用椭圆角凹模消除水管接头盖成形缺陷的研究

为了消除某机械产品的水管接头盖成形缺陷，提出了一种凹模口部设计成椭圆角的工艺方法，分析了椭圆角凹模拉深的力学特征，阐明了这种结构能提高板坯成形极限成形能力的技术关键；以带凸缘的杯形件为研究对象，建立椭圆角凹模口部的有限元模型，运用ANSYS/LS-DYNA分别进行了杯形件拉深模拟，模拟结果显示，椭圆角凹模口部极大地提高了板料的极限成形能力；最后，采用椭圆角凹模消除了该零件成形裂缝问题。

Study on forming defect elimination for water pipe fitting cover by elliptic die shoulder

To eliminate the forming defect of water pipe fitting cover ,an elliptic die shoulder was proposed to replace the radius one .The formability limitation of the deep drawing die with an elliptic die shoulder was illustrated after analyzing the mechanical characteristics of an elliptic die shoulder .To cylinderical cup ,finite element method （FEM ） models of press tools with an elliptic/radius die shoulder for deep drawing were set up ,and then two processes to form cylinderical cup were simulated respectively by ANSYS/LS-DYNA . It is shown that this forming process by elliptic die shoulder is very ideal in two processes ,and the crack in such a drawing parts is eliminated by elliptic die shoulder .