基于逆向推算法的发动机盖外板坯料波浪轮廓优化

Optimization of wavy contour of the stamping blank for engine cover based on reverse reckoning

针对发动机盖外板成形缺陷与材料利用率较低的问题,运用Dynaform数值模拟软件对发盖外板拉深过程进行模拟,分析坯料边界流动量,并采取逆向推算法获得了波浪形坯料线,将材料利用率提高到64.2%。对模具型面进行优化设计,对比分析凸凹模截面线与板料初始安放位置对棱线滑移的影响,有效地解决了棱线滑移距离过大的表面缺陷问题。运用波浪形坯料及改进后的模具进行外板拉深成形实验,成形件无开裂且零件外表面无残留波纹,4条棱线滑移线控制在5 mm以内;表面曲率连续,面品质量较高。之后,尝试运用网格应变测量技术验证了波浪轮廓坯料安全裕度,确保无成形开裂风险。

For issues of forming defects and low material utilization ratio of the automotive engine cover plate,the deep drawing process of the automotive engine cover plate was simulated by software Dynaform,and the blank boundary flow was analyzed. Then,the wavy contour line of the stamping blank of engine cover was deduced by the reversed algorithm so as to improve material utilizing rate by 64. 2%. Furtherly,the surface design of the die was optimized and the influences of the outline of the die cross section and the initial position of sheet on the distance of ridge line were analyzed. The surface defect of ridge sliding was solved efficiently. The experiment of deep drawing was carried out with the wavy blank and the improved die. The results show that the part is obtained without crack and residual ripple. The sliding distance of four ridge lines are controlled in less than 5 mm,so the surface curvature is continuous and the quality of surface is high. Afterwards,the safety margin of the wavy blank after forming is verified by the strain grid measuring technology. The risk of forming crack is suppressed.