All Composites articles – Page 7
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ArticleA measure of success
Quality inspection in car body construction is moving towards more speed, greater flexibility and the use of intelligent software, writes Judith SchwarzThe automotive industry is placing new challenges on car body construction: more flexible and increasingly complex production processes and systems are required as the number of models grows. Increasingly, ...
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ArticleFord and DowAksa to advance carbon fibre production
US – The two companies are accelerating joint research to develop high-volume manufacturing techniques for automotive-grade carbon fibre, with the aim of reducing vehicle weight and boosting fuel efficiency and performance. They will join the government’s new Institute for Advanced Composites Manufacturing Innovation.The aim of the venture, and the mission ...
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ArticleVW joins new composites institute
US – Led by the University of Tennessee, the 122-member Institute for Advanced Composites Manufacturing Innovation (IACMI) will seek to develop improved composite materials and technologies for rapid roll-out across the automotive, wind turbine and compressed gas storage industries. IACMI was given national institute status by the US Department of ...
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ArticleNot so Far-fetched?
New technologies are claimed to make composite vehicle bodies affordable at small volumesThe production of carbon fibre chassis is an expensive business – just ask BMW. The German vehicle-maker and its partners have between them spent upwards of €700m ($870m) on the mass-production of its i3 and i8 models which ...
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ArticleCompósitos: Em boa forma
Uma variedade de materiais compósitos estão agora disponíveis para as montadoras de veículos, embora desafios permaneçam como o custo e a velocidade de produção - além de reciclagem...Embora as vantagens de compósitos poliméricos sejam bem conhecidas na indústria automotiva, a sua utilização tem sido impedida pelos elevados custos de materiais, ...
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WebinarComau webinar: Light weighting manufacturing technologies
