Developing truly innovative and interesting projectsMost people in the AM industry know that 4D printing adds fourth-dimensional time to the 3D printing equation by creating a structure that changes when exposed to external forces (such as light, temperature, humidity), self-assembly, or shape shift Medium or magnetic. Currently, most 4D printing applications are limited to research, although there are some truly innovative and interesting projects under development. For example, at Rutgers University, engineers have created a 4D printing method for creating deformed smart gel structures, while MIT engineers have recently introduced soft 3D printed structures that can be controlled using magnets. However, the project undertaken by CityU and led by Professor Lu Jian is the first time we have seen a combination of ceramics and 4D printing.
Ceramics is a fast-growing part of the AM industryCeramics are a rapidly growing part of the AM industry, with high melting points, making them difficult to use laser-based printing methods. 3D printable ceramic precursors are inherently difficult to deform, which hinders the production of complex ceramics. In light of these challenges, CityU researchers have developed a ceramic ink that is a mixture of polymers and ceramic nanoparticles. These ceramic precursor nanoparticles are known for their soft and stretchable properties. As the research team explained, the ceramic precursor can be stretched more than three times its original length, which enables the manufacture of complex shapes, including folded structures like origami. CityU researchers use elastic energy in elastic precursors to achieve shape deformation. More specifically, when the stretched ceramic precursors are released from their stretched state, they are automatically reshaped. Then, once the object is heat treated, the ceramic precursor becomes a hard, mechanically strong ceramic. The research team said that these ceramics have a higher compressive strength-density ratio (547 MPa on the 1.6 g cm-3 microlattice) and can be made into larger structures than other printed ceramics. “The whole process sounds simple, but it’s not the case,” said Professor Lu, a vice president and professor of mechanical engineering at CityU. “From trying to make the ink to developing the printing system, we tried many times and different methods. Just like squeezing the icing on the cake, there are many factors that can affect the result, from the type of cream and the size of the nozzle to the squeezed Speed and force, and temperature. ” In fact, 4D printed ceramics have been around for a long time because it has taken more than 2.5 years. The research team has overcome the challenges and presented the ceramic 4D printing process. The project’s research, recently published in the journal Science Advances, describes the various stages of the research. In the first molding method, researchers 3D printed ceramic precursors and substrates using ceramic inks. The substrate was then stretched using a biaxial stretching device, and a joint for connecting the precursor was 3D printed thereon. With the joint in place, the precursor is applied to a stretched substrate. When the latter is released, the material deforms into a pre-designed shape in a controlled manner. In the second method described by the researchers, the designed pattern was printed directly onto a stretched ceramic precursor. The structure is then released and deforms itself while being controlled by computer programming.
Link：The first 4D printed ceramic process appeared in Hong KongREF: Hearing Aids Supplier , Hearing amplifier, Digital Hearing Aids
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