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Journal of Zhejiang University SCIENCE A
ISSN 1673-565X(Print), 1862-1775(Online), Monthly
2014 Vol.15 No.6 P.432-446
A numerical study of the effects of roller paths on dimensional precision in die-less spinning of sheet metal
Abstract: Die-less spinning eliminates the dependence upon the mandrel of traditional spinning, but bringing about comparatively poor dimensional accuracy which needs to be improved. In this paper, roller paths in the first pass of die-less spinning, including concave, convex, linear and combined ones are parameterized according to the degree of bending and their effects on dimensional precision (thickness variation and shape deviation) have been studied by using experiments of finite element (FE) analysis. The effects of roller paths on thickness variation, shape deviation, tool forces, and stress and strain variations have been analyzed numerically. The results showed that for concave roller paths, the thickness variation is not very sensitive to the degree of bending, while a low degree of bending of the roller path can result in a low shape deviation. For convex roller paths, a low degree of bending leads to both low thickness reduction and low shape deviation. Further research shows that a combined roller path with convex-concave curve could contribute a low shape deviation, while an inverse combined roller path gives better thickness precision.
Key words: Sheet metal, Die-less spinning, Roller paths, Dimensional precision, Tool forces
Chinese Summary <39> 无芯模旋压旋轮轨迹曲线对其成形精度影响的仿真研究
创新要点：基于贝塞尔曲线实现对于无芯模旋压旋轮轨迹曲线的参数化控制；通过构建包括成形与回弹工艺过程的无芯模旋压仿真模型，研究参数化轨迹曲线对成形件壁厚及形状精度的影响趋势及关系，同时对成形过程变形区应力应变进行了深入探究分析。
研究方法：1. 基于三次贝塞尔曲线实现对于旋轮轨迹曲线的拟合以及参数化控制（图3）；2. 利用LS-DYNA软件实现对无芯模旋压成形及回弹工艺综合仿真及其过程、结果数据的提取；
3. 研究不同参数化轨迹曲线下成形件壁厚及形状精度变化趋势（图12和13），获取量化轨迹曲线对于零件成形精度影响关系（表3），并通过增加实验组验证所获关系模型；
4. 提取成形过程中及成形后板料变形区应力及应变数据（图14–19），深入探究上述变形机理。
重要结论：凹轨迹曲线下，坯料中部出现最大减薄及变形程度，且降低曲线曲率，形状精度提高；凸轨迹曲线下，最大减薄及变形区域出现在坯料后部，且降低曲线曲率，壁厚及形状精度均提高。
关键词组：
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DOI:
10.1631/jzus.A1300405
CLC number:
TG306; TH162+.1
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On-line Access:
2014-06-04
Received:
2013-12-23
Revision Accepted:
2014-05-06
Crosschecked:
2014-05-21
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