打开APP
userphoto
未登录

开通VIP,畅享免费电子书等14项超值服

开通VIP
『工艺的秘密. 材料特辑2』塑料的生产和对环境的影响(中英)




塑料工艺提示

NOTES ON MANUFACTURING


不同分子结构的塑料有着不同的生产方式。热塑性塑料需要加热至熔融状态方可塑形,因此他们的原材料(母料)都是颗粒状,而类似热成型(压塑或吸塑等)需要在板状或者片状的塑料上进行加工(板状或片状的塑料也是通过颗粒状的塑料母料加工拉伸塑形),不过这一前期加工会增加成本。热塑性塑料也同样适用于并纺纤维赫塑料薄膜的制作。


Plastics with different molecular structures lend themselves to different methods of manufacture .  Thermoplastic are shaped by heating them until they are soft or liquid enough to be formed . So they are generally supplied in granulated form . Processes such as thermoforming require sheet materials , which are extruded from granules . This increases the material costs due to the extra price that is required. Thermopile are also  available as drawn fire and blown film.





塑料不同的结晶度同样也会影响生产工艺。例如,非结晶塑料无法实现像结晶塑料制品那样尖锐锋利的细节,因此他们更适用于热成型工艺,因为他们在一定温度内会保持松软和熔融状态。然而,结晶塑料再加热后流动性很强,所以更适用于制作薄壁和复杂的造型。由于以上二者的差异,不是所有的热塑性塑料兜兼容,尤其当设计师利用多点注塑和塑料焊接来加强材料之间连接的时候,需要格外注意。但是材料之间的不可兼容性有的时候也很有用,例如可作为脱模剂和润滑剂。


Different amounts of crystallinity also affect processing. For example , amorphous materials do not have a sharp melting point like crystalline materials . Therefore , they are more suited to processes like thermoforming because the material stays soft and formable over a wider temperature range . in contrast , crystalline materials will flow more easily in the mold due  to their sharp melting point and are therefore more suitable for thin wall sections and complex features. Due to their different properties , not all thermoplastics are compatible care must be taken when using processes such as multi-shot injection molding and plastics welding to ensure a strong inter material bond material incompatibility is sometimes used as an advantage , for example , in release agents and lubricants.





热固性塑料在模具中成型。 某些甚至可以在室温下加工成型,例如聚酯,环氧树脂和聚亚安酯,原材料是液体状态,并混合催化剂和加固剂,可以通过注射和浇灌的方式进入模具。或者,粉末状和固体状的热固性塑料母料可以通过加热来形成分子之间的交叉连接。


Thermosets are cured in the mold. Some are engineered to cure at room temperature such as polyester and epoxy,and polyurethane. These are supplied in liquid form and mixed with a catalyst or hardener, they can be poured or injected into a mold. Alternatively , powdered , liquid or solid thermosets are heated in a mold to trigger the formation of cross-links. 





有机塑料的加工方式横跨了热固和热塑性塑料:他们可以通过热塑性塑料加工方式成型,但是正果过程是不可重复的(不可逆的)。CA和PLA的成型方式和热塑性塑料大同小异。例如,有些食物的包装就是通过压制淀粉粉末成型。


The production of bioplastics crosses over with both thermoplastics and thermosets : they can be molded with thermoplastic technology . But the process may not be repeatable . Cellulose acetate ( CA ) and Polylactic acid are processed using similar techniques to thermoplastics . For example , Potatopak food packaging is produced by compression molding powdered starch.






材料的发展

MATERIAL DEVELOPMENTS


塑料产业一直在发展,新的混合剂,化合物和添加剂的研发给塑料产业提供了很多潜在机会,从而提升生产质量并降低成本。快速成型技术的发展也革新的设计过程,除了把成品误差控制在几微米之间外,也可以实现传统塑料工艺不能实现的产品造型。某些塑料,例如环氧树脂,填充尼龙,玻璃和碳填充尼龙,这些塑料之前的生产方式一直和大批量生产级塑料一样(如ABS和PMMA)。然而,如今已经这些塑料已经可以实现小批量和单件生产,当然也包括产品手板。


The plastics industry is constantly evolving . New blends , compounds and additives are being developed to create opportunities , improve performance and reduce cost . Rapid prototyping has revolutionized the design process . not only are models accurate to within a few microns , but also this process is capable of producing plastic parts that cannot be made in piece in any other way . Plastics available include epoxy resin , unfilled nylon , and glass or carbon filled nylon. Traditionally these materials have been engineered to mimic production grade plastics such as acrylonitrile butadiene styrene and poly methyl methacrylate acrylic. Recent developments have made it suitable for direct manufacturing low volume parts and one offs as well as pre - production models.





