Experimental Drawbeads Design Research

In order to constrain the restraining force and control the speed of metal flow, drawbeads are widely used in industry. They prevent wrinkling or necking in formed panels, reduce the binder force, and minimize the usage of sheet metal to make a part. Different drawbead configurations can satisfy various stamping production. Besides local design of drawbeads, other factors like pulling directions, binder angles and single or multiple beads play an important role too. Moreover, it was found that the same beads configuration can own a different rate of change of pulling force on different gaps by experience. In this paper, to study the effect of each factor, the Aluminum and Steel sheet metals were tested to obtain the pulling force as they passed through a draw bead. Three gap cases between a male and a female beads are set to figure out the trend of pulling force. Drawbeads are installed in a Stretch-Bend-Draw-System (SBDS) test device while a tensile machine was used to record the pulling force. The results validate that the sensitivity of drawbeads vary with the increase of gap. Details of the sensitivity change and other effects were illustrated and discussed in the paper.