A method of constructing smooth tool surfaces for FE prediction of springback in sheet metal forming

In sheet metal forming applications, errors of formed parts due to springback can be compensated by offsetting tool surfaces, which are often defined by a set of scattered data points in FE forming simulation. A method for constructing smooth tool surfaces over scattered data points is presented for the application in predicting springback in sheet metal forming. A system has been developed to assess the error between the FE formed and original CAD sheet metal parts, to offset tool surface for springback compensation, to construct a smooth tool surface from offset scattered data points and input the tool surface definition to a commercial FE code for further FE simulation. A case study is carried out for the determination of the tool shape in forming an autobody part.