基于Moldflow的汽车仪表板大型塑件注塑模工艺优化

以大型汽车仪表板塑件为例,采用模流分析软件Moldflow分析了多浇口的最佳浇口位置。以翘曲变形量为主要分析指标建立了正交实验方案,通过分析比对获得了最佳的工艺组合。通过模拟分析,发现翘曲变形量过大和表面有熔接痕是主要缺陷。不均匀收缩、取向效应和冷却不均是导致翘曲变形量过大的主要原因。通过采用顺序阀浇口技术、优化相关注射成型工艺参数以及浇注系统和冷却系统的结构、尺寸,基本消除外观表面上的明显熔接痕,翘曲变形量满足企业生产需求,并最终获得了优化的工艺参数和模具结构。结果表明,采用Moldflow对大型塑件进行计算机辅助工程（CAE）分析可大幅提高塑件的成型质量,有效缩短产品的开发周期,节能减排,降低生产成本。     

基于CAE技术的塑料水杯注射成型分析与工艺优化

以日常生活用品塑料水杯为例,介绍了利用计算机辅助工程(CAE)分析软件辅助设计塑料注射成型过程中的浇注系统和冷却系统。在此基础上,针对初次填充冷却分析后,翘曲变形较大的问题,提出以翘曲变形结果为优化指标,保压时间、保压压力、模具温度三个工艺参数作为关键因素进行正交试验,从而确定各因子对产品翘曲变形的影响程度。最后,结合实际,选出一组最佳工艺参数,达到提高注射成型效率的目的。     

基于Moldflow的某气象监测装置端盖注塑分析与优化

以某气象监测装置为例,运用Moldflow软件,在模具设计前对其端盖进行注塑成型的模拟以及结果分析。通过软件的浇口位置分析功能确定了最佳浇口位置,分析初始方案下塑件成型的主要缺陷,并确定塑件成型工艺方案。所涉及的塑件容易产生的主要缺陷是填充不完全及翘曲变形,利用软件对浇注系统和冷却系统工艺参数进行优化,从而减少制品产生的缺陷,同时通过调整保压曲线进一步减少了翘曲变形。确保了该气象装置端盖的浇注精度和浇注质量。     

基于正交试验与CAE模拟的烟雾报警器外壳翘曲优化分析

利用CAE及Moldflow软件对烟雾报警器外壳模型进行浇注系统以及冷却系统的建立,基于正交试验与CAE模拟技术对烟雾报警器外壳模型进行翘曲优化分析,产品的翘曲变形主要由于收缩不均引起,初始翘曲变形量为0.572 0 mm。各工艺参数对翘曲变形量的影响程度最大的为溶体温度,其次为保压压力、保压时间、冷却时间,最小为模具温度。在熔体温度220℃、模具温度60℃、保压压力140 MPa、保压时间10.0 s、冷却时间30 s的工艺参数设置下,产品翘曲变形量为0.183 0 mm,翘曲变形量最小,与初始翘曲变形量相比降低68.01%,产品精度显著提高。     

模流分析在电饭煲上座注塑模设计中的应用

基于计算机辅助工程(CAE)技术设计了电饭煲上座注塑模。利用Moldflow软件对熔体充填型腔进行了模拟。基于浇口位置分析设计了合理的浇注系统;通过成型窗口分析确定了最佳工艺参数:模温50℃,熔体温度240℃,注射时间1.5 s;根据塑件结构建立了合理的冷却系统。通过流动分析、冷却分析及翘曲分析预测了填充质量及可能产生的熔接痕、气穴等缺陷,分析了冷却不均、取向效果及材料收缩3个因素引起的变形量,发现材料收缩是引起翘曲变形的主要原因;最后设计了模具总体结构。结果表明,通过模流分析技术的应用可以提高模具设计的合理性及效率,优化工艺参数,提高产品质量。     

基于Moldflow的肥皂盒注塑模具设计北大核心

以一种聚丙烯沥水长方形肥皂盒为例,结合实际情况,对其浇注系统和冷却系统进行初步设计,通过分析肥皂盒的充填过程,优化浇注系统的流动不平衡缺陷,并利用Moldflow软件对肥皂盒塑件进行流道分析。结果表明:优化后的浇注系统和冷却系统均设计合理;由翘曲变形分析可知,收缩不均对塑件变形影响最大,但变形量均在允许范围内;最后,通过对模具分型面、型芯、型腔、推出机构和模架结构等进行合理设计,得到一整套符合实际生产需求的肥皂盒注塑模具。     

基于Moldflow的喇叭罩注塑模具优化分析

利用Moldflow软件对喇叭罩进行模型建立、网格划分和修改,设计分析最佳浇口位置与冷却系统,并通过制品充填时间、气穴、熔接痕的模拟,对塑件的流动性进行分析。同时,进一步分析了形成翘曲变形的原因,得出收缩不均是形成翘曲的主要因素,调整保压曲线对成型工艺参数进行优化,减少试模次数,提升产品质量。     

基于Moldflow的汽车手套箱箱盖的翘曲变形优化分析

为了预测和降低翘曲风险,在模具设计及制造前,利用Moldflow模流分析软件对产品的翘曲变形进行分析及预测。以汽车手套箱盖的翘曲变形量为质量评价目标,针对翘曲变形产生的3个主要因素（取向效应、冷却不均、收缩不均）逐一进行优化。结果表明,在模具结构方面,调整浇口位置和调整冷却系统使翘曲变形量明显降低;在工艺方面,对熔体温度、模具温度、保压压力、保压时间4个工艺参数进行正交试验,通过极差分析,得出各个工艺参数的影响程度及最佳工艺方案,对此方案进行保压曲线优化后,翘曲变形量进一步降低,形成最终方案;计算机辅助工程（CAE）数值模拟对模具设计有很强的指导性作用,可大大减少修模次数并降低模具报废的机率。     

基于Moldflow超声波探测器外壳注塑模具优化设计

超声波探测器是停车场智能化改造的重要设备之一,其外壳一般通过注塑成型加工而成,对于保护内部超声波传感器不受外界冲击及干扰起着十分重要的作用。利用计算机辅助技术,基于Moldflow软件,设计了某型号超声波探测器外壳注塑模具的浇注系统和冷却系统,分析了熔体在型腔内部的流动性和模具的翘曲变形,采用正交试验法,利用极差数据分析法和方差数据分析法,探究了影响翘曲变形的关键因素,并对注塑工艺参数进行了优化。试验结果表明:充填压力是影响超声波探测器外壳翘曲变形的主要因素;优化后的工艺参数使由所有效应、冷却不均效应、收缩不均效应造成的最大翘曲变形量分别为降低了22.41%、27.21%和22.48%,使流动不平衡性降低了1.41%,相比初始参数有了显著改善。     

基于计算机辅助技术的防尘摄像机注塑模具优化分析

以某型号防尘摄像机为实例,分析塑件的结构,选择合适的成型材料,设计模具的浇注系统和冷却系统。基于模流分析技术,对塑件的翘曲变形进行分析,产生翘曲变形的主要原因是收缩变形,翘曲变形最大为0.955 7 mm。通过极差和方差分析,得出影响翘曲变形最明显的因素是熔体温度,以及最优的工艺参数:熔体温度200℃、模具表面温度70℃和充填压力96 MPa,此时的翘曲变形量为0.832 5 mm,相比初始工艺参数翘曲变形降低12.89%,塑件翘曲变形量明显降低,满足成型的需求。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料，介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比，介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序，对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.