| 摘要: | 本文首先以動顯函有限元素法模擬銅箔U型精微彎曲，接著使用靜隱函有限元素法分析銅箔除荷後之回彈。並假設材料於等向性之條件下進行數值分析，以探討U型精微彎曲之沖頭負荷與衝程關係、成形歷程、除荷後之工件角度、回彈量，及側壁蜷曲現象。另設計一組U型精微彎曲之模具進行實驗比較，以驗證本文之有限元素分析程式可合理模擬U型精微彎曲成形製程。
本文針對沖模圓弧角半徑與間隔墊片厚度之改變，對除荷後之工件角度、回彈量，及側壁蜷曲之影響進行探討。經數值分析與實驗結果比較得知，沖頭負荷會隨著沖模圓弧角半徑增加而遞減，除荷後鄰近沖頭角隅處與鄰近沖模圓弧角之工件角度、回彈量，及蜷曲半徑則隨之遞增。此外，沖頭負荷會隨著間隔墊片厚度增加而遞減，除荷後鄰近沖頭角隅處之工件角度與回彈量亦隨之遞減，然而鄰近沖模圓弧角之工件角度、回彈量，及蜷曲半徑則隨之遞增。由於數值分析均與實驗結果相符合，故本文之有限元素分析程式可有效預測U型精微彎曲成形與回彈分析。
This study first simulated the U-shaped micro bending of copper foil using the dynamic-explicit finite element method, and then analyzed the springback of unloaded copper foil using the static-implicit finite element method. The numerical analysis was conducted under the assumption that materials were isotropic in order to explore the relationship between punch load and punch stroke, deformation history, workpiece angle after unloading, springback amount, and sidewall curl. In addition, another U-shaped micro bending mold was designed for comparison, to verify that the finite element method proposed in this study can reasonably simulate the process of U-shaped micro bending.
This study explored the influence on changes in arc radius of die and spacer thickness on unloaded workpiece angle, springback amount, and sidewall curl. According to the results of the numerical analysis and experiment results, when arc radius of die increased, punch load decreased, and workpiece angle, springback amount, and radius of curvature near punch corner and die arc increased after unloading. Besides, when spacer thickness increased, punch load decreased, and workpiece angle and springback amount near punch corner also decreased after unloading, while workpiece angle, springback amount, and radius of curvature near die arc increased after unloading. The results of the numerical analysis and the experiment were consistent; thus the finite element method proposed by this study can effectively predict deformation and springback of U- shaped micro bending. |
