基于Moldflow的注塑模流道平衡分析

在不同体积型腔的模具流道设计中,利用MPI软件对组合型腔的熔体流动进行对比分析,得到能够使注射达到尽可能平衡的流道设计。此外,再辅以螺杆速度曲线的调节,最后利用分析出的比例值确定产品流道截面的尺寸,尽可能减小了塑件的缺陷。     

基于MPI的注塑模流道平衡设计与分析

在不同体积型腔的模具流道设计中,利用MPI软件对不同流道的设计进行对比分析,根据对产品的需求选择合适的流道设计,确定产品流道截面的尺寸,尽可能减小了塑件的缺陷.     

基于Moldflow的注塑模流道平衡设计与分析

以手机前盖及前饰板两个非等体件共模结构为分析实例,阐述在不同体积型腔的模具流道设计中,利用MPI软件对不同流道的设计进行对比分析。主要对比分析了三种典型的浇注方式对浇注时间、转换压力及锁模力三个要素的影响,再根据产品的需求选择合适的流道设计,最后利用分析出的两腔填充时间比值确定产品流道截面的尺寸。优化了分流道,使塑件的填充达到了流动平衡,尽可能减小了塑件的缺陷。     

一种新型多流道分配机头的设计及其流场分析

本文涉及一种新型的多流道熔体分配机头,其分配流道的设计能够尽可能保证熔体流动路径的一致性。运用基于有限元的CFD分析软件Polyflow对熔体进行了模拟计算,并运用后处理软件Fieldview,对三种不同流道的分配机头模型的压力场、速度场及黏度场进行了分析比较,得出了一些有关该新型分配机头的设计要点。     

板型机头流道的有限元计算辅助设计

在板型机头中聚合物流动的有限元分析基础上,建立了一种利用有限元计算设计板型机头流道的方法,建立了流道设计原则,编制了设计计算程序,井用该方法对φ65挤出机平板机头流道进行了校验和再设计。实践表明:该机头流道经重新设计后,其内的胶料速度分布与停留时间分布有明显改善,这说明了本文所提出的板型机头流道设计方法的可行性。     

基于正交试验与数值模拟的木塑异型材挤出机头流道设计方法

建立了一种基于正交试验与数值模拟的木塑异型材挤出机头流道的设计方法,其主要原理是在结合木塑复合材料流变数据的基础上,将异型材挤出机头流道的主要几何参数定义为正交试验的试验因素,利用正交试验设计方法对这些几何参数进行试验安排;使用Inventor软件三维参数化尺寸驱动系统实现流道模型的迅速建立;通过专业计算流体力学有限元分析软件Polyflow完成机头流道内熔体的模拟计算和仿真分析;选择适当的评价标准对模拟结果进行正交优化,最终获得机头流道的合理参数。依据这种方法,对立柱木塑异型材进行了机头流道的设计,最终得到其理想的设计结果。     

应用Flow 2000软件分析功能块成型结构的设计

利用Flow 2000软件，从3个方面对塑料异型材挤出模头中功能块成型结构的设计进行了分析，即进行部分功能块的结构改进、流道中功能块局部流速过慢的处理、流道中功能块局部流速过快的处理。从而确保成型区上功能块的流道截面图形设计及平直段长度的设计满足挤出模头流道设计的基本要求，提高了挤出模具的设计水平，缩小了与国外设计上的差距。     

POLYFLOW在橡胶挤出机流道研发设计中的应用

以单螺杆挤出机内衬层胶片挤出为例,详细介绍了如何应用POLYFLOW软件对单螺杆橡胶机头流道内部流场分析与设计。研究结果表明,通过POLYFLOW能够预测胶料在机头内复杂的流动情况,并利用其挤出功能可以提高流道设计的一次成功率,缩短流道研发周期和现场修复时间,降低研发设计成本。     

巴顿菲尔格罗斯特展示9-层吹膜前沿技术

随着层数增加的趋势,模具制造商面临着许多挑战。巴顿菲尔格罗斯特工程公司的9层O pti-flow TMLP(低模体)模头采用与它的5-层和7-层O ptiflow TM模头同样的设计理念——使聚合物的停留时间尽可能短。更短的流道在合并各层熔体时不会产生界面的不稳定。经过改进的螺旋流道设计和     

