分层注塑厚壁光学透镜模具设计及其模拟分析

设计一种退芯模具,用以实现光学厚壁透镜的分层注塑,并使用Moldflow进行数值模拟分析;以三棱镜作为光学厚壁透镜制品代表,聚甲基丙烯酸甲酯(PMMA)为原材料,以光的相移角度为制品质量参照,模拟分析分层注射对注塑光学厚壁透镜制品光学质量的影响规律。结果表明,不同的分层工艺方式对注塑光学厚壁透镜的光学质量有着明显差异。通过模拟实验得到在该双层注射三棱镜模型中,层与层之间5 s的间隔、外层薄内层厚、先外后内包裹注射的分层方式最佳,层厚分布在各项工艺方式中对注塑效果影响最大,通过分层注射,可以减小光学厚壁透镜的平均体积收缩率。     

聚碳酸酯厚壁制品的注射成形

分析聚碳酸酯的工艺特性，针对特定的厚壁制品，要做好材料的选择和处理、设备的选择、模具的设计、并设置合理的工艺参数和后处理。     

注塑模具型腔壁面疲劳应力开裂的研究

研究具有局部凹陷结构的板状制品注塑模具型腔的熔体充模过程，得出导致型腔壁面疲劳应力开裂的型芯凸块侧推力计算公式。指出采用合理的成型工艺条件、提高模具材料性能和模具的热处理质量等措施只能起到阻缓此类注塑模具型腔壁面疲劳应力开裂产生的作用，而具有局部凹陷结构的板状制品注塑模具型腔壁面疲劳应力开裂的根本解决措施是合理选择进料口位置，或注塑制品结构尽量避免采用具有局部凹陷的结构形式。     

如何选择脱模剂

注塑制品脱模顺利与否主要取决于成型模具结构的合理设计和注塑制品工艺参数的合理选择。在注射成型生产中，由于工艺条件的波动，有时也会出现制品脱模困难的现象。为了保证制品注射成型的生产顺利进行，避免因制品脱模困难而造成制品生产周期延长，成型模具的型腔表面要喷涂或擦涂一层脱模剂。     

基于响应面法的注塑件残余应力优化

考虑模具温度、熔体温度、保压压力和保压时间等4个注塑工艺参数,利用响应面法进行实验设计,通过Moldflow注塑模拟软件对所设计的实验进行有限元分析,得到注塑工艺参数对制品残余应力值的影响.结果发现4个工艺参数中,熔体温度和保压压力对注塑制品残余应力值的影响极为显著,而模具温度和保压时间对制品残余应力值的影响则不显著.文章的研究结果为注塑工艺参数的调整、选取和优化,为获得残余应力值最小的优质塑料制品提供了方法和思路.     

基于响应面法和CAE的注塑件翘曲变形优化

考虑模具温度、熔体温度、保压压力和保压时间等4个注塑工艺参数,利用响应面法进行实验设计,通过CAE软件对所设计的实验进行有限元模拟分析,得到注塑工艺参数对制品翘曲变形的影响。结果发现4个工艺参数中,保压压力对制品翘曲变形的影响极为显著,其次是模具温度,而熔体温度和保压时间对制品翘曲变形的影响不显著。各参数对翘曲变形的影响不是简单的线性关系,有极强的非线性耦合作用。文章的研究结果为合理选取和优化注塑工艺参数以获得翘曲变形量最小的注塑制品提供了方法。     

模内贴标注塑模具的设计及成型要点

综述了模内帖标(IML)技术的基本原理,并对IML注塑模具的制品结构、模具分型面、浇口等设计与普通注塑模具的设计进行了对比。结果表明:用IML注塑模具生产的制品要求脱模角度更大,外轮廓圆角半径至少0.2 mm,制品收缩率相对较小,取0.3%为宜;为防止注射时将标签上的油墨冲开,IML注塑模具的浇口处进料采用潜伏式;标签拾取主要采用静电吸附,并选择与制品收缩率相近的标签材料。最后总结了IML注塑模具的成型要点,并给出了成型标签的技术要求。     

