逆向工程在塑料产品及其模具设计中的应用

介绍了一种基于逆向工程技术的塑料产品模具数字化设计方法,分析了塑料产品在逆向造型过程中应遵循的基本原则和要点,然后以某车灯反射器为例对其进行了说明。此过程中,先借助三维激光扫描仪采集了反射器曲面的点云数据,然后利用Geomagic Studio软件进行了数据处理和快速曲面重构,最后将曲面模型导入Pro/E软件中进行反射器的三维模型重建并分模,形成模具型腔。实践表明,此方法能够实现注塑模的快速设计,缩短产品的开发周期,尤其对曲面形状复杂、缺失原始几何数据等产品的设计与制造具有参考意义。     

基于Imageware和MoldfloW的后视镜逆向设计与注塑成型模拟分析

简述了逆向工程的设计过程和方法以及Moldflow在注塑成型分析中的应用.利用Imageware软件对测量设备得到的摩托车后视镜点云数据进行处理、曲线拟合与曲面重构.然后将反求模型导入Moldflow/MPI软件中进行注塑模拟仿真及工艺优化,并进一步优化模具结构指导生产.通过逆向设计和Moldflow结合,可以快速获得高质量的塑件产品,从而提高产品和模具的研发速度.     

基于Imageware和UG技术的逆向曲面重构及模具设计方法

采用逆向辅助技术,对一款结构较为复杂的某制品进行快速而精确的模具设计,先利用三维激光扫描仪得到其点云数据,再使用Imageware软件进行点云处理和曲面重构,然后在UG软件中进行三维造型及相应的优化设计,最终以最合理的设计方法得到完整的模具图,用于后续的模具加工与生产。结果表明,此方法既能提高模具及产品的精度,又能大大缩短设计周期,节约成本。尤其对一些具有结构复杂、曲面要求高或者缺失原始几何数据的制品,此方法更能发挥其优势。     

基于RE的安全帽三维造型及其注塑模设计

根据逆向工程对实体安全帽进行三维数据采集,得到点云数据,运用Imageware以及SolidWorks软件对点云进行处理以及三维模型的重建,通过快速成型机3D打印出实体。基于Moldflow软件平台对三维模型进行流道模拟充填分析,并在此基础上设计注塑模具。逆向工程用于模具制造,大大缩短了产品的设计生产周期,降低生产成本,提高设计精度。     

基于塑料产品快速开发的逆向工程

针对塑料产品开发中设计周期长、设计复杂和模具一次试验成功率低的现状,在模具CAD/CAM逆向工程的基础上,探讨了塑料产品快速开发的方案,并对曲面重构、三维建模、产品再设计等关键技术作了初步研究。实例证明:在塑料产品开发中利用数字化逆向工程技术,可大大缩短塑料产品的开发周期,对快速响应市场产生显著效果。     

基于RE/RP技术的儿童牙刷柄快速设计开发

以卡通牙刷柄为研究对象,阐述了逆向工程的概念。并且应用三维扫描仪结合逆向工程(RE)技术对该巧虎产品进行数据获取、数据处理、曲面重构与造型优化,利用Geomagic DesignX实现了卡通牙刷手柄的复杂曲面设计。最后应用快速成型技术对模型堆积制造,加工出样件。此过程验证了RE技术和快速成型(RP)技术在卡通牙刷手柄中的有效性与实用性,构建的模型有利于形象观察与修改,大大缩短了产品开发设计及制造周期。     

基于UG的笔记本外壳注塑模设计及工艺分析

采用计算机辅助软件UG和有限元分析软件Moldflow相结合的方法进行笔记本外壳的注塑模具设计,创建了笔记本外壳的三维实体模型和模流分析有限元模型,最后采用UG软件创建了经过优化和调整的注塑模具实体模型,是当前CAD/CAE技术中缩短开发时间,提高设计质量的有效手段之一。     

复杂曲面玻璃制品的逆向设计研究

针对玻璃制品的特点,以某玻璃工艺品鼠标的曲面造型设计为研究对象。通过三坐标测量机的非接触测量获取零件表面的点云数据,并利用Imageware软件对测量数据进行处理,采用基于NURBS曲面重构理论进行鼠标造型覆盖面重构,最终实现了鼠标的曲面重构。与传统的玻璃造型设计方法相比,该方法对缩短产品研发周期、快速响应市场有显著效果。     

基于逆向工程和Moldflow的玩具兵人躯干设计及注塑成型预测研究

逆向工程技术在注塑模具设计中的应用十分广泛,以玩具兵人为例,构建玩具兵人躯干的概念设计模型,应用激光扫描仪进行数据采集,采用逆向工程软件及UG三维造型软件进行产品的曲面重构反求出产品的工程模型,进一步完成产品的结构设计。然后采用Moldflow对材料为ABS的玩具兵人躯干前盖的注塑成型过程进行了预测,包括浇口位置、充填时间、翘曲变形的大小与产生原因、熔接痕位置、气穴等,以期为进一步设计及改进模具结构提供参考。预测结果主要是翘曲变形,产生翘曲的主要原因是材料在冷却过程中收缩不均所致,通过改进模具结构、改善成型工艺条件等方法来减小收缩,从而减小翘曲变形。试模结果和CAE预测吻合较好,且满足质量要求。     

基于Geomagic软件的汽车缸盖气道芯子逆向工程设计

针对汽车缸盖气道芯子的特点,利用光栅结构光扫描仪,测出点云数据。然后将测量的点云数据用Geomagic软件进行各项优化处理,创建多边形网格及NURBS曲面,然后利用CATIA软件的曲面造型功能,做出CAD模型。实现了汽车缸盖气道芯子由实物到点云、再由点云到三维模型及模具的快速逆向设计。     

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.