Automotive manufacturing relies on the use of efficient, high-volume processes which guarantee productivity and quality. In practical terms, this can be translated into effective performance-based Body-in-White solutions that deliver speed, precision and the flexibility to handle the growing use of multiple materials.In an exclusive Comau webinar, Martin Kinsella, Director of ...
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ArticleSteel's stiff competition
New developments have made composite materials an increasingly viable option in vehicle manufacturingThe phrase ‘the right material in the right place’ has become something of a mantra for vehicle-makers in recent years in their efforts to reduce the weight of their cars. While the use of aluminium is increasing, many ...
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Article复合材料：完美成型
现在有大量复合材料都可以应用到汽车制造，每种材料又具有不同的性能和生产工艺，但是仍面临制造成本和速度方面的难题 — 还有就是再循环利用问题尽管使用高分子复合材料的好处在汽车制造业家喻户晓，但是由于材料成本高、生产率低、再循环能力不明、以及行业总体上缺乏经验和确定性（相对于金属应用而言），而无法广泛使用。复合材料生产商和汽车制造商都在不分昼夜地寻找解决之道，但是还有许多问题有待解决。复合材料是指两种以上的材料结合在一起，呈现出比单个成分更好的性能。与金属合金相比，每个材料都保持其化学、物理以及力学特征。高分子复合材料的两个成分中包括一种纤维增强材料 — 基于碳、玻璃或天然材料，比如亚麻 — 和一种聚合物基体。这种增强材料能使复合材料更加强大而且坚硬，而基体能将材料牢牢地黏在一起。碳纤维通常表现出超长的拉力和抗压强度，具有高模量（硬度），出色的疲劳特性，并且不会腐蚀。碳纤维早在1981年就应用于一级方程式赛车上，但是一直都认为造价太高，只能用于高性能跑车上。碳纤维的生产始于其前身 — 一般热塑性聚丙烯腈(PAN)，它具有高分子定向，高熔点和高产的特点。在一个复杂而高耗能的工艺里，这种前身的构成要素被一个一个地取缔，最终形成一种仅仅由稳定的纯碳石墨晶体结构组成的纤维。PAN的价格依赖于石油的价格，而石油的价格在近些年来很高，而且很不稳定。此外，碳纤维的生产只占丙烯腈的产量很少部分，因此，行业并未能与热塑性塑料的生产商协商取得更优惠的价格优势。总之，与金属生产相比，碳纤维的生产是一个昂贵而且 — 从环保角度上 — 肮脏的工艺。目前，集约利用碳纤维用于量产的车型是BMW i3 citycar. 高成本效益碳纤维SGL汽车碳纤维(ACF)工厂位于华盛顿州的Moses Lake，为BMWi车型生产碳纤维。这是宝马公司与西格里集团（SGL Group）的合资企业。企业使用当地的水力发电产生的能源，极大降低了能源消耗，也降低了生产工艺对环境的破坏。在拓展规模经济的过程中，公司通过提高工厂的产量来降低了生产碳纤维的成本。SGL-ACF工厂计划斥资2亿欧元（约合2.5亿美元）到2015年为止将Moses Lake工厂的年产量翻三番，从3kt提高到9kt。通过扩大生产，宝马公司可以提高其他车型内部里碳素纤维增强塑料（CFRP）的成分；到2015年，公司将开始在7系列车型使用该材质。还可以使用另一种PAN更为便宜的碳纤维，比如木质素(lignin)，目前由橡树岭国家实验室（ORNL）的聚合物基复合材料团队研究。研究者还在开发一种用聚乙烯（PE）生产碳纤维的方法，这要比PAN碳纤维产量高得多（86%比65%），而且还可以从消费后回收的废物中提取。 高产量，低成本玻璃纤维具有低成本、高张力、高抗击性，以及优良的耐化学性的特征，因此广泛应用于高量产汽车。然而，玻璃纤维同时相对碳纤维还具有模量低、疲劳性能差的特性。应用于汽车复合材料的最常用两种玻璃纤维类型是：无碱玻璃(E-Glass)，这种材料价格便宜，而且能良好综合抗张强度和模数；S玻璃纤维，比无碱玻璃昂贵，但抗张强度高出40%。总部位于美国的材料供应商公司AGY，打算使用S-1 HM玻璃纤维来弥补两种纤维的不足。这种专利玻璃配方，可以最大提高性能，并能实现高产量和节约生产。与传统E玻璃纤维相比，S-1 HM纤维能显著提高模量，增强抗疲劳性能。举例来说，该纤维具有90Gpa的拉伸模量，比E玻璃纤维高出20%。AGY公司业务发展经理Tim Gollins说，“虽然碳素纤维增强塑料展示出高硬度与强度，但是这些‘高模量’从某种程度上就是碳纤维复合材料‘易碎’的代名词。在抗冲击、抗疲劳、与抗损坏以及损伤容限方面，S-1HM复合材料不断使其竞争系统相形见绌。”