导电多聚物融合了塑料工艺和金属导电性的优势,例如:电路打印,发光塑料和导电活性多聚物。电路打印是在塑料上进行的,这种新兴科技可以改变我们的阅读方式;依靠传统非结晶硅显示的硬质玻璃背板已经被塑料取代,意味着显示屏变得更加轻薄;通过电发光原理的发光多聚物,当电流经过多聚物时可以自发光,如今已经可以放射不同颜色的光,从而实现了薄板显示屏。


Conductive polymers combine the benefits of plastics technology with the conductivity of metals . Developments include printed circuitry , light emitting plastics and electroactive polymers. Printed circuitry is used in plastic. This technology has the potential to revolutionize the way we read books . reports and even the morning paper. The rigid glass back pane required for conventional amorphous silicon-based displays has been replaced by a plastic . which means the display can be flexible thinner and more lightweight. Light emitting polymers are based on the principles of electroluminescence. Polymer lights up when an electrical current is passed through it it is now possible to emit different colours of light to produce very thin flat panel displays.








环境影响

ENVIRONMENTAL IMPACTS


为了降低塑料对环境的影响,人类也做了很多努力尝试。例如,一次性塑料现在由添加的生物活性添加剂的热塑性塑料制成,热塑性的循环利用率很高,有些甚至是100%的可循环材料。设计师的责任应该是确保塑料可以在污染最小的情况下被回收,尽量使用单中塑料制作产品部件,时刻把可回收和可拆卸带入自己的设计步骤中。


There have been many develop that reduce the environmental impacts of plastics . For example , many disposable products are produced in bioplastics thermoplastic with bioactive additives. Thermoplastics are very efficient to recycle there is minimal degradation of quality and some products are from 100 % recycled materials. the role of the designer is to ensure that plastics can be recycled with minimal contamination therefore parts should be designed in a single material if possible and with recycling and disassembly in mind.




提起污染,塑料常常因为需要千年来完全降解而被人诟病,有一些塑料甚至在生产中就对环境有伤害,例如:聚酯,含有苯乙烯的环氧树脂,酚脂。这些都是有污染和一定毒性的。


This book cannot avoid mentioning the negative environmental impacts of certain plastics not only do they take thousands of years to biodegrade, some are also harmful in production . For example , polyester and epoxy contain styrene ,phenolic resin .these chemicals are known pollutants and are toxic.





有一些塑料被认为是不稳定的,具有致癌性的有机化合物。在生产过程中,一定要防止吸入人体。有一些塑料在使用周期里甚至会释放有害气体,降低空气质量并污染环境。


Some are referred to as volatile organic compounds and are known carcinogens . during production care must be taken to avoid inhaling them , and some plastics will continue to off - gas during their lifetime and so both reduce indoor air quality and pollute the atmosphere.









相关推送



10种塑料成型工艺





本站仅提供存储服务,所有内容均由用户发布,如发现有害或侵权内容,请点击举报
打开APP,阅读全文并永久保存 查看更多类似文章
猜你喜欢
类似文章
【热】打开小程序,算一算2024你的财运
23张动图了解各种塑料生产工艺,塑料没有那么白
这些注塑动图让你分分钟搞定所有塑料工艺!
精选论文|基于 Moldflow 的揭盖式洗发水瓶盖注塑模具设计
挤塑
Clothing fabric
全面解析3D打印FDM技术
更多类似文章 >>
生活服务
热点新闻
分享 收藏 导长图 关注 下载文章
绑定账号成功
后续可登录账号畅享VIP特权!
如果VIP功能使用有故障,
可点击这里联系客服!

联系客服