Radical new high-speed liquid technology could bring 3D printing into mainstream manufacturing

March 18, 2015

A new 3D-printing technology developed by Silicon Valley startup Carbon3D Inc. enables fabricated objects to rise from a liquid media continuously rather than via a series of 2D layers.

Described in the journal Science on Monday March 16, the technology enables ready-to-use products to be made 25 to 100 times faster than other methods, and promises to advance the industry beyond basic prototyping to 3D manufacturing, according to the company. It creates previously unachievable precision geometries that open opportunities for innovation in major industries such as healthcare, automotive, and aviation.

Light-controlled precision fabrication

The technology, called Continuous Liquid Interface Production (CLIP), manipulates light and oxygen to fuse objects in liquid media. It works by projecting beams of light through an oxygen-permeable window into a liquid resin to rapidly transform 3D models into physical objects.

At the heart of the CLIP process is a special window that is transparent to light and permeable to oxygen, much like a contact lens. By controlling the oxygen flux through the window, CLIP creates a “dead zone” in the resin pool just tens of microns thick where photopolymerization cannot occur. As a series of cross-sectional images of a 3D model is played like a movie into the resin pool from underneath, the physical object emerges continuously from just above the dead zone. (credit: Carbon3D)

Working in tandem, UV light, which triggers photo polymerization, interacts with oxygen, which inhibits the reaction, to control the solidification of the resin, creating commercially viable objects that can have feature sizes below 20 microns, or less than one-quarter of the width of a piece of paper. This is the first 3D-printing process that uses tunable photochemistry instead of the layer-by-layer approach that has defined the technology for decades.

Faster, stronger, predictable

CLIP enables a very wide range of materials to be used to make 3D parts with novel properties, including elastomers, silicones, nylon-like materials, ceramics and biodegradable materials, and could allow for synthesizing novel materials that can advance research in materials science.

Conventionally made 3D printed parts are notorious for having mechanical properties that vary depending on the direction the parts were printed because of the layer-by-layer approach. Much more like injection-molded parts, CLIP produces consistent and predictable mechanical properties, smooth on the outside and solid on the inside, the company says.

“By rethinking the whole approach to 3D printing, and the chemistry and physics behind the process, we have developed a new technology that can create parts radically faster than traditional technologies by essentially ‘growing’ them in a pool of liquid,” said Joseph M. DeSimone, professor of chemistry at University of North Carolina-Chapel Hill and of chemical engineering at North Carolina State and CEO of Carbon3D, who co-invented the method.

“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.”

DeSimone revealed the technology at a TED talk Monday March 16 in the opening session of the conference in Vancouver, British Columbia.

Carbon3D | Carbon3D CLIP Animation

Carbon3D  | Carbon3D Demo

Carbon3D | Carbon3D Elastomer Demo

Abstract of Continuous liquid interface production of 3D objects

Additive manufacturing processes such as 3D printing use time-consuming, stepwise layer-by-layer approaches to object fabrication. We demonstrate the continuous generation of monolithic polymeric parts up to tens of centimeters in size with feature resolution below 100 micrometers. Continuous liquid interface production is achieved with an oxygen-permeable window below the ultraviolet image projection plane, which creates a “dead zone” (persistent liquid interface) where photopolymerization is inhibited between the window and the polymerizing part. We delineate critical control parameters and show that complex solid parts can be drawn out of the resin at rates of hundreds of millimeters per hour. These print speeds allow parts to be produced in minutes instead of hours.