水滴形歧管的结构分析

本文就衣架式模头水滴形歧管的结构设计，根据聚合物加工的流变理论，结合生产实际对水滴形截面的歧管流道分配系统进行分析，使得所设计的挤塑模在尽可能高的流速下，生产出符合尺寸及形状公差的均质片材。     

汽车内饰件组合型腔注塑模设计

将模具计算机辅助工程（CAE）技术引入汽车内饰件组合型腔注塑模的设计。根据流动过程的模拟分析,改善模具浇注系统的结构尺寸,流动不平衡率从7 %降为1.4 %,利用气穴分析和冷却分析优化了排气系统和冷却系统的设计,提高了模具的设计质量,为组合型腔模具的优化设计提供了参考依据。     

海豚充电器产品与模具开发制造

以海豚充电器上壳模具开发制造为例,重点探讨运用数字化建模制造技术、模流分析理论以及现代成型技术设计制造模具的过程,包括产品造型、成型零件的加工、型腔数量及模架确定、浇注系统设计、推出方式确定、以及冷却系统设计.     

Model for the outer cavity of a dual‐cavity die with parameters determined by two‐dimensional finite‐element analysis

A coating die forms liquid layers of uniform thickness for application to a substrate. In a dual‐cavity coating die an outer cavity and slot improves flow distribution from an inner cavity and slot. A model for axial flow in the outer cavity must consider the ever‐present cross flow. A 1‐D equation for the pressure gradient for a power‐law liquid is obtained as a small departure from a uniform flow distribution and no axial flow. The equation contains a shape factor dependent on cavity shape, Reynolds number, and power‐law index. The shape factor for five triangular cavity shapes is obtained by finite‐element analysis and correlated for application to die design up to the onset of flow recirculation which arises at the junction of the cavity and outer slot. The performance of the combined cavity and slot is considered and the most effective design determined. © 2017 American Institute of Chemical Engineers AIChE J, 64: 708–716, 2018     

Liquid re-circulation in turbulent vertical pipe flow behind a cylindrical bluff body and a ventilated cavity attached to a sparger

The turbulent flow field (Re=60024) in the wake of a cylindrical bluff body in a 0.105 m internal diameter pipe with an area blockage ratio of 82% in turbulent single-phase flow was studied using laser Doppler velocimetry (LDV). The results for the time-averaged velocity showed a toroidal vortex below the bluff body. The axial location below the bluff body where both the time-averaged radial and axial velocity components were zero (eye of the vortex) was found at approximately 0.72D. The end of the re-circulation region as defined by a stagnation point on the centreline of the pipe was found at an axial location below the bluff body of approximately 1.3D. These two locations did not change when altering the liquid superficial velocity confirming that the geometry (i.e., size) of the toroidal vortex is not dependent on the superficial liquid velocity or the speed of the vortex.Similar measurements using LDV were taken in the wake of a ventilated cavity in a vertical 0.105 m internal diameter pipe, with an area blockage ratio of 80%. The flow beneath the cavity was turbulent two-phase bubbly flow and the liquid-only flow ahead of the cavity was turbulent (Re=45618). The cavity was attached to a (central) sparger, which is a scale-up of the design used by Bacon (1995). The average gas void fraction in the wake of the cavity was 7%. The results for the time-averaged velocity confirmed the formation of a toroidal vortex remarkably similar to the vortex formed below the bluff body. The eye of the vortex and the end of the re-circulation region were found at an axial location below the ventilated cavity of 0.78 and 1.35D, respectively, i.e., almost identical to the results for the bluff body.The LDV results of the cylindrical bluff body and the ventilated cavity were compared with the fully predictive model of the velocity distribution in the vortex proposed by Thorpe et al. (2001) and good agreement was found in both cases. The model also agreed well with the data of van Hout et al. (2002) for a Taylor bubble rising in stagnant liquid in a 0.025 m internal diameter pipe. The CFX simulations of Thorpe et al. (2001) carried out for a 0.050 m internal diameter pipe, agreed well with the experimental data of the cylindrical bluff body, the ventilated cavity and the data obtained by van Hout et al. (2002) when correlating the results in the appropriate dimensionless form. Our analysis showed that the maximum axial re-circulation velocity in the centre of the vortex ring was directly proportional to the mean velocity in the annulus at the base of the cylindrical bluff body, the ventilated cavity or the Taylor bubble. The proportionality constant for all cases was found to be approximately 0.38 confirming the value proposed by Thorpe et al. (2001).     

