What a 3D Printer Is and How It Works
3D打印面面观

文/杰里米•许   译/淡晓红
By Jeremy Hsu

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A 3D printer cannot make any object on demand like the Star Trek replicators of science fiction. But a growing array of 3D printing machines has already begun to revolutionize the business of making things in the real world.
[2] 3D printers work by following a computer’s digital instructions to “print” an object using materials such as plastic, ceramics and metal. The printing process involves building up an object one layer at a time until it’s complete. For instance, some 3D printers squirt out a stream of heated, semi-liquid plastic that solidifies as the printer’s head moves around to create the outline of each layer within the object.
[3] The instructions used by 3D printers often take the form of computer-aided design (CAD) files—digital blueprints for making different objects. That means a person can design an object on their computer using 3D modeling software, hook the computer up to a 3D printer, and then watch the 3D printer build the object right before his or her eyes.

History of 3D printing
[4] Manufacturers have quietly used 3D printing technology—also known as additive manufacturing—to build models and prototypes of products over the past 20 years.
[5] Charles Hull invented the first commercial 3D printer and offered it for sale through his company 3D Systems in 1986. Hull’s machine used stereolithography1, a technique that relies upon a laser to solidify an ultraviolet-sensitive polymer material wherever the ultraviolet laser touches.
[6] The technology remained relatively unknown to the greater public until the second decade of the 21st century. A combination of U.S. government funding and commercial startups has created a new wave of unprecedented popularity around the idea of 3D printing since that time.
[7] First, President Barack Obama’s administration awarded $30 million to create the National Additive Manufacturing Innovation Institute (NAMII) in 2012 as a way of helping to revitalize U.S. manufacturing. NAMII acts as an umbrella organization2 for a network of universities and companies that aims to refine 3D printing technology for rapid deployment in the manufacturing sector.
[8] Second, a new wave of startups has made the idea of 3D printing popular within the so-called “Maker” movement3. Many of those companies offer 3D printing services or sell relatively cheap 3D printers that can cost just hundreds rather than thousands of dollars.

Future of 3D printing
[9] 3D printing probably won’t replace many of the usual assembly-line methods for building standard products. Instead, the technology offers the advantage of making individual, specifically tailored parts on demand—something more suited to creating specialized parts for U.S. military aircraft rather than making thousands of trash cans for sale at Wal-Mart.
[10] The medical industry has also taken advantage of 3D printing’s ability to make unique objects that might otherwise be tough to build using traditional methods. U.S. surgeons implanted a 3D-printed skull piece to replace 75 percent of a patient’s skull during an operation in March 2013.
[11] The spread of 3D printing technology around the world could also shrink geographical distances for both homeowners and businesses. Online marketplaces already allow individuals to upload 3D-printable designs for objects and sell them anywhere in the world. Rather than pay hefty shipping fees and import taxes, sellers can simply arrange for a sold product to be printed at whatever 3D printing facility is closest to the buyer.
[12] Businesses won’t be alone in benefiting from 3D printing’s print-on-demand-anywhere capability. The U.S. military has deployed 3D printing labs to Afghanistan as a way to speed up the pace of battlefield innovation and rapidly build whatever soldiers might need onsite.
[13] Most 3D printers don’t go beyond the size of household appliances such as refrigerators, but 3D printing could even scale up in size to build objects as big as a house.

Limitations of 3D printing
[14] But 3D printing still has its limits. Most 3D printers can only print objects using a specific type of material—a serious limitation that prevents 3D printers from creating complex objects such as an Apple iPhone. Yet researchers and commercial companies have begun developing workarounds. Optomec, a company based in Albuquerque, New Mexico, has already made a 3D printer capable of printing electronic circuitry onto objects.
[15] The 3D printing boom could eventually prove disruptive in both a positive and negative sense. For instance, the ability to easily share digital blueprints online and print out the objects at home has proven a huge boon for do-it-yourself makers. But security experts worry about 3D printing’s ability to magnify the effects of digital piracy and the sharing of knowledge that could prove dangerous in the wrong hands.  ■

