色拉油瓶盖注塑模具设计

分析了色拉油瓶盖侧面多处带有凸起、凹槽及内螺纹的成型工艺特点,介绍了一种成型该塑料件的注塑模具的设计方法。首先确定了模具的三板模结构,阐述了模具通过开模机构和二次推出机构,利用塑料件本身的弹性变形实现塑料件强制脱模。     

机器人关节轴螺纹自动脱模注塑模设计

给出了机器人关节轴液压油缸自动脱螺纹的注射模具详细结构,该模具采用点浇口转侧浇口浇注系统,通过采用"液压油缸+齿条+齿轮"的组合传动方式实现螺纹自动脱模,通过采用斜滑块内侧抽芯和外侧抽芯实现成型塑料件的侧向抽芯。通过采用小拉杆、弹簧和限位螺钉的内置定距分型机构保证模具的开模顺序和开模距离。模具在定模板、动模板和斜滑块上均设计了冷却水道。模具成型零件均采用活动式结构,导向定位机构采用12支导柱,成型塑料件最后由推板推出。模具结构复杂,动作繁多,投产后各机构运行顺畅,成型塑料件质量稳定。     

双联圆柱直齿轮注塑模具设计

针对聚甲醛(POM)塑料双联圆柱直齿轮的精度和外观质量要求,通过对塑料件结构和成型工艺特性分析,设计出了一套注塑模具.型腔、型芯采用组合式结构,设计了型芯安装定位杆以保证嵌件在型腔中的位置.模具采用点浇口浇注形式,推出机构采用推管推出.并对注射成型工艺参数进行优化,该模具可以实现自动化生产,提高产量.     

台灯底座下盖注塑模具设计

分析了台灯底座下盖塑料件的产品特点,确定了台灯底座下盖注射成型工艺,在此基础上,确定型腔数量及排列方式,设计了模具结构,优化了模具型芯、型腔、冷却系统等的设计,并重点介绍了主流道、衬套、推出机构等典型零部件的设计,其设计思路对相关塑料件的设计具有一定的借鉴意义。     

移动硬盘盒精密热流道注塑模具设计

热流道注塑模具在模具行业中的应用越来越广泛,采用热流道系统不仅可以保证塑件质量、提高材料的利用率,还能显著提高塑件的生产效率。通过对移动硬盘塑料件的结构及成型工艺特点进行分析,设计了移动硬盘塑料件热流道注射模具,重点对热流道模具热平衡计算和热流道浇注系统进行了分析计算,模具采用单点热流道、一模两件潜伏式浇口、外滑块抽芯机构及斜推杆抽芯成型倒扣设计。实践证明,该移动硬盘塑料件模具设计结构合理,在提高塑料件成型质量的同时,提高了材料的利用率及生产效率,为同类结构特点的热流道注塑模设计提供了参考。     

带有螺纹塑料件的自动退扣模具设计

通过分析内、外表面带有螺纹的塑料件结构,阐述带有螺纹的塑料件的设计特点,对分型面的选择、型腔数目的确定、浇注系统以及推出机构的设计进行了讨论.确定推出机构采用齿轮、齿条自动退螺纹的模具结构.此模具结构简单,成本低,可确保产品质量,适用于批量生产.     

汽车雾灯装饰盖倒装双色注塑模设计

针对某车型雾灯装饰盖双色塑料件,采用倒装模的模具方案,设计了一副双色注塑模具.该双色注塑模第一射注射成型双色塑料件的硬胶产品,第二射注塑双色塑料件的软胶产品.为实现该双色塑料件的结构成型,在双色模的定模侧和动模侧分别设计了顶出系统和同步拉钩机构.在双色模具注塑完成进行开模运动过程中,利用同步拉钩机构驱动硬胶模具和软胶模...     

塑料盖板热流道注塑模具设计

在塑料模具设计中采用热流道系统不仅可以保证塑件质量,还能显著提高材料的利用率。通过对塑料盖板塑料件的结构及成型工艺特点进行分析,设计了塑料盖板热流道注塑模具,重点对热流道浇注系统和流道板的热膨胀补偿进行了分析计算,模具采用单点偏心热流道设计、动模液压顶出机构设计、外滑块抽芯机构及斜推杆抽芯成型倒扣设计。实践证明:该模具设计结构合理,在提高塑料件成型质量的同时,保证了产品质量,提高了生产效率,为同类结构特点的注塑模设计提供了参考。     

定模推出的塑料壳盖注塑模设计

针对塑料件表面质量要求较高的特点,设计出一款定模推出的倒装式注塑模具,并详细介绍了其工作过程.该模具采用了嵌套式连接拉杆机构,通过连接拉杆及其外套的相对运动实现了多分型面长距离分型情况下的定模推出.实践证明,该模具结构合理、紧凑、动作可靠,塑料件成型质量符合要求.     

汽车副仪表板注塑模设计

用CAE分析软件(Moldflow)对塑料件进行模流分析,选择针阀式热流道、搭接式浇口进胶方式,采用分体式滑块结构减少加工量和加工变形,在大滑块上设计弹块和成型拉块辅助脱模机构,保证产品不粘滑块,可以使产品在向外变形状态时顶出,解决了塑料件侧壁脱模时倒扣的干涉问题。设计了大滑块与型芯及型腔的定位结构,模具结构可靠,注塑产品成型完整,脱模顺利。采用模具快速接插接头系统实现模具注塑装夹时的快速切换,提高了生产效率。在汽车副仪表板模具的开发方面,有一定技术参考价值     

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.     

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.     

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。