Engineers work in the lab to discover how to make 3-D printed parts stronger. Source: Texas A&M University Most 3-D printed parts today are fragile and cheap, often used for prototyping of larger devices or as a toy.

Researchers at Texas A&M University are looking to make 3-D printed parts stronger and applicable for real-world applications by using traditional welding concepts that bond the submillimeter layers in a 3-D printed part together while in a microwave.

3-D printed objects are made up of thin layers of materials—often plastics—that are deposited on top of each other to form a desired shape. These layers are prone to fracturing resulting in durability and reliability issues when used in a real-world application.

"I knew that nearly the entire industry was facing this problem," says Brandon Sweeney, a postdoctoral student at Texas A&M. "Currently, prototype parts can be 3-D printed to see if something will fit in a certain design, but they cannot actually be used for a purpose beyond that."

The idea is to integrate carbon nanotubes in 3-D printed parts coupled with microwave energy to weld the layers of parts together. Because 3-D printed parts can’t be stuck in an oven because it will melt, the researchers looked at welding because you use a point source of heat, like a torch, to join the interface of the parts together. Because the layers making up the 3-D printed parts are incredibly small, special materials are used to control where the heat hits and bonds the layers together.

"What we do is take 3-D printer filament and put a thin layer of our material, a carbon nanotube composite, on the outside," Sweeney says. "When you print the parts out, that thin layer gets embedded at the interfaces of all the plastic strands. Then we stick it in a microwave, we use a bit more of a sophisticated microwave oven in this research, and monitor the temperature with an infrared camera."

As the part is being printed, the welding process is happening simultaneously. The method is currently in beta phase but has the potential to be included on every industrial and consumer 3-D printer where stronger parts are needed, Texas A&M says.

The full research can be found in the journal Science Advances.