气体辅助注射成型技术

介绍了消除厚壁制件所出现的缩痕、凹痕缺陷的一种新型塑料成型工艺－－气体辅助注射成型技术的工作原理,技术关键、设备配置及其应用,并重点介绍了内置气体辅助成型和表面气体辅助成型技术。     

工艺参数对气体辅助注射成型结果的影响

以轿车保险杠为例，利用正交设计法和模塑流动软件定量分析了气体辅助注射成型的四个主要工艺参数对成型结果的影响。结果表明，制件的最终质量是各参数综合作用的结果，其中，熔体／气体延迟时间对成型结果的影响最大，气体注塑压力次之，预注射量最小。     

基于正交实验法的气体辅助注射成型工艺参数优化

以CD机体盖为例,以Moldflow作为主要分析研究工具,考察了气体辅助注射成型时制件的气体穿透长度和气指效应情况.以熔体的预注射量、气体延迟时间、熔体注射温度、注气压力等为关键工艺因素,采用正交实验法,利用Moldflow对正交实验方案进行模拟试验,得到不同工艺因素对气体穿透长度、气指效应的影响情况,并确定了最佳工艺参数组合.     

流体辅助注射成型技术

流体辅助注射成型技术是一种塑料与流体的复合注射技术，它包括气体辅助注射成型和水辅助注射成型2种形式。分别介绍了气体辅助注射成型和水辅助注射成型的工艺过程、设备及特点。     

外部气体辅助注射成型制品加强筋表面凹痕实验分析

通过外部气体辅助注射成型（EGAIM）工艺对不同加强筋所造成的平板表面凹痕深度进行实验研究。单因素实验揭示了模具温度、熔体温度、注气延迟时间、注气压力及注气保压时间对不同加强筋制品表面凹痕具有不同程度的影响;正交实验发现,注气延迟时间与注气压力是影响制品表面凹痕的主要因素;在工艺参数最佳化的EGAIM中,与制品厚度比高达1.5的加强筋造成的凹痕深度（1.3 μm）小于传统注塑成型中比值为0.6所造成的凹痕深度（2.3 μm）,表明EGAIM优化工艺能有效改善较大厚度加强筋所造成的表面凹痕、提高制品设计自由度。     

气体辅助注射成型过程中工艺参数对产品质量的影响

以一个管状与平板相结合的气体辅助注射成型制品作为研究对象,引入了正交实验法和CAE技术,首先筛选出了影响制品质量的关键因素,再通过实际的气体辅助注塑成型实验,着重讨论了气体注射延迟时间和气体注射压力两个工艺参数对制品质量的影响,通过调节气体注射延迟时间和气体注射压力两个工艺参数的设置,参考气体穿透的变化情况,均能获得较好气体穿透效果的工艺参数组合.     

气体辅助注射成型技术原理及应用

本文详细介绍了气体辅助注射成型技术的工艺过程与装备，分析了气体辅助注射成型的特点和应用，并对气体辅助注射成型CAE技术作了简要说明。     

水辅助注射成型技术研究进展

介绍了水辅助注射成型技术的发展、成型原理及成型的方法种类。与气体辅助注射成型技术进行了对比，指出采用水辅助注射成型技术具有冷却效率高、成型周期短、制品壁厚小、能成型直径较大的制品等优点，这些优点可拓宽该技术的应用领域。最后分析了目前制约水辅助注射成型技术广泛应用的原因．     

气体辅助注塑及其产品设计特点

介绍了气体辅助注射成型技术及其产品的一些设计特点,并将气体辅助注塑工艺与传统注塑工艺的优缺点进行了比较。     

加成型液体硅橡胶注射成型工艺

文中综述了加成型液体硅橡胶的注射成型工艺，介绍了液体注射成型工艺、共注射成型工艺和气体辅助注射成型工艺及冷流道技术在液体硅橡胶中的应用。     

复杂壳体类塑料件气体辅助注射成型工艺参数优化研究

以21英寸彩电前壳作为研究对象,将Moldflow 2010作为CAE模拟试验平台,以熔体温度、模具温度、熔体注射时间、气体延迟时间、气体压力为关键工艺因素,考察了复杂壳体类塑料件气体辅助注射成型(GAIM)时制件的翘曲变形量和气体穿透情况。以正交试验设计方法为基础,利用遗传算法并结合径向基神经网络建立GAIM工艺参数优化系统,可用于工艺参数组合的快速确定,为GAIM过程中工艺参数优化提供了一种新的求解思路。     

气体辅助注射成型工艺参数优化研究

为了解决气体辅助注射成型(GAIM)中制品所出现的缺陷,采用数值模拟方法对影响制品质量的工艺参数进行了优化研究.首先,建立GAIM过程的数学模型,得出影响GAIM制品质量的主要工艺因素;随后,利用数值模拟法分析熔体预注射量、熔体/气体延迟时间、充气压力与熔体注射温度等关键工艺因素与GAIM制品缺陷的关系;最后,基于数值模拟分析结果,对GAIM制品的工艺参数进行了优化选择与设定.     

