(FORTUNE Small Business) – Since he built a low-cost 3-D printer, Scott Crump, CEO of Stratasys, based in Eden Prairie, Minn., has seen company revenues jump from $39 million four years ago to $70 million last year.

ENGINEERING GROWTH: Crump, 51, introduced his first three-dimensional printer in the 1990s. Known as the Genesis, the rapid-prototyping device allowed automotive and aerospace engineers to quickly create plastic molds of their drawings. But its pricetag kept Genesis out of the hands of many customers that Crump hoped to reach: industrial designers and students in engineering schools. "I felt that it was very important to have a 3-D printer for engineers to visualize what they were working on," he says.

A MODEL BUSINESS: By February 2002, Crump had perfected the Dimension, which, with its $30,000 pricetag, costs a tenth as much as most competing machines. "I've been in business now 28 years, and I've never seen a product take off as well as it has," he says. "It's now roughly a third of our business." This year Crump, whose company earned the No. 17 spot among the fastest-growing businesses on the 2005 FSB 100, expects sales of at least $84 million. "There's an opportunity to sell more than 500,000 of these printers at the right price," he says. --TERRELL JOHNSON