However, 3-D printing truly will transform certain industries. But there remains a big gap between its industrial applications and its home applications. In the home, it’s something like a Lego or K’Nex set for the 21st century: wondrously stimulating for kids and DIY enthusiasts, but with limited practical applications. It could evolve into something more—something essential—or it could remain a snazzy but unnecessary toy, the iPad of the 3-D realm.
In the hands of professionals, 3-D printing has already become essential in many contexts. Its first great success was in rapid prototyping, where it gave product designers the ability to quickly mock up plastic models without having to order them from a machine shop. Now, using new technologies such as selective laser sintering, industrial 3-D printers can also build final products using a wide array of materials, from glass to metal, in a process called additive manufacturing. These types of highly specialized printers compete not with consumer outlets like Wal-Mart, but with processes such as injection molding, which has dominated the precision manufacturing world for decades.
3-D printing has several advantages over traditional techniques. Injection molding, which requires toolmakers to build metal molds into which heated plastic can be cast, tends to be cost-efficient only for large-scale production runs of a single part or object. In contrast, the marginal cost of 3-D printing is roughly the same whether you build one or 1 million. This allows for near-infinite customizability, which is why the eyeglasses and prosthetic limbs invoked by Diamandis and Kotler make good examples of its uses. Parts for Formula 1 cars or Boeing Dreamliners, of which only a few dozen may be produced in a year, are also good candidates for 3-D printing.
That the same machine can produce virtually any shape also makes spur-of-the-moment manufacturing workable in places it has never been before: in space, for instance, or in the back of a military Humvee. Why try to stock every little space station part that might break when you can bring one 3-D printer?
It’s not surprising that there should be such a dichotomy between the uses of industrial 3-D printers and the home models: The same was true of computers for decades. In many ways, the progression of 3-D printing from giant warehouses to living rooms has happened faster than anyone had a right to expect. 2-D printing was the exclusive province of industrial presses and foundries for centuries. Computers were refrigerator-size beasts for decades before the Commodore PET and the Apple II. And yet 3-D printers have gone from lab to living room in less than 20 years—and at prices that are already coming within reach of the upper-middle class. (The Thing-o-Matic will set you back $1,099; Fab@Home printers start at about $2,000.)
The technology’s evolution is likely to continue rapidly, thanks in large part to the open-source mentality embodied in the Thingiverse, a community of DIY-ers who make their designs available for free download. When everyone can see and improve on everyone else’s work, progress flows faster and easier than it does in cloistered corporate labs.
Still, the error that some futurists make is to assume that progress in 3-D printing will follow something similar to Moore’s Law: the principle of exponential growth that was first applied to the number of transistors that could fit on an integrated circuit. That seems not to hold in the world of physical things of a more substantial size. Bespoke Innovation’s Scott Summit, one of the leading 3-D printing evangelists, says he has no doubt the technology has the potential to change the world—“It will scale crazily in a lot of directions people don’t expect,” he predicted—but it won’t change everything about the world. It’s a point of frustration among industry insiders that the public expects 3-D printers to perform like Star Trek’s replicators: All you have to do is say, “Tea, Earl Grey, hot.”
On Star Trek, though, replicators weren’t perfected until the 24th century. By then, it’s a safe bet we’ll be using 3-D printers to create things far more interesting than tea or a bike.