The aim of this study is to investigate the balance between 2D and 3D (or twist) springback of copper-based thin sheets after a deep drawing process. Such materials are widely used in the manufacturing of electric and electronic components, but getting an accurate final geometry is usually difficult due to springback. Three copper-based materials are considered in this study, and in a first step, the mechanical behavior is investigated with uniaxial loading-unloading tension, monotonic and cyclic simple shear and hydraulic bulge tests. In a second step, thin blanks made of these copper alloys are deformed in a U-bending process, in which they are intentionally misaligned by 2° from the tool symmetry axis; then, the deformed geometry is measured with a laser scanner and the 2D springback and twisting parameters are calculated. It is shown that pure copper and the copper-iron alloy exhibit a rather limited 2D springback but a significant twisting whereas the opposite trend is observed for the copper-beryllium alloy. Finite element simulations are carried out with isotropic and mixed hardening models, calibrated from the experimental database. The comparison of experimental and predicted punch forces, 2D springback data and twisting parameters shows the accuracy of the numerical simulations. Moreover, the distinct springback characteristics of the three copper-based materials are correctly predicted and the influence of the mechanical properties on the relative 2D and 3D contributions to springback is analyzed.

本研究的目的是调查深拉工艺后铜基薄板的 2D 和 3D（或扭曲）回弹之间的平衡。这种材料广泛用于制造电气和电子元件，但由于回弹，通常很难获得准确的最终几何形状。本研究考虑了三种铜基材料，第一步，通过单轴加载-卸载张力、单调和循环简单剪切和液压膨胀试验研究了机械行为。在第二步中，由这些铜合金制成的薄毛坯在 U 形弯曲过程中变形，其中它们有意地与工具对称轴错位 2°；然后，使用激光扫描仪测量变形的几何形状，并计算 2D 回弹和扭曲参数。结果表明，纯铜和铜铁合金表现出相当有限的 2D 回弹但显着扭曲，而铜铍合金则观察到相反的趋势。有限元模拟使用各向同性和混合硬化模型进行，从实验数据库校准。实验和预测的冲头力、2D 回弹数据和扭曲参数的比较显示了数值模拟的准确性。此外，正确预测了三种铜基材料的不同回弹特性，并分析了机械性能对回弹的相对 2D 和 3D 贡献的影响。