Engineering students recycle plastic bottles to make 3D printing filament

Saving Tech money and reducing plastic waste isn’t a grind on engineering students who are making history with Project Regrind.             

Project Regrind converts plastic water bottles into the filament needed for 3D printing. This eliminates the cost to print while reducing waste.

The project began in 2016 when Charles Davies, a senior mechanical engineering student, wanted to prevent students paying to use the printer.

The process begins with an industrial grinder. Washed water bottles are inserted into the grinder and it ejects flakes of plastic. Next, the flakes go into an extruder, which heats plastic, and produces filament. Finally, the filament which is a clear, thin cylindrical material, is put onto a spool and used for 3D printing.

The 1970’s extruder belongs to Dr. Holly Stretz, a chemical engineering professor, Davies said.

When Davies found the dusty extruder, it needed some repairs, he said.

“So, I contacted the Sustainable Campus Committee to get a grant fund to repair it. It was going to be significantly less expensive to repair it than get a new one, we’re talking upwards of $50,000 verses $20,000,” Davies said.

“I wanted to see, is it possible for me to make a sustainable filament to use on campus. There was a big talk of charging students to print, and I didn’t want that,” Davies said.

Davies said he took the Sustainable Campus Committee a proposal they loved, and the project received grant funding.

The project can save Tech money and prevent students having to pay to print, because a kilogram spool of filament is $25 on average and can last about a week, Davies said.

Davies said, about 200 bottles produces one kilogram of filament.

“We’re just using the plastic, which is really thin. So, when you grind this down to flakes, you’re getting rid of all that air that’s inside the bottle and just using the flakes,” Davies said.  

Davies said, they hope to print a spool of filament daily once everything is completed, which usually last a couple weeks.  

“We are printing a piece for 43 hours straight right now and it won’t even take up a whole spool,” Madison Dittner, a mechanical engineering student involved in the design project said.

Roya Eatebarian, a senior mechanical engineering student, said the project can help students stay creative.

“So initially, what was so cool about the maker space was it was like an Eden of creativity, it was really exciting for engineer students. Then there was talk of it costing money, and that’s not really sustainable to have people constantly using the resource without having any way of getting the resource. So that’s what prompted them to do it,” Eatebarian said.

Davies said the project is now a senior design project, for which the students receive class credit.

“We wanted to make it more efficient. Because we thought about you know, we want work study students to work on this. It’s kind of very complex right now. There’s no user manual, so I entered senior design, got a team, and now we have a lot more people working on it,” Davies said.

The team is still working on getting everything running more efficiently, so others can use the extruder, Eatebarian said.

“Eventually the goal is to have work study students, it’ll be their job to make stuff. Because they’re employed through the school. So, it’ll be their job to come in here and grind out some filament for the makers space,” Eatebarian said.

Davies said he hopes to share this knowledge to help surrounding high schools.

“A lot of this project was just to promote STEM learning. Another thing is we want to give the filament to surrounding high schools that have 3D printing for free so they can learn about this stuff,” Davies said.

This project is the first of its kind on a collegiant level, Davies said.

Dr. Dale Wilson is the professor of the senior design project.

“From what they’re telling me is this will be the first students who are doing this kind of thing on campus anywhere in the country,” Wilson said.