基于Moldfl ow的注塑光学厚壁透镜工艺优化

利用Moldflow数值模拟分析并结合正交试验法,以光学厚壁透镜制品的光相移角度(双折射)为参照,对注塑光学厚壁透镜的工艺条件进行优化,且模拟分析了分层注射对注塑光学厚壁透镜残余内应力的影响规律。结果表明:优化注射工艺参数能够降低制品的残余内应力,减小光学透镜的双折射缺陷,其最优注射条件为:模具温度90℃、熔体温度240℃、注射时间9 s、保压压力60 MPa。此外,分层注射可以有效减小制品的残余内应力,并使其分布更加均匀,该效果与分层方式以及层厚、层数有关。     

巧用浇口解决注塑制品成型缺陷

通过对摩托车主梁上护盖制品材料、形状、成型缺陷等进行综合分析,合理地选择注塑模具的浇口位置和形式,解决了实际生产中的成型困难和制品缺陷,提高了制品质量。     

注射成型工艺参数对注塑制品翘曲变形的影响研究

采用Taguchi实验设计技术设计了L9(34)实验矩阵进行实验,运用标准变量分析技术分析了模具温度、熔体温度、注射速率、保压压力等工艺参数对注塑制品翘曲变形的影响,预测最小翘曲变形并优化工艺参数。研究表明,所选择的工艺参数对X、Y、Z方向上的翘曲变形有不同程度的影响。通过优化工艺参数,可使所需方向上的翘曲变形最小,进而提高注塑制品的质量。     

聚碳酸酯的注射成型特点

介绍了聚碳酸酯(PC)注射成型的工艺特点,着重分析了PC注射成型前的注意事项及成型工艺条件(温度、压力、时间)的正确选择。     

The effect of injection molding process parameters on mechanical and fracture behavior of polycarbonate polymer

In this work, the mechanical and failure behavior of injection molded aviation standard optical grade polycarbonate (PC) was investigated through uniaxial tensile testing. The effect of different injection molding process parameters including injection velocity, packing pressure, cooling time, mold temperature, and melt temperature were determined to observe their effect on yield and postyield behavior of PC. Out of these examined parameters, the mold and melt temperature show significant effect on mechanical behavior of studied polymer. The yield and flow stresses in polymer increase with the increase in mold and melt temperature during injection molding. However, other process parameters i.e., packing pressure, injection velocity, and cooling time showed little effect on mechanical performance of the polymer. The molded specimens were annealed at different temperatures and residence time to evaluate its effect on mechanical behavior and fracture morphology. The yield stress increases gradually with the increase in annealing temperature and time. The annealing treatment also changed the failure mode of PC specimens from ductile to brittle. In addition to process parameters, the effect of increased loading rate was also undertaken which shows substantial effect on mechanical and failure behavior of PC. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44474.     

树脂传递模塑工艺中工艺参数对树脂-纤维界面的影响

本文系统研究了工艺参数对由树脂传递模塑成型的复合材料的拉伸强度和树脂-纤维界面的影响.这些参数包括注射压力和模腔/纤维毡的温度.在较低的注射压力和较高的成型温度下,纤维得到良好的浸润和粘结,成型复合材料的拉伸强度也较高.     

直板手机镜片注射模设计

直板薄型手机镜片的美观要求很高,最好采用注射成型的方法来代替传统的型材切割加工方法。目前手机镜片注射成型难点主要是注射模具的设计。镜片注射模设计的关键在于浇注系统、排溢系统、模具刚度的设计及模具材料的选择、热处理。针对镜片薄形成型、塑料材料透明等不利于注射成型的特点,选择适当的浇口位置和浇口形式。根据产品的尺寸和结构,合理设计浇口的尺寸,并结合模具的冷却系统和推出机构的设计,实现和加强模具的排气功能。必要时采用CAE软件验证设计,保证镜片的质量。     

注射成型保压冷却过程的控制及对策

本文研究了注射成型保压冷却阶段与制品质量的关系，运用ＴａｉｔＰＶＴ方程和等密冷却原理，建立了此阶段聚合物的压力、温度、时间、模温及型腔厚度的关系模型，提出了控制制品质量和提高生产率的简便而又行之有效的办法。     

