NCCR Bio-Inspired Materials researchers have developed a new 3D printing system that will allow them to create models that closely mimic complex functional structures found in nature.
3D printing has almost become ‘old hat’ over the past few years. It has gone from creating cute plastic robots to building sophisticated aircraft parts. Anyone with enough money can invest in a 3D printer and create whatever they wish out of plastic or even metal.
However, look more closely and the result can seem rough and ready. Higher precision techniques require substantial investment and in the industrial world, 3D printing is still often limited to prototyping before using more traditional fabrication techniques.
3D printing can also help build complex parts that would be impossible to build otherwise. And now NCCR Bio-Inspired Materials researcher André Studart and his team at the Swiss Federal Institute of Technology in Zurich (ETHZ) have devised a method that provides further control to the shaping process.
“The layer-by-layer approach used for printing resembles in several ways the biomineralization steps followed by living organisms to build biological materials in nature,” says Studart. “This provides us with a unique tool to fabricate synthetic architectures that more closely mimic the complex functional structures found in the natural world.”
The so-called multimaterial magnetically assisted 3D printing platform (MM-3D printing) developed by Studart and his colleagues adds an extra dimension to the design possibilities by including anisotropic particles – particles in this case whose orientation can be controlled by a low magnetic field - during the printing process. Add to the mix the use of multiple precisely dosed materials and it becomes possible to produce a highly complex end product with specific properties such as the object with an internal helicoidal staircase pictured above .
“The key challenge was to identify the processing window that would allow us to print filaments that are distortion-free but also internally textured, ie with aligned particles,” says Studart. “We developed two separate inks: one is used for particle alignment through a magnetic field and the other is used to shape the outer contours of the desired object.”
The aim for Studart and his colleagues is to develop functional materials with microscopic structural features that have only been seen so far in natural biological materials. This includes soft materials that can shift their shape based on external stimuli.
Possible applications include biomedical implants or soft robots with autonomous shape changing capabilities; tough and lightweight composites using sustainable bio-derived polymers; and morphing wings for unmanned air vehicles.
Studart says the next steps include using the MM-3D printing platform to create bioinspired materials with novel functionalities and properties. He also wants to create heterogeneous composites that will help understand which optimization criteria drove the natural evolution of some biological materials.