Optimization of the Blank Holder Force Using Genetic Algorithm Method in Case of a U - Shaped Part

In case of sheet metal forming the main dimensional errors are caused by the springback phenomena. The present work deals with numerical simulation related to draw bending and springback of U - shaped parts. The current paper is trying to prove out the important role of the blank holder force variation during the forming process. The Dynaform 5.8 software was used to simulate the forming process, in which the blank holder force varies in four steps between 0 and 50 kN. The factorial simulations test plan was made to cover completely the variation domain and 256 simulations were necessarily to be performed. The part obtained after each simulation is analyzed and measured to quantify the errors caused by springback. Parameters as: angle between flange and sidewall, angle between sidewall and part bottom, chamfer radius between part bottom and sidewall or chamfer radius between sidewall and flange are recorded in a data base. The initial simulations plan together with the generated data base is used as an input for the genetic algorithm optimization method. With the optimized process parameters a new simulation is made and the final shape of the part is compared with the ideal geometry. The shape of the part obtained with the optimized parameters is proving the capability of the proposed method.