Study on Rolling of a Double Thickness of the Sheet by DEFORM

本研究嘗試以一道次輥軋製程製備雙重厚度板材，相較多道次輥軋成形能減少生產成本，且藉有限元素軟體DEFORM分析，就簡單外型之金屬型材，探討外型參數、製程參數對輥軋成形之影響。建立外型參數為減薄寬度、減薄距離；製程參數為對稱式輥軋下相異速度比、輥徑，非對稱式輥軋下相異輥徑比、二輥軸距離。外型參數分析結果得知，減薄寬度與減薄距離設定大小，影響輥軋成形時板材於輥軋方向之速度分布，速度差異過大時將使板材橫向截面呈波浪狀。由製程參數分析結果得知，對稱式輥徑設定下，輥徑大小影響板材成行之厚度尺寸，及板材進入模具之波振幅與離開模具之彎曲特性，而速度比差異能使速度慢之模具成特定扭矩關係；非對稱式輥軋設定下，二輥軸距大小影響成形後之厚度尺寸及板材離開模具之彎曲特性，輥徑比大小影響模具徑向負荷與扭矩負荷，而板材進入模具之波振幅於非對稱輥軋設定則大幅減緩。本研究就簡單外型金屬型材設定下，製程設定以非對稱式輥徑為佳，於成形特徵、模具負荷及成形特性比較下，為次之或最佳之選項，可供一道次輥軋成形具不同厚度板材之應用參考。This study tries to produce a double thickness of the sheet by the one-pass rolling process. Compared to multi pass rolling, this method can reduce the production cost. The finite element software, DEFORM, can analyze the simple profile metal to understand how appearance parameters and process parameters impact the roll forming. The appearance parameters are the width of thickness reduction and the distance of thickness reduction; the process parameters are the varying speed ratio under the symmetrical roll, the roll diameter, the varying roll diameter ratio under the asymmetric roll, and the roll gap. The results of the process parameters analysis show that the setting of the width of thickness reduction and the distance of thickness reduction will impact the velocity distribution in the rolling direction during the roll forming process. The huge difference in velocity will contribute to the wavy transverse cross-section of the plate. From the analysis of the process parameters under the setting of symmetrical roll, the size of the roller would affect the thickness of the plate as well as the wave amplitude which caused when the plate gets into the mold, and the bending characters when the plate leaves the mold. The speed difference can make a slow speed mold a specific torque. Under the setting of asymmetric rolling, the distance between two rollers would affect the thickness of the finished plate and the bending characters when the plate leaves the mold. The size ratio of the roller would affect the mold’s radial load and torque load. The wave amplitude formed when the plate gets into the mold would be significantly reduced under the setting of asymmetric roller diameter. This study concludes that under the setting of simple profile metal, the asymmetric rolling is the best process setting. Comparing to the formation characteristics, the mold load, and the formation nature, it would be the second or the best choice. This study can provide a reference of application for making the different thickness of one-pass rolling.謝辭 i 摘要 ii Abstract iii 圖目錄 vii 表目錄 x 符號表 xi 1 前言 1 1.1 文獻回顧 2 1.1.1 金屬型材 2 1.1.2 輥軋基本介紹 4 1.1.2.1 輥軋幾何與三角關係 5 1.1.2.2 摩擦對輥軋成形之影響 7 1.1.2.3 輥軋負荷 9 1.1.2.4 輥軋製品缺陷 12 1.1.3 非對稱輥軋 14 1.1.4 特殊之輥軋技術 15 1.1.5 輥軋模擬相關 18 1.1.6 文獻結語 20 1.2 研究目的與方法 20 2 系統設定 21 2.1 參數設計與規劃 21 2.2 參數建立 22 2.2.1 外型參數建立 23 2.2.2 製程參數建立 24 2.3 有限元素分析軟體建模與設定 26 2.4 曲率計算 29 3 結果與討論 30 3.1 外型參數之有限元素分析 30 3.2 製程參數之有限元素分析 33 3.2.1 對稱式輥軋分析結果 33 3.2.1.1 成形特徵 33 3.2.1.2 模具負荷 35 3.2.1.3 成形特性討論 39 3.2.2 非對稱式輥軋分析結果 43 3.2.2.1 成形特徵 43 3.2.2.2 模具負荷 45 3.2.2.3 成形特性討論 48 3.2.3 小結 51 4 結論 53 5 參考文獻 54 附錄A 方型管等分折角展開 58 附錄B 模具設定 60 附錄C 網格劃分之模擬誤差 62 附錄D 壓板設定 63 附錄E 規劃求解區間設定 64 附錄F 外型參數之模擬結果 65 附錄G 薄板輥軋模擬與實驗比較 66 附錄H 板寬-板厚曲線擷取 68 附錄I 不同輥徑之側向速度分布 70 附錄J 非對稱式輥軋軸距250 mm設定之厚度曲線 7