Ric Fulop, the 43-year-old cofounder and chief executive of Desktop Metal, is eager to show off the skunkworks for the company’s giant 3-D metal printers, which can produce stainless steel, aluminum and other metal alloy parts at assembly-line speeds and in large quantities. It’s the first time he’s taken an outsider to the facility in Nashua, New Hampshire, just across the state line from Desktop Metal’s headquarters in Burlington, Massachusetts. The four machines—which are 16 feet long, 6 feet tall and weigh about as much as an SUV—are in various states of production. They’ll be able to 3-D print 100 times faster than existing high-end 3-D printing systems used for aerospace, and at one-twentieth the cost, without the tooling required for traditional manufacturing processes. “It’s the first metal printing press,” says Fulop, an exuberant, heavyset man with a slight accent from his native Venezuela.