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3-D Printing

Movers And Shakers

Carbon is C&EN’s Company of the Year for 2019

The company is helping to bring 3-D printing from the design studio to the manufacturing floor

by Alexander H. Tullo
January 3, 2020 | A version of this story appeared in Volume 98, Issue 1


A photo of bicycle saddles being 3-D printed.
Credit: Carbon
Carbon machines are beginning to print bicycle saddles from the bicycle company Specialized.

Carbon, a 3-D printing start-up based in Redwood City, California, is coming off an enormous year.

The company raised $260 million in a venture capital round, bringing its total financing to $680 million. The fundraising values Carbon at $2.4 billion, more than the stock market capitalization of at least a dozen publicly traded US chemical companies.

Carbon at a glance

Specialty: Machinery, software, and materials for 3-D printing

Headquarters: Redwood City, California

Number of employees: 400

Key executives: Ellen J. Kullman, CEO; Joseph DeSimone, executive chairman and co-founder

Year founded: 2013

Funding to date: $680 million

Investors: Adidas, Archina Capital, Arkema, Autodesk, Baillie Gifford, BMW, Emerson Elemental, Eshelman Ventures, Fidelity, General Electric, Google, Johnson & Johnson, JSR, Madrone Capital Partners, Nikon, Northgate Partners, Piedmont Capital, Reinet Investments, Sequoia Capital, Silver Lake Kraftwerk, Temasek, Wakefield Group, Yuri Milner

Carbon also got a new, top-shelf CEO: ex-DuPont chief Ellen J. Kullman, who presided over DuPont’s purchase of Danisco and its spin-off of Chemours. She had been a Carbon director since 2016.

Joseph DeSimone, a chemistry professor at the University of North Carolina at Chapel Hill, who co-founded Carbon in 2013 and launched it at a TED talk in 2015, is stepping into an executive chair position. That role will allow him to continue to evangelize on the potential of Carbon’s 3-D printing machines and materials.

DeSimone will no doubt be talking up the L1, Carbon’s latest-generation printer. Unveiled last year, it boasts a build area of 1,000 cm2, 5 times larger than the firm’s previous machine. Customers such as Adidas and the helmet-maker Riddell are already using it to make parts for consumer goods.

The world right now is rightfully focused on the excesses of plastics—the discarded materials piling up in landfills and polluting oceans. Top of the agenda for polymer makers and users is trying to solve the problem through recycling and reductions in use.

Carbon is a throwback to a time when plastics were on the offensive. Spanning the better part of the last century, it was an era in which scientists and engineers at companies like DuPont pushed polymers into applications that had long been the domain of paper, glass, metal, and natural fibers. Carbon continues in that spirit with printers that are making form-fitting helmet liners to protect football players, more affordable dentures and orthodontic aligners, and, soon, even personalized bioresorbable implants.

For these reasons, C&EN has named Carbon its Company of the Year for 2019.

Carbon isn’t the only company advancing 3-D printing. Scores of other firms came before and after it, offering machines and materials for tracing out parts layer by layer. Their techniques include depositing a filament of molten plastic, curing photopolymers with light, and melting fine powders.

Carbon has taken 3-D printing a step further with a photopolymer technology that it calls “digital light synthesis.” A key to this approach is an oxygen-permeable window under the machine. Oxygen enters and creates a “dead zone” beneath the part where curing doesn’t take place, so the surface being formed is constantly saturated with resin. The printing is continuous rather than stepwise.

Another element of Carbon’s technology is dual curing—secondary chemical reactions that build polymer chains and strengthen printed parts after the initial UV cure. Dual curing opens the technology to a wide range of materials. Other photopolymer 3-D printing technologies are limited to epoxy and acrylate chemistry. Carbon’s printers can handle those polymers, as well as polyurethanes, polyureas, silicones, and cyanate esters.

This versatility helps Carbon’s materials scientists come up with resins that can compete with established engineering polymers. “Our materials have properties and advantages on par with polymers traditionally used in injection molding,” Kullman tells C&EN. “Some perform like unfilled thermoplastics.”

With prices starting at $50 per L—many times more than conventional thermoplastics—Carbon’s materials can be expensive.

