鈑金在一般的成型過程中,在摩擦力的量測方面一般主要以引伸珠試驗(draw bead test)與衝鎚實驗(punch friction test)為主。其中引伸珠實驗主要是測量鈑金與引伸珠之間的摩擦力,而衝鎚實驗是以軸對稱鈑金成型時衝頭與鈑金之間摩擦的狀況為研究重點。但在以往摩擦理論中,大部分使用簡單的定摩擦模式,或以不計摩擦力的計算方式,進而忽略在真實摩擦中的各種複雜因素的影響重要性性。 為此建立一套完整在引伸珠實驗的真實摩擦模式,除了考慮傳統的外參數(界面壓力、表面滑動速度)外,並考慮內參數(潤滑油種類、厚度及模具和鈑材的表面粗度)的影響,並從油膜厚度和表面粗度的比值,將界面摩潤行為分類出厚油膜、薄油膜、混合油膜、及邊界油膜等四種完整摩擦理論。再配合徐澤志博士、劉志嘉、郭祥貴及林禹君先生等人所發展的鈑金成型含粗糙度影響下的雷諾方程式,並結合電腦軟體作有限元素法的分析;所模擬獲得之摩擦係數再與相關論文文獻作一探討、比較。希望由此比較結果,提供在真摩擦狀態下金屬成形之摩擦理論及模擬結果。
In the sheet metal forming process, the drawbead test is mainly designed to test the friction stress between the sheet metal forming and the drawbead. How ever, in the past most of the friction theories used the simple fixed friction coefficient model, or used the method of no friction stress, so as to neglect the importance of the affection of complex factor in the real friction. With an aim to setting up a set of complete real friction model in drawbead test, we developed an analytical model that combines finite element code with four kinds of different lubrication regimes in the complete friction theory. Based on the computer software’s simulated analyses, the friction coefficient that had been attained by the imitation needs to be investigated and compared with the related essay records. Through this outcome of comparison, we hope to provide the friction theory and imitate the result of the sheet metal forming in the real friction situation.