汽车吸尘器封盖注射模设计

Design of Injection Mould for Automobile Vacuum Cleaner Cover

汽车吸尘器封盖使用聚碳酸酯(PC)/丙烯腈-丁二烯-苯乙烯塑料(ABS)合金注塑成型,结合塑件结构特点和无卤阻燃PC/ABS改性塑料的特性,采用二维计算机辅助设计平面排位设计方法设计了一副单个点浇口三板模具用于塑件的注射成型。为简化模具结构,模具定模一侧使用2个导动楔紧块驱动滑块机构观察孔和倒扣边的成型和脱模,并通过三板模开模动力进行驱动,动模一侧使用倒扣顶杆+顶针二次顶出抽芯机构实施基座外壁倒扣的成型和脱模,也通过模具动模的开模运动来进行驱动,有效简化了模具结构,降低了模具制造成本。二次顶出机构中,简化为依靠挡位块定位进行分离驱动,即动模打开后下行一定距离,注射机顶杆顶住第二次顶出板而使塑件获得第一次共同顶出,随着顶出的继续上行,动模模脚上开设的侧凹挡住第一次顶出板边上的挡块而迫使第一次顶出停止顶出,而第二次顶出板则可以继续顶出完成塑件的第二次完全顶出脱模,从而获得了变形较小的注塑成品。浇注系统使用点浇口+侧浇口复合式浇注系统,便于对塑件模腔浇口位置的灵活选择,保证了模腔充填的可靠性。

The cover of automobile vacuum cleaner was moulded with polycarbonate(PC)/acrylonitrile butadiene styrene plastics(ABS)alloy.Combining the structural characteristics of plastic parts and the characteristics of halogen-free flame-retardant PC/ABS modified plastic,a set of single-point gate three-plate mould was designed by two-dimensional CAD plane arrangement design method for injection moulding of plastic parts.In order to simplify the mould structure,two guide wedges were used to drive the slider mechanism on the fixed side of the mould to form and demould the observation hole and the undercut edge,and were driven by the three-plate mould opening power.The movable side of the mould used the undercut ejector rod+ejector pin secondary ejection core-pulling mechanism to form and demould the undercut on the outer wall of the base,and was also driven by the opening movement of the movable mould,effectively simplifying the mould structure and reducing the mould manufacturing cost.In the secondary ejection mechanism,it was simplified to rely on the positioning of a stop block for separation and driving,that is,after the dynamic mould was opened,it descended a certain distance,and the injection machine's ejecting-rod presses against the second ejection plate to achieve the first common ejection of the plastic part.As the ejection continues to rise,the side concave on the foot of the moving-mould blocked the stop block on the edge of the first ejection plate,forcing the first ejection to stop,the second ejection plate can continue to eject to complete the second complete ejection and demoulding of the plastic part,thus obtaining injection molded products with less deformation.The gating system used a composite gating system of point gate and side gate,which facilitates flexible selection of the gate position for the plastic mould cavity and ensures the reliability of mould cavity filling.