Additive Manufacturing: A Printed Smile

增材制造：打印的笑容

 

3D printing is coming of age as a manufacturing technique

3D打印制造技术已渐成熟

 

A set of straight and gleaming teeth makes for a beautiful smile. But how many people who have undergone a little dental maintenance know that they may have inside their mouths some of the first products of a new industrial revolution? Tens of millions of dental crowns, bridges and orthodontic braces have now been produced with the help of additive manufacturing, popularly known as 3D printing. Forget the idea of hobbyists printing off small plastic trinkets at home. Industrial 3D printers, which can cost up to $1m, are changing manufacturing.

 

一口整齐而闪亮的牙齿会让您的笑容更加美丽。但又有多少做过牙科治疗的人知道，新工业革命带来的第一批产品就在自己口中呢？如今，数以千万计的牙冠、牙桥和牙箍都是依靠增材制造，也就是俗称的3D打印生产出来的。别再觉得它只是爱好者在家里打印几个小塑料玩意了。价格可高达百万美金的工业3D打印机正在改变着制造业。

 

The business of dentures shows how. For the metal bits in false teeth, dentists have long relied upon a process called “investment casting”. This involves creating an individual model of a person’s tooth, often in wax, enclosing it in a ceramic casing, melting out the wax and then pouring molten metal into the cavity left behind. When the cast is split open, the new metal tooth is removed. It is fiddly, labour-intensive and not always accurate; then again, the casting method is some 5,000 years old.

 

牙科行业就是一个明证。对于假牙中的金属件，牙医们长期以来都依靠一种名为“熔模铸造”的工艺。它要先做出患者的牙齿模型（一般是蜡制），封上陶瓷，再把蜡熔化后倒出，在其留下的空腔中注入熔融的金属。最后打开铸模，拿出新的金属牙齿。整个过程十分繁琐，相当辛苦而且并不总是很准确。再说，铸造法已经有5000年的历史了。

 

Things are done differently at an industrial unit in Miskin, near Cardiff, set up by Renishaw, a British engineering company. The plant is equipped with three of the firm’s 3D printers; more will be added soon. Each machine produces a batch of more than 200 dental crowns and bridges from digital scans of patients’ teeth. The machines use a laser to steadily melt successive layers of a cobalt-chrome alloy powder into the required shapes. The process is a bit like watching paint dry – it can take eight to ten hours – but the printers run unattended and make each individual tooth to a design that is unique to every patient. Once complete, the parts are shipped to dental laboratories all over Europe where craftsmen add a layer of porcelain. Some researchers are now working on 3D printing the porcelain, too.

 

位于英国卡迪夫附近米斯金村（Miskin）的一家工厂则采取完全不同的做法。该工厂由英国工程公司雷尼绍（Renishaw）设立，配备了三台公司自产的3D打印机，很快还会再添数台。根据患者牙齿的数字扫描，每台机器一批可以生产200多个牙冠和牙桥。机器用激光将一层层钴铬合金粉末稳定地熔融成所需的形状。整个过程有点像坐等油漆干燥，可能需要8到10个小时——但打印机可以无人值守运行，按照每位患者独一无二的设计来制作牙齿。制作完成后，产品会被送往遍布欧洲的牙科实验室，手工加上瓷层。还有一些研究人员已经在研究3D打印陶瓷了。

 

Say “ah”

说“啊”

 

The mouth is not the only bodily testing-ground for 3D-printed products. Figures gleaned by Tim Caffrey of Wohlers Associates, an American consultancy that tracks additive manufacturing, show that more than 60m custom-shaped hearing-aid shells and earmoulds have been made with 3D printers since 2000. Hundreds of thousands of people have been fitted with 3D-printed orthopaedic implants, from hip-replacement joints to titanium jawbones, as well as various prosthetics. An untold number have benefited from more accurate surgery carried out using 3D-printed surgical guides; around 100,000 knee replacements are now performed this way every year.

 

口腔并不是3D打印产品在身体上唯一的试验场。关注增材制造的美国咨询公司Wholers Associates收集的数据显示，2000年以来，利用3D打印机定制生产的助听器壳体和耳模已逾6000万件。从人工髋关节到钛颚骨再加上各种假肢，数十万患者已经安装了3D打印的骨科植入体。3D打印的手术导板让手术更为精确，造福无数患者。如今每年约有10万例膝关节置换手术是以这种方式进行的。

 

That the health-care industry has so swiftly adopted additive manufacturing should be no surprise. People come in all shapes and sizes, so the ability of a 3D printer to offer customised production is a boon. The machines run on computer-aided design (CAD) software, which instructs a printer to build up objects from successive layers of material; a medical scan in effect functions as your CAD file. And software is faster and cheaper to change than tools used in a traditional factory, which is designed to churn out identical products.

