Scientists have developed a printer that can change shape after being exposed to heat or other stimuli. The new technology can help with 4-D printing in medicine, aerospace and other industries. Researchers presented their work at the latest American Chemical Society (ACS) meeting.
In 4-D printing, 3-D-printed components change shape after exposure to heat, light, humidity and other environmental triggers over time. It previously proved challenging due to requiring multiple time consuming and complex post-processing steps to mechanically programme each component. Commercially available printers are also only able to print 4-D structures that contain a single material.
Scientists at Georgia Institute of Technology collaborated with a team at the Singapore University of Technology and Design, to make objects that changed shape up to 90 percent faster than previously possible due to the extensive mechanical programming steps. The team created the 4-D objects by using a commercial printer and a heat source, along with a composite made from acrylic and epoxy.
We are on the cusp of creating a new generation of devices that could vastly expand the practical applications for 3-D and 4-D printing.
Professor H. Jerry Qi, Professor at Georgia Institute of Technology
The machine combines four different printing techniques, including inkjet, aerosol, direct ink and fused deposition modeling. The printer uses a variety of both stiff and elastic materials, ranging from hydrogels and silver nanoparticle-based conductive inks to liquid crystal elastomers and shape memory polymers (SMPs). SMPs can be programmed to remember a shape and transform when heated, so they are commonly used in 4-D printing. With this new technology, the researchers can print more intricate, higher-quality SMPs.
The new printer incorporates conductive wiring directly into the shape changes. Electrical wiring can be printed directly onto an antenna, sensor or other electrical device with the printer using a direct-ink-write method. It produces a line of silver nanoparticle ink, and then a photonic cure unit dries and coalesces the nanoparticles to form the wire. The printer's ink-jet component can then create a plastic coating to encase the wire.
The printer can also to project a range of shades of light to form a component into a solid. The grayscale lighting causes a crosslinking reaction that alters the component's behavior, dependant on the grayscale of shade used. A brighter light shade creates harder parts, while a darker shade produces softer parts.
The team at team Georgia Institute of Technology is hoping that the new technology could be used to print prosthetic hands for children born with malformed arms. They are working with Children's Healthcare of Atlanta, and Professor Qi explains “These children have a lot of challenges in their daily lives, and we hope our new 4-D printer will help them overcome some of these difficulties."
Thumbnail Image Credit: Monkey Business Images/Shutterstock