3D printers already produce everything from prosthetic hands and engine parts to basketball shoes and fancy chocolates. But as with any technological advance, new possibilities come with new perils.​​​​​​​

A new RAND paper, Additive Manufacturing in 2040: Powerful Enabler, Disruptive Threat, explores how 3D printers will affect personal, national, and international security. The paper is part of RAND's Security 2040 initiative, which looks over the horizon to anticipate future threats.

The same technology that might one day custom-print heart valves can just as easily produce gun parts. The same machines that allow astronauts on the international space station to print their own tools might also help a state like North Korea print military or industrial equipment to get around international sanctions. Here are four areas to watch as 3D printing makes the leap from high tech to home tech.

Hackers Could Use Printers to Cause Real-World Damage

For one minute and 43 seconds, nothing about the small drone's flight seemed unusual. Then one of its propellers blew apart. The drone lurched to one side, wobbled, and plummeted to the ground, shattering on impact.

Photo by kalasek/Getty Images

The 2016 experiment demonstrated the ease with which hackers could turn malicious code into real-world damage with a 3D printer. A team of university researchers had hacked into a desktop computer and altered a few lines of code in the 3D blueprint for the drone's propeller. The printed propeller looked flawless, even under close scrutiny—but microscopic weaknesses in its blade doomed it to fail. It was an unsettling lesson, especially as 3D printers manufacture more and more critical parts, including airplane engine components.​​​​​​​​​​​​​​​​​​​​​

Those industrial printers have much more rigorous defenses than a home computer. But committed hackers can usually find their way into even the most-sensitive networks—as the Pentagon, the White House, and any number of hospitals can attest. The result could be a new kind of threat: cyber sabotage in the physical world.

The result [of hackers infiltrating digital blueprints] could be a new kind of threat: cyber sabotage in the physical world.

"Right now, if you have a cyber hack, then, worst-case scenario, your information gets compromised and you have to cancel a credit card or fight some kind of identity theft,” said Troy Smith, an associate economist at RAND and co-author of the paper. "I don't want to minimize that. But with digital becoming physical, you could implant weaknesses into airplanes, into military tanks, into buildings. You could target people by implanting some kind of flaw that causes their personal devices to critically malfunction.”​​​​​​​

The 2016 drone experiment was meant to be a wakeup call, especially for companies looking to manufacture critical parts with 3D printers. As team member Mark Yampolskiy, a computer science professor at the University of South Alabama put it: "They should start investing heavily in security.”

Yampolskiy's team is working on an answer. It has developed a computer algorithm that can listen to the sounds of a working printer and detect even tiny deviations in its output.

Printers Could Enable New Criminal and Security Threats

Photo by Sunny Burns, ARDEC/U.S. Army

The U.S. Army calls it the Rapid Additively Manufactured Ballistics Ordnance: A 3D printed grenade launcher that fires 3D printed grenades. R.A.M.B.O. for short. The idea that desktop 3D printers could be used to mint weapons has been around almost as long as the printers themselves. The fact that soldiers can print the parts for a grenade launcher means that someone else could try, too.

Analysts already fear that terrorist groups might soon be able to print the parts for suicide attack drones, a dangerous step up from the improvised explosive devices that proved so lethal in Iraq and Afghanistan. With enough planning, time, and luck, attackers could also commandeer a printer inside a sensitive location and build a weapon behind the security perimeter. In addition, it will become much more difficult to track violent extremist groups when they can print what they need anywhere that has an electric outlet.

Printed Guns Are Not the Biggest Risk

Most of the attention around printed weapons has focused instead on homemade guns. Tens of thousands of people have downloaded files for gun parts. Transportation Security Administration agents found one such gun in 2016, printed in plastic, in a carry-on bag at the airport in Reno, Nev.

But the RAND researchers concluded that printed guns are not likely to pose a major new threat. They tend to be flimsy and unreliable; and its neither difficult nor expensive to buy a professional made gun. What will change is how—or even whether—governments can regulate the sale of guns and other weapons at the point of purchase.​​​​​​​

The hazard comes from who may choose to use 3D printers to create guns. Captain Craig Schwartz, Santa Rosa Police Department in California

The challenge "is not that a society bereft of firearms will suddenly be flooded with guns,” Capt. Craig Schwartz of the Santa Rosa Police Department in California wrote in a 2015 article for The Police Chief magazine. "Instead, the hazard comes from who may choose to use 3D printers to create guns.”

Schwartz said in an interview that he also worries about the potential for new street drugs, custom-printed from chemicals, and about identity thieves printing devices to skim information from credit-card readers. But he's measured about the day-to-day dangers of 3D printing: "The neighbor who's printing up a body for a drone in his garage, I really look at that and say, ‘That's kind of cool.'”

