Eliminating weldlines of an injection-molded part with the aid of high-frequency induction heating

High-frequency induction is an efficient way to heat mold surface by non-contact electromagnetic induction. It has been recently applied to injection molding because of its capability to heat and cool mold surface rapidly. This study applies high-frequency induction heating to eliminate weldlines in an injection-molded plastic part. To eliminate or reduce weldlines, the mold temperature at the corresponding weld locations should be maintained higher than the glass transition temperature of the resin material. Through 3 s of induction heating, the maximum temperature of 143 °C is obtained on the mold surface around the elliptic coil, while the temperature of the mold plate is lower than 60 °C. An injection molding experiment is then performed with the aid of induction heating, and the effect of induction heating conditions on the surface appearance of the weldline is investigated. The weldline on the heated region is almost eliminated, from which we can obtain the good surface appearance of the part.     

薄壳成型制品熔接线强度预测模型研究

在总结分析传统塑料制品的熔接线强度预测模型的基础上,引入WLF半经验方程,建立了用于预测高压成型条件下的薄壳薄壳塑料制品熔接线强度模型,讨论了压力对聚合物熔体特征的影响,高压导致高粘度,低分子扩散,低粘结度,从而降低了熔接线强度,同时进行了实验研究,并将两种强度模型的预测结果与实验结果加以比较,表明薄壳制品熔接线强度预测模型能够很好地预测薄壳制品的熔接线强度。     

注塑件成型工艺参数优化研究

以手机外壳为例,应用CAE软件模拟了注塑件的注塑成型过程。通过正交试验方法与模拟仿真实验的结合,对注塑成型的填充、保压、冷却和翘曲变形过程进行仿真实验分析,获得了制件不同条件下的翘曲变形值。并通过对试验数据的极差分析,得到了不同工艺参数对注塑过程翘曲变形的影响程度,进而得到一组优化的工艺参数组合,同时对优化后的工艺参数组合进行仿真模拟分析,得到了符合产品要求的翘曲变形量,为同类制品的工艺参数优化提供了依据。     

滑雪板底板注射模设计

介绍在卧式注射机上生产滑雪板底板,底板中间层的不锈钢片采用嵌件方式进行生产,一方面保证了产品的质量,另一方面减少了装配,保证了产品的外观。金属嵌件注射模的生产一般在立式注射机上进行,较少使用卧式注射机,如何设计在卧式注射机上生产的金属嵌件注射模,要考虑的问题很多,就不锈钢嵌件在模具中的定位问题、注射成型工艺、顶出结构系统等注射生产中涉及到的内容进行论述交流。     

基于RE／CAD／CAE集成的注塑件协同制造系统研究

目前注塑产品开发趋于多样化,许多注塑产品的设计来源于既有的实物。本文提出了基于ＲＥ／ＣＡＤ／ＣＡＥ集成的协同制造系统,通过反向工程技术获取数据,ＣＡＤ用于实体造型,通过ＣＡＥ软件进行的塑件和注塑模分析。集成系统可以缩短产品的开发周期,降低设计成本,提高企业的市场竞争力。     

Process parameters optimization of injection molding using a fast strip analysis as a surrogate model

Injection molding process parameters such as injection temperature, mold temperature, and injection time have direct influence on the quality and cost of products. However, the optimization of these parameters is a complex and difficult task. In this paper, a novel surrogate-based evolutionary algorithm for process parameters optimization is proposed. Considering that most injection molded parts have a sheet like geometry, a fast strip analysis model is adopted as a surrogate model to approximate the time-consuming computer simulation software for predicating the filling characteristics of injection molding, in which the original part is represented by a rectangular strip, and a finite difference method is adopted to solve one dimensional flow in the strip. Having established the surrogate model, a particle swarm optimization algorithm is employed to find out the optimum process parameters over a space of all feasible process parameters. Case studies show that the proposed optimization algorithm can optimize the process parameters effectively.     

