PP高分子板材多道次渐进成形实验研究

Experimental study on multi-stage incremental forming of PP sheet

通过聚丙烯(PP)高分子板材的多道次渐进成形实验,研究多道次渐进成形零件的材料流动、应变及壁厚分布状况。研究结果表明,PP板多道次渐进成形的第一、第二主应变随成形深度的增大而呈上升趋势,且壁厚随着成形深度的增大而明显减小,无法成形深度过大的零件。通过实验数据,分析零件壁厚变化的原因,指出因道次间角度差的存在产生的成形台阶是导致零件底部下沉和壁厚骤减的原因。此外,针对壁厚问题,提出影响零件成形质量的因素,并结合实验验证,得出结论:增加道次次数、采用圆弧轨迹和减小道次间角度差可以在不同程度上改善壁厚分布状况。

The material flow,strain and wall thickness distribution of multi-stage incremental forming parts were studied by multi-stage incremental forming experiment of polypropylene(PP)sheet.The results show that the first and the second principal strain of PP sheet multi-stage incremental forming increase with the increase of forming depth,and the wall thickness decreases obviously with the increase of forming depth,thus it is hard to form a deep part.The cause of wall thickness change was analyzed based on experimental data,pointing out that the forming step caused by the angle difference between the stages leads to the sinking of the part bottom and the sudden decreasing of the wall thickness.Additionally,with respect to the wall thickness,the factors that affect the quality of parts were put forward and verified by experiments.It is concluded that the wall thickness distribution can be improved to a certain extent by increasing the stage times,adopting the arc trajectory and reducing the angle difference between the stages.