Mold-filling studies for the injection molding of thermoplastic materials. Part I: The flow of plastic materials in hot- and cold-walled circular channels

A finite difference analysis has been developed which predicts the temperature, pressure, and velocity distributions for the flow of thermoplastic materials in straight and tapered, hot and cold walled circular flow channels. This analysis when combined with the cavity filling analysis described in Part II, gives the molding engineer the capability of modeling the injection molding process from the shot to the cavity during injection. The information that is obtained from these analyses is useful in equipment design and modification since it allows numerical experiments to be performed so that one may ascertain the effects on moldability of flow channel and cavity geometry, material properties, and operating conditions. In addition, the information is useful in problem diagnosis and analysis to ascertain causes of and evaluate potential solutions to molding problems.     

多型腔注塑模的流动平衡计算与分析

给出一种基于流动模拟的多型腔注塑模流动平衡计算方法,在流道和型腔布置确定后,根据流动模拟的结果,通过迭代调整流道和浇口尺寸,自动实现非平衡布置多型腔注塑模的流动平衡。利用数值模拟试验研究了注射时间、料温和模温等成型条件变化对流动平衡的影响,结果表明,注射时间的变化对流动平衡有显著影响。     

塑料石英钟机芯注塑模的设计与制造工艺

介绍了塑料石英钟机芯的产品结构设计要点、高精度的模具设计要点以及机芯模具型腔加工特殊的加工工艺流程。     

并行微通道内液液两相流及介尺度效应

使用高速摄像仪研究了T形并行微通道液液两相流的流型。以甘油-水溶液为分散相、含5%（质量分数）道康宁的硅油为连续相,下游通道中观察到了塞状流、液滴流、环状流和并行流4种流型,绘制了流型图及流型转变线。研究了后空腔中液滴群的形态,运用介尺度概念分析了后空腔中液滴群的行为对流量分配的影响。观察到后空腔中液滴群的挤压、松散、有序排列和并行排列等4种形态,不同形态的转变主要受两相流量比的控制。研究了两相流量比对并行微通道内流量分配的影响,以及分析了不同操作条件下影响流量分配的主导因素。在两相流量比较小时,流量分配由下游通道的流体阻力主导,而两相流量比较大时由后空腔内液滴群动力学主导。     

Optimization analysis of the staggered herringbone micromixer based on the slip-driven method

In this paper the mixing effect of the staggered herringbone micromixer (SHM) was investigated by using the slip-driven method. This method simplified the 3D flow in the staggered herringbone micromixer into a 2D cavity flow with an axial Poiseuille flow. The solution of the 2D cavity flow was obtained by solving the biharmonic equation. An improved design with a cosine asymmetric factor P(z) was proposed, and its mixing effect was demonstrated by comparing the effect with the original design [Stroock, A.D., Dertinger, S.K.W., Ajdari, A., Mezic, I., Stone, H.A. and Whitesides, G.M., 2002, Chaotic mixer for microchannels, Science, 295: 647–651; Stroock, A.D., Dertinger, S.K.W., Whitesides, G.M. and Ajdari, A., 2002, Patterning flows using grooved surfaces, Anal Chem, 74: 5306–5312]. Four methods evaluating the mixing effect were used: (1) mixing images at different cycles; (2) Poincaré Sections; (3) segregation intensity and (4) stretching computation. Finally, an optimized value of P₀ = 1/6 was obtained, and the mixing effect of the improved design for different P₀ is discussed.