How It Works
3-D printers can be massive, industrial-strength machines the size of office copiers, costing tens of thousands of dollars, but they're also available in desktop models, for consumers and hobbyists, priced at about $2,000. You can already design some 3-D objects on your smartphone using mobile apps. Draw a shape with your finger and hit the print icon, and your 3-D printer can start building your design instantly.
Printers that make plastic objects start with a small, football-sized spool of plastic, which resembles spaghetti. The printer extrudes the material, bit by bit, as dictated by the design: a bracelet, a toy mold, a wrench. Some objects are printed whole, while others require modest assembly.
The kind of plastic used is already advancing. ABS, which is more pliable, can be sanded to create finished products in which the additive layers are less visible.
Then there's metal 3-D printing—what Fischer and his team do at Wisconsin Precision Casting. Unlike plastic's spaghetti-like threads, metal printing uses lasers to weld metallic powder into structures. In other applications, spools of metal wires are beaded into shapes.
No longer limited by the shapes that conventional machines can stamp out, manufacturers are limited only by their imaginations. Envision honeycomb structures rather than solid ones, spiral rather than straight shapes.
"When I saw the 3-D printing process in action, I knew I had seen the death of machining as we know it today," said Christian Joest, president of Imperial Machine & Tool, based in Columbia, N.J. It makes military hardware for objects such as door-gun mounts and howitzers. "Additive manufacturing has the potential to transform American industry and the entire way we do things."
3-D Printing of Battlefield Surgical Instruments
Medical applications of 3-D printing are particularly mind-blowing. Prosthesis makers are using the technology to create custom artificial limbs—no more ill-fitting, generic parts.
(Read More: How Technology Is Reinventing the Prosthesis)
And consider combat surgery. Keeping sterile instruments in stock on the battlefield is a constant challenge. Combat surgeons have been known to use vodka and bleach to sterilize surgical tools.
Additive manufacturers have found a way to fashion durable, plastic surgical instruments that when printed on-site, emerge sterile. And because products are designed digitally, 3-D printing allows for mass customization.
For example, a combat surgeon who prefers to palm an instrument (instead of looping fingers through cumbersome handles) can redesign the handles. Spring rates can also be tailored to surgeons' preferences.
"It's no problem," said Shayne Kondor, a medical modeling engineer who helped develop a 90-day program with the Defense Advanced Research Projects Agency, or DARPA, part of the Defense Department. "You just make a file" of 3-D instruments for each surgeon, he said during a RAPID presentation last week.
(Read More: 3-D Printers and the Cool Stuff They Make)