Proto Technologies Inc., a Liberty Lake-based rapid-prototyping company, says it has added four employees in the last two months and has purchased a 3-D "printer" that allows it to create models using multiple materials at the same time.

The company's variety of customers is enabling it to continue growing despite the tough national economy, says President Rory Nay, who owns Proto Technologies with her husband, Greg.

"We're a diverse company in terms of the companies we work with," says Nay. "With our type of industry, we can serve any type of industry."

Proto Technologies leases 20,000 square feet of space in a building at 22808 E. Appleway that the Nays own and currently employs 30 people, Nay says. The company, which has seen its sales grow 35 percent this year over 2007, should continue its upward trend in 2009, she says.

Proto Technologies recently created a general manager position, filled it, and hired three parts-finishing technicians as it added the four employees. Nay says Proto Technologies also is interviewing to fill two computer numerical control (CNC) machinist-programmer positions, and plans to hire people for those positions next month.

The company works with customers in the medical, electronic, aerospace, and manufacturing industries, she says.

The 3-D printer Proto Technologies bought is a Connex500 printing system made by Objet Geometries Ltd., headquartered in Israel. Bruce Bradshaw, a spokesman for Objet Geometries, says the printer, one of the latest pieces of equipment used in the prototyping industry, sells for around $250,000. In this context, the word printer doesn't refer to a machine that puts ink on paper, but rather one that makes three-dimensional objects based on computer images.

Proto Technologies' new machine can "print" parts and assemblies made of multiple model materials, with different mechanical and physical properties, in a single "build" process, says Bradshaw.

"The Connex500 brings development much closer to realizing the final product at an early stage," he says. When parts are printed using multiple model materials, it eliminates the need to design, print, and glue together separate model parts to make a complete model, leading to savings in printing and post-processing time, he says.

Previously, Nay says, Proto Technologies created prototypes using a single model material, or resin, with a machine called a stereo lithography apparatus.

The advantage now, she says, is Proto Technologies is able to create more realistic parts. The 3-D printer produces models that are closer, in terms of appearance and feel, to a customer's desired end product, Nay says.