车用法兰螺母冷挤压成形工艺分析及优化

以车用法兰螺母冷挤压成形为研究对象,根据其结构特点设计6工位成形工艺,选取其中易出现缺陷的六角成形工序,采用有限元分析软件DEFOMR-3D对其成形过程进行模拟分析,采用双顶杆结构替代原有单顶杆结构,成功解决成形过程中的材料折叠问题。同时,为降低成形载荷,选取凹模圆角半径、模芯切入角、凸模切入角、摩擦系数作为因素,设计正交试验对参数进行优选,得出各因素对成形载荷的影响趋势,确定最优工艺参数为:凹模圆角半径为0.5 mm、模芯切入角为20°、凸模切入角为10°、摩擦系数为0.12,采用优化后的模具结构及参数进行试模,制件符合成形要求,成形载荷与模拟结果基本一致,为法兰螺母生产提供理论基础。

Analysis and optimization on cold extrusion process of flange nuts for vehicles

For the cold extrusion process of vehicles flange nuts,the six-position forming process was designed based on its structure features.Then,the hexagonal forming process prone to defect was selected,and its forming process was simulated by finite element analysis software DEFORM-3D.Furthermore,the material folding during forming process was solved successfully by replacing the original singleejector structure with the double-ejector structure.At the same time,the radius of die,the cut-in angle of die core,the cut-in angle of punch and the friction coefficient were selected as the factors to reduce the forming load,and the orthogonal experiment was designed to optimize those parameters.Finally,the influence trends of each factor on forming load were obtained,and the optimal parameters were obtained with the radius of 0.5 mm,the cut-in angle of die core of 20°,the cut-in angle of punch of 10°and the friction coefficient of 0.12.After using the optimized mold structure and process parameters to test,the obtained parts meet the forming requirements,and the actual forming load is a good consistent with the result of finite element analysis to provide the theoretical basis for the actual production of flange nuts.