恒流堵塞器的建模和参数分析

恒流堵塞器是油田分层注水系统中的重要部件,在注水压力和地层压力变化时,它可以保证注水流量基本不变,从而达到恒流注水的目的。文中利用物理系统建模的通用方法—键合图法建立了恒流堵塞器的模型,通过仿真软件20-SIM进行了仿真,并且分析了物理参数对性能的影响。     

注塑模数字化设计技术研究

阐述了一种注塑模数字化设计技术.运用Pro/E软件的通用功能模块和模架设计专家(EMX)模块,进行塑件及注塑模设计.以相机面壳注塑模设计为例,验证了该方法的可行性.该方法可以提高塑料注射模具的开发效率.     

车灯光导中锯齿宽度和深度对点亮外观的影响

锯齿的设计是光导设计中的关键技术,其位置和尺寸对配光有很大的影响,同时也会影响到光导的点亮外观。光导的均匀性是外观评价的重要方面,介绍了一种使光导发光面不产生暗区的最小锯齿宽度的计算方法,并通过仿真软件进行建模模拟,模拟结果与计算结果吻合。     

基于Moldflow的塑料箱注塑成型CAE分析

详细阐述了Moldflow技术的重要作用及地位,通过应用Moldflow/MPI软件对塑料箱模具进行CAE综合分析,用仿真注塑工艺参数来模拟产品的实际生产过程,显示了Moldflow技术在模具开发过程中对于优化塑料制品设计、优化塑料模设计和优化注射工艺参数等方面所起到的显著作用。     

基于Moldflow的薄壁件翘曲变形研究

翘曲变形是注塑件的主要缺陷,利用电器后盖对薄壁成型工艺进行研究。采用Moldflow软件对塑件成型过程进行数值模拟,研究了保压压力、塑件材料对注塑件翘曲变形的影响。对薄壁注塑件的数值仿真模拟结果进行统计分析,并且对影响注塑翘曲变形量的工艺参数进行综合分析,得到最优的工艺参数组合。研究结果表明:最佳的工艺参数组合可以使得塑件翘曲量变得最小。     

基于混合映射的高动态范围场景再现

高动态范围场景再现技术广泛应用于消费电子、虚拟现实、摄影以及计算机视觉等领域。针对目前大多数高动态范围场景再现方法很难有效兼顾场景的整体效果和局部细节的问题,本文提出了基于混合映射的高动态范围场景再现方法。首先将输入的高动态范围场景从RGB颜色空间转换到HSV颜色空间,得到原始图像的3个分量:色调、饱和度和亮度;然后利用对数方程将亮度分量转换到对数域,以便符合人类对场景亮度的感知机理,并利用具有sigmoidal函数特性的反正切函数自适应地压缩全局动态范围,以得到良好的整体效果;接着采用改进的SSR方法对全局压缩后的亮度图像进行局部映射,以增强图像亮区和暗区的细节信息;最后,对饱和度分量进行自适应调整,并将图像由HSV颜色空间转换到RGB颜色空间得到最终的映射图像。选取10组不同的高动态范围场景,从主观和客观两方面进行比较分析。实验结果表明:本文提出的方法既保持了良好的整体效果,又充分保留了图像的局部细节,使图像看起来更加生动自然;同时该方法计算速度快,具有很高的效率。本文算法优于其他5种典型的比较算法,在大多数高动态范围场景再现过程中取得了令人满意的效果。     

基于Moldflow Insight 2010的残余应力优化分析

注塑制品的残余应力影响制品的形状、表面质量及使用性能。在分析残余应力产生机理和原因的基础上,应用软件模拟实验方法,介绍了降低残余应力的方法,结果发现冷却方式与熔体温度对残余应力的影响很大,其次是保压压力、保压时间和螺杆速度的影响,程度依次递减。得出的结论对工程实际有一定的指导意义。     

Investigation of the influence of technological parameters on surface color of plastic parts