3D打印机虽然没法像科幻电影《星际迷航》中的复制器那样按需复制万物,但越来越多的3D打印机器已开始彻底颠覆现实世界的制造业。
〔2〕按照计算机的数字指令,3D打印机可采用塑料、陶瓷、金属等材料“打印”物件。打印物件时,一次打印一层,逐层堆叠,直至成型,例如,某些3D打印机会喷出一股加热的半液体状塑料,随着喷嘴来回转动,打造出物体每一层的轮廓,最后凝固成型。
〔3〕3D打印机采用的指令通常以计算机辅助设计文档的形式存在,这是制作不同物件的数字设计图。这意味着,我们可以采用3D建模软件在计算机上设计物件,将计算机与3D打印机连接,然后静观打印机将所设计的物件呈现眼前。

3D打印的历史
〔4〕3D打印技术也称增材制造技术,过去20年,制造商已在悄无声息地使用这种技术制造产品模型和原型。
〔5〕1986年,查尔斯•赫尔发明了第一台商用3D打印机,并通过他的3D Systems公司销售。这款打印机采用激光光固化技术,该技术依靠的是紫外激光器,在该激光器的照射范围内,液态光敏树脂材料将会固化。
〔6〕但直到2010年,更多的人才开始慢慢了解这种技术。自此,美国政府的资助以及新的商业公司的联合推动,掀起了一波围绕3D打印概念的史无前例的新热潮。
〔7〕首先,奥巴马政府2012年拨款3000万美元,筹建美国国家增材制造创新研究所,以帮助重振美国的制造业。作为大学与企业的联合组织,该所旨在进一步研发3D打印技术,将其快速应用于制造业。
〔8〕其次,一批新崛起的公司使3D打印的概念在所谓的“自造者”运动中流行起来。这些公司中有很多都提供3D打印服务,或者销售相对便宜的3D打印机,用不着几千美元,只需数百美元即可购得一台。

3D打印的未来
〔9〕3D打印技术可能不会取代制造标准产品时通常采用的多种流水作业法,但3D打印技术的优势在于可以按需定制个性化产品,比如更适合制造美国军用飞机的某些专用零件,而非沃尔玛超市里卖的数千个垃圾桶。
〔10〕医疗行业也利用了3D打印技术的优点,制造那些采用传统方法可能很难制造的特殊物件。2013年3月,美国外科医生在一次手术中用一块3D打印的颅骨为一个病人置换了其75%的颅骨。
〔11〕3D打印技术在全球的普及还可能为业主和企业缩短地理距离。人们可以将用于打印的3D设计图上传到网上市场,向世界各地销售。卖方用不着支付高昂的运费和进口关税,只需安排所售产品在离买家最近的3D打印设施上打印即可。
〔12〕企业不会是3D打印按需随地打印功能的唯一受益者。美国军方已在阿富汗建立了一个3D打印实验室,以加快战场创新的步伐,快速制造士兵随时可能需要的任何东西。
〔13〕大多数3D打印机的大小都不超过冰箱这样的家用电器,但3D打印却能制作像房子那么大的物件。

3D打印的局限性
〔14〕不过,3D打印也有其局限。大多数3D打印机只能采用特定类型的材料打印东西——这一局限影响很大,使3D打印机无法打印iPhone那样复杂的产品,但研究人员和商业公司已着手探索应变之法。Optomec是一家总部设在新墨西哥州阿布奎基市的公司,已经制造出一种3D打印机,可以将电路打印到物件上。
〔15〕不论从积极还是消极的意义上讲,最终都可能证明,3D打印技术的蓬勃发展具有破坏性,例如,可以轻松在线共享数字设计图,并在家打印出那些物件,这种功能给喜欢自己动手做东西的人带来了巨大实惠,但安全专家担忧,3D打印技术会放大数字盗版和知识共享的影响,那些知识一旦落入坏人之手可能十分危险。  □

1. 又称光敏树脂选择性固化。
2. 联合组织;综合机构。
3. 也称“创客运动”,指消费者利用3D打印等各种新兴技术,自行设计制造各种产品的运动,近两年风靡欧美。

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