes, constitutive equations, FEM algorithms, contact and friction rules, integral point selections, and dummy punch velocity selections, is analyzed systematically. The analysis indicates that the simulation precision can be improved when the material type is shell element, the element size is small shell element, the contact law is explicit simulation, the friction is calculated by the classical Coulomb rule and there is seven Gauss integral points.