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本文对不同模具间隙值情况下t=0.5毫米的铜、低碳钢、康铜、可伐合金、黄铜和t=0.2毫米的康铜、可伐合金、黄铜等材料的拉延件形状及各部分尺寸作了系统的测量及初步分析。在拉延过程中,由于冲件各部分的应力及变形状态不同,回弹作用使不同模具间隙情况下的拉延件形状及尺寸差异很大。当模具间隙值增大时,冲件要产生明显的畸变。随着模具间隙值的增加,冲件口部直径的回弹明显增大,口部的壁厚逐渐变厚,而冲件的高度则有所减小。在冲件口部和侧壁部分之间的上口部分产生了突然向里的“凹坑”,位于“凹坑”处的相对直径之差其模具间隙值近似于抛物线的关系。在冲件底部圆角的两侧有两个细颈区。模具间隙值对靠近底部一侧细颈区Ⅱ处材料的变薄影响并不太显著;而对靠近侧壁部分一处的细颈区Ⅰ的变薄影响则比较明显。随着模具间隙值的增加,两处细颈区材料的厚度近似于呈直线地减小。
In this paper, different mold gap values of t = 0.5 mm of copper, mild steel, constantan, Kovar, brass and t = 0.2 mm of Hong Tong, Kovar, brass and other materials, the shape of the drawing parts And the size of each part made a systematic measurement and preliminary analysis. In the drawing process, due to different parts of the stress and deformation of different parts of the state, the role of rebound in the case of different mold gap pull the shape and size of a great difference. When the die gap value increases, the punch to produce significant distortion. With the increase of the die gap, the rebound of the punch mouth diameter increases obviously, the wall thickness of the mouth gradually becomes thick, and the height of the punch decreases. A sudden inward “crater” is created in the upper mouth portion between the punch mouth and the sidewall portion, and the difference in relative diameters at the “crater” has a mold parabolic value that approximates a parabolic relationship. There are two narrow neck areas on either side of the fillet at the bottom of the punch. The effect of die clearance on the thinning of the material near the necked area II is not significant, while the thinning of the thin necked area I near the sidewall is more obvious. As the die clearance increases, the thickness of the material in both neck regions decreases approximately linearly.