Abstract
With the widespread adoption of high-strength steel sheets in sheet metal forming industries, new technologies that can control and suppress three-dimensional springback are highly required. In particular, in the stamping of curved beams, torsional springback is likely to occur, which is very difficult to suppress by conventional technologies such as die-shape change and blank-holder force control. In this paper, we propose a new method of springback compensation by setting the appropriate heights of draw-beads on a die face. We verify this new method by performing a benchmark test using S-rail. In this verification, 1 GPa high-strength steel sheets were utilized as the blank. To determine the appropriate heights of draw-beads, an optimization technique based on finite-element simulation was utilized. Using thus determined draw-beads, we have succeeded in reducing springback markedly from 4 degrees to 0.5 degrees in torsional angle, which was confirmed by the S-rail forming experiment.
