3D printer that “grows” polymer parts in minutes unveiled in Vancouver

At the TED conference in Vancouver this week, 3D printer start-up, Carbon3D, emerged from stealth mode to announce an advance in polymer-based additive manufacturing that radically cuts build time from hours down to minutes. Named Continuous Liquid Interface Production (CLIP), the technology takes a new tack on the DLP printing process to “grow” parts from a pool of resin rather than build them layer-by-layer.

According to third-party tests commissioned by the company, a model that requires 11.5 hours to build by a traditional SLA printer (or approximately 3 hours with SLS and polyjet technology) can be produced by the new process in only six and a half minutes.

“Current 3D printing technology has failed to deliver on its promise to revolutionize manufacturing,” said Dr. Joseph DeSimone, Carbon3D co-counder and professor of chemical engineering at North Carolina State, where he co-invented the method with Carbon 3D CTO Alex Ermoshkin, and Edward Samulski, also professor of chemistry at UNC. “Our CLIP technology offers the game-changing speed, consistent mechanical properties and choice of materials required for complex commercial-quality parts.”

The Carbon3D printer’s remarkable speed is due to the addition of a razor-thin buffer or “dead zone” that allows for the elimination of a number of mechanical steps from the usual SLA/DLP printer process. In a typical DLP printer, light is projected up through the glass bottom of a relatively shallow pool of resin by a Digital Light Processor – a “chip” containing thousands of tiny mirrors that can be individually turned on and off. Slices of the 3D model tell the DLP chip which of those mirrors to turn on and thereby project a precise cross-section of light into the resin. The build platform is upside-down and rises up in steps as each layer is cured.

To cure a layer, a thin film of resin in pressed between the bottom edges of the model and the glass bottom of the resin pool. The DLP then flashes the light pattern of a particular layer. At a considerable cost in build time, the DLP machine then has to pry the model away from the glass and reset the platform’s z-axis before another layer can be cured.

To eliminate these mechanical steps, Carbon3D has replaced the glass with a gas-permeable amorphous fluoroplastic (Teflon AF). This allows oxygen to infuse a microns thick layer of the resin, which inhibits it from curing. Introducing this fluid buffer – or “dead zone” as the company calls it – means the part never binds to the glass and therefore doesn’t have to be pried away.

More importantly, it also means the Carbon3D DLP projector can illuminate and cure the part continuously, projecting a “movie” of part cross sections, complete with smooth transitions, rather than the “slide-show” of a conventional DLP printer. In this way, the resulting part isn’t so much built of discrete layers but progressively “grown” as the build platform rises way from the resin pool.

Beyond its speed, the Carbon3D printer, its creators say, also makes parts that are smoother (i.e. less stair-stepping) and with consistent mechanical properties; instead of solid layers bonded to each other with variable strength, Carbon3D parts are a contiguous whole, akin to a plastic injected part. According to the company, their printer features resolution below 100 micrometers and produces commercially viable parts out of a wide range of materials including elastomers, silicones, biodegradable, ceramics and nylon-like materials.

“In addition to using new materials, CLIP can allow us to make stronger objects with unique geometries that other techniques cannot achieve, such as cardiac stents personally tailored to meet the needs of a specific patient,” said DeSimone. “Since CLIP facilitates 3D polymeric object fabrication in a matter of minutes instead of hours or days, it would not be impossible within coming years to enable personalized coronary stents, dental implants or prosthetics to be 3D printed on-demand in a medical setting.”

During its TED conference presentation, Carbon3D announced it had partnered with Sequoia Capital to lead the company’s Series A financing in 2013 along with Northgate Partners, Piedmont Capital Partners and Wakefield Group. Silver Lake Kraftwerk led the Series B round of financing in 2014 with Northgate Capital and Sequoia Capital, for a total raise of $41 million to commercialize the technology.
www.carbon3d.com