New Manufacturing Capabilities Could Endanger Jobs

Jim Reid has been a machinist all his adult life. He's a craftsman, trained over years on the factory floor to cut parts with extraordinary precision. It's a job that a 3D printer can do with a mouse click.​​​​​​​

"Will we all be our own independent businesses, just printing our own parts and trying to sell them to the highest bidder?" he said. "I can see the societal benefits to (3D printing), but it's still putting somebody out of work somewhere. If we're making things, how can we have people that can afford to buy them?"​​​​​​​

Industrial printers are fast becoming "factories in a box," able to print almost anything, with one big advantage over traditional manufacturing. They can produce a precision part for an airplane at roughly the same cost as producing a toothbrush. Industry experts call that "complexity for free."

Will we all be our own independent businesses, just printing our own parts and trying to sell them to the highest bidder? Jim Reid, machinist

Estimating the Impact

It's hard to say how much of an economic and social impact this technological advance will have. Experts interviewed by the RAND team estimated that 3D printers might produce only 5 percent of all consumer goods in the coming years—or it's possible it could be more like 90 percent. Millions of jobs could hang in the balance.

A recent analysis by the World Economic Forum, for example, estimated that 3D printing, robotics, and other advanced technologies could contribute to a new loss of 5 million jobs from major economies in the next five years. But other studies have concluded that 3D printing could be part of a new industrial revolution, eliminating the advantage of cheap labor in such places as China and bringing production back to the United States.

That's where Jim Reid has put his hope. "We understand technology, we understand progress," said Reid, now the director of safety, health, and apprenticeship programs at the International Association of Machinists and Aerospace Workers. "But let's train the people who are being put out of work to run the printers. There's opportunity for growth there."

His union set up a 3D printer in the main hall of its 2016 convention, to show its members what was coming. As the printer churned out a crescent wrench and then the union logo, Reid remembers, the reaction was "wow." And then: "But it can't do my job."

"No, it can't do your job exactly," he said. "It can probably print the parts you make, though."

Printers Could Change the Rules in International Affairs

Photo by umenie/Getty Images

For years, Iran Air has been near the top of any list of the world's most dangerous airlines. Until recently, its rusty aircraft—dubbed "flying coffins" by some passengers—had to rely on salvaged or smuggled parts to stay in service after economic sanctions locked it out of the international market.

A few industrial-sized 3D printers could change all of that. Ticket-holders on Iran Air might welcome such a development, but it would undercut some of the most powerful tools the international community has to enforce rules and norms.

Economic sanctions and trade embargoes would become far less effective if rogue states could simply print what they need. Isolated regimes or extremist groups could also use printers to manufacture weapons that previously required industrial expertise.

"Perversely," the RAND researchers wrote, "(3D printing) might indirectly support the survival and rise of such states as North Korea, which would no longer suffer the same costs of withdrawing from the international community."

Leapfrogging Borders, Sanctions, and Tariffs

At the same time, the trade ties that have held together nations—incentivizing cooperation over conflict—could fray. A car company, for example, might print and assemble the parts it needs on site, rather than making the parts in one country, shipping them to another for assembly, and selling the final product in a third. A recent report by trade analysts at ING predicted that 3D printing could wipe out almost a quarter of cross-border trade by 2060. Those trade ties and supply chains, the RAND researchers noted, have contributed to a dramatic decrease in interstate war since World War II.

3D printing "could profoundly alter global and local economies and affect international security," the RAND team wrote. "(It has) the potential to dramatically disrupt the prevailing state system and international order."

Getting It Right (Including Regulation)

A powerful earthquake ripped through central Nepal in April 2015, flattening villages, killing thousands, and leaving thousands more homeless. When a team from a humanitarian aid group called Field Ready made its way to a makeshift camp for displaced people, it found a small but potentially life-threatening problem. A water pipe serving the camp had sprung a leak—an entry point for disease and contamination. But the team had a 3D printer rigged to its pickup truck. It was able to manufacture a pipe fitting on the spot—one that was still holding the pipe together months later.

It was a small victory, but it shows the potential for 3D printing to meet real needs—and improve real lives—in ways that have never been possible. There are reasons to be cautious about this new technology, the RAND researchers concluded, but there is also danger in overreacting, overregulating, and smothering what could be a new era of innovation.

The researchers offered a few ideas to help thread that needle. Countries could limit supplies of rare or dangerous raw materials, for example. They also could require online printer registration or require that printers encode a traceable identifying tag in their products. They could train workers in traditional manufacturing jobs to take on the 3D printing jobs of the future, which might help avert the social instability that would follow widespread unemployment.

What is really needed is more awareness of what 3D printing could make possible. That means more thought and research into what 3D printing will mean for national security, international trade, and global stability—without losing sight of that pipe fitting in Nepal.

"This is powerful, amazing technology," RAND's Smith said. "There are positives and there are potential negatives, and it makes sense to think through those negatives before they become major issues that society is not prepared to deal with.

"That's why we did this study, to start that conversation."