Kurt Campbell, Greg Nay Stereolithography Adds New Dimensions To Molding Industry

Ever write in lemon juice when you were a kid?

Hold the seemingly blank paper over a flame, and the singed citric script appears.

Now, imagine that magic trick in three dimensions.

Called stereolithography, the process creates full-scale prototypes of components for computers, engines or, in perhaps its most sophisticated application, body parts.

Proto Technologies of Spokane is one of the few Northwest companies with stereolithography equipment. Most, like Key Tronic Corp., restrict its use to in-house needs.

Proto Technologies has other modeling and molding capabilities, say co-owners Kurt Campbell and Greg Nay, but the company was built around stereolithography.

“We saw a need for this process in the Northwest,” said Nay, who was a model-maker and senior mechanical engineer at Key Tronic.

Campbell, another former Key Tronic staffer, said stereolithography starts with a drawing. It could be as crude as a sketch or as finished as a rendering from computer-assisted drafting.

Finished designs are one of the services Proto Technologies provides clients, he said.

Once a design is loaded into a computer, the piece is sliced into 6,000 cross-sections. Then the stereolithographer goes to work.

Guided by the computer, a laser squiggles across the surface of liquid, photo-sensitive polymer. The beam fuses the material it touches.

Once one layer is completed, the piece is lowered, a squeegee removes excess liquid, and the laser renews its dance.

“We literally just grow the part from the bottom up,” Campbell said.

The resin-colored pieces are removed and sanded, then are used to make molds for small production runs.

In another room at the company’s small Spokane Valley facility, urethane parts can be vacuum cast at the rate of two per hour, instead of one in 18 hours using some old curing processes.

Proto Technologies also has a computer-controlled vertical milling machine, as well as manual tools.

Campbell said the company, mostly thanks to stereolithography, can telescope the time needed to create prototypes from weeks to hours.

Often, he said, customers want them yesterday.

Proto Technologies staffs its plant seven days a week to be ready for unanticipated orders, Campbell said.

“You walk in the front door with a design,” he said. “You walk out the back door with the part.”

Campbell said the models can be used to test tolerances, detect potential production problems, or as sales tools companies may want to show their customers.

Companies preparing for trade shows are a major source of business, Nay said.

Campbell said the maker of the stereolithography equipment is taking the process a step further by offering customers cast metal parts copied from the resin pieces.

The metal part can be used to make molds for plastic injection.

“That’s going to be a very rapid growth area,” he said.

Rapid turnaround is critical because product cycles keep shrinking, Campbell said. “The first product on the market gets 80 percent of the sales.”

More businesses understand that advantage, he said, and the broader availability of computer drafting is putting the ability to respond quickly to the market in more hands.

Nay, a lifelong Spokane Valley resident, said Proto Technologies has almost 100 customers. Most are from the Spokane area, but the company has sent parts all the way to Germany.

Proto Technology computers can accept drawings over the Internet in several software formats, Campbell noted.

Nay said much of what the company does cannot be discussed because customers do not want confidentiality on their newest products breached.

But he did show off a keyboard casing done for Toshiba, adding that he and Campbell occasionally spot products with components they helped produce in places like Sears.

Nay said Proto Technologies is trying to interest local doctors in a new application for stereolithography - replacement bones and joints.

In the case of a jaw shattered on one side, for example, computers can flip an image of the intact side generated by a magnetic resonance scan.

The reversed image can then be used to produce a twin of the healthy side of the jaw in the stereolithography machine.

A replacement for the shattered half-jaw can be cast from a mold taken from the resin replica.

The replacement can either be implanted or used to practice new or complicated surgery, Nay said.

He said Proto Technologies will keep pace with these innovations, and others.

“Our goal is to offer more services,” Nay said.

, DataTimes ILLUSTRATION: Photo