塑料微注射成型流动裹气机理研究

项目名称： 塑料微注射成型流动裹气机理研究

项目编号： No.11272291

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 曹伟

作者单位： 郑州大学

项目金额： 82万元

中文摘要： 微注射成型中流动前沿失稳形成的裹气是用普通仪器难以检测的质量缺陷，已有的微注射成型理论和方法也不能预测这种现象。本项目根据流变实验和无量纲方法建立熔体流动的多模态非线性黏弹性本构方程和控制方程，基于两项流原理建立与之耦合的黏性气体流动的控制方程和界面边界条件，结合流线上风法、黏弹性分裂算法、松弛迭代法构造数值求解方法，开发模拟程序预测流场变化、裹气位置及尺寸。开展典型微制品缺料注射试验，结合模拟结果掌握流动前沿失稳及射流偏转的触发机理，探索边界条件及表面张力对气- - 熔界面演化及熔体裹气的影响，揭示裹气与充填速度、制品形状、材料特性及熔体流入型腔方向等因素的关系，建立前沿失稳及射流偏转的Re数、Wi数判别准则，提出避免熔体流动裹气的模具设计、工艺设计方案，为研究微注射成型中的复杂物理问题提供理论支撑。

中文关键词： 裹气；两相流；喷射；微注射成型；

英文摘要： The air entrapment formed by the unsteady melt front during micro-injection molding is hard detected by usual instruments. The existing theory and method for micro-injection molding are unable to predict this phenomenon either. In this project, we will establish the multi-mode nonlinear viscoelastic constitutive model and governing equations for melt flow by rheological experiments and dimensionless method, and the coupled viscous flow equations and interface conditions for air according to two-phase flow principle, construct numerical method to solve the flow problem with combining the Streamline Up-Wind Scheme, Elastic Viscous Stress Split and Successive Over-Relaxation methods, and develop the simulating software to predict the flow field and the air entrapment. Combining the short shot experiments for typical products and simulated results to master the triggering mechanism for unsteady melt front and jetting swerve, explore the influence of boundary condition and surface tension on the evolution of air-melt interface, disclose the relationship between the air entrapment and filling velocity, part shape, material properties and melt entrance direction to cavity. In addition, we will establish the judge rule in terms of Re, Wi for the unsteady melt front and jetting swerve, and propose the mold design and pro

英文关键词： air entrapment；two-phase flow；jetting；micro-injection molding；