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3-D Printing

3-D printing start-up Carbon seeks to be found everywhere

The start-up is taking the technology deeper into manufacturing

by Alexander H. Tullo
July 1, 2018 | A version of this story appeared in Volume 96, Issue 27

A photo of an Adidas shoe midsole as it comes out of a Carbon machine.
Credit: Adidas
Carbon's technology will be used to make 100,000 shoe midsoles this year.

In early 2015, Joseph M. DeSimone, then best known as an influential chemist at the University of North Carolina and North Carolina State University, took to the technology world’s hippest stage and brought the house down.

Carbon at a glance

Technology: 3-D printing

Location: Redwood City, Calif.

Founders: Joseph DeSimone, Alex Ermoshkin, and Edward Samulski

Funding: $422 million

Backers: GV, Johnson & Johnson Innovation, Emerson Collective, GE Ventures, Fidelity, Adidas, JSR, Sequoia Capital, Silver Lake Kraftwerk, and others

It was a TED Talk, and DeSimone was pitching his new three-dimensional printing company Carbon. An overhead projection boasted that Carbon’s process was 25 to 100 times as fast as other 3-D printing technologies. To prove it, one of his machines made a part—a ball consisting of concentric geodesic layers—live on stage.

While it was emerging from a bath of red fluid, DeSimone recalled how he and the technology’s other inventors were inspired by the scene in the movie “Terminator 2” when the robot baddie reassembles itself from a pool of liquid metal. When the ball was completed toward the end of his 10-minute talk, the room erupted in applause.

For two decades, people have pinned many hopes on 3-D printing. By now, we were supposed to be using products that were 3-D printed, perhaps even 3-D printing parts for ourselves at home. And 3-D printing has made important gains. It is assisting manufacturers in rapid prototyping, factory tooling, and making molds for casting metal parts.

But so far, the processes and materials available for 3-D printing haven’t been enough to realize the full vision for the technique. DeSimone says Carbon might be the one to revolutionize mass production.

Since that TED talk, the firm has raised more than $400 million from big backers, giving it a valuation of $1.7 billion. More importantly, its machines are already printing tens of thousands of parts for big companies with familiar names. Soon, they expect to be printing millions.

DeSimone says Carbon can do this because its version of 3-D printing isn’t like those that preceded it. The most common of them, fused filament fabrication, uses a robotic nozzle to trace parts layer by layer with a molten thermoplastic. In laser sintering, a laser melts a fine thermoplastic powder into desired shapes. Stereolithography employs lasers to draw parts out of ultraviolet-curable acrylates and epoxies.

Carbon’s process resembles stereolithography but with some important twists that make the initial print time much faster. In stereolithography, the part being fabricated rests in a pool of resin and is inched up out of the vat each time the UV laser draws and cures a new layer.

Carbon’s innovation is a window at the bottom of the machine that is permeable to oxygen, which slows the UV curing. The oxygen creates a “dead zone” of about 20 to 30 μm below where the UV laser draws and cures new layers. In this dead zone, the part isn’t curing, and its surface is constantly saturated with uncured resin. The printing process is thus rendered continuous rather than discrete. “By having oxygen coming through that window in addition to light, you have taken the mechanics fundamentally out of the 3-D printing process,” DeSimone says. “This becomes a software-controlled chemical reaction to grow parts.”


The high speed of the process opens it up to dual curing. The UV curing locks in the basic shape of the part. And then a thermal curing step sets off a secondary chemical reaction that builds the resin’s polymer chains and causes the materials to adapt and strengthen.

DeSimone says the standard stereolithography process is too slow for dual curing. The resin would chemically cure before the UV light gets a chance to shape it. As a result, stereolithography is relegated to acrylic and epoxy systems that cure with UV light alone.

Carbon’s machines can process those resins—plus polyurethanes, polyureas, silicones, cyanate esters, and other chemistries. The wider range gives Carbon’s scientists the chance to emulate traditional injection molding of thermoplastic parts, which is the target market for its materials.

Developing new materials is largely a matter of identifying established polymers with desirable properties and getting them to work in Carbon’s process. “We have to reposition the chemistries and have to imbue photocuring,” DeSimone says.

For example, in May, Carbon released EPX 82, an epoxy system that has properties similar to those of glass-filled engineering polymers such as polybutylene terephthalate. The product was developed in collaboration with the auto parts supplier Aptiv and designed for electrical connector housings. Carbon also introduced EPU 41, a polyurethane that can be printed in elaborate lattice structures to compete with energy-dampening foams.

Dayton Horvath, an independent consultant in 3-D printing, agrees that dual curing provides Carbon with a wider range of materials than stereolithography. It has given the company enough elastomers and plastics to keep it busy in consumer goods.

In applications where manufacturers are looking for resins with high-temperature resistance or other exclusive properties—polyaryl ether ketones used in medical implants, for example—Carbon will have a tougher go of it, Horvath says. “But they don’t necessarily need those” to build a significant business, he adds.

Another twist to Carbon’s business model is that it leases its machines, instead of selling them. This mitigates risk for customers who might be reluctant to plunge into an emerging technology only to find themselves with obsolete equipment. Over-the-air software upgrades, like the ones beamed to a Tesla car, ensure that machines in the field can handle process improvements and new materials.

Big investors, including Silicon Valley’s elect, like what they see in Carbon’s process and business model. GV, formerly Google Ventures—Google founders Larry Page and Sergey Brin were in the audience at the TED Talk—led a financing round. Late last year, Carbon garnered $200 million in additional financing, bringing its total take to $422 million. Johnson & Johnson Innovation participated in this round, as did GE; the chemical firm JSR; Emerson Collective, founded by Laurene Powell Jobs; Fidelity Management & Research; and Adidas.

Adidas is also a customer. It is scaling up 3-D printing to uncharted levels. This year, Carbon machines will churn out 100,000 elastomer lattice midsoles for the Adidas Futurecraft 4D shoe, according to Phil DeSimone, Carbon’s vice president of business development and Joseph DeSimone’s son. Next year, Adidas will make millions, he says. The ultimate goal is to reach 50 million 3-D-printed shoes annually—about 10% of Adidas’s total production.

“Adidas will be the largest user of 3-D printers in the world by the end of this year by a long shot,” Phil DeSimone says.

Adidas isn’t Carbon’s only big customer. Vitamix is using its machines to make tens of thousands of nozzles for a blender. The printed part consolidates six injection-molded parts into one, is one-third the mass, and lasts longer, Carbon says.

The company is also making inroads into dentistry. Last month, it signed an agreement with National Dentex Labs to install printers at dental labs around the U.S. to make models, casts, and implant guides.

Carbon experienced 300% growth last year, the younger DeSimone says, and he expects another triple-digit performance this year. The company has nearly 300 employees. About 100 are in R&D; a third of those are molecular scientists. “My goal is to be the largest equipment maker in 3-D printing,” he says. “We will be there certainly by the end of next year.”

Horvath, the consultant, says the current big player in 3-D printing, Stratasys, has tens of thousands of machines comparable in cost to Carbon’s in operation. “I would be impressed if Carbon was delivering many thousands of printers in three year’s time,” he says.

Joseph DeSimone, who is winding down his academic career and focusing on Carbon “more than full time,” is thrilled with his company’s fast start. “I’m living the dream,” he says. “If you’re a polymer person, it doesn’t get any better than this.”.


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