T2紫铜箔材的U型弯曲变形

设计了箔板U型弯曲试验方案,使用不同凹模槽宽尺寸和圆角半径的微型模具,在三思微型试验机上完成了试验,分析了模具几何尺寸、箔板厚度等对箔板U型弯曲变形中冲头载荷、回弹以及表面质量的影响。研究结果表明,槽宽尺寸或圆角半径减小时,最大冲头载荷显著增加,且冲头载荷上升和下降速率都明显增大;对比两种不同厚度箔板的冲头载荷显示,冲头载荷减小速率明显快于横截面面积的减小速率,说明产生了明显的尺寸效应;另外,圆角半径或板厚减小,导致回弹角度增大,成形件精度降低;虽然成形件表面比较平整,但侧面出现划痕提示需要提高模具表面质量和采取润滑措施。以上研究结果对指导箔板微成形工艺设计具有重要意义。

U-bending process of T2 copper foil

A U-bending test was designed by using a micro female mold with different groove widths and corner radii on a micro extension tester made by SANS company. The effects of the mold dimension and foil thickness on the maximum punch load, springback and surface quality were analyzed during the micro U-bending process. The results indicate that the reductions of groove width or radius leads to the increases of maximum punch load and the rates of increasing or decreasing of punch load increase greatly.By comparison of the punch loads of foils with different thicknesses,it is shown that the decreasing rate of punch load is larger than that of cross section area, and the size effect occurs obviously. Furthermore,the springback angle increases with the decreasing of thickness or radius, which reduces the accuracy of microparts. As the scratch appears at the side surface of a micro bending part, it suggests that the surface quality of the mold should be improved and the lubricating should be taken. The results have an important significance on the design of foil microforming process.