注塑模CAE流动模拟技术概述

注塑模CAE软件根据塑料成型流变学、热传学和数值计算方法的基本理论,建立熔体在模具型腔内的流动、热传的物理数学模型,利用计算机图形学技术在计算机上形象,直观地模拟出在实际成型过程中熔体在模腔中的动态填充过程、保压过程和冷却过程,定量地给出成型过程的状态参数.     

注塑模CAE流动模拟技术概述

注塑模CAE软件根据塑料成型流变学、热传学和数值计算方法的基本理论,建立熔体在模具型腔内的流动、热传的物理数学模型,利用计算机图形学技术在计算机上形象,直观地模拟出在实际成型过程中熔体在模腔中的动态填充过程、保压过程和冷却过程,定量地给出成型过程的状态参数.……     

变模温注射成型数值仿真

针对传统的恒定模温控制技术易导致塑件表面产生熔接痕、流动痕和凹陷等表面缺陷的问题,采用Moldex 3D对某典型型腔进行流动分析,预测模型中熔接痕产生的位置;利用该软件中的暂态冷却模块,采用改变冷却方式和注射时间的方法对普通冷却与变模温技术的保压和冷却效果进行对比.分析结果表明,变模温技术能在不影响生产效率的基础上,达到提升制品品质的目的.     

(大连理工大学精密与特种加工教育部重点实验室，辽宁 大连，116024)

基于微注塑成型中熔体充模流动理论,对微尺度下熔体与壁面间的传热系数对熔体充模流动影响进行了研究.在分析两相间传热机理的基础上,讨论了宏观尺度流道和微观尺度流道中传热系数取值对熔体温度分布的影响.在引入传热系数模型的基础上,对正方形截面分别为500μm、300μm和200μm的三种长方形微流道中熔体充模流动进行三维数值模拟.通过与已有实验数据相比较,验证了模型的合理性,并分析了不同的模具温度和熔体温度下,采用常数传热系数和传热系数模型得到的熔体温度分布及其随微流道特征尺度变化规律.     

Z-MOLD塑料注射模CAE软件

Ｚ－ＭＯＬＤ软件是郑州工业大学橡塑模具国家工程研究中心开发的具有自主版权的计算机辅助工程软件,将工程设计、试验与分析贯穿于产品研制过程的ＣＡＥ技术应用系统中。它以塑料加工流变学、传热学和数值计算方法为理论基础,利用计算机图形学的技术将塑料熔体在模具型腔中的流动和传热的物理数学模型反映在计算机屏幕上,使设计人员可以在计算机上模拟出实际成型中熔体的动态充填、保压过程、冷却过程,这样就可以在制造模具之前就能计算出注射模浇口及流道的配置和尺寸、冷却管道的尺寸、布置及连接方式等参数,为设计人员修改设计、设…     

HsCAE冷却模拟技术在注塑产品设计中的应用

HsCAE冷却模拟模块采用交互设计的方式,可以预测制品与模具上的温度场、热流密度场、温差分布和冷却时间,优化冷却结构与工艺设计,达到均匀冷却效果。     

双螺杆挤出机模具过渡和稳流段流场的数值模拟

采用Carreau模型描述熔体的黏度特征,使用POLYFLOW软件数值模拟了异向旋转双螺杆挤出机模具过渡和稳流段的三维等温流场。在不同的工艺参数下,分析比较了模具过渡和稳流段内的速度场、压强场、剪切速率场、剪切应力场以及黏度场。结果表明在模具过渡和稳流段内,螺杆的旋转是该聚合物熔体流变性能的最大影响因素,螺杆头对高黏度熔体的影响范围不大,只限于螺杆头的周围;进入稳流段后,在稳流段作用下熔体的流动逐渐变得稳定均匀;在本文讨论的转速和流量范围内,转速和流量的增加,分别会在不同的区域使熔体受到的剪切速率和剪切应力明显地增大。研究结果为某企业设计双螺杆模具和优化工艺条件提供理论依据。     

塑料卡板成型的流动分析

MPI/Flow的流动分析功能能够模拟聚合物在模具中的流动,并能够帮助设计人员优化模腔的布局、材料的选择、填充和压实的工艺参数,获得最佳保压阶段设置,从而尽可能降低由保压引起的制品收缩和翘曲等质量缺陷.在产品允许的强度范围和合理的充模情况下,设计人员可以适当减少模腔的壁厚,把熔接线和困气定位于结构和外观允许的位置上,并且定义个范围较宽的工艺条件,而不必考虑生产车间条件的变化.MPI/Flow能够从塑件设计、模具设计到成型工艺等方面,对注塑成型提供全面的、并行的解决方案.     

