Goshen High School freshman Ivonne Lopez may have cerebral palsy, but she insists on being as independent as possible.

That means she hangs a backpack for her textbooks on her walker so no one has to carry it for her. Unfortunately though, the pack kept knocking her seat down, tripping her up and making her fall.

That's when seniors Evan Smith and Nick Truex stepped in with their teacher's 3D printer. They designed and printed four clips which attached to a piece of 8020 extruded aluminum to hold the seat in place, allowing Lopez to stay on her feet and maintain as much independence as possible.

"The motivation for them on the project was not about the grade," said JJ Johnson, technology and education instructor at Goshen High School, in Goshen, Indiana. "The motivation was improving someone's life. There was more motivation from those two than for anything I could have assigned. This was not graded."

It all started back in October, when Lopez's paraprofessional walked into Johnson's lab and explained the situation during a lunch break. Smith and Truex happened to be in the lab doing some extra work, so Johnson turned to them.

"I said, 'You guys were here, you heard the background, what do you think?'" Johnson said.

Smith recalled a kayaking trip he and his father took last summer.

"I thought about the clips we used to keep the paddles in place on the kayaks and thought that would work," Smith said.

      The final 3d printed clip

The two set to work and 3D printed a clip within 55 minutes.

Unfortunately though, it didn't work. The ABS from which they made the clip was too brittle. The clip quickly broke, and it was back to the drawing board.

"Evan had a lot of background in getting things done on the 3D printer, while Nick was more of the CAD guy," Johnson said. "Evan would come up with ideas they needed to try, and Nick was really good with making that happen on a computer modeling in Autodesk Inventor."

It took them another six tries over the next couple of weeks to get something that worked. They tried using T-Glase filament, as well as rotating the clip during the process to make it stronger, among other things.

"Too strong and we found they were breaking, but they wouldn't hold without enough material," Johnson said.

"We didn't want to drill any holes or alter the walker in any way," Johnson said.

In the end, they came up with a clip made from ABS with a hollow body made from 54 cents worth of filament.

"It works wonderful," said Lopez to WSBT-TV in South Bend, Indiana. "It makes life so easy for me."

Both Evans and Truex want to study engineering next year when they go to college.

"It kind of showed me there's a little more to engineering than marketing," Evans said. "We did this just to help someone else, instead of making a piece someone is going to sell."

Goshen High School got its first 3D printer back in the fall of 2012.

"I saw a flyer on a wall in a 7-11 for a 3D printer for sale," Johnson said.

Johnson convinced the school board to buy one from the SeeMeCNC 3D printer manufacturing company, which is based in Goshen.

"They thought, 'For $500, he'll stop bugging us,'" Johnson said.

Actually, he personally owns the two 3D printers his students are using right now, but he is hoping to convince the school board to buy another one or two.

"This is only the beginning of what we are going to be 3D printing, I can guarantee that," Johnson said.

The 3D printers are not only a great educational tool in and of themselves, Johnson incorporates them in other projects. For instance, the school's Shell Eco Marathon Team has 3D printed parts for their cars to keep the weight down.

The goal of the Shell Eco Marathon is to build the most energy efficient (go-kart sized) car. In the last two years' competitions, the Goshen High School team has built cars that have gone 535 miles and 555 miles respectively on a single gallon of gas while traveling an average speed of about 35 mph.

"This year we're shooting for a 1,000 miles per gallon," Johnson said.

They can be followed on Twitter at @GHSEngineering.com.