塑料注射成型的流动仿真

注塑件大多为薄壁制件,在进行熔体的流动仿真时,可采用合理而必要的假设,建立塑料熔体在流道和型腔中流动的数学模型;采用有限元和有限差分混合方法求解;编制相应的模拟程序,并将程序的预测结果与实验值进行比较。     

塑料注射成型仿真系统技术

华中科技大学“塑料注射成型模拟软件”课题组，经过近8年的艰苦攻关，成功开发出了具有自主知识产权的注射成型全过程模拟软件HsCAE。     

塑料注射成型CAD与流动传热分析

本文介绍了我国已经开始使用的两个注塑模具CAD软件Moldflow和C－Mold，说明了流动传热分析在注塑模CAD软件设计中的作用，并简单讨论了注射成型过程中流动传热的基本数学模型。     

塑料注射虚拟成型教学系统

塑料注射成型技术的发展与注射模具设计人员需求的增长十分迅速,模具设计人员学习必要的塑料成型基本原理是掌握塑料注射模具设计方法的现实需要。在自主开发的虚拟注射成型单元技术的基础上,研究开发了一个塑料注射虚拟成型教学系统,通过建立知识化、数字化、可视化的教学工具来提高设计人员的学习效率、学习兴趣及对问题理解的深入程度。     

塑料注射成型新工艺

简要介绍了气体（水）辅助注射、模具滑动注射、熔芯注射、受控低压注射、注射－压缩、剪切控制取向注射、推－拉注射、层状注射、微孔发泡注射等注塑料工艺的原理，特点及应用前景，说明塑料注射成型工艺的发展趋势主要以节能，节约原材料，提高成型效率，改进制品性能，提高其附加值为前提。     

微孔塑料的注射成型研究进展

在简要回顾了微孔塑料基本特征的基础上,重点讨论了微孔发泡塑料的注射成型机理、工艺特点及主要影响因素;并特别介绍了几种国内外微孔塑料注射成型加工工艺的最新技术动态以及其主要的工作原理。最后,就微孔塑料注射成型技术的工艺特点,以及性能优点介绍了几种典型应用。     

塑料注射成型技术及其进展

简要介绍了气体辅助注射、多点进料注射、推拉注射、熔芯注射、层状注射、受控低压注射、注射－压缩、反应注射及结构发泡注射等注射成型新工艺的原理及特点。     

热固性塑料注射成型 (二)无流道热固性塑料注射成型

论述了无流道热固性塑料注射成型的方法、工艺、设备和模具设计方面的问题。     

Coupled Part and Mold Temperature Simulation for Injection Molding Based on Solid Geometry

This paper presents a coupled method that determines the interface temperatures by filling and cooling analyses simultaneously to simulate the mold and part temperature distributions for injection molding. The mold temperature is assumed to be changing and is calculated with melt together at the filling stage instead of keeping constants as is usually done in conventional methods. The mold temperature is first determined with a 3-D finite element method by specifying the heat-flow rate at the interface between mold and part. Then the finite difference approach is employed to solve the melt thermal problem to get melt temperature distributions inside the cavity and the heat-flow rate at the interface. The under-relax scheme is used to correct the boundary condition and to resolve both mold and melt thermal problems until the solutions are convergent. This method can simulate transient and multicycle problems with more complex process conditions. The simulated results agree with experimental data.     

3D Flow Simulation for Viscous Nonisothermal Incompressible Fluid in Injection Molding

ABSTRACT

The major drawbacks of the Hele-Shaw approximation, commonly used today as a means of simplifying the simulation of the injection molding process, are the inherent loss of the ability to predict important physical phenomena and the ambiguity involved in the definition of a midplane. With the objective of eliminating many of these problems, a fully three-dimensional mold filling simulation program has been developed. The governing Equations are in terms of Navier-Stokes problems for the viscous, incompressible, nonisothermal, and non-Newtonian fluid. To avoid the simultaneous determination of the coupled velocity and pressure, this article introduces an iterative method that at any given time step solves the components independently. This method reduces memory needs in simulation and enhances the stability of numerical scheme. In addition, this article also presents a mixed implicit and “up-wind” scheme to discrete the energy equation. It can overcome the spatial oscillations of temperature in numerical simulation. Good agreements with both analytic solution and the actual processes are found in the current investigation. This method can successfully predict the flow features in injection molding.     

Numerical Simulation for Injection Molding with a Rapidly Heated Mold,Part I: Flow Simulation for Thin Wall Parts

The rapid thermal response (RTR) injection molding is a novel process developed to raise the mold surface temperature rapidly to the polymer melt temperature prior to the injection stage and then cool rapidly. The resulting filling process is achieved inside a hot mold cavity by prohibiting formation of frozen layer so as to enable thin wall injection molding without filling difficulty. The present work covers flow simulation of thin wall injection molding using the RTR molding process. Both 2.5-D shell analysis and 3-D solid analysis were performed, and the simulation results were compared with the prior experimental results. Coupled analysis with transient heat transfer simulation was also studied to realize more reliable thin-wall-flow estimation for the RTR molding process. The proposed coupled simulation approach based on solid elements provides reliable flow estimation by accounting for the effects of the unique thermal boundary conditions of the RTR mold.     

塑料注塑成型中的传热分析

采用了有限差分法和边界元法,对塑料注塑成型中的传热进行了分析     

Computer Filling Simulation of Injection Molding Based on 3D Surface Model

Computer simulation packages have been successful in predicting filling behavior in extremely complicated geometries, and most of the current numerical solutions are based on a hybrid finite-element/finite-difference scheme and the middle-plane model. This imported model causes some inconvenience during applications. This study introduces surface model as the datum plane, instead of the traditional middle-plane model and additional boundary conditions in the gapwise direction are employed to keep the flows in the surfaces at the same section coordinative. The simulation presented here is compared with the experimental results obtained with instrumented test mold and C-Mold results. It is demonstrated that the present formulation is well suited to handle cavities generated directly by mold design process with computer aided design (CAD) tools.     

基于计算机仿真的注塑成型工艺优化研究

为了优化注塑成型工艺,研究了注塑成型的数学模型,以及产生翘曲形变的原因,在此基础上利用Moldflow软件对薄壁件塑料注塑成型过程中的宽浇口平板进行了仿真实验,并采用了无定型塑料丙烯腈-丁二烯-苯乙烯共聚物+聚碳酸酯(ABS+PC)对其进行注射、保压、冷却等流程模拟,选定了保压压力、熔体温度、冷却时间、模具温度、注射时间、保压时间等主要工艺参数,并通过方差比较的方法对这些工艺参数进行了评价,最终确定了注塑成型的优化方案。通过实验得出了ABS+PC的最优工艺参数组合,有效降低薄壳制件的翘曲量并优化了其制品性能。     

注射成型过程数值模拟的辩证认识

注射成型模拟软件的发展十分迅速,本文从基础层面讨论数值软件的根本问题     

塑料注射成型熔体前沿的流动模拟

讨论了塑料注射成型流动过程分析中熔体前沿喷泉效应的近似处理方法和数值分析方法。     

薄壁注塑成型模具的设计

针对薄壁塑料制品注塑成型具有的特点，本文论述了在设计薄壁塑件注塑成型模具时应重点考虑的几项内容。     

注射成型流动模拟技术的发展

介绍了塑料成型过程中注射成型流动模拟技术的三个发展阶段,并分析了三种不同网格模型的特点。