Moldflow在某大型薄壁异形件注塑成型模拟分析中的应用

Moldflow注塑成型与模拟软件系列用于帮助制件设计者和模具设计者检测其设计的工艺性.Moldflow软件在注塑模设计中的作用主要体现在以下三个方面,首先可以优化塑料制品,运用Moldflow软件,可以得到制品的实际最小壁厚,从而优化制品结构,降低材料成本,缩短生产周期,保证制品能全部充满;其次运用Moldflow软件可以优化模具结构,可以得到最佳的浇口数量与位置、合理的流道系统与冷却系统,并对型腔尺寸、浇口尺寸、流道尺寸和冷却系统尺寸进行优化,在计算机上进行试模、修模,大大提高模具质量,减少修模次数;最后通过Moldflow软件,用户可以非常方便地优化注塑工艺参数,用户可以确定最佳的注射压力、保压压力、锁模力、模具温度、熔体温度、注射时间、保压时间和冷却时间,以注塑出最佳的塑料制品.     

小议热处理工艺在模具制造过程中的应用

模具制作是工业发展中的基础性产业,对模具制作环节中实施的热加工技术展开系统地分析和归纳,可知恰当有效的热加工过程在很大程度上关联着模具制品的制造质量.力学品质、使用周期和制作费用是代表模具品质及使用周期的基本要素.笔者同时对模具热加工技术在模具制品制作环节中的运用趋势展开估判.     

Visualizing analysis for weld line forming in micro injection molding by experimental method

In micro injection molding, the melt flow behavior is important for the final product quality. However, the current process monitoring and measurement technology are not adequate enough to provide a direct analysis access. In the presented study, a glass insert mold designed for performing the direct visual analysis for melt flow phenomena in micro injection molding is introduced. The micro tensile specimen with 0.1 × 0.4 mm² (depth × width) cross section dimension is chosen as the objective part. The correlation between processing parameters (injection pressure, injection speed, mold temperature) and flow behavior was investigated and analyzed. The results show that the injection pressure put an obvious effect on the filling speed through micro cavity. Injection speed can influence the filling time dramatically also. Higher mold temperature brings positive influence with the flowing speed, due to the lower viscosity of polymers in higher mold temperature.     

基于涡流式传感器检测的连铸结晶器液位控制研究

本文主要运用涡流式传感器检测的连铸结晶器液位控制问题研究,文章简要叙述了电涡流传感器的工作原理、电涡流式传感器等效电路,通过电涡流传感器采集钢水液位的信号,构建了液位检测连铸结晶器系统控制系统的数学模型,分别构建了电涡流传感器模型、伺服电动机系统模型、塞棒流量特性模型、连铸结晶器模型,并用MATLAB软件下的组态Simulink进行仿真,经仿真表明,该算法可以很好地对结晶器实施控制,经过实际运行该算法是完全正确的、可行的、有效的。实验结果表明,该控制算法连铸结晶器液位控制效果良好。     

Numerical Simulation of Injection Molding of three-Dimensional Thin Parts

This paper is concerned with the numerical simulation of the injection mold filling process.A mathematical model based on generalized Hele-Shaw flow for an inelastic non-Newtonian fluid undernonisothermal conditions is used.A hybrid numerical scheme is employed.The numerical simulating re-sults,pressure and temperature profile,location of the melt fronts,are in a good agreement with the ex-perimental ones.     

基于CAE技术的注塑模组合型腔流动平衡设计及工艺分析

利用注塑模CAE软件Moldflow Insight 2010对结构复杂的组合型腔制件进行了流动、充填和流道平衡模拟分析,确定了单浇口组合型腔浇注系统布置方案,优化了特定条件下可使二型腔平衡进料的浇注系统尺寸。采用综合平衡法设计正交试验并开展CAE模拟实验,通过对因素与水平的直观分析,讨论了模具温度和熔体温度等工艺对注塑成型中流动平衡的影响,并给出了特定条件下工艺参数的最优组合。     

Liquid-Gas Two-Phase Flow Simulation in Mold Filling Process with Level Set Method

Air entrapped in liquid metal during the mold filling process seriously affects the casting quality, thus it is important to track its behavior in the mold cavity. A liquid-gas two-phase flow model is developed to describe the mold filling process and predict the air entrapment defect. The model is based on the combination of SOLA and Level Set Method. The pressure and velocity fields are calculated by SOLA,and the interface movement is simulated by Level Set method as the most common interface tracking met...     

