Designers still can't prevent the sorts of low-tech failures that have bedeviled armies for millennia. A missing bolt can stop a convoy. A bent machine-gun mount can leave soldiers vulnerable, or make a Humvee unusable.
But military engineers have developed a high-tech way to fix these failures on the fly. At sites in Iraq and Kuwait the Army has deployed a factory that fits in an air-transportable container. It's called the Mobile Parts Hospital, and inside, technicians use workstations and robotic machine tools to fabricate parts on the fly. In the next phase, lasers will "print" powdered metal, layer by layer, to create fully functional replacements. Talk about just in time: The approach can save months, compared to waiting for resupply. What's more, like the M*A*S*H units after which they're modeled, "the Parts Hospital has saved lives," writes Bruce Neighbor, a second lieutenant with the 1486th Transportation Company in Iraq in an e-mail.
The rollout of the MPH is a landmark for the army and may mark the beginning of a new kind of manufacturing. From their origins as design tools, three-dimensional printers are evolving into minifactories for the workaday world, able to transform digital designs into plastic, ceramic, or metal reality. And as these systems get cheaper, more versatile, and smaller, "rapid manufacturing" promises to transform supply chains by cutting the need for large stocks of parts, as well as the trucks to move them, and the warehouses to store them. It could also help unleash an era of personalized customization. "The passionate demand is from people making quirky personal inventions -- for stuff that you can't get at Wal-Mart," says Neil Gershenfeld, author of FAB: The Coming Revolution on Your Desktop -- From Personal Computers to Personal Fabrication and director of the Center for Bits & Atoms at Massachusetts Institute of Technology.
Supercharged growth is a sign that the 3D printing industry is already transforming. Though still small, the cozy club of companies that has been nurturing these technologies since the first patents were filed in the 1980s is growing fast. Sales of 3D printers, supplies, and services are predicted to surge by 31% this year, hitting nearly $1 billion. That's on top of 33% industrywide growth in 2004, to $705 million.
Industry sales are dominated by a trio of U.S. companies. 3D Systems (TDSC ), Stratasys (SSYS ), and Z Corp. top the list, followed by Germany's EOS, and then a few dozen smaller, specialized startups in Europe and Japan. Among big multinational corporations, only Sony Corp. (SNE ) and DuPont (DD ) have notable activities in the market.
For now, most of the demand comes from companies that make one-off 3D models. So-called "rapid prototyping" can speed up designers' work and cut costs by reducing errors in final projects. But the shift to full-blown rapid manufacturing is following naturally. "Manufacturers are realizing their design prototypes are as durable as traditionally made components," says Scott Crump, CEO of Stratasys Inc., based in Eden Prairie, Minn. Indeed, in four years, the percentage of companies with 3D printers who report doing some rapid manufacturing has gone from practically nil to about 8%. "Going from one printer making prototypes to many units producing tens, or hundreds of objects, that's rapid manufacturing," says Terry Wohlers, founder of Wohlers Associates Inc., a market research consultancy in Fort Collins, Colo. In time, he says, rapid manufacturing will become the industry's biggest application.
The Army's MPH offers a vision of what's to come. Despite huge improvements in recent years, the U.S. military still faces challenges keeping war machines running. With no FedEx (FDX ) trucks near the front lines, anything not in stock must be sent for via slow military supply channels. If it's not in stock, even a simple cotter pin can take weeks to get.
Now, instead of shipping in replacements, a Mobile Parts Hospital can fabricate some of what breaks. The MPH fits into two 20-ft. containers, narrow enough to squeeze into a standard C-130 military transport plane, or on the back of a truck. When a broken part shows up, technicians download specs for a replacement via the Internet from a library of engineering data stored on PTC Inc.'s Windchill product data management system at the Army Tank-automotive & Armaments Command (TACOM) in Warren, Mich. If data are not available, as is often the case with older parts, the staff uses laser scanners to take meticulous measurements of the broken part, input them into a computer workstation, and repair the digital version.
Once the 3D blueprints are ready, the workstation zaps them to the MPH's fabricating module. There, robotic milling machines and lathes whittle down basic metal bars into useable forms -- anything from U-shaped gun mounts to cylindrical trailer hitches -- in a few hours.
The next upgrade to the MPH, due in a year or two, is a mind-bender. At the Army Tank-automotive Research, Development & Engineering Center (TARDEC) in Warren, Mich., engineers are refining a patented process called Laser-Engineered Net Shaping. Inside a fridge-size box, a computer-controlled nozzle deposits a fine path of powdered steel, tracing a series of cross sections of the part-in-progress. Trailing behind is a laser that fuses the metal particles, layer by layer. At a rate of about 3.5 cubic inches of material per hour, a new part emerges.
It's costly to make parts one at a time, but the Army figures the gains in logistics and uptime more than make up for it. "They've saved countless months of equipment downtime," says Todd Richman, project manager for the MPH program at TARDEC. After more than four years and $16 million-plus to develop the MPHs, the units in Kuwait and Iraq have already made nearly 13,000 parts. A third is due in Afghanistan in June. Richman estimates a fully containerized parts hospital costs $1 million.
For private companies, rapid manufacturers can offer big up-front savings. Making complex parts typically requires costly dies -- molds into which metal or plastic is poured or stamped. These are so expensive that making small batches of a new product is usually unthinkable. But using a rapid manufacturing process, British carmaker MG Rover last year saved six weeks and more than $80,000 by "printing" 1,800 plastic clips.
Routinely customized jobs are another good fit. Diebold Inc., based in Canton, Ohio, relies on a Stratasys system to make customized plastic faces for the cash machine it sells to banks. The ATM covers must be able to weather a Minnesota winter night as well as a hot summer day in Phoenix. The high-durability plastics able to do this are a recent addition to the materials that Stratasys' machines can handle.
New materials are helping rapid manufacturing find uses in medicine too. Medical Modeling LLC in Golden, Colo., uses CT scan data to produce 3D models that help surgeons plan complex procedures. Therics Inc., a wholly owned subsidiary of Tredegar Corp. makes a specialized 3D printer that produces bone-friendly ceramic bone substitute, layer by layer. The process yields superfine channels that help draw blood and new bone cells into the material, says Thomas J. Bradbury, Therics' director of technology development. In 6 to 12 months, natural bone grows to replace the synthetic ceramic. Last year the FDA approved the Princeton (N.J.) company's bone void filler. Now, Therics is investigating ways to customize the implants.
3D printers may never fulfill the sci-fi fantasy of a desktop box that fabricates anything you desire. But given their widening use by manufacturing companies, it's easy to imagine one at your local garage, spitting out replacement brake disks for your Honda. Or in your dentist's office, making a new bridge while you wait. Or at a local FedEx Kinko's, where the kids are printing out custom iPod holders. However that plays out, manufacturing will never look the same.
By Adam Aston in New York