Stratasys Ltd. of Eden Prairie filed a patent infringement suit against Microboards Technology of Chanhassen, which makes the Afinia H-Series consumer 3-D printer.

The suit, filed in federal court in Minneapolis, seeks unspecified damages from Microboards and a permanent injunction preventing sales of the Afinia printer. Stratasys alleges violation of four of its patents.

Microboards President Mitch Ackmann could not be reached for comment.

3-D printers hold out the promise of revolutionizing both prototype development and the manufacture of some products. The devices print physical objects by layering deposits of sprayed material.

Stratasys recently acquired MakerBot, a consumer 3-D printer firm based in New York, putting it in direct competition with the Microboards Afinia printer. Stratasys said the action marked the first time in its 24 years that it has filed a patent infringement suit.

"Intellectual property infringement discourages companies from investing in innovation," Stratasys CEO David Reis said in a statement. "Stratasys pioneered 3-D printing, and invests millions of dollars each year to develop our technologies. In 2012 alone, Stratasys Ltd invested $33.3 million or 9.3 percent of its revenues in R&D. We intend to protect that investment."

The Stratasys patents in the suit cover the ways a 3-D model is created by spraying liquid material that hardens to form an object.

One Stratasys patent is about the rate at which liquid material is sprayed to give the model different degrees of hollowness between its layers. A different patent is a method for keeping freshly sprayed material above the temperature at which it would solidify. Another patent covers the control of the temperature of the material before it is sprayed. Still another is for a method for concealing the seams caused by layering sprayed material.

Steve Alexander • 612-673-4553