- 期刊
鋁合金避震器支架之溫間鍛造模具設計
Die Design for Warm Forging of Aluminum Alloy Shock Stay
摘要
電腦輔助工程分析（Computer-Aided Engineering，CAE）技術是利用數值分析方法在電腦上模擬鍛造製程，不僅可取代實際試模，並可預測缺陷之產生如未填滿、疊料等，因此使用CAE在設計階段時即可評估模具設計之可行性，並於試模階段尋找問題發生之原因及改善對策之擬訂。在本研究中，將選用腳踏車鋁合金AA6061避震器支架作為研究載具進行CAE之模擬分析。使用有限元素進行模擬分析時，材料鋁合金AA6061之機械性質為基本之成形性參考指標，亦是有限元素模擬分析不可缺之參數，故要從材料拉伸實驗中建立材料的應力－應變曲線；包含降伏應力、塑性變形區曲線、加工硬化指數等。此外，鍛造工程因使用不同之潤滑劑，也直接影響模具與胚料間的定剪摩擦因子，故本研究也從圓環壓縮實驗結果來建立定剪摩擦因子資料庫，除供有限元素模擬分析參數數入外，也提供廠商鍛造製程之參考。本研究為驗證有限元素軟體DFORM 3D之正確性，採用製造廠商目前正在生產之產品進行模擬分析並與實際鍛造製程做分析比對。此外，本研究也針對載具於鍛造時經常發生如胚料未填滿模穴及疊料問題，從不同初始外形胚料及胚料擺放位置對其成形之影響進行模擬分析，從模擬分析結果中找出最佳外形胚料進行鍛造製程，本研究除了驗證有限元素分析軟體用於鍛造工程之可行性外，也從模擬分析結果中提出解決問題的方法，並獲得實際成品之的驗證。
並列摘要
In this study, CAE analysis was performed to study the forging die design for an aluminum alloy AA6061 bicycle shock stay. The material properties of aluminum alloy AA6061 were the fundamental inducator for formability and the indispensable parameters in the CAE analysis. The mechanical properties of AA6061 was acquired by the compression tests, including the stress-strain curves, the yielding stress, the plastic deformation curves, and the work hardening factor. Since the process of forging used different lubricants, there were different friction factors between the die and the workpiece. So the database of friction factor was built from the ring compress tests to provide the parameter for the CAE analysis and the reference for manufacturers. The tooling geometries were constructed by a CAD software, PRO/E, and were converted into CAE mesh, using the software DELTAMESH. The tooling was treated as rigid bodies, and the 4-node solid element was adopted to construct the mesh for blank. The other simulation parameters used in the initial run were: blank temperature at 350℃, die temperature at 125℃, forging velocity at 150 mm/sec, and friction shear factor of 0.7. The finite element software, DEFORM 3D was employed to perform the analysis, and the simulations were performed on a desktop PC. In order to validate the accuracy of the simulation analysis, the actual process of forging was conducted. Besides, effects of process parameters on the occurrence of the defects such as under filling and overlapping, were studied with different initial billet geometrical shapes and billet positions. From the simulation results, the optimum billet shape is determined.