汽车用前保险杠注塑模具设计及试验验证

Design and test verification of injection mould for automobile front bumper

对某型号汽车前保险杠结构进行特征分析,发现制品上倒扣特征及侧孔特征分布较多,不能顺利脱模,需设置多组抽芯机构。保险杠两侧侧孔中心线与开模方向不共线,不能直接开模,针对部分侧孔特征设计了抽芯机构;制品定模侧存在台阶侧孔,无法从动模侧设计抽芯机构,在定模设计了气缸装换抽芯机构;顶出系统采用“镶件+直顶+斜顶”顶出方式,最大程度增加了制品与顶出系统的接触面积,针对不能设置镶件的区域,设置直顶杆及斜顶杆。考虑料流等长及均衡充填,制品每侧设置4个浇口,保证了充填效率及熔接效果,在制品中心线上设置了“料流回路”,将熔接状态较差的料流前锋引出制品外侧,保证了制品外观面光泽均匀。经试验验证,制品充填饱满,没有溢料飞边等缺陷,外观面光泽均匀,没有缩痕及熔接痕产生,验证了热流道布局合理,“料流回路”设置恰当;倒扣特征及侧孔特征成型完全,没有出现破孔及拉伤缺陷,验证了各抽芯机构设计合理,机构动作准确,相互间没有干涉。

By analyzing the characteristics of the front bumper structure of a certain model of automobile,it is found that the features of upside-down and side holes in the product are more distributed,and the mould can not be removed smoothly,so it is necessary to set several groups of core pulling mechanisms.The center line of the side hole on both sides of the bumper is not collinear with the direction of the mould opening,so the mould cannot be opened directly.There are step holes in the mould side of the product,and the core pulling mechanism cannot be designed from the mould side,so the cylinder loading and replacing core pulling mechanism is designed in the mould.The ejector system adopts the ejector mode of"insert+straight top+inclined top"to maximize the contact area between the product and the ejector system.For the area where the insert cannot be set,the straight ejector rod and the inclined ejector rod are set.Considering the equal length of the material flow and balanced filling,4 gates are set on each side of the product to ensure the filling efficiency and welding effect.A"material flow loop"is set on the center line of the product,and the material flow front with poor welding state is led out of the product to ensure the uniform appearance of the product.The test verifies that the product is full filled,there are no defects such as overflow and flash,the appearance of uniform luster,no shrinkage and welding marks,which verifies that the hot runner layout is reasonable and the"material flow loop"is set properly.The reverse buckle feature and side hole feature are completely formed,and there are no broken holes and strains,which verifies that the design of each core pulling mechanism is reasonable,the mechanism action is accurate,and there is no interference between each other.