A method for optimal blank shape determination in sheet metal forming based on numerical simulations

The main benefit in using optimally shaped blanks in sheet metal forming is in maximizing the efficiency of the forming process and, since there is no need for additional cutting operations after the finished forming operation, in substantial reduction of the overall production cost. The paper presents a numerical method for optimal blank shape determination which is suitable in various sheet metal forming applications. The optimal blank shape is determined in iterative way so that the edge geometry of the formed product fits its reference geometry as close as possible. The iterative process starts at blank shape from which the product is produced with its edge fitting its reference geometry just approximately. In subsequent iterations the blank shape is continuously improved in accordance with the developed optimisation method. In order to determine the product edge geometry resulting from the current blank shape, a computer simulation of the forming process and the springback is performed in each iteration. Since its effectiveness highly depends on the quality and physical objectivity of the computer simulation, the developed numerical blank shape optimisation procedure has been validated also experimentally by considering forming of a product with rather complex edge geometry as the case study.