Those who have been following the 3D printing industry more recently have had the opportunity to witness the birth of composite 3D printing technologies. Starting with Markforged, which introduced continuous carbon fiber printing to the world in 2013, we’ve since seen numerous companies come forth with new methods for 3D printing fiber reinforcements, usually highlighting carbon fiber as the reinforcement of choice.
One of the latest startups to emerge is Fortify, which has a completely novel approach to composite 3D printing. One of the ways that the firm stands out from the other innovators in the space is its use of magnetics to orient reinforcement fibers within a part. To learn more, we spoke to Fortify CEO and cofounder Josh Martin.
Founding Fortify on the Building Blocks of Nature
Every new 3D printing technology has to have a name. In the case of Fortify, it’s Digital Composite Manufacturing (DCM) and it was born out of PhD work Martin was pursuing at Northeastern University.
At the Directed Assembly of Particles and Suspensions lab of Fortify, cofounder Randall Erb, Martin and several other cofounders were exploring possibilities for the magnetic assembly of structures found in nature, such as bone, that are strong, stiff and tough.
“What’s unique is that [these materials found in nature are] typically made of pretty simple building blocks. In [the case of bone] it’s essentially collagen and biominerals,” Martin said. “We started using this technique to replicate biological structures and then realized that it could be used to change the way that 3D printing composites was approached.”
Digital Composite Manufacturing
The hardware behind DCM, is based on a digital light processing (DLP) platform, meaning that a projector is used to cure photopolymer resin layer by layer using ultraviolet (UV) light. In the case of DCM, this resin is a slurry filled with reinforcing additives that are aligned using a magnetic field. The UV light then solidifies the resin, with the additive material reinforcing the structure of a part.
The ability to magnetically orient reinforcement fibers is key to achieving the physical characteristics typically desired of materials like carbon fiber, such as strength and abrasion resistance. This is because most composites are anisotropic, meaning that their material properties are directionally dependent. Just as the strength of a piece of wood is dependent on the grain, the strength of a carbon composite depends on the orientation of the fibers.
At the moment, parts made by Fortify can be designed to take advantage of these properties and provide the best strength possible to the proper locations. In the future, however, it may also be possible to achieve isotropic properties throughout the part.
“What we’ve done is explore options for designing isotropic properties, while still using reinforcement additives and there are a couple clever ways you can do this. That’s an issue that we’re trying to stay in front of,” Martin said. “That said, if the use case has a bunch of different failure modes or criteria you can plan for that as well in an anisotropic state.”
Fortify’s technology can now 3D print with advanced ceramic additives, used for their interesting physical characteristics, such as their electromagnetic properties.
DCM vs DLP
If the company is able to achieve isotropy with carbon fiber parts, it will achieve a breakthrough in the composites industry. However, even as it stands, DCM provides a number of advantages over traditional carbon fiber layup, which is typically a costly and labor-intensive process.
“There are a lot of high-performance, fiber-filled plastics in the world today. They are all very expensive and need to be machined down,” Martin said. For this reason, the company is leveraging an open material network in an attempt to develop more reinforced materials for use on its platform. Rather than spend time and money performing manual carbon fiber layup, Fortify is able to produce parts quickly, cheaply and in any geometry already possible with DLP and stereolithography.
Not only is the geometric complexity on par with these existing 3D printing processes, but the strength of the reinforcement material gives DCM the ability to fabricate parts with fewer support structures and greater overhangs.
“One of the exciting things with our materials is the reinforced green body strength is much higher than in a neat resin,” Martin said. “You can do more drastic overhangs. You do still have standard DLP practices where you might need to support a few features here and there, but generally speaking you’re dealing with a toolbox that is pretty robust.”
Commercialization Strategy
The system that Fortify has currently developed has a build envelope of 8" x 4.6" in the X-Y axis and roughly 12" along the Z-axis. Fortify has plans to sell this model to beta customers in the first half of 2020. Currently, those customers are purchasing parts made by Fortify to evaluate the materials being used.
“Essentially, this allows us to get market validation before having to ship the system, so we can de-risk a lot of the adoption,” Martin said.
One of the promising applications that the firm has already discovered is the fabrication of tooling for injection molding. Tools printed with DCM have, according to Fortify, improved surface finish, detail resolution and accuracy. Benchmark testing has demonstrated that tool life is extended by 10 to 100 times. Perhaps the biggest benefit is the fact that inserts for injection molding can be made in hours, meaning that customers don’t have to wait days or weeks for their tooling.
In addition to its Fluxprint hardware, Fortify has also developed a generative design software and two materials, one of which the startup claims is the strongest material system on the market. The company is already working with materials companies, such as DSM, to develop more resins for use with its technology. Another partner will be announced at formnext 2019 in November.
So far, Fortify has closed its Series A funding with a total funding reaching $13 million. To learn more, visit the company website.