Article source: IMechE
Practical devices which change shape after exposure to heat or other stimuli are a step closer after researchers developed a powerful “4D printer.”
The advanced machine, so-called because it 3D-prints objects which transform, could lead to printers making shape-shifting parts for sectors including aerospace and medicine. Researchers from the Georgia Institute of Technology in the US will present their work tomorrow at the 255th annual American Chemical Society meeting, after developing the printer with scientists at the Singapore University of Technology and Design.
Objects created using 4D printers could have several advantages over static 3D-printed parts. By using external stimuli such as heat, light or humidity to trigger transformations, engineers may no longer need to add motors to machines for simple tasks. The technique also means manufacturers could create devices bigger than their printers, as the objects can be programmed to unfold and spread after printing.
“We are on the cusp of creating a new generation of devices that could vastly expand the practical applications for 3D and 4D-printing,” said team leader H. Jerry Qi.
The researchers said their printer is the first to combine four different printing techniques – aerosol, inkjet, direct ink write and fused deposition modelling – and a range of printable materials, including hydrogels, silver nanoparticle-based conductive inks, liquid crystal elastomers and shape memory polymers.
The polymers are the most commonly-used substances for 4D-printing, as they are programmed to “remember” shapes and transform to them when printed. By combining printing techniques and materials, the Georgia team said they can print more intricate shapes than ever before, opening the door to many different functional applications and designs.
“We can use a variety of materials to create hard and soft components at the same time, incorporate conductive wiring directly into shape-changing structures, and ultimately set the stage for the development of a host of 4D products that could reshape our world,” said Qi.
The team is currently working with Children’s Healthcare of Atlanta, investigating the technology’s suitability for printing prosthetic hands for children born with malformed arms.
“Only a small group of children have this condition, so there isn’t a lot of commercial interest in it and most insurance does not cover the expense,” Qi says. “But these children have a lot of challenges in their daily lives, and we hope our new 4D printer will help them overcome some of these difficulties.”