Researchers Claim the Holy Grail of 3D Printing, Boosting Part Strength to Match Injection Moulding
Coating printed layers in carbon nanotubes and heating them using an electric current carried by plasma results in much stronger prints.
Researchers from Texas A&M and Essentium have developed a technology which they believe solves one of the biggest problems in 3D printing: poor bonding between layers.
A 3D printer works in layers: A 3D object file is separated into 2D "slices" the thickness of the material being printed, and then each slice is printed one on top of the other to build up the finished object. Poor adhesion between the layers, however, leads to warping, breakage, and an imperfect creation — and it's this issue Texas A&M and Essentium claim to have fixed.
"Finding a way to remedy the inadequate bonding between printed layers has been an ongoing quest in the 3D printing field," notes Professor Micah Green of his team's work. "We have now developed a sophisticated technology that can bolster welding between these layers all while printing the 3D part."
The secret behind improving layer bonding: carbon nanotubes. Each layer is coated with carbon nanotubes as they are printed, and an electric current is then applied though a beam of plasma — without ever touching the print — to heat the layer and soften the plastic so it can be better welded to the next layer.
The process sounds a little sci-fi, but it's been proven in the lab - to the point where the researchers have been able to retrofit the technology to existing 3D printers. The results are promising, too: Objects printed on a modified printer shows greatly increased strength than the same objects on an unmodified printer - to the point where they were comparable to parts made using injection moulding instead.
"The holy grail of 3D printing has been to get the strength of the 3D-printed part to match that of a moulded part,” explains Green. "In this study, we have successfully used localised heating to strengthen 3D-printed parts so that their mechanical properties now rival those of moulded parts. With our technology, users can now print a custom part, like an individually tailored prosthetic, and this heat-treated part will be much stronger than before."
The team's work has been published in the journal Nano Letters under closed-access terms.