薄板件多点成形与模具成形时起皱现象的对比分析

起皱是传统冲压成形和多点成形时共有的现象,尤其在无压边成形方式下很容易发生。文章采用有限元数值模拟手段,针对两种多点成形工艺和整体模具成形过程中产生的起皱现象进行了探讨,分析了无压边成形过程中不同的成形工艺对球形件起皱的影响。文章用显式动力学算法进行了数值模拟,结果表明,采用多点模具成形工艺成形1mm厚度的板料时,曲率半径为200mm的成形件起皱明显;但在相同条件下,用多点压机成形工艺的成形件结果良好,甚至成形厚度为0.5mm,曲率半径为150mm的球形件也没有起皱;而在这两种条件下,整体模具成形都有微小的起皱发生。也就是说,多点压机成形方式比多点模具成形方式以及整体模具成形方式效果更好,缺陷少,能够得到更大的变形量。

Contrast analyzing to wrinkle of sheet metal in the multi-point forming and whole-die forming

Wrinkling is a common phenomenon in conventional stamping technology and Multi-point forming(MPF).it occurs easily in the mode of no blank holder.FEA Numerical simulation is used in this paper to simulate wrinkle in the figuration of two MPFs and die,and influence of different forming modes on global wrinkling is analyzed without blank holder.Furthermore the forming processes of the globe part were simulated by explicit software.Results indicate that the sheet metal with the thickness of 1mm and curvature radius 200mm sharply wrinkle in the multi-point die(MPD) forming mode.Under the same condition good forming results can be obtained in the multi-point press(MPP) forming mode,even in the thickness of 0.5mm and curvature radius 150mm.In the two kinds of condition the whole die forming has simple wrinkle.Namely MPP is a high efficiency form mode than MPD and whole die,forming defects can be reduced by this mode,sheet metal parts with large curvature can be formed by MPP.