Abstract Micro-deep drawing (MDD) is a promising micro-manufacturing technology. Size effects complicate and signify the influence of the blank holder-die gap on MDD, which was investigated in this study. Annealing of SUS304 foils of 50 µm thick was conducted to obtain various grain sizes. Micro-tensile testing was carried out to acquire the stress-strain curves of the foils, followed by MDD experiments. Advanced FE models were developed to simulate the MDD process taking into account material inhomogeneity and surface morphology of the foils at micro-scale. Bending dominates the early stage of MDD. A combination of proper gap size and punch/die corner radius may incur in-process springback before the occurrence of the maximum drawing force, benefiting the MDD process. A relatively small gap is favourable to a uniform distribution of wall thickness without obviously increasing the risk of fracture. It also improves the overall shape accuracy of outer surface whilst may result in the inner surface distortion. The complex development of the shape accuracy in three defined areas on the drawn cup can be attributed to the integrated effect of the gap size, material inhomogeneity and surface morphology of the foil. The combined design and multi-object optimisation of the gap size and the corner radii of punch and die should be conducted for improving the MDD process.

中文翻译：

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压边模间隙对SUS304杯微深拉深的影响

摘要 微深拉伸（MDD）是一种很有前途的微制造技术。尺寸效应使压边模间隙对 MDD 的影响变得复杂并表明了该影响，这在本研究中进行了调查。对 50 µm 厚的 SUS304 箔进行退火以获得各种晶粒尺寸。进行微拉伸测试以获取箔的应力-应变曲线，然后进行 MDD 实验。开发了先进的有限元模型来模拟 MDD 过程，同时考虑了微观尺度上箔的材料不均匀性和表面形态。弯曲在 MDD 的早期阶段占主导地位。适当的间隙尺寸和冲头/模具拐角半径的组合可能会在最大拉拔力出现之前引起过程中的回弹，有利于 MDD 过程。较小的间隙有利于壁厚分布均匀，而不会明显增加断裂风险。它还可以提高外表面的整体形状精度，同时可能会导致内表面变形。拉伸杯上三个定义区域的形状精度的复杂发展可归因于间隙尺寸、材料不均匀性和箔表面形态的综合影响。为了改进MDD工艺，应进行间隙尺寸和冲头和模具角半径的组合设计和多目标优化。拉制杯上三个定义区域的形状精度的复杂发展可归因于间隙尺寸、材料不均匀性和箔表面形态的综合影响。为了改进MDD工艺，应进行间隙尺寸和冲头和模具角半径的组合设计和多目标优化。拉伸杯上三个定义区域的形状精度的复杂发展可归因于间隙尺寸、材料不均匀性和箔表面形态的综合影响。为了改进MDD工艺，应进行间隙尺寸和冲头和模具角半径的组合设计和多目标优化。