平面压边拉深工艺参数对内皱影响及试验研究

Influence of plane drawing process parameters on internal wrinkle and experimental study

曲面零件拉深时悬空区易发生内皱,增加压边力可防止内皱的产生,而临界压边力的大小则受到各工艺参数的影响。根据平面压边拉深的变形特点,进行了内皱临界计算,获得锥形件和球形件曲面零件不起内皱的临界条件。以锥形件为例,通过试验方法研究了材料性质、相对厚度、拉深系数及凸凹模半径比等主要参数对内皱发生时刻的影响。研究结果表明,当材料硬化指数、凸凹模半径比和相对厚度减小时,内皱发生时刻提前,而当减小拉深系数时,可延缓起皱的发生。因此,合理的选择工艺参数将有效地防止曲面零件拉深时内皱的发生。

The inner-wrinkle is easy to be produced at the suspending zone during drawing the curved surface parts. In creasing the holder force can avoid the inner-wrinkle, and the critical holder force is decided by some processing param eters. According to the deformation of drawing under blank holder, critical calculation for innere-wrinkle was carried out, and the checking condition for drawing cone and sphericity parts were gained. Then, the effect of main parame ters on inner-wrinkle was studied by experiment for drawing cone parts, such as material characteristics, relative thickness, drawing coefficient and so on. The results show that decreasing material hardenability value, radius ratio of punch-die and the relative thickness, the trend of inner-wrinkle is increased; but reducing drawing coefficient, the inner- wrinkle is postponed. Therefore, reasonably selecting the processing parameters shall avoid the inner- wrinkle during drawing curved surface parts.