The latest is RPU 130, introduced in October at the K 2019 plastics fair in Dusseldorf, Germany. The material is a polyurethane that incorporates nearly 30% biobased content in the form of propanediol produced by DuPont Tate & Lyle Bio Products. Carbon says RPU 130 has properties similar to durable thermoplastics such as acrylonitrile-butadiene-styrene, nylon, and polypropylene.

The company’s core competency is across materials, hardware, software, and application development to create a solutions approach for customers with unique manufacturing needs.
Dayton Horvath, a principal at the investment bank NewCap Partners and an independent 3-D printing consultant

Rather than sell its machines, Carbon leases them to customers for fees that, for the L1, run about $250,000 per year. Over-the-air software updates are sent every 6 to 8 weeks, allowing machines already in the field to run the firm’s newest resins.

This approach mitigates technology risk. Customers don’t have to worry about committing capital to equipment that might become obsolete.

Kullman says Carbon’s business plan has been to make 3-D printing relevant to manufacturing in a way it wasn’t before. “Preconceived notions about poor-quality parts are common; many still think of 3-D printing as a slow, prototyping tool,” she says. “This is not totally an unreasonable perception given that, until quite recently, 3-D printing hadn’t delivered on its promise as a real manufacturing technology.”

Manufacturers are using Carbon’s printers for parts in goods that consumers can buy right now. The most famous example is probably from Adidas, which uses Carbon’s machines to make the lattice-structure midsoles of its 4D shoes. Over the past several years, the sportswear company has made more than 100,000 of the shoes, which retail for about $300 a pair.

Riddell has been making football helmets lined with a similar elastomeric lattice structure that fits the exact contours of a player’s head. National Football League players began using the new liner in 2018, and the technology was rolled out more broadly last year. Specialized Bicycle Components is starting to use a 3-D printed lattice structure in bicycle saddles.

Carbon has made inroads into medical and dental 3-D printing as well. Working with Dentsply Sirona, the company has introduced a system for 3-D printing of denture arches. And Carbon’s printers are making forms for producing dental aligners. In both cases, the technology replaces the traditional artisanal process of making casts in patients’ mouths.

Carbon also has resins for customized surgical tools. Soon, it will release a polyester elastomer for bioresorbable implants, the result of a collaboration with Johnson & Johnson.

Even the auto industry, which is notoriously conservative in adopting new materials, is leasing Carbon’s 3-D printers. The Italian sports car company Lamborghini is using them to produce dashboard air vents, fuel caps, and air-duct components. Ford Motor is using the machines to make parts, including a parking-brake bracket on the Mustang GT500.

“Carbon has done very well in commercializing its technology,” says Dayton Horvath, a principal at the investment bank NewCap Partners and an independent 3-D printing consultant. “The company’s core competency is across materials, hardware, software, and application development to create a solutions approach for customers with unique manufacturing needs.” He adds that though Carbon isn’t the answer to every manufacturing need, it is to some, “and Carbon has identified that product-market fit very well.”

The 3-D printing companies finding success are ones focusing on particular applications rather than pushing their technologies too broadly, Horvath says. “The interesting thing about Carbon is that it has taken a technology and developed applications in enough number and enough size to continue to grow.”

Attracted to that growth potential, investors have been placing big bets on ­Carbon. The $260 million investment round, completed in June, was led by Madrone Capital Partners and Baillie Gifford. It included two new investors, the Singapore sovereign wealth fund Temasek and the chemical maker Arkema. The company’s existing investors include Adidas, Johnson & Johnson, General Electric, Google, and JSR.

An initial public offering seems like a logical future step for Carbon. When an experienced executive takes over from a start-up’s founder—in particular a founding scientist or engineer—it often can be taken as a sign that the company is dressing up for an IPO.

Carbon is arguably a little different. DeSimone has proved himself a capable leader who has taken the company far. And he has been a businessperson as well as a scientist for ages. In 1995, he formed Micell Technologies to commercialize a dry-cleaning system based on specialty surfactants and liquid carbon dioxide.

Kullman punts when asked about floating the company’s stock. “Right now we’re focused on delivering the best products and services to our customers and partners,” she says.

It’s the answer you would expect from a new CEO. But both Kullman and DeSimone know that, eventually, investors will want a return on their investment. Carbon has cool technology, for sure, but it will need to make money.


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