As a team, we love to highlight and share the work we see being done by researchers using NovaCentrix equipment and materials. While we regularly do this internally, my hope in sharing and writing about this recently published work for a broader audience is that it helps spread some interest in new tech, as well as bring attention to these great results. Researchers at the Army Research Laboratory and Duke University have shown that PulseForge curing can dramatically improve the electrical performance of 3D printed conductive filament composite materials.
3D printing, or additive manufacturing, has seen commercial efforts over several decades with a quick rise in interest over the past several years. A Gartner analysis from 2019 showed a 300% growth in enterprise 3D printer manufacturers over the preceding 3 years. Aerospace and medical device industries were among the first to create real value by using additive manufactur
ing to reduce weight and consolidate the assembly of components. Their success has paved the way for many other industries to evaluate new 3D printing techniques for their own processes.
Functional 3D printing and multi-material 3D printing have the potential to dramatically increase the value of 3D printed components, but only recently have a few conductive materials been developed which are compatible with “fused filament fabrication” (FFF) – the most widely available and often lowest cost 3D printing technique. Conductive filaments which can be used for functional 3D printing are new and there is a significant need to improve their electrical performance in 3D printed components to deliver on the promise of functional multi-material 3D printing.
A team led by researchers Dr. Jorge Cardenas and Dr. Nathan Lazarus have shown that PulseForge processing of 3D printed conductive filament reduced the sheet resistance of the printed pattern by
up to 100 times. The high intensity pulsed light triggered a “flash ablation metallization,” the creation of a metal-rich surface layer by removal of the exposed thermoplastic, to make the filament-printed pattern more conductive.
Their work, published in the journal Additive Manufacturing, demonstrates that photonic processing can be a “rapid, non-contact (curing technique that takes place) in-line with the rest of the printing process in an autonomous manner.” The conductive filament, available from Multi3D as Electrifi, is a composite thermoplastic with metallic flakes. After printing, the pattern traces could be PulseForge cured to give a 100 x reduction in sheet resistance, with final sheet resistances < 1 Ω/□. This curing process showed effectiveness at a variety of surface angles with respect to the lamp window and a number of demonstration circuits were printed along 3D surfaces and cured. I encourage readers to read the full article which shows the full scope and detail of this exciting work.
Cardenas, Jorge A, Harvey Tsang, Huayu Tong, Hattan Abuzaid, Katherine Price, Mutya A Cruz, Benjamin J Wiley, Aaron D Franklin, and Nathan Lazarus. 2020. “Flash Ablation Metallization of Conductive Thermoplastics.” Additive Manufacturing, no. March: 101409.
The report also highlights how the PulseForge was a valuable tool for developing a curing process window. The PulseForge allowed the researchers to quickly experiment with a range of pulse profiles and monitor the effects of each pulse condition on the sample. The results draw a distinction between the effect of high instantaneous power and higher overall pulse energy. The flexibility of the PulseForge to independently control these aspects of the curing pulse both allow for better overall electronic performance of the printed pattern as well as providing some clues about possible curing mechanisms. These built-in capabilities allow researchers to direct their development paths more effectively by providing quantitative process parameters and validated models.
“In addition to supplying the high exposure energy needed to ablate a layer of thermoplastic off of conductive composite films," says Jorge Cardenas, who is now leading research at a fellowship with Sandia National Labs, "the PulseForge provided the capability to quickly modify and preview each pulse's width and output power, which was instrumental in finding optimal exposure conditions."
We are always encouraged to see excellent research and development work done with our materials and processing equipment. These new results have both the potential to yield even better electronic properties in functional 3D prints, as well as impact additive manufacturing more broadly. Our flexible organization allows for more active or less active involvement in the development efforts, depending on our partner’s preference. In this case we are excited to see this work published and to assist into the future.