John Danko got his Baltimore company's first 3-D printer four years ago, and he said it's given him a front-row seat for a manufacturing revolution.

In an office across the street from the foundry where Danko Arlington's molten metal flows, he prints out the industrial patterns he said he could no longer find skilled workers to do by hand. Employees designing products on computers use the technology to spit out prototypes more quickly.

Some see in this the potential for a change as substantial as the Industrial Revolution — a different way of making things that could kick-start tiny operations, disrupt entire industries and literally transform the landscape.

"You won't have factories in the future," said Danko, president of Danko Arlington, a nearly century-old company that makes components for military, aerospace and commercial customers. "They're going to be more like office buildings."

The printers build items layer by layer — "additive" manufacturing as opposed to subtractive methods like machining — with materials ranging from plastic to metal to glass. Some machines print chocolate. Some print biomaterials like living cells.

The basic technology isn't new. It's three decades old, in fact. But only in recent years — as costs dropped, quality improved and companies began to grasp the possibilities — has it rippled into manufacturing beyond the early adopters.

Management consulting firm McKinsey & Co. said in a report this year that the technology has reached a tipping point. It appears "ready to emerge from its niche status," McKinsey concluded, and "could lead to profound changes in the way many things are designed, developed, produced, and supported."

And maybe even how they're moved.

"People spend a lot of money shipping goods around the world," said Tim Gornet, manager of the Rapid Prototyping Center at the University of Louisville in Kentucky, over the hum of two 3-D printers. "It'd be much cheaper to ship data around the world."

What all this could mean for manufacturing jobs — globally or domestically — is a big question.

Printers can replace machinists and other human specialists in some cases now, and perhaps in many more cases later. But the machines could be a boon to startups by lowering the high cost of entry to get into manufacturing. And they could dilute the labor cost advantage enjoyed by countries such as China.

Bill Davidson is on the optimist side of the jobs debate. He's CEO of the 60-employee UAV Solutions in Jessup, which builds unmanned aerial systems and parts for those systems, and he thinks 3-D printing will mean more U.S. manufacturing jobs.

Nearly everything his company makes now uses 3-D printing in some way, and he credits it for some of the project growth that's added more than 20 jobs to his business in the last two years. He also sees 3-D printing shifting work from areas Maryland hasn't put a priority on for training — like machining — to tech and software fields that are a focus here, which could make recruiting easier.

Davidson expects to see more manufacturers spring up. His five industrial-grade printers are about $150,000 apiece, but he's sure prices will continue to fall. And even the low-cost desktop models, the ones for a few thousand dollars or less, are good enough these days that an enterprising person with a great idea could start prototyping.

"You could see from an entrepreneurial standpoint, a guy just starting up — this could be huge," Davidson said. "He could do it on his own."

The National Association of Manufacturers doesn't track the number of members using 3-D printers. But officials there see more and more firms incorporating it into research and development, or the manufacturing process itself.

Some items are made entirely on printers or rely on the technology for a key part of their manufacture. Invisalign orthodontic appliances. Replacement parts in F-18 fighter jets. Millions of hearing aids.

Mass production of the exact same items remains cheaper with traditional manufacturing methods — for now. And the time-honed methods of machining and injection molding are better in some cases.

But 3-D printing allows for mass customization, like the Invisalign clear "braces" that are different for every mouth. The technology produces complex shapes that older-school manufacturing can't replicate. And it produces less waste.

"3-D printing has been hyped as though it's going to replace traditional manufacturing, and at some point that could be," said Todd Ramsburg, supervisor of the Advanced Mechanical Fabrication Group at the Johns Hopkins Applied Physics Laboratory, which has used the printers for years. "But I think the sweet spot in the next few years will be a combination of 3-D printing and traditional manufacturing — and really leveraging the advantage of each."