板材之孔凸緣背壓擠伸成形試驗

Tool Trial-out of Hole-Flanging with Counter-Pressure on Sheet Metals

林恆勝(H. S. Lin) ； 許源泉(Y. C. Hsu) ； 楊東昇(T. S. Yang) ； 董志偉(J. W. Dong)

《鍛造》 15卷2期 (2006/07) Pp. 28-34

https://doi.org/10.29791/Forging.200607.0005

摘要

一般金屬板材在進行孔凸緣沖壓成形時，凸緣高度和軸壁厚度通常受材料伸長率的限制，往往在未達所需凸緣高度前，板材即發生頸縮或破裂的現象。本文改採「孔凸緣背壓擠伸成形」法，以背壓來拘束杯狀胚料底部的膨脹，且在模具結構上另設計「複動化」模組，以克服沖頭強度弱化或胚料產生挫屈的現象。模具試驗結果顯示，使用鍍鋅鋼板和鋁合金板在擠伸較大凸緣孔徑時，皆可擠出相當高且均勻壁厚的凸緣，而使用鍍鋅鋼板在擠伸小凸緣孔徑時，較不易被擠伸成形，顯示應用本製程對高強度胚料進行高擠伸比成形時，必須使用較大的背壓以及成形負荷，反而容易造成模具的變形，不利胚料擠出。

關鍵字

孔凸緣成形 ； 擠伸 ； 背壓

並列摘要

Flange height and lip thickness are generally restricted by the formability of sheet metals in the conventional hole flanging operation. The blank is susceptible to necking or fracture before the desired flange height is achieved. In the current work counter-pressure was applied to suppress the dilation on the bottom of the cup-shaped preform, while multi-action forming die was designed to enhance the strength of the bunch at the same time to avoid the buckling on the workpiece. The tool trial-out showed substantial flange height and lip thickness can be formed with flange extrusion of larger inner diameters with steel and aluminum cups. Flanges of smaller inner diameters were difficult to be extruded in steel cups indicating that the process requires higher counter-pressure in extruding small flanges on high-strength materials. Tool would deform and consequently become unfavorable to flange extrusion when the die set subject too much forming load.

並列關鍵字

hole flanging ； extrusion ； counter-pressure