 

医疗保健行业如此迅速地接受增材制造并不奇怪。人的身材尺寸各异，因而 3D打印机定制化生产的能力是一个福音。计算机辅助设计（CAD）软件控制这些打印机，引导它们一层层地堆积材料来构建物体，医学扫描实际上就是你的CAD文件。传统工厂中的工具更适合批量生产一模一样的产品，而软件改动起来则更快速、更经济。

 

Compared with the $70 billion machine-tool market, additive manufacturing is still tiny. But it is expanding rapidly, and not just in health care. Overall, Wohlers estimates that 3D-printed products and services grew by 26% last year, to be worth nearly $5.2 billion. That is just the tip of a bigger mountain in the making. McKinsey, a management consultancy, reckons that in terms of things like better products, lower prices and improved health, 3D printing could have an economic impact of up to $550 billion a year by 2025.

 

和700亿美元的机床市场相比，增材制造仍然微小。但它扩张迅速，而且并不限于医疗保健行业。Wohlers估计， 3D打印产品和服务在去年整体增长了26%，总价值近52亿美元。而这只是日渐庞大的冰山初露的一角。管理咨询公司麦肯锡估计，如果考虑到更好的产品、更低的价格和健康的改善，到2025年，3D打印的经济影响将达到每年5500亿美元。

 

One reason why 3D printers are becoming more mainstream is that the “inks” they use are getting better thanks to advances in materials science, says Andy Middleton, the European head of Stratasys, an Israeli-American company that makes 3D printers. One method Stratasys uses, called PolyJet, is similar to inkjet printing: cartridges deposit layers of a liquid polymer which are cured with ultraviolet light. The company has just unveiled a new PolyJet model called the J750. It uses multiple cartridges to print items in 360,000 different colours and any combination of six different materials, which can be rigid or flexible, opaque or transparent.

 

3D打印机日益跻身主流的一大原因是，随着材料科学的进步，它们使用的“油墨”越来越好了，生产3D打印机的以色列-美国公司Stratasys的欧洲负责人安迪·米德尔顿（Andy Middleton）表示。Stratasys公司使用的一种名为PolyJet的方法和喷墨打印类似：墨盒会逐层累积液体聚合物，并用紫外线灯使之硬化。该公司刚刚推出了一种新的PolyJet型号，称为J750。它使用多个墨盒，打印的色彩达36万种，并可将任意六种刚性或柔性，不透明或透明的材料组合起来。

 

The machine is intended to make prototypes as the polymers are not yet robust enough for a final product. Nevertheless, that allows a manufacturer of trainers, for instance, to print a complete shoe in one go, with a rubbery sole and a leather-like upper. The ability to make realistic prototypes greatly speeds up product approval and the time it takes to get to market.

 

这台机器本来只是用来制作原型的，因为聚合物的强度还不足以制作最终产品。然而，这让运动鞋的制造商可以一口气打印出一只完整的具有橡胶鞋底和皮革般鞋面的鞋。做出逼真原型的能力大大减少了产品审批和推向市场所需的时间。

 

Increasingly, however, 3D-printed objects are being produced as finished items, rather than as models or prototypes. This leads consultants at PWC to conclude in a new report that additive manufacturing “is crossing from a period of hype and experimentation into one of rapid maturation”. Their research found more than two-thirds of American manufacturers are now using 3D printing in some form or the other.

 

然而，越来越多的3D打印物体被作为成品生产出来，而不只是用作模型或原型。这让普华永道的顾问在一份新的报告中得出了增材制造“正在从炒作和实验期进入快速成熟期”的结论。他们的研究发现，美国超过三分之二的制造商在使用某种形式的3D打印。

 

Another 3D-printing process used by Stratasys builds parts layer by layer, by heating and extruding thermoplastic filaments. Airbus now uses these machines to print internal cabin fittings for its new A350 XWB airliner. The printers use a resin that meets the safety standards on aircraft. As airlines often specify custom fittings, 3D printing saves on re-tooling. It also allows multiple components to be consolidated into a single part, which reduces assembly costs. It will not be long, some in the industry reckon, before carmakers will offer interior customisation using 3D printers, too.