基于BP神经网络的导管接头注塑工艺参数优化

以医用介入导管接头为研究对象,基于塑料成型理论在Moldflow软件中进行导管接头模流分析,通过正交实验极差分析,确定了注塑工艺参数对导管接头缩痕指数的影响趋势,得到最佳工艺参数组合。针对实际生产中出现的缩痕缺陷,建立导管接头缩痕指数的BP神经网络参数模型,并用遗传算法进行优化,同时对结果进行仿真模拟,得到缩痕指数为0.0752%,此时的最佳注塑工艺参数为熔体温度238℃、模具温度71℃、注塑压力68 MPa、注塑时间0.61 s、保压压力27 MPa、保压时间24 s,其结果比极差分析法的优化结果(0.088%)减少了14.5%。将遗传算法优化BP神经网络后的注塑工艺参数组合应用于导管接头加工试生产,得到产品外观无明显熔接痕,表面质量良好,满足企业设计要求。     

Computer simulation of the filling process in gas‐assisted injection molding based on gas‐penetration modeling

Gas‐assisted injection molding can effectively produce parts free of sink marks in thick sections and free of warpage in long plates. This article concerns the numerical simulation of melt flow and gas penetration during the filling stage in gas‐assisted injection molding. By taking the influence of gas penetration on the melt flow as boundary conditions of the melt‐filling region, a hybrid finite‐element/finite‐difference method similar to conventional‐injection molding simulation was used in the gas‐assisted injection molding‐filling simulation. For gas penetration within the gas channel, an analytical formulation of the gas‐penetration thickness ratio was deduced based on the matching asymptotic expansion method. Finally, an experiment was employed to verify this proposed simulation scheme and gas‐penetration model, by comparing the results of the experiment with the simulation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2377–2384, 2003     

气辅成型过程气体穿透行为

对气体辅助注射成型过程在不同工艺参数设定下的气体穿透行为进行研究，通过实验对延迟时间、熔体的注射量，以及延迟时间与注射压力间的交互作用对气体穿透长度的影响进行了讨论，并对“无进气点”进行了讨论分析。     

气辅成型过程气体穿透行为与工艺参数优化的试验研究

基于带平板的回形管式气体辅助成型样件对气体穿透行为和残余壁厚与气辅工艺参数的关系进行了研究分析.试验结果表明,气辅工艺参数如气体延迟时间、气体注射压力和熔体预注射量是影响气体辅助成型中气体穿透长度和残余壁厚的重要因素,而各参数间的交互作用致使气体穿透与残余壁厚的变化趋势更为复杂.     

Morphology of gas‐assisted and conventional injection molded polycarbonate/polyethylene blend

The skin‐core structure of the gas‐assisted and conventional injection molded polycarbonate (PC)/polyethylene (PE) blend was investigated. The results indicated that both the size and the shape of the dispersed PC phase depended not only on the nature of PC/PE blend and molding parameters, but also on its location in the parts. Although the gas‐assisted injection molding (GAIM) parts and conventional injection molding (CIM) part have the similar skin‐core structure, the morphology evolution of PC phase in the GAIM moldings and the CIM moldings showed completely different characteristics. In the section perpendicular to the melt flow direction, the morphology of the GAIM moldings included five layers, skin intermediate layer, subskin, core layer, core intermediate layer as well as gas channel intermediate layer, according to the degree of deformation. PC phase changed severely in the core layer of GAIM moldings, as well as in the subskin of CIM moldings. In GAIM parts, PC phase in the core layer of the nongate end changed far more intensely and aligned much orderly than that in the gate end. The morphology of PC phase in the GAIM part molded with higher gas pressure changed more severe than that in the GAIM part molded with lower gas pressure. In a word, PC phase showed more obvious fibrillation in the GAIM moldings than that in the CIM moldings. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3069–3077, 2006     

Hierarchical crystalline structure of HDPE molded by gas-assisted injection molding

To understand the crystalline morphology of the parts molded by gas-assisted injection molding (GAIM), in this work, the hierarchical structures and the crystalline morphology of gas-assisted injection molded high-density polyethylene (HDPE) were investigated. According to the comparison between the results of the GAIM part and those of the conventional injection molded counterpart, it is found that gas penetration can remarkably enhance the shear rate during GAIM process and oriented lamellar structure, shish-kebab structure and common spherulites arise in the skin, subskin and gas channel region, respectively, owing to the different shear rate in these regions. Meanwhile, cooling rate also plays an important role in the formation of the oriented crystalline structure.     

Gas-assisted Injection Molded Polypropylene/Glass Fiber Composite: Foaming Structure and Tensile Strength

Tensile strength of isotactic polypropylene (iPP)/glass fiber (GF) composites and neat iPP molded respectively by gas-assisted injection molding (GAIM) was examined. For comparison, tensile strength of the counterparts, which were molded by conventional injection molding (CIM) under the same processing conditions but without gas penetration, was also examined. Tensile strength of the CIM parts steadily increases with the increase of the GF content. For neat iPP molded by GAIM, as the gas pressure increases the tensile strength increases. However, for the iPP/GF composites, the tensile strength generally decreases when the gas pressure increases. And, at a given content of GF, tensile strength of the parts molded by GAIM is unexpectedly lower than that of the counterparts molded by CIM. At a given gas pressure, the higher the fiber content, the lower the tensile strength. In addition, scanning electron microscope (SEM) results show that foaming structure should be responsible for the poor tensile strength of the composites molded by GAIM. The poor adhesion between the glass fibers and the matrix and the unique properties of the gas used in GAIM process are the substantial factors in the formation of foaming structure.     

基于正交试验的气体辅助注射成型工艺参数优化

以21英寸彩电前壳为例,将Moldflow 2010作为CAE模拟试验平台,以熔体温度、模具温度、熔体注射时间、气体延迟时间、气体压力为关键工艺因素,考察了气体辅助注射成型时制品的翘曲变形量和气体穿透情况.采用正交试验法及极差分析法对Moldflow模拟试验结果进行分析,确定并验证了较优工艺参数组合的正确性.