Instrumented film-insert injection compression molding for lens encapsulation of liquid crystal displays

A film-insert injection compression molding process was introduced to encapsulate cholesteric liquid crystal displays with flexible and rigid lens for full protection of displays to replace the currently used time consuming hand lamination technique. For this purpose, a new interchangeable cavity instrumented hot runner mold was designed and constructed. This complex method was carefully optimized considering challenges arising from an insert multilayer display with +80% liquid crystal content as well as different thermal expansion coefficients between the layers and the lens material as a high potential of delamination and warpage. Concerning the desired physical properties including transparency, low melt viscosity and melting temperature as well as a wide range of hardness grades from soft (flexible) to hard (rigid), three different hardness grades of thermoplastic polyurethanes were found to be the best candidates for this lens application. During proposed lens encapsulation, the pressure changes were evaluated with screw and mold movements using position detection via displacement transducers attached to track the mold closure and screw forward motion. The quality of encapsulation and shrinkage related problems, as well as their elimination, were all discussed. Display substrate material selection criteria for lowered warpage were defined with supporting thermal characterizations. Among the process parameters, tested also by applying the design of experiments with Taguchi method, mold temperature was found to be the most influential parameter on warpage, followed by pin gate opening time, packing pressure, and cooling time.     

Simulation of the filling process in molding components with micro channels

In micro molding of components with micro features, the ability for the polymer melt to flow into the micro channels is a crucial factor for successful molding. In this case, the molded volume is about the same as the conventional molding. The penetration distance into the microstructure depends on the flow rate and the cooling rate of the micro features, which is function of the geometric dimensions. In this study, a simplified model was established to estimate the injection distance into the micro channels of a mold insert. The effect of the mold temperature, injection rate, and micro channel dimension on the filling distance was investigated based on the model. The filling distance increases dramatically with respect to the increase of the channel width. In molding of components with micro features as those analyzed in this study, decrease of the part thickness could enhance the filling in the micro features.The authors would like to thank for the financial support from National Science Council in Republic of China under the contract number of NSC 91-2212-E006-131.     

An integrated simulation for the whole forming process of the picture tube panel

An integrated model for the whole forming operation of the picture tube panel is developed in this paper, which couples the behaviors of glass and mold. The molten glass is modeled by an incompressible Newtonian liquid undergoing flow. And a three-dimensional finite element method is used to perform the simulation of the fluid and heat flow. A local one-dimensional transient analysis in the thickness direction is adopted for the part cooling stage after pressing, which employs the finite-difference method. The mold heat transfer is established by boundary conditions analysis and its numerical implementation is a three-dimensional boundary element method. The glass and mold simulations are coupled by matching the temperature and heat flux on the glass-mold interface. For residual stresses analysis, a thermo-rheologically simple viscoelastic material model is introduced to consider the stresses relaxation effect and to describe the mechanical behavior according to the temperature change. The shrinkage of formed parts induced by the residual stresses is calculated based on the theory of shells, represented as an assembly of flat elements formed by combining the constant strain and the discrete Kirchhoff triangular elements. A thermoelastic model is presented to predict the deformation of the mold blocks during pressing, which is based on the steady mold temperature field and thermoelastic boundary element method.     

映射技术在液-液混合中的应用

本文给出了描述非周期液-液混合流的映射方法．根据非周期混合流的特点,对周期映射方法进行了改进．针对不同时刻的映射矩阵,建立了计算该矩阵非零分量的优化算法．为减小网格单元重叠所导致的单元信息传递误差,用最初网格代替变形网格,提出了重构映射矩阵的概念用以传递映射过程中的相关变量．对不同雷诺数背景流体中单液滴和双液滴混合初始阶段的流变特征进行了模拟．数值实验表明:用偏析强度表征的混合质量随时间呈指数增长;较高的背景流体雷诺数,有利于混合质量的提高;多液滴之间的相互交融对混合过程存在较大影响．