 

Stratasys公司使用的另一种3D打印工艺则是通过加热和挤压的热塑性塑料丝来逐层构建零件。空中客车公司现在使用这些机器来为其新的A350 XWB客机打印内部座舱配件，打印机使用的树脂也符合飞机安全标准。由于航空公司往往自己定制机舱内部装饰，3D打印可节省更换工具的费用。它还可以把多个组件合并为一个部件，从而降低了组装成本。一些业内人士估计，在不久的将来，汽车制造商就会使用3D打印机来制作定制内饰了。

 

Although further development is needed to speed up additive-manufacturing systems and improve the surface finish, the technology is already trusted enough to be used in products that have to withstand high stresses and strains. GE has spent $50m installing a 3D-printing facility at a plant in Auburn, Alabama, to print up to 40,000 fuel nozzles a year for the new LEAP jet engine it is making in partnership with Snecma, a French company. The nozzles will be printed in one go, instead of being assembled from 20 different parts. They are made from a powered “super alloy” of cobalt, chrome and molybdenum. The finished item will be 25% lighter and five times more durable than a fuel nozzle made with conventional processes.

 

虽然对于增材制造系统而言，要提高速度并改善表面光洁度还需要进一步的开发，但技术已经足够可靠，可以用于需承受高应力和应变的产品。GE花费了5000万美元，在阿拉巴马州奥本市的一家工厂中安装了一台3D打印设备，每年为其与法国斯奈克玛（Snecma）公司合作生产的新型LEAP喷气式引擎打印至多4万个燃料喷嘴。喷嘴不再需要把20个零件组装起来，而是用钴、铬和钼制成的“超级合金”一次打印成型。成品将比用传统方法制造的燃料喷嘴轻25%，寿命更可延长五倍。

 

Materials companies are coming up with more and more specialised ingredients for additive manufacturing. Alcoa, a leading producer of aluminium, recently said it would supply Airbus with 3D-printed titanium fuselage parts and the pylons used to attach engines to wings. Alcoa is spending $60m expanding its R&D centre in Pennsylvania to accelerate the development of advanced 3D-printing materials and processes.

 

材料公司为增材制造推出了越来越多的专用原料。领先的铝生产商美国铝业公司（Alcoa）近日表示，将为空中客车公司提供3D打印的钛机身部件以及把发动机连接到机翼上的挂架。美铝投资6000万美元扩建其位于宾夕法尼亚州的研发中心，为先进的3D打印材料和工艺的研发助力。

 

Large 3D printers are also emerging to make big things. Oak Ridge National Laboratory in Tennessee is working with a company called Local Motors to print cars, or at least much of their structure, using a blend of plastic and carbon fibre. The lab has also teamed up with Skidmore, Owings and Merrill, a firm of architects, to print substantial sections of buildings. The idea is to develop an additive-building process that results in no waste.

 

生产大家伙的大型3D打印机也不断涌现。位于田纳西州的橡树岭国家实验室正在与一家名为Local Motors的公司合作，采用塑料和碳纤维的混合物打印汽车，至少是打印汽车的主体构造。该实验室还联手SOM建筑设计事务所（Skidmore, Owings & Merrill）来打印出庞大的建筑部件，其想法是开发没有浪费的增材建筑工艺。

 

Some factory bosses have said that 3D printing will never replace mass manufacturing. Perhaps, but it does not have to in order to transform production processes. Additive-manufacturing systems are being mashed together with traditional production methods, which themselves are improving with digital technologies. Even old-fashioned metal bashing and welding is going high-tech.

 

一些工厂老板表示，3D打印将永远无法取代大规模生产。或许此言不虚，但它不必做到这一点就可以改造生产工艺。增材制造系统正在与传统生产方法融合，而后者本身也在利用数字技术进行改进，连古老的打铁和焊接也将迎来高科技。

 

Perhaps the surest evidence comes from China. LITE-ON, a leading contract manufacturer, has just installed a set of 3D printers in a Guangzhou factory that makes millions of smartphones and other portable consumer electronics. The printers, made by Optomec, an Albuquerque-based firm, use a process called Aerosol Jet to focus a mist of microdroplets into a tightly controlled beam, which can print features as small as 10 microns (millionths of a metre). LITE-ON is using the machines to print electronic circuits, such as antennae and sensors, directly into products instead of making those components separately and assembling them into the devices either by robot or by hand. When a manufacturing technology arrives in the workshop of the world, it really is coming of age.

 

也许最可靠的证据来自中国。领先的合同制造商LITE-ON刚刚在广州一家工厂中安装了一组3D打印机，生产数以百万计的智能手机和其他便携式消费类电子产品。这些打印机由总部位于新墨西哥州阿尔伯克基市的Optomec制造，使用名为“气溶胶喷射”（Aerosol Jet）的工艺将微滴雾聚焦成一个精密控制的集束，打印的细部可小至10微米（百万分之一米）。LITE-ON使用这些机器来直接在产品中打印天线和传感器等电子电路，而无需另行生产这些部件，再用机器人或手工组装起来。一种制造技术来到了世界工厂，就意味着它真的成熟起来了。