New one-pot process to produce gasoline-grade biofuel from the bacterial biopolymer PHB
Tsinghua studies on alcohol-gasoline dual fuel engines show fuel efficiency and particle number benefits

Additive manufacturing company Carbon3D named Technology Pioneer by World Economic Forum; work with Ford

Additive manufacturing (3D printing) company Carbon3D Inc. was named one of the World Economic Forum’s 49 Technology Pioneers for 2015. Carbon3D joins the Technology Pioneers program as the first additive manufacturing company to be selected. Carbon3D recently emerged from stealth mode to introduce an innovative approach to polymer-based 3D printing that it says will advance the industry beyond basic prototyping to 3D manufacturing.

The new Continuous Liquid Interface Production technology (CLIP) uses a tuneable photochemical process instead of the traditional mechanical approach, eliminating the shortcomings of conventional layer-by-layer 3D printing technology, rapidly to transform 3D models into final parts in a range of engineering-grade materials. Ford has been working with Carbon 3D since December 2014, and has produced elastomer grommets for the Ford Focus Electric and damping bumper parts for the Transit Connect.

Carbon3D’s CLIP technology uses a tunable photochemical process instead of the traditional mechanical approach, eliminating the shortcomings of conventional layer-by-layer 3D printing technology, to rapidly transform 3D models into physical objects. CLIP carefully balances the interaction of UV light, which triggers photo polymerization, and oxygen, which inhibits the reaction, allowing for continuously grown objects from a pool of resin.

F1.large
Schematic of CLIP printer where the part (gyroid) is produced continuously by simultaneously elevating the build support plate while changing the 2D cross-sectional UV images from the imaging unit. The oxygen-permeable window creates a dead zone (persistent liquid interface) between the elevating part and the window. Tumbleston et al. Click to enlarge.

The resulting parts feature mechanical properties that are applicable for a range of industries, including aerospace, industrial goods, medical, dental and of course automotive. These predictable mechanical properties allow for part creation across the range of needs for Ford vehicles including under the hood, interiors and high strength to weight ratio parts.

Ford worked to produce elastomer grommets for the Focus Electric and tested them against those made by traditional 3D printing methods. Not only were the grommets made in less than a third of the time with the CLIP-based device, the material properties were much closer to the final desired properties for the part.

In a similar study, several alternative designs were evaluated for a damping bumper part on the Ford Transit Connect using CLIP technology. The manufacturing time allowed engineers to make design iterations much more quickly than with traditional methods.

Most recently, Ford needed to address a major engineering issue that arose after placing a V8 engine into a new vehicle body design. The vehicle’s design created an unreachable oil filler cap because the engine sat lower and farther back under the hood. The product engineering team realized the opportunity to quickly address the issue using Carbon3D’s CLIP-based device. The team was able to rapidly design, prototype and manufacture an oil connector using rigid polyurethane and elastomer materials to access the oil fill tube without needing major redesigns to several components of the vehicle.

Beyond the current vehicle applications, Ford has also been able to expand its own materials research because of CLIP’s gentle process and dedication to high quality polymeric materials. To date, the team has tested several materials including resins reinforced with nano-sized particles. The automaker is investigating resin modifications for improved mechanical properties and considering the creation of thermally and electrically conductive materials for future vehicle applications.

Carbon3D introduced the CLIP technology (CLIP) simultaneously at TED 2015 and to the scientific community on the cover of Science Magazine.

Conventional additive manufacturing methods such as fused deposition modeling, selective laser sintering, and stereolithography rely on layer-by-layer printing processes. As a result, the Carbon3D team argues, those processes are “inordinately slow”.

For additive manufacturing to be viable in mass production, print speeds must increase by at least an order of magnitude while maintaining excellent part accuracy. Although oxygen inhibition of free radical polymerization is a widely encountered obstacle to photopolymerizing UV-curable resins in air, we show how controlled oxygen inhibition can be used to enable simpler and faster stereolithography.

Typically, oxygen inhibition leads to incomplete cure and surface tackiness when photo-polymerization is conducted in air. Oxygen can either quench the photoexcited photoinitiator or create peroxides by combining with the free radical from the photocleaved photoinitiator. If these oxygen inhibition pathways can be avoided, efficient initiation and propagation of polymer chains will result.

When stereolithography is conducted above an oxygen-permeable build window, continuous liquid interface production (CLIP) is enabled by creating an oxygen-containing “dead zone,” a thin uncured liquid layer between the window and the cured part surface. We show that dead zone thicknesses on the order of tens of micrometers are maintained by judicious selection of control parameters (e.g., photon flux and resin optical and curing properties). Simple relationships describe the dead zone thickness and resin curing process, and, in turn, result in a straightforward relationship between print speed and part resolution. We demonstrate that CLIP can be applied to a range of part sizes from undercut micropaddles with stem diameters of 50 mm to complex hand-held objects greater than 25 cm in size.

—Tumbleston et al.

CLIP works by projecting light through an oxygen-permeable window into a reservoir of UV-curable resin. The build platform lifts continuously as the object is grown. By controlling the oxygen flux through the window, CLIP creates the “dead zone”. This makes it possible to grow without stopping. As a continuous sequence of UV images are projected, the object is drawn from the resin bath. Software manages the entire process by controlling the variables.

Carbon3D has received $41 million in funding through Series A and B financing rounds led by Sequoia Capital and Silver Lake Kraftwerk respectively. Most recently, Carbon3D also received a $10 million direct investment from Autodesk’s Spark Investment Fund.

Resources

  • John R. Tumbleston, David Shirvanyants, Nikita Ermoshkin, Rima Janusziewicz, Ashley R. Johnson, David Kelly, Kai Chen, Robert Pinschmidt, Jason P. Rolland, Alexander Ermoshkin, Edward T. Samulski, and Joseph M. DeSimone (2015) “Continuous liquid interface production of 3D objects” Science doi: 10.1126/science.aaa2397

Comments

The comments to this entry are closed.