Young-Won Yun, Hyung-Sub Bae, Myeong-Kwan Park*
The Journal of Mechanical Science and Technology, vol. 24, no. 11, pp.2281-2288, 2010

Abstract : The predominant failure modes (wrinkling and tearing) must be avoided during the drawing process in sheet metal forming. These defects may be eliminated by using a controllable device for which the blank holding force (BHF) is adjustable. The purpose of this research is to verify the possibility of using a magneto-rheological (MR) damper for obtaining an almost constant BHF in drawing presses. The damper force is controlled by adjusting the current that is applied to the MR fluid, which is a functional material. To realize this aim, a prototypical press system is manufactured. A control test using a closed-loop PID controller is carried out for achieving the objective where by a constant BHF is retained at a constant prescribed force, while the press slide translates at a constant velocity. The results show that the BHF of the drawing press can be controlled effectively by using the proposed MR damper.

Keyword : Blank holding force; Closed-loop control; Damper; Drawing press; Magneto-rheological fluids