基于灰色关联的皮卡尾门外板的拉延工艺参数优化

为了解决皮卡尾门外板拉延过程中产生的破裂、起皱的问题,采用数值模拟和灰色关联法相结合的方法对拉延工艺参数进行优化。将料厚最大减薄率和最大增厚率作为优化目标,以圆角和直边段的拉延筋阻力系数、压边力、冲压速度、摩擦系数为工艺参数变量进行5因素4水平的正交试验。在Auto Form软件中进行有限元数值模拟。基于灰色关联分析法,计算出各工艺参数对破裂和起皱综合指标的关联度,给出了最优的工艺参数方案:圆角段拉延筋阻力系数为0.15,直边段拉延筋阻力系数为0.45,压边力为800 k N,冲压速度为3.5 m·s-1,摩擦系数为0.13。应用最优工艺参数组合进行模具制造和现场实际生产,得到了质量良好的冲压件,有效控制了破裂和起皱风险。

Optimization on drawing process parameters for pick-up tailgate outer panel based on gray relational analysis

In order to solve the crack and wrinkle defects during the drawing process,the drawing process parameters were optimized by combining gray relation analysis with numerical simulation.Then,the orthogonal experiment with five factors and four levels was carried out by setting the maximum thinning rate and the maximum thickening rate as the optimization objectives and setting the drag coefficient from rounded and straight edge of drawbead,the blank holder force,the forming speed and the friction coefficient as the process parameter variables.Then,the finite element numerical simulation was conducted by AutoForm software.Based on the gray relational analysis method,the gray relational degrees of each process parameter to the comprehensive index of crack and wrinkle were calculated respectively,and the optimum process parameters were obtained with the drag coefficient of the round drawbead of 0.15,the drag coefficient of the straight edge drawbead of 0.45,the blank holder force of 800 kN,the forming speed of 3.5 m·s-1 and the friction coefficient of 0.13.In addition,by applying the optimal combination of process parameters to manufacture die and product on-site,the stamping parts with good quality were obtained,and the risk of crack and wrinkle could be controlled effectively.