基于改性PP成型的工控机电路板支撑架注射模设计

Design of injection mould for industrial computer circuit board support frame based on modified PP moulding

针对工控机电路板支撑架大型塑件的成型,选用了一种玻纤改性增强聚丙烯(PP)复合材料用于塑件的注射成型。模具结构为三板模结构,分3次开模打开。为保证塑件模腔充填均衡性、饱满性而设计了两个点浇口用于模腔的浇注。针对塑件二级子特征较多,特别是异型螺柱深筋位较多的特点,设计了多个局部镶件用于这些局部特征的成型,在提高局部成型镶件强度的同时,降低了这些成型件的加工难度。针对模腔局部位置排气难点,设置了多个透气镶件以增强排气。设置了锁扣机构、定距拉杆机构用于模具的开模闭模控制;设计了弹料机构用于流道废料的可靠脱模、定位机构以确保塑件的成型精度和模具工作寿命;3个滑块机构用于塑件侧壁直壁及直壁上侧孔的成型与脱模。模具结构形式合理,成型件便于加工且实用可靠,能为同类模具设计提供有益借鉴。

A glass fiber modified and reinforced polypropylene(PP)composite was selected for injection moulding of large plastic parts for the support frame of industrial control computer circuit boards.The mould structure was a three plate mould structure,which was opened in three stages.To ensure the balanced and full filling of the plastic mould cavity,two point gates were designed for the pouring of the mould cavity.In response to the high number of secondary sub features on plastic parts,especially the high number of special-shaped bolts and deep ribs,multiple local inserts had been designed for the formation of these local features,improving the strength of local formed inserts while reducing the processing difficulty of these formed parts.Multiple breathable inserts had been installed to enhance exhaust in response to the difficulty of local exhaust in the mould cavity.In the mould,a locking mechanism and a fixed distance pull rod mechanism were installed for controlling the opening and closing of the mould;A spring material mechanism for reliable demoulding of runner waste was designed,and a positioning mechanism to ensure the forming accuracy of plastic parts and the working life of the mould;Three slider mechanisms was designed for the moulding and demoulding of plastic parts with straight walls and side holes on the straight walls.The selection of mould structure form is reason‐able,the formed parts are easy to process and work reliably,and the selection of mechanism is practical and reliable,which can provide useful reference for similar mould design.