铝合金型材聚氨酯柔性垫弯曲研究

Research into the bending of Aluminum alloy profiles with polyurethane pad

型材聚氨酯垫弯曲是一种将超弹性的聚氨酯垫作为弯曲凹模的型材弯曲新技术。通过调节型材压入聚氨酯垫的深度,可得到具有不同曲率半径甚至变曲率半径分布的零件。文章首先设计并制造了聚氨酯垫柔性弯曲装置。利用研制的聚氨酯垫柔性弯曲装置,以槽形截面铝合金型材为对象,通过实验,研究了压入深度和型材曲率半径的关系,以及型材截面形状对曲率半径的影响。结果表明,对于所研究型材,其曲率半径随压入深度的增加而减小。当压入深度较小时,曲率半径迅速减小;随着压入深度的继续增加,曲率半径的缓慢减小。当采用不同弯曲方式时,型材截面抗弯模量的变化以及截面中性层位置的变化,都对弯曲件的曲率半径有重要影响。截面抗弯模量越大弯曲越困难,截面中性层与压辊轴线的距离越大,曲率半径越小。

Bending with polyurethane pad is a newly developed flexible bending method for profile and extrusion. In the bending, polyurethane pad （PUR pad） is used as lower die, which can provide distributed bending moment on the profile. By controlling the penetration of profile into the PUR pad, bent profile with different curvature radius can be manufactured. Device for PUR pad bending is designed and manufactured first. Experimental works of trough-shaped aluminum alloy profile are carried out based on the bending device developed above. Profiles are bent with constant penetration depth but with different bending layouts, i. e. ,normal bending, reverse bending and side bending. The results show the curvature radius of bent profile will decrease sharply when penetration depth begin to increase. However, this change will be slight for bigger penetration depth. For different bending layouts, both the change of section modulus of bending and the position of neutral surface have significant effect on the curvature radius of bent profile. Profile with bigger section modulus of bending will be more difficult to bend, and the bigger the distance from neutral surface to the axis of the roller, the smaller the curvature radius.