首先阐述了型材无模多点拉弯成形的基本原理，分析了多点拉弯成形中形状偏差和表面压痕缺陷的形成机理以及影响因素;然后针对传统的模具型面补偿优化的局限性，提出了控制形状偏差和表面压痕缺陷的模具型面优化设计方法，并建立了多点拉弯成形模具型面迭代模型;最后以某铝型材为研究对象，进行了模具型面迭代优化试验研究．结果表明:模具型面形状及位置经过迭代优化后，形状偏差量明显降低(最大形状偏差量从 2． 32mm 降低至 0． 61mm)，表面压痕缺陷得到有效抑制．

Firstly,the basic formation principle of multi-point stretch bending profiles was expounded,and the cau- ses as well as the influence factors of shape deviation and surface indentation defect for multi-point stretch bending profiles were analyzed.Secondly,by taking into consideration the limitations of conventional profile compensation optimization methods,a new optimization method to control shape deviation and avoid indentation defect was pro- posed.Then,an iterative model of multi-point stretch bending profiles was constructed.Finally,some experiments were carried out to verify the effectiveness of the proposed model.The results indicate that,after the iterative opti- mization of die shape and location,the shape deviation decreases greatly from the maximum 2.32mm to 0.61mm,and the surface indentation defect is controlled effectively.