The color quality of plastic parts is considered to be a significant attribute of final product acceptance, especially in cases in which esthetic appearance is of importance. This article explores the influence of technological factors on the color parameters of plastic parts. To this end, experiments were designed to identify positive and negative factors affecting the color quality and determine the optimal combination of control factors and noncontrollable factors to reach optimal properties of the color. Process parameter selection for the experiments was performed using Taguchi L9 orthogonal design, and measurements of surface were carried out using a commercial spectrophotometer. The results showed that this method was a useful tool in determining the parameters and sensitivities of the plastic injection molding process that influence surface color. Properties of the surface color were explored through so-called tristimulus values and mathematical model using the L*a*b* color space. In order to analyze the relations between the properties of the individual parameters under the given conditions, correlation analysis was performed. This statistical analysis showed that a significant positive correlation was found between variables a* and b* in both cases, i.e., for mean values and SNT values.     

结晶性塑料制品注塑成形质量在线监测方法研究

结晶性材料的结晶度与塑料制品质量有紧密联系.利用电容传感器的物理特性,通过测量注塑成形过程中的结晶度来实现制品质量的在线监测,重点研究了熔体温度、注塑压力、注塑时间及保压压力对结晶度的影响机制,同时分析了工艺参数结晶度力学性能的关系,设计并制造出了一套注塑模具进行试验验证.试验结果表明,随着结晶度的增大,注塑件的拉伸强...     

基于Pro／E的电源按钮注塑模具设计

分析了电源按钮的成形工艺性,介绍了利用Pro／E软件中的模具制造模块及其注塑模设计专家（EMX4．1）设计电源按钮注塑模具的过程。对于产品尾部的小孔采用侧向分型抽芯机构,为降低侧型芯的加工难度,采用了组合式侧滑块。实践证明：该模具结构合理可靠,并能保证产品成形质量,对此类产品的注塑模具设计有一定的参考价值。     

Moldflow在汽车挡风网基座注塑成型过程中的应用

以Autodesk Simulation Moldflow作为分析平台,采用结构较复杂的某汽车天窗挡风网基座为分析对象,对其表面出现的外观问题进行分析;运用Moldflow软件,模拟零件的注塑成型过程,通过调整浇口阀开启顺序、优化工艺参数等预测出零件的缺陷.根据分析的结果,进行了现场试模和调试,零件的优化结果符合预期....     

基于DEFORM的等径三通浮动式锻造工艺分析

本文针对等径三通传统的液压胀形工艺成品存在的背部皱折、凹陷等缺陷,提出了等径三通浮动式锻造工艺。运用UG-NX软件建立锻造模拟过程中所需构件的模型,并运用DEFORM-3D软件对等径三通的浮动锻造工艺过程进行模拟,分析材料变化情况。较传统工艺相比,通过此工艺生产的等径三通具有更好的力学性能,金属利用率更高,成品外观更加完整,为三通的制作提供一种新的发展思路。     

A study on compound contents for plastic injection molding products of metallic resin pigment

Injection molding process is widely used for producing most plastic products. In order to make a metal-colored plastic product especially in modern luxury home alliances, metallic pigments which are mixed to a basic resin material for injection molding are available. However, the process control for the metal-colored plastic product is extremely difficult due to non-uniform melt flow of the metallic resin pigments. To improve the process efficiency, a rapid mold cooling method by a compressed cryogenic fluid and electricity mold are also proposed to decrease undesired compound contents within a molded plastic product. In this study, a quality of the metal-colored plastic product is evaluated with process parameters; injection speed, injection pressure, and pigment contents, and an influence of the rapid cooling and heating system is demonstrated.

     

基于ANN和GA的机床结构优化设计

机床主轴是机床中的重要部件,其设计对机床性能影响很大。在对主轴设计的各项要求中,刚度和振动稳定性是主要考虑的指标,将其归纳在一个含区域和性能约束的主轴结构优化设计数学模型中。借助有限元软件可获得不同主轴尺寸下的各项性能指标,利用人工神经网络(ANN)实现主轴各项性能指标的近似分析,并采用遗传算法(GA)实现了性能指标为设计变量隐式表达下的机床主轴结构优化设计。