As an important forming parameter, the influence of punch-die clearance on thick plate blanking has been extensively discussed. In contrast, the analysis and prediction of metallic foil blanking are more difficult due to the size effect caused by thickness reduction. To explore the clearance effects at a meso-scale, a series of blanking tests of 304 stainless steel foils with 100 μm thickness were carried out at 5, 10, and 15 μm punch-die clearances. Corresponding working conditions were also numerical simulated, where the damage mechanism was described using an extended Gurson-Tvergaard-Needleman model while the size effect was characterized using a mechanism-based strain gradient (MSG) theory. The results indicated that damage was observed to evolve as a function of the machining process. Furthermore, shear damage was underestimated without considering the size effect, resulting in inaccurate failure punch penetration prediction. In terms of forming quality, a decrease in the clearance resulted in a proximate damage value on the punch and die side materials along with a decrease in the shear band width. The change in clearance is negatively correlated to the rollover and burnish lengths, and positively correlated to the fracture length. The introduction of the MSG theory made the simulation results more consistent with the scanning electron microscope (SEM) observations of the sheared edges. Overall, this study presented an advanced simulation method and contributes to optimal clearance selection with respect to forming quality prediction for foil blanking.

作为重要的成形参数，冲模间隙对厚板冲裁的影响已被广泛讨论。相比之下，由于厚度减少引起的尺寸效应，金属箔下料的分析和预测更加困难。为了在细观尺度上探索间隙效应，在 5、10 和 15 μm 的冲模间隙下对 100 μm 厚度的 304 不锈钢箔进行了一系列冲裁试验。相应的工作条件也进行了数值模拟，其中使用扩展的 Gurson-Tvergaard-Needleman 模型描述了损伤机制，而使用基于机制的应变梯度 (MSG) 理论来表征尺寸效应。结果表明，观察到损伤随着加工过程的变化而演变。此外，在不考虑尺寸效应的情况下，剪切损伤被低估了，从而导致了不准确的故障冲头穿透预测。在成形质量方面，间隙的减小导致冲头和模具侧材料的近似损伤值以及剪切带宽度的减小。间隙的变化与翻转和抛光长度呈负相关，与断裂长度呈正相关。MSG理论的引入使模拟结果与剪切边缘的扫描电子显微镜（SEM）观察结果更加一致。总体而言，这项研究提出了一种先进的模拟方法，有助于为箔下料的成形质量预测提供最佳间隙选择。在成形质量方面，间隙的减小导致冲头和模具侧材料的近似损伤值以及剪切带宽度的减小。间隙的变化与翻转和抛光长度呈负相关，与断裂长度呈正相关。MSG理论的引入使模拟结果与剪切边缘的扫描电子显微镜（SEM）观察结果更加一致。总体而言，这项研究提出了一种先进的模拟方法，有助于为箔下料的成形质量预测提供最佳间隙选择。在成形质量方面，间隙的减小导致冲头和模具侧材料的近似损伤值以及剪切带宽度的减小。间隙的变化与翻转和抛光长度呈负相关，与断裂长度呈正相关。MSG理论的引入使模拟结果与剪切边缘的扫描电子显微镜（SEM）观察结果更加一致。总体而言，这项研究提出了一种先进的模拟方法，有助于为箔下料的成形质量预测提供最佳间隙选择。间隙的变化与翻转和抛光长度呈负相关，与断裂长度呈正相关。MSG理论的引入使模拟结果与剪切边缘的扫描电子显微镜（SEM）观察结果更加一致。总体而言，这项研究提出了一种先进的模拟方法，有助于为箔下料的成形质量预测提供最佳间隙选择。间隙的变化与翻转和抛光长度呈负相关，与断裂长度呈正相关。MSG理论的引入使模拟结果与剪切边缘的扫描电子显微镜（SEM）观察结果更加一致。总体而言，这项研究提出了一种先进的模拟方法，有助于为箔下料的成形质量预测提供最佳间隙选择。