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。     

逆向工程技术在塑料模具设计中的应用

介绍了一种基于反求工程技术的注塑模具快速设计方法,并以手电钻外壳为例对其流程进行了详细说明。在此过程中,先利用三维激光扫描仪采集了电钻外壳曲面的点云数据,并对数据进行了拼合、去噪和重采样等处理,然后应用Pro/e软件的逆向造型功能重构了电钻壳的CAD模型,最后利用重构完成的三维模型,设计了电钻外壳的注塑模具。结果表明,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极具潜力。     

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。     

基于逆向工程的产品设计研究

工程生产中的产品设计一般采用正向工程设计,主要根据产品的功能与用途提出构想思路,借助计算机三维软件建模,最后通过技术手段加工成型。针对其设计方法存在的设计周期较长问题,提出一种逆向工程设计思维并通过鞋底的逆向工程设计实验进行验证。首先针对鞋底的结构进行研究分析,并用三维扫描设备获取实物模型表面的点云数据,并在geomagic studio软件平台上处理点云数据得到目标曲面的NURBS曲面数据,然后利用geomagic studio软件与UG软件的交互功能将数据导入到UG中进行正向建模工作,在正向建模过程中借助软件对其结构进行分析并对存在的问题进行结构优化处理,实现逆向工程设计模仿之外的再创新意图,最终利用3D打印技术得到升级产品的实物模型。通过实例的结果证明,混合建模的设计方法能在保证产品质量的条件下可尽量缩短设计周期,降低研发成本。     

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.     

基于逆向技术医疗外固定支具的设计

现有外固定支具比较笨重,不美观,不透气,与患部不能很好贴合,对康复效果造成影响。采用逆向技术,通过三维扫描仪扫描采集患者患部,获取三维点云数据,对点云数据进行处理得到三维数据模型。利用UG软件进行正向建模设计,根据医生及患者的要求设计出符合人体工程学特性的外固定支具。将逆向与正向建模设计相结合,为个性化医疗外固定支具设计提供一种高效的方法。     

UG在自由曲面产品逆向工程与模具设计中的应用

详细介绍了逆向工程在复合材料头盔设计中的具体应用,包括逆向软件的选取、测绘方法、曲面重构、曲面评价及实体形成的具体思路,成功实现了在UG中头盔的三维自由曲面逆向设计。在三维实体模型的基础上,生成了模具三维结构设计图与二维工程图,为成型加工提供了数据,并提高了设计效率。     

CATIA逆向工程技术在注塑模具设计中的应用

介绍了现代制造业中逆向工程的概念及逆向工程的一般方法和CATIA软件的逆向功能模块,以汽车仪表盘注塑模具为例,说明利用CATIA逆向工程技术设计注塑模具的具体过程,包括点云滤除、网格铺面及网格面修补、创建边界特征曲线、重建曲面、曲面品质分析和建立CAD模型。     

CAD/CAE在安全带护盖支架注塑模设计中的应用

介绍了Pro/E和Moldllow软件在汽车安全带护盖支架注塑模具设计中的应用.运用Moldmow对最佳浇注点进行了分析,采用Pro/E软件建立塑料件实体模型,创建模具体积块,对模具进行了铸模模拟,确保了模具运行可靠.基于模具体积块利用外挂模块EMX4.1进行了模架调用与装配.结果表明,采用三维CAD/CAE技术能直接进行从制品到模具体积块的设计,缩短了产品的开发周期,模具实体感强、质量高,大大降低了模具的设计和制造成本.     

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。