【作者】 沈琴；

【导师】 王存堂；

【作者基本信息】 江苏大学 ， 机械电子工程， 2017， 硕士

【摘要】 随着塑料工业的飞速发展,使得塑件的应用更为广泛,因此对塑料模具的设计提出更高的要求。本文以汽车中央通道为研究对象,运用热流道技术、CAE技术及注塑成型工艺优化技术对其模具的浇注、冷却系统和成型工艺优化展开设计,为注塑模具的节材设计、高效设计奠定基础。首先,结合塑件结构特点利用Moldflow进行模流分析,分析结果表明浇注系统选取多个浇注点、冷流道和热流道相互结合的方式,可以有效的解决由塑件结构复杂,充填流程长引起的充填时间长、注射压力大、充填不均以及塑件翘曲量大等情况,通过方案对比确定浇口数量。运用流变学理论,揭示了浇注系统各管道尺寸与浇注平衡的关系,运算得出各浇注管道的尺寸,为浇注系统高效设计提供理论依据。其次,依据冷却时间短、成型质量高的原则对冷却系统进行设计。系统选取了直通式的冷却方式,运用传热学理论运算出凹模与凸模的冷却管道直径。利用Moldflow进行冷却仿真,结合塑件的外形结构对冷却管道布局进行优化调整。最后,对注塑成型工艺展开优化,以翘曲量为优化目标。先应用Taguchi正交实验设计法展开成型实验,得到工艺参数局部最优解。然后以Taguchi正交实验矩阵当做样本数据,通过Matlab构建出工艺参数与翘曲量的BP神经网络模型,运用遗传算法展开优化,寻找出工艺参数的全局最优解。主要研究结论如下:1.当浇口数量是四个时效果最佳,浇注系统采取一个主流道、四个分流道方案。通过改变各分流道管道直径,解决浇注口不对称引起的浇注不平衡问题。2.由于凹、凸模传递热量不等,冷却管道直径根据凹、凸模带走热量的多少来确定。管道布局也应在塑件热量集中区域紧密分布。3.BP神经网络模型结合遗传算法的优化方式,能够快速寻找出工艺参数的全局最优解。相比传统试制方式,大大缩短了模具的研发时间,节约了研发成本,提升了产品的生产效率,增强了产品的产出质量。更多还原

【Abstract】 With the rapid development of plastic industry,the application of plastic parts is more extensive,so the plastic mold design is put forward higher requirements.Taking the car central channel as the research object and using hot runner technology,CAE technology and injection molding processing optimization technology,the paper carries out the design of its gating,cooling system and the optimization of the forming process,which will lay the foundation for the material-saving design and efficient design of injection mold.Firstly,combined with the structural characteristics of plastic parts,Moldflow is used to analyze the mold flow.The results show that the gating system selects the way to combine multiple gate points,cold runner and hot runner,which can effectively solve the problems such as long filling time,large injection pressure,uneven filling and large warpage of plastic parts,etc.caused by the complex structure of plastic parts and the long filling process.The number of gates by program comparison is determined.Using rheology theory reveals the relationship between the each pipeline size of gating system and the gating equilibrium.Each pipeline size obtained from operation will provide a theoretical basis for efficient design of gating system.Secondly,with the principle that the cooling time is short and the forming quality is high,the cooling system is designed.The system selects a straight-through cooling method and heat transfer theory is used to calculate the diameter of the cooling pipe concave of die and punch.Cooling simulation is carried out by using Moldflow,combined with the appearance of plastic parts to optimize the layout of cooling pipe.Finally,the optimization of injection molding process is carried out,taking warpage as the optimization target.Firstly,the Taguchi orthogonal experimental design method is used to develop forming experiment so that local optimal solution of process parameters is obtained.Then the Taguchi orthogonal experimental matrix is used as the sample data.The BP neural network model of process parameters and warpage is established by Matlab.By using genetic algorithm,optimization is carried out to find out the global optimum solution of the process parameters.The main research conclusion is as follows:1.The four gates will have the best effect.Gating system takes the program with a main channel and four branch channels,by changing the diameter of pipeline of branch channels to solve gating unbalance problem caused by the asymmetry of a sprue gates.2.Because of the unequal heat transfer between concave and convex dies,the diameter of the cooling pipe is determined by the quantity of heat taken by the concave and convex die.Pipeline layout should also be closely distributed in heat concentrated area of plastic parts.3.By using optimization method of BP neural network model combined with genetic algorithm,the global optimal solution can be found quickly.Compared with traditional trial production,the development time of the mold is greatly shortened,development cost is saved,the production efficiency of the products is also improved and product quality is enhanced.更多还原