Carbon nanotube technology and plasma science integration produces more reliable 3D-printed parts

Written by Georgi Makin

Scientists from Texas A&M University (TX, USA) and Essentium, Inc (TX, USA) have utilized a new combination of materials science concepts, improving the strength and reliability of 3D-printed parts.

A collaborative team of scientists from Texas A&M University (TX, USA) and Essentium, Inc (TX, USA) has utilized a novel combination of carbon nanotube technology and plasma science, improving the strength and reliability of 3D-printed parts.

Described in Nano Letters, the team claims that their approach addresses the 3D printing ‘weak spot’ caused by imperfect bonding between individual printed layers. By combining carbon nanotube technology and plasma science, the team reports that the layers have been welded together more effectively.

Finding a way to remedy the inadequate bonding between printed layers has been an ongoing quest in the 3D printing field. We have now developed a sophisticated technology that can bolster welding between these layers all while printing the 3D part,” explained Micah Green, Associate Professor in the Artie McFerrin Department of Chemical Engineering (Texas A&M University).

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Previous studies have shown that plastics 3D printed by fused-deposition modeling can have imperfect joining between layers. An additional heating step can facilitate a more thorough joint between the interfaces, but this step can cause a compromised shape integrity.

If you put something in an oven, it’s going to heat everything, so a 3D-printed part can warp and melt, losing its shape. What we really needed was some way to heat only the interfaces between printed layers and not the whole part,” Green added.

By incorporating carbon nanotubes into the 3D-printed part, the team was able to promote inter-layer bonding by applying an electrical current through it. In order to connect the part with an electrical current as it was being printed, the team further chose to work with a ‘beam of charged air particles’ or plasma. The plasma allowed the electric current to pass through the object to heat the nanotubes and better weld adjacent layers.

The team tested their new approach using conventional 3D printers, observing the 3D-printed objects had strength and reliability comparable to objects produced by injection molding.

Green concluded:

The holy grail of 3D printing has been to get the strength of the 3D-printed part to match that of a molded part. In this study, we have successfully used localized heating to strengthen 3D-printed parts so that their mechanical properties now rival those of molded 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.”

Sources: Sweeney CB, Burnette ML, Pospisil MJ et al. Dielectric barrier discharge applicator for heating carbon nanotube-loaded interfaces and enhancing 3D-printed bond strength. Nano Lett. 20(4) 2310–2315 (2020);