Inline feedback control for deep drawing applications

Abstract

In series production of deep drawing products the quality of the parts is significantly influenced by material scatter. To guarantee a robust manufacturing the processes are designed to have a large process window. As the different material properties can lead to a drift in the process, the press settings have to be adjusted to keep the quality. In the scope of the work a feedback control system is proposed to keep the operation point inside the process window. The blank draw-in measured in predefined points is used as the primary indicator of the expected part quality. A simulation based meta model is then used to design the control algorithm with the blank holder forces as control variable. As the draw-in measurements are carried out punctually, their positioning within the tool becomes of critical importance. A simulation based study is therefore presented for the identification of sensor positions with the highest significance in relation to the process outcome. The baseline calibration of the controller is also based on the meta model. The validation of the proposed control system is illustrated based on experiments in a production line.