不同的多点成形工艺方式对回弹的影响
Influence of different technology modes on spring-back in multi-point forming
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摘要: 采用有限元数值模拟手段针对多点成形过程中产生的回弹现象进行了探讨.主要对比了多点模具成形和多点压机成形两种不同工艺,分析了不同的工艺条件对回弹的影响.采用先显式方法计算成形,后隐式方法计算回弹,对1mm与2mm厚度的球形曲面件进行了数值模拟.结果表明:在冲头为10×10的多点模具成形方式下,采用无压边成形,成形1mm厚度的板料时,曲率半径为400mm的成形件回弹量沿纵向最大为1.22mm;但在相同条件下,用多点压机成形工艺的成形件,回弹量仅为0.24mm,即一次成形时,多点压机成形的板料比多点模具成形的板料回弹量仅为1/5;多点压机成形厚度为2mm的板料回弹约为0.多点压机成形方式比多点模具成形方式成形效果好,回弹量明显减小.Abstract: Finite element method was used to numerically simulate spring-back in multi-point forming (MPF). By contrasting two forming modes of multi-point die (MPD) and multi-point press (MPP), the influence of different forming modes on spring-back was analyzed. Firstly figuration was simulated by explicit method, and then implicit method was imported to calculate the spring-back of the spherical parts of 1 mm and 2 mm in thickness. The results indicate that when forming a figuration piece of 400 mm in curvature and 1 mm in thickness by the MPD forming mode of 10×10 array without hold blank, its spring-back value is 1.22 mm up to the most. But under the same condition, the spring-back value only is 0.24 mm by MPP. Namely the spring-back value of a metal sheet by MPP is 1/5 that by MPD. Moreover the spring back value is approximately 0 when forming a spherical part of 2 mm in thickness by MPP. It is concluded that MPP is better for MPF than MPD, and spring back value is sharply reduced.