(TNS) — BARBERTON, Ohio — David Kaser's students at Barberton High School are learning about all the cool things a 3-D printer can do.

They've designed and printed cellphone stands, Star Wars figures and signs for themselves.

But Kaser also is teaching them about the cool things 3-D printers can do for others. This week, students in his STEM 1 classes are assembling parts for 25 to 30 plastic prosthetic hands, which will be sent to organizations that will test them, find size matches and distribute them to children and others in need around the world. Kaser printed out all the parts on six printers at the school over the last three weeks.

On Wednesday, the students worked in pairs, watching YouTube videos on Chromebooks to see how to assemble the hands. Some threaded high tension fishing line and elastic bead cord through the fingers and then through the hands, while others placed the plastic pins that would help the fingers bend and curl.

The hand is meant for someone who has basic wrist function but is missing fingers, Kaser said. The wrist function allows the person to move a hinge that allows the hand to grasp. The hand is padded and attached to the forearm by Velcro straps.

"They primarily make them for children because they grow so fast," he said. In a country that doesn't have a good health system, it is expensive to have to keep refitting. Kaser estimated the cost of each hand at $30 to $50.

"It's pretty intuitive," Kaser said. "They just strap it on and they'll figure it out pretty quick. It doesn't allow for a lot of fine motor skills, but it does allow for carrying a bag or holding onto a bucket or whatever they might need, even if it's just to readjust the grip in the good hand."

The hands come in several colors, different sizes and three designs.

Kaser had seen a presentation on the hands at a tech conference a few years earlier and found designs online from mechanical engineers and design specialists at universities. Last year he had a student who built three as a project. Now studying mechanical engineering at the University of Akron, she kept one for herself as a souvenir and left the other two with Kaser. He sent one for testing. The design worked, which meant Kaser and his students could make more for shipment overseas. The other he has in his classroom, a hot pink reminder of the potential for good.

The 3-D printers work sort of like "a finely tuned, high-tech hot-glue gun," Kaser explained. Rolls of filament that come in different colors snake into the print head, where it is heated to 205 degrees Celsius (410 degrees Fahrenheit) in what's called a hot end, then comes out a nozzle and is swirled onto the print bed. Fans blow on it so that it dries and hardens immediately. The object grows layer by layer. Software tells the printer what coordinates to use in the design.

On Wednesday, the printer corner looked like a Mardi Gras celebration with filament in yellow, green and purple snaking through the machines, each printing something different. In the works were several dice, a box for batteries and other objects that students designed using computer-assisted design software.

A single finger takes about an hour and a half to print, Kaser said. Because they are surrounded by little support material, they sometimes break during printing, so Kaser figured out a way to attach a set of five to a single bed, then break them off when they are done. Because parts such as knuckles need to move, they are purposely broken off so that can happen, hence the threading. Sometimes parts' edges are rough and must be sanded.

Sarah Stacy, 16, a 10th-grader, designed a cellphone holder that fits over and rests on a charger when it is plugged into a wall outlet.

"I didn't like the way they worked," she said of ones she had seen online. "I wanted to make it my own. ... I don't have to lay my phone on the ground or get it stepped on."

She took measurements, designed it on paper with 3-D and multi-view drawings, then used the computer to get a 3-D image. Kaser printed a prototype, Sarah made fixes, then printed out the final product. She thinks it's "awesome" the hand project is going to help others.

Classmate Zachary Wilson, 18, a senior who loves movies, is working on a lens hood for his camera. "I think it's cool that we can print something and actually use it, too," he said.

He was busy in class adding the cords to the fingers of a light-blue adult-sized hand. He thinks the project is "cool" and "is going to be a catalyst for the future of prosthetics. We're only in the beginning," he said. "There's going to be a lot to come."

"I'm happy to give our kids a chance to do this," Kaser said. "I want them to see that they can help other people. The opportunities are endless for them."

Monica L. Thomas can be reached at 330-996-3827 or mthomas@thebeaconjournal.com. Follow her on Twitter @MLThomasABJ  and www.facebook.com/MLThomasABJ.

©2017 the Akron Beacon Journal (Akron, Ohio), distributed by Tribune Content Agency, LLC.