管件進行彎曲成形時可能產生如壁厚減薄與斷面的變形等缺陷，使管件的強度不足或是造成介質無法在管件內順利傳輸，因此在相關應用產業會要求準確的減薄率，故管件之減薄率預估是製程規劃的重要參考指標。
從力學的角度來看，若要降低管件減薄的程度，應將應變中性層往曲率半徑之外側移動，或者降低管件外側之拉應力。一般的做法是以壓模施加側向推力，達到控制減薄的效果，而近年又發展了更具作用的助推裝置。本文將探討助推裝置與其它製程參數在彎管成形中的影響，並搭配田口方法了解各參數的影響程度，找出最佳參數組合以提升彎管成形品質。
本研究針對彎管製程之影響因素進行探討，研究內容包括模擬分析與實驗驗證，分析成形過程中之應力應變狀態，並搭配實驗與觀察成形變化，進而將模擬結果整理成製程視窗，可應用於製程規劃。
本研究結果顯示彎曲模與助推裝置之速度同步的情況下，管件之成形性較佳。經由實驗歸納，將內側與外側之減薄率比值做為判斷起皺的指標，進一步透過田口方法獲得各參數於製程中的影響程度與最佳成形參數組合。從重要成形參數對製程的影響之探討得知：管件與芯軸芯珠間的間隙與摩擦係數會影響管件的應力應變狀態，進而影響管件的成形性。

In this study, the factors of tube bending process were discussed. The research includes simulation and experiments. The stress and strain states during the forming process were analyze by the finite element simulation, and the forming changes were observed by experiments. Further, the simulation results will be expressed in a process window, which can be used for process planning.
The results of this study showed that the tubes have better formability in the case of the speed synchronization of the bending die with the auxiliary pushing device. Besides, through the experiments, the rate of thinning of tubes in the ratio of the inner to outer can be a judgement indicator for the wrinkling defect. Furthermore, Taguchi method was used for obtaining the degree of influence of each parameter and the best combination of forming parameters. Finally, the effect of important forming parameters on the tube formability was investigated for the process. The friction coefficients and the gaps between the tube and both the mandrel and the core beads affect the stress-strain state of tubes and thereby affect the formability of tubes.

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