这些增强材料融进聚合物内成为短纤维，提高了使用压缩与注塑工艺制造的零部件的强度。不织布纤维然而，为了能充分驾驭这些增强材料的潜力，提高塑料零部件的力学性能，他们需要编制称织物纤维，或不织布纤维。这些纤维是由总部位于英国的Formax公司生产。据公司创新主任Tom James透露，相同面积重量的纤维在力学性能上有很多变化，在针距、针脚和纤维平行度的结构上都有变化。一个纤维必须经过长期实验，在强度、硬度和易注性上进行优化，然后在一个特定组件投入生产之前决定最佳参数。 褶皱和纤维平衡度是使用树脂传递模塑(RTM)工艺生产碳纤维过程中最重要的两个参数，该工艺被宝马公司用于量产CFRP构造组件上了。所有这些变量都成为汽车设计师们最为头痛的问题，因为之前都是使用相对简单直接的金属。Formax公司目前正在开发能模仿铸模过程中干燥织物状况的软件，这样就能简化纤维选择过程了。强化塑料的对称特性（意思是在三个互相垂直的方向上的性能都不相同）也成为设计师头痛的问题。James说：“传统的复合材料能制造成准证各向异性（在X与Y轴形成的多方向纤维），因此能用与金属类似的方法来解决平面加载的问题。“然而，传统复合材料的厚度方向性能通常由基体的低性能支配，因为纤维缺乏Z轴，因此这被认为是复合材料的致命弱点。Formax公司目前进行多个合作项目，努力攻克这个难题。”是什么构成了基体？基体能赋予复合材料组件以形体，其本质可以是热固性的或者热塑性的。 热固性材料在通过热量或化学方法进行固化时，就会在实质上变得不熔化和不溶解。在固化完成之后，热固性材料就无法回到未加工时的状态。 热固性材料相对比较昂贵，但是具有高强度。就其本身而言，热固性材料广泛用于不连续玻璃纤维强化板的生产，和块状模塑料（SMC和BMC）的生产上。这些组件可以用于非结构性汽车零部件的大容量注塑和加压模塑。除此之外，一些像环氧基树脂这样的热固性材料，因其低粘度特性非常适合用于高压树脂传递模塑（HP-RTM）工艺，用一个混频头将树脂注入一个封闭的模腔内，并以高压填满干纤维预制体。事实上，环氧树脂是目前广受欢迎的结构构件生产材质。 为了生产i3单体壳，宝马公司使用了亨斯迈先进材料公司的（Huntsman Advanced Material）Araldite Ly 3585/ Hardener XB 3358环氧基树脂系统，用于生产i3汽车的CFRP单体壳。亨斯迈公司称，系统的低粘度是整个工艺的关键，从配料、混合到注入的整个过程里，都能保证纤维在模子里充分浸透。这个系统能在100摄氏度的温度下，短短5分钟内就完成固化。 与热固性材料（这种材料的固化反应无法逆转）相比，热塑性塑料是在冷却时才固化，而继续保持塑料特性；这种材料在重新加热到高于加工温度是就可以重新塑形。热塑性塑料逐渐变得便宜，并且可以增加抗冲击力，在相对低温下就可以迅速成型，这样就可以在短的周期内快速生产强化热塑性零部件。 不连续碳纤维增强热塑性塑料，比如聚丙烯（PP），通常用于注塑模具前端载体，仪表板载体，车门支架，支柱和踏板。然而，热塑性塑料的高粘度导致无法用于结构构件的批量生产，因为这与RTM工艺不兼容。缩短循环次数这种情形会很快发生改变。Teijin与通用汽车合作研究材料和工艺，使连续碳纤维增强热塑性结构组件的冲压成型在1分钟以内就完成循环周期。该技术称为Sereebo，自2011年3月宣布以来已经铺天盖地、遍地开花。Sereebo技术是在美国Teijin复合材料应用中心（TCAC）开发的，范围包括三种中间材料。第一个叫做U Series，是一种单向媒介，定向强度高。第二个叫I Series，是一种各项同性媒介，具有形状平衡、容易铸模以及多方向强度的特点。第三种叫P Series，是一种长纤维增强热塑性塑料(LFT)颗粒，是由高强度碳纤维制造而成，适用于复杂组件的铸模。 TCAC之外很少有人了解Sereebo（至少那些没有签署保密协议的人）。该技术将如何发展，还有待观察。循环利用的难题理论上，热塑性塑料可以重新熔化的这一事实，使其比热固性材料更容易回收利用。欧盟寿命终止指令规定，新车上80%的材料要重新回收利用。 有一个更为直接简单的回收复合材料的方法：碾碎然后用于水泥填充物。对于低价位填充塑料来说，这个方法是可行的，但是对于高价位的CFRP来说，这可不是体面的归宿。如果碳纤维可以从聚合物基体中分离出来，就可以当做廉价原始碳纤维，用于非结构性应用当中。重新使用废弃碳纤维和织物的工作发展顺利，可以在市场上买到利用回收来的碳纤维制造的织物。Formax公司出售一种强化产品，叫做reFORM，是完全由多向的生产废料制作而成，应用很广，包括各行各业的构造性应用。Formax公司称，这种纤维具有高度的褶皱和渗透率、准各向同性力学特征，以及在加工应用过程中具有高耐热性。 从固化的基质和非固化基质中分离纤维，并进行重新利用，这是非常具有难度的，但是已经有好几个公司正在做这个工作。 在南卡罗丽娜州Lake City的MIT-RCF工厂就利用热解的方法 — 即将CFRP碎片在缺氧的状态下加热到400摄氏度到500摄氏度，能生产出纯净的碳纤维，并且保留90-95%的原有力学性能 — 来循环使用CFRP零部件，每年能加工1.36-2.27kt的材料。除了生产切碎的碳纤维之外，MIT工厂还利用专利三维工程执行工艺（3-DEP），将回收材料制造成复杂的坯料，提供给零部件制造商。公司首席执行官Mark Housley说，“对于保守的结构零件，主要的障碍就是碳纤维，即使是回收的碳纤维成本，也要比铝、钢和玻璃纤维昂贵得多。但以切碎的形式的话，回收的碳已经在热塑性混合物中广泛应用，因此零部件设计和制造系统也已经成型。所以，这是相当简单的程序。” ...
