Quick Fixture

By Sara Ferris

Wair Products (Bloomington, MN) had a hot product in development, but supplier lead times were slowing the testing process. The company manufactures a liquid oxygen economizer valve, a valve that regulates oxygen flow from portable oxygen tanks to humans. It designed a test fixture that clamps to the valve and automatically sets its pressure. Once the valve pressure is set, the fixture does a complete pressure test of the valve assembly.

Before shipping customer orders, Wair Products needed additional fixtures to test the valves. The aluminum tooling company that had previously machined the fixture needed a three-to-four week lead time. The fixture's complex geometries made it extremely difficult to machine from aluminum. The tooling company ended up machining eight parts that had to be assembled before the fixture could actually test the valves.

Wair Products uses this fixture to test and set pressure on its liquid oxygen economizer valve, a valve that regulates flow from portable oxygen tanks.

Wair Products looked for an alternate manufacturing solution. Pete Nelson, owner of Wair Products, was familiar with the RedEye rapid prototyping and manufacturing service. "One of our former employees works for RedEye now, and we decided to see what they had to offer," he says.

This was the first jig and fixture order RedEye had received. "We were confident in our ability to quickly produce the part for the fixture," said Jeff Hanson, sales manager at RedEye. "This opportunity opened a new door for us in a niche that we didn't realize could utilize our services."

RedEye took on the project to manufacture the valve test fixture, which measures about 8" X 10" X 10". Wair Products uses Autodesk Inventor for its design work, so was able to output an STL file for RedEye's FDM (fused deposition modeling) prototyping systems. One challenge on Wair's end was learning to design without constraints's to make it easier to machine the complex geometries. It took RedEye three days to complete the build.

"There were too many parts associated with the original," said Chris Howells, engineering manager at Wair Products. "Digitally manufacturing the fixture with polycarbonate took it from eight pieces to one, a more accurate piece that lines up." Ultimately, digital manufacturing produced a cleaner design of the assembly fixture. Using a plastic material also reduced its cost.

"People are constantly lifting these fixtures on and off of the shelves to test valves," said Nelson. "By using plastic, we significantly decreased its weight. Our employees are glad we switched to plastic too."

RedEye was able to build the fixture as a single part using its FDM prototyping systems.

Although RedEye produced only one fixture this time around, Wair Products expects to use the technology in the near future as orders for the valves increase. "We can easily submit a file without redoing it, which saves us engineering time and in the end, money," said Howells.

Wair Products was surprised by the design time saved using RedEye's services. "We are valve designers, not fixture designers, but we must design one to get the other," said Nelson. "By simplifying the design process, we can get back to our core competency."

"We automated the process of testing the valve, which used to be a manual process," Pete added. "Now we are a key player because we were able to automate the manufacturing process too."

Wair Products was established in 1988 as a spin-off from a mobile equipment hydraulic valve manufacturer. The first product it introduced was a sanitizing system for bulk beverage syrup tanks distributed to the fast food industry.