Concluding Remarks

Abstract

This book has introduced process control for sheet metal stamping, including theory and experiments. Real-time, in-process adjustment of blank holder forces enables one to achieve the desired flow of the blank material into the die without tearing and wrinkling even in the presence of process disturbances, such as changes in lubrication and/or material properties (e.g., material formability, sheet thickness). Such a process control system for stamping can be achieved using a reconfigurable array of hydraulic actuators to provide variable binder force capability together with punch force sensors to provide in-process feedback. Multi-input multi-output process controllers (fixed gain or adaptive) can be used to ensure consistent operation, even in hard to form materials, despite process disturbances. Such a system can be retrofitted for use with existing mechanical presses and can also be implemented in modern hydraulic presses. Benefits include elimination of tearing, wrinkling and springback with reduced die try-out times, as well as consistent part quality in production even in the presence of disturbances. The potential economic benefits of such systems can be enormous. The controller designs presented herein have been shown to be effective in experimental tests on production automotive stamped parts. However, in this chapter we also discuss some potential limitations and future areas of research and development that will further enhance this technology.