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ArticleComposites: On good form
An array of composite materials are now available to vehicle-makers, each with special properties and production processes; but challenges remain in the cost and speed of manufacture – plus recyclabilityAlthough the advantages of polymer composites are well known in the automotive industry, their use has been impeded by high material ...
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ArticleA measure of success
Quality inspection in car body construction is moving towards more speed, greater flexibility and the use of intelligent software, writes Judith SchwarzThe automotive industry is placing new challenges on car body construction: more flexible and increasingly complex processes and systems are required as the number of models grows. Increasingly, process ...
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WebinarWEBINAR: Comau – lightweighting
Automotive manufacturing relies on the use of efficient, high-volume processes which guarantee productivity and quality. In practical terms, this can be translated into effective performance-based body-in-white solutions that deliver speed, precision and the flexibility to handle the growing use of multiple materials.In an exclusive Comau webinar on November 20, Martin ...
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ArticleFabrics of the future
Multiaxial reinforcement manufacturer Formax is tailoring lightweight materials to automotive needs If you think of carbon fibre you more than likely envision the familiar woven sheet, but there is more to this high-tech, lightweight material – as a visit to multiaxial reinforcement manufacturer Formax reveals. Based in Leicestershire, UK, the ...
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ArticleNon-destructive testing of composites
The Omniscan MX2 Phased Array ultrasonic flaw detector has been added to the Ashtead Technology rental fleet of advanced NDT instruments. The company claims that the MX2 can be combined with other components to form a complete inspection system. For example, phased array probes, scanners, analysis software, and other accessories ...
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As aluminium becomes increasingly used by carmakers, Mark Simms looks at the mechanical methods required to join this material Ever increasing pressures to reduce fuel consumption and vehicle emissions have seen a raft of technical innovations introduced to the automotive industry, but ultimately it is weight that has the single ...
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ArticleJoining aluminium
As aluminium becomes increasingly used by carmakers, Mark Simms looks at the mechanical methods required to join this material Ever increasing pressures to reduce fuel consumption and vehicle emissions have seen a raft of technical innovations introduced to the automotive industry, but ultimately it is weight that has the single ...
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ArticleMeet the metalworkers
The biennial AMB Show in Stuttgart from September 16-20 should bring together some important exhibitors for the automotive industry Located in the Baden-Wurttemberg Province, at the very heart of the German engineering and metalworking industries, the biennial AMB Show brings together exhibitors and visitors from around the world; but while ...
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ArticleHigh-strength steel: Strong, lightweight & cost effective
SSAB discusses the benefits of using advanced high-strength steel in vehicle structures “When it comes to cost efficiency, environmental issues and value for money, nothing can compete with advanced-high strength steel [AHSS]. The only problem we have today is that our top product could probably use a more sexy image”. ...
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ArticleInterview: John Pacanovsky, Scigrip
As the use of composites increases in the automotive industry, the head of R&D at an adhesives supplier talks about the advantages of this type of bondingAMS: Scigrip does some work with Renault and Fiat trucks, is that correct?John Pacanovsky (JP): Whilst we can’t name specific models, Scigrip is a ...
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ArticleHandling with care
New materials and the drive for greater flexibility in production have created new challenges in handlingWalk through almost any modern automotive assembly plant and the major trends in automotive assembly aren’t difficult to spot. Equally clear to see are the tensions and trade-offs that exist between them. The inexorable march ...
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ArticleMoulding tools for the future
What visitors to EuroMold 2013 can expect at the mould-making and tooling expo in Frankfurt this DecemberThe programme for 2013Exhibitors with automotive interestsAs the world trade fair for mould-making and tooling design and development, EuroMold brings together buyers, suppliers and process experts from all parts of the globe. This year’s ...