附V型壓環之精密剪斷有限元素分析

Abstract

精密剪斷是一種不須修邊、銑削等二次加工，即可獲得平滑斷面的金屬成形方法，其光滑的剪斷面、良好的製品平坦度等特性，相較於傳統剪斷製品有著許多優點。 然而，精密剪斷製程比傳統剪斷多了逆壓板及含有附V型壓環之壓料板，逆壓板使得落料形狀更加的平坦，含有V型壓環之壓料板的使用則直接影響剪切面的品質。以往使用者對於V型壓環的形狀及位置多依經驗決定，但加工的材料種類繁多，每種材料各有其不同的特性，所以一旦材質或形狀、尺寸，加工條件改變，使用者即須試驗嘗試建立新的經驗，對於模具的開發製程條件的確立既耗時又增加成本。 本研究的目的，乃以有限元素法為基礎，根據Cockroft & Latham的破壞準則提出一個評估方法以判斷剪斷面破壞型態的改變檢討壓料板V型環等參數對剪斷面的影響，本研究使用DEFORM-2D有限元素分析軟體來模擬精密剪斷加工過程，探討V型壓環的位置、型狀、壓板荷重等參數對工件斷面形狀的影響，並與實驗值相比對，以建立完整分析技術，供往後業界參考使用。

Fine blanking is one of the metal forming technique which a smooth shearing surface can be obtained without further secondaryfinish. Compared with traditional blanking of metal sheets, fineblanking provides products with better shearing surface and betterflatness. In the process of fine blanking, very often a counter punch whichpromote surface flatness, and V-type blank holder which directly affects shearing surface quality are added. In the past, Dimensions and position of the V on the blank holder were decided from experience, however, whenever the material, dimension, on process conditions were changed, a series of try and error will required in order to establish the new perience. Thus time and cost are increased in the development of a new product. In this study, Cockcroft & Latham’s fracture criterion was incorporated in the finite element analysis package for determine the quality of shearing surface. Effects of the dimension position and load of V on the shearing surface quality were discussed. It is found the results provides good coincidence with the experiments.