Evaluation of processing effects in injection‐molded amorphous and crystalline thermoplastics using an excimer laser

The ablation behavior of amorphous [polystyrene (PS), polycarbonate (PC)] and crystalline [PET, glass‐filled poly(butylene terephthalate) (PBT)] polymers by 248‐nm KrF excimer laser irradiation were investigated for different injection‐molding conditions, namely, injection flow rate, injection pressure, and mold temperature, as a possible method for evaluating processing effects in the specimens. For this purpose, dumbbell‐shaped samples were injection‐molded under different sets of processing conditions, and weight loss measurements were carried out for the different injection‐molding conditions. Some of the crystalline (PET) samples were annealed at different annealing times and temperatures. For PET, the weight loss decreased with increasing mold temperature and remained insensitive to injection flow rate. Annealing time and temperature significantly reduced weight loss in PET. For PBT, the weight loss due to laser ablation decreased with increasing material packing due to pressure, and it also showed some sensitivity to flow rate variation. The major effect was seen with glass‐filled PBT samples. The weight loss decreased drastically with increasing glass fiber content. Laser ablation allowed us to observe process‐induced fiber orientation by scanning electron microscopy in PBT samples. For PS and PC, the weight loss increased with increasing injection flow rate and mold temperature and decreased with increasing injection pressure. The position near the gate showed higher ablation than the position at the end for all the conditions. A decrease in the material orientation with injection speed and mold temperature led to an increase in the weight loss, whereas an increase in the injection pressure, and consequently orientation, led to a lower weight loss for PS and PC. Higher residual stress samples showed higher weight losses. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 2006     

Effect of molecular weight and molding conditions on the replication of injection moldings with micro‐scale v‐groove features

Injection molded optical plastic parts require accurate replication of micro‐scale features. The effects of melt viscosity and molding conditions on replication of microscopic v‐groove features in injection molded parts were examined for PC with different molecular weight. The micro‐scale feature size was a continuous v‐groove with 20 μm in depth and 50 μm in width. For injection molding conditions, melt temperature, mold temperature, injection velocity and holding pressure were varied in three levels. As the result, the mold temperature had significantly affected replication for all polymers with different molecular weight. Additionally, the molding conditions that lower melt viscosity led to improved replication. In the case of polymer with high molecular weight, the viscosity decreased with increasing melt temperature. It has been found that high replication of micro‐scale features could be achieved by higher mold temperature and higher melt temperature even with high viscosity PC. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

可熔型芯注射模塑新工艺

阐述了用可熔型芯注射成型热固性塑料的工艺过程和原理、工艺控制要点。用低熔点合金制成可熔型芯替代注射模具中的抽芯部件,在升温固化制件的同时熔化可熔型芯,用熔芯代替抽芯取出制件。通过合理控制成型过程各阶段的温度和时间,将制件的热固化过程、可熔型芯的熔化与再浇铸过程结合在一起同时进行,既实现了无法抽芯的中空异形制件的整体成型,又简化了模具结构,同时充分利用了热能、降低了成本、提高了生产效率。     

热压注机喷浆问题的分析及采取的措施

简要介绍了热压注机的原理性结构及工作原理，着重从注浆模的受力着手分析了热压注机喷浆问题的原因，并提出了解决方法。另外，对热压注机的工作原理作了进一步探讨，并提出了一些新的设计思路。     

聚碳酸酯注射成型制品力学性能的Taguchi分析

采用Taguchi分析方法考察了注射成型工艺参数对聚碳酸酯(PC)力学性能的影响。结果表明,注射成型工艺参数对PC的拉伸强度影响较大,对弯曲强度和冲击强度影响较小;方差分析结果表明,模具温度对拉伸强度的影响最大,注射压力和冷却时间次之,熔体温度的影响最小;模具温度降低,熔体冷却固化层厚度增加,取向程度增大,拉伸强度增加;同时结果表明Taguchi分析方法可以准确地对优选出的成型工艺制备的PC试样的拉伸强度进行预测,其预测值与测量值的偏差仅为0.75%。