3D Printing Tech Digest - April 2017

Heat affected objects

A team of researchers from Georgia Institute of Technology and two other institutions has developed a method to 3D print objects that respond to heat by changing shape. The printed objects’ bendability is owing to the use of shape memory polymers during the printing process. When the 3D printed objects were immersed in a bath of warm water the objects expanded or contracted. A short film released by the university shows petals printed with the material folding in on themselves, a lattice work structure spreading out and a six-pointed star forming into a concave semi-sphere. The team envision this being used in future products that react to stimuli, and could be used to create a space structures, robots, toys etc. 

Speedfactory updates

Adidas has formed partnerships with Siemens and, separately, Carbon to help it in its goal of printing 100,000 pairs of 3D printed trainers at the sporting goods company’s Speedfactory. 
Siemens is providing Adidas with computer simulations, testing and optimisation of the 3D printing specialised factory. Siemens claims this will speed up time to market, bring greater flexibility, and provide improved manufacturing quality and efficiency. 
Carbon has provided 3D printers capable of digital light synthesis to print the midsole of Adidas’ Futurecraft 4D line of running shoes. Digital light synthesis is a printing process developed by Carbon which uses a liquid resin platform that can be moulded by light then set by heat. 5000 pairs of Futurecraft 4D shoes will be available to consumers in the autumn/winter of 2017.  

Glass printing

A team of scientists at the University of Karlsruhe (KIT), Germany, have discovered a way to 3D print glass. The printing procedure is conducted by creating a bath of nanoparticles of quartz glass and liquid polymers that is then cured by light (stereolithography) at determined points. When the non-cured liquid is removed, the remaining cured structure remains from which the polymers are removed by heating. The final step is to heat the remaining glass structure so that it solidifies. The team sees 3D printed glass being used in optics, data technology and medical technologies.  

Cartilage in a cartridge

Duke University scientists have 3D printed a material that mimics human cartilage using a USD300 printer.  The biocompatible menisci are made of a combination of a strong and a soft hydrogel that shares a similar molecular make up to cartilage. Through the addition of nanoparticle clay the hydrogel becomes amenable to 3D printing. The printing process takes one day. The team are excited about the form versatility offered by 3D printing for patient-individualised menisci. 

Space armour

Scientists at NASA’s Jet Propulsion Laboratory in Pasadena, California, have developed a woven metal fabric for use in space bound large antennas and other devices. The plated armour-like material was manufactured by 3D printing. The material’s reflectivity, passive heat management, foldability and malleability make it well suited to possible uses as a shield to protect spacecraft from meteorites, as a spacesuit material, or for capturing objects on other planets, the scientists claim. 

Furniture printed in suspension

Massachusetts Institute of Technology (MIT) researchers have developed Rapid Liquid Printing – a way to 3D print objects which overcomes gravity’s restrictions. The team at the Self Assembly Lab demonstrated printing into a gel suspension creating objects with intricate designs exhibiting variable line thickness and complex geometries, including a tabletop. The scientists claim that this is a solution to the obstacles holding back widespread industry adoption of 3D printing. Using their method:
1)    Production’s faster (producing structures in a few minutes).
2)    Large-scale objects can be printed (such as furniture).
3)    Real-world industrial-grade materials can be used. 

Bioprinting still beating

Stories about advances in 3D bioprinting continue to regularly trickle into newsfeeds, here are two recent stories.
Universidad Carlos III de Madrid (UC3M), CIEMAT (Centre for Energy, Environmental and Technological Research), Hospital General Universitario Gregorio Marañón, in collaboration with the firm BioDan Group, claim to have created a 3D bioprinter capable of printing functional human skin. The skin is composed of all the biological components that natural skin has: epidermis, stratum corneum, dermis (containing fibroblasts that produce human collagen). The team says that other methods use animal collagen but theirs uses human collagen. The skin produced by the method is awaiting approval by European regulatory agencies to ensure that it is safe for use in skin transplants and skin grafts. The skin could also be used for cosmetic testing.
Meanwhile at Seoul National University of Science and Technology, South Korea, scientists have released schematics for an open source 3D bioprinter. The printer has been demonstrated printing a cylinder with lattice structure, a hydrogel lattice, and a 3D cylinder scaffold of PLGA (polylactic-co-glycolic acid, an US FDA (Food and Drug Administration) approved polymer) and cell laden hydrogel. They believe the printer is reproducible at an affordable price.

Healing hearts 

A team of biomedical engineering researchers led by the University of Minnesota has demonstrated a 3D bioprinted patch that can help heal post-heart-attack scar-tissue. In the study the team used laser-based bioprinting techniques to insert human heart stem cells on a matrix that then began to contract (beat) in the lab dish. The patch was applied to a mouse that had been given an induced heart attack, and the researchers saw a significant increase in heart function in four weeks. The patch merged with the heart, meaning it didn’t need to be removed. The team plan to scale up the patch and test it on pigs. 

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