- 學位論文
超薄板料連續沖彎成形分析與模具設計
Forming analysis and die design of the progressive shearing-bending processes for the ultra thin sheet metal
摘要
本研究結合有限元素模擬軟體與沖模設計理論，探討光碟機固定用彈片之沖壓製程分析與模具設計。在沖剪成形分析上，主要探討模具間隙與壓料壓力對沖剪斷面之影響；在彎曲成形分析上，則是探討模具間隙、壓料壓力以及沖彎速度對於板材成形性之影響，分別透過有限元素分析軟體對沖剪與彎曲行為進行分析，並驗證CAE模擬板材成形之正確性。利用沖模設計理論探討如何設計一套光碟機固定用彈片之沖彎連續模具，首先從產品預評分析、產品加工性分析、板料展開樣式、料條佈置與排列、製程參數計算、模具總體設計、模具零件設計等開發流程，建構出適用於板材沖彎開發與設計系統。 本研究透過板材試驗建構出SUS304板材完整的資料庫。經由研究結果顯示，在板材沖剪方面，當模具間隙越小時，模輥面與撕裂面尺寸值越小，而剪切面尺寸則會越大；當壓料壓力越大時，模輥面與撕裂面尺寸值越小，而剪切面尺寸則會越大。在板材彎曲方面，影響尺寸精度及回彈量之主要參數為模具間隙與壓料壓力；影響板材應變之主要參數為模具間隙與沖彎速度。在模具設計方面，在料條佈置設計上，必須注意到每個道次之間的關聯性與連續性，考慮到帶料、拉料、力量平衡、回彈等問題，以有效地完成3D實體料帶佈置與排列，而在模具總體設計方面，建構出沖模行程、浮料高度、沖頭高度和脫料板行程等資訊，建立出一個實體模具。 將沖彎連續模具進行模具加工與組裝，藉由實際沖彎測試來驗證模擬與設計之可行性，並檢測光碟機固定用彈片之尺寸精度、回彈量以及沖剪斷面情形，經由實驗數據與模擬分析之數據互相比對後，其分析結果顯示 模擬與實際相符合，更加驗證有限元素分析軟體應用於板材沖剪與彎曲成形之可行性與可靠性。 在有限元素模擬軟體及沖模設計軟體的雙管齊下中，不但可以節省模具開發時程和成本，更可以提高成品的尺寸精度，就目前工業的發展來看，對於產品已經有微小化的趨勢，欲達到此目的，利用科學方法，有助於提升模具品質和產品精度。透過本文對於板材沖彎之開發與研究，有助於提供學術界與產業界之參考。
並列摘要
In this current study, finite element method (FEM) software and stamping die design theories were employed to investigate the stamping processes and die design of the immoveable spring chip in CD-ROM. The shearing and the bending were analyzed by finite element method software and then the accuracy of sheets forming simulated through CAE was tested. In the shearing analysis, focuses were mainly on the effects of clearance and pressure on the shearing surface quality, while in the bending analysis, the effects of die clearance, strip hold pressure, and shearing-bending velocity on sheets forming was explored. In addition, stamping die design theories were employed to investigate the die design system of sheets metal punching-bending for the immoveable spring chip in CD-ROM. Through the development processes, such as products assessment, stamping analysis, blank development, strip layout, process parameters calculation, die overall designs, and part design of dies, the development and design system for sheets metal punching-bending was constructed. In this study, a complete database for the SUS304 sheets metal detail properties was also constructed through the tensile test. Results of the study showed that the size values of the rollover plane and the fracture plane decrease as the die clearance decreases, but the burnish plane increases as the die clearance decreases. However, when the strip hold pressure increases, the size values of rollover plane and the fracture plane decrease accordingly, and the size of burnish plane increases as the strip hold pressure increases. In the aspect of bending analysis, the major parameters affecting the dimensions accuracy and the springback were the die clearance and strip hold pressure, while the die clearance and shearing-bending velocity were the main parameters which influenced the sheets metal strain. In the design of the strip, attention should be paid to the relations and continuity between the strip designs, such as strip design, strip feeding, force balance, and springback. Then, the overall solid progressive die was constructed after the press stroke, blank lifting height, punch length and stripper travel distances had been determined. The feasibility of the simulation and the dies deign was confirmed by dies manufacturing, erection and experiment. Furthermore, dimensions accuracy, springback and shearing-bending section of the immoveable spring chip in CD-ROM were examined. The results showed that the numerical values agree with the simulation ones with a reasonable accuracy, which further confirmed the feasibility and reliability of the application of FEM software for the sheets metal shearing-bending process. Harnessing both FEM and stamping die design software has been proved not only to save the time for, and the cost of, the die development, but also to raise the quality and precision of the products. When the current trend of industrial development is product miniaturization, the exploitation of scientific methods surely will be the core to the satisfaction of the purpose. The results found in the current study will shed some lights on the research and development of sheets metal shearing-bending process for the academia and industry.