Numerous fields have been greatly impacted by 3D printing, from technological and industrial fields, pharmacology to electronics
This method is popular because it can significantly reduce the amount of time required to produce a good while maintaining the product’s quality.
The use of 4D printing takes this to the next level because the parts produced not only have complex 3D structures
but also change shape or configuration after being printed.
According to Wenzheng Wu,
a professor at Jilin University in China,
“4D printing refers to 3D printing of responsive parts that can change their shapes or properties in a programmed way under external stimulations
, such as humidity, light, heat, electric fields, magnetic fields, and so on.”
As per Luquan Ren, a professor at the same university,
“this technique is a novel manufacturing technology,
which can save process time, energy, and materials.”
It can be used to fix aerospace industry equipment, such as damaged satellite or space station components.
In general, parts sustain random damage, and their sizes and shapes vary,
increasing the likelihood that a satellite will malfunction.
The parts can be used in space if this method is used to control the shape transformation of the parts.
These new features do, notwithstanding, introduce new manufacturing difficulties.
Polymers, which are made up of big molecules with numerous repeating subunits,
and unique shape-memory alloys,
which deform when cooled but take on their original shape when heated
, are the only materials that have so far been used in 4D printing.
4D-printed metallic parts
Li, Ren, Wu, and their collaborators proposed adding a laser during the printing process to produce stronger and more adaptable parts and expand the use of 4D printing to a wider class of materials.
They were able to significantly improve upon a method known as laser powder bed diffusion used in 3D printing,
in which metal powders are melted and then solidified layer by layer.
Their study was published in Advanced Science.
According to professor Qingping Liu, a co-author of the article,
“Residual stresses are frequently produced during the standard 3D printing process due to the high cooling rates and large temperature gradients,
which in turn cause processing defects such as delamination,
cracks, and deformations.”
Contrarily, the deformability brought on by laser-induced thermal stress can be controlled to reshape 3D printed structures, leading to the development of a new 4D printing technique.
The scientists were able to produce 14 metallic structures in the forms of flowers,
mimosas, frog tongues, dragonflies,
swallows, butterflies, hands, and claws using their 4D laser printing technique.
Once the structures cooled, they took on the expected mechanical characteristics.
Even though the technology is still in its infancy and the team could only print very basic objects,
they still think the research represents a significant advancement.
The scientists anticipate that their method will be used in many branches of science and technology, particularly in the aerospace and aviation sectors.
For space stations that are currently in use,
this could be used to fix irregular shell damage with standard spare parts.
Source: Sciences Advanced
