How 4D Printing can impact the existing 3D industry?

We have been familiar with the technology of 3D printing for quite a while now. While thought to be the initial replacement of CNC machining, Plastic Mould injection and Casting, 3D printing through FDM and SLA have revolutionized the production lines. Basically, it is about making digital blueprints of physical objects by building them layer by layer. Hence, it is also referred to as the Additive Manufacturing process. Not only, machinery parts, but we can also use 3D printing for making bones and muscles, toys, pizzas and pastries, body organs, and building parts too. But before you assume that there is anything beyond this technology, researchers have started experimenting with what is called 4D printing.

4D printing is similar to 3D printing but with an upgrade. It has an additional parameter called time. A 4D printed object will have the ability to react to the environmental changes like temperature, pressure, humidity variation, and adjust to them accordingly. So it is based on Stereolithography (SLA) like 3D printing. SLA is a technique that uses photo-polymeric liquid to build a 3D object layer upon layer. So along with SLA, a 4D print needs geometric code that informs the angles and dimensions of the object it builds. When an element is added, the object will contort to this predefined manner or state. It is important to remember that the structure of the 4D print is preprogrammed in detail according to the desired change of shape.

Materials

For 4D printing, one needs a special type of smart material. This is because 4D prints rely on the materials that can react to stimuli and with accurate execution of designs that allow changes in the material to manifest as actual changes in the form of the final product. The Self-Assembly Printing Lab at MIT calls these materials as programmable matter. These include,

Hydrogel: Materials capable of absorbing a large amount of water

Electroactive polymers: Liquids or gasses that can become a totally different medium with new properties when exposed to certain light sources, wavelengths, or humidity levels.

Shape Memory Polymers and Alloys: Materials with the ability to return to their original shape from a deformed shape when stimuli applied

Applications

Numerous researches are going in the field of 4D printing—most of these projects showcase the promising potential of this technology. For instance, one can use magnetic fields to stiffen and loosen a material. Self-Assembly Printing Lab from MIT stated that 4D printing could also be used in fashion for making clothes that could change accordingly to the weather or the activity. For instance, shoes could change their shape when you start running to provide you with better comfort and amortization. In the aviation sector, Airbus has collaborated with the Self-Assembly Printing Lab of MIT to develop a programmable carbon fiber inlet component using 4D printing. The inlet component is made from programmable carbon fiber. This adjusts automatically to control the airflow which, in turn, allows the engine of the aircraft to cool. The advantage of this innovation is that this can replace the heavy mechanical control systems while reducing fuel costs.

A team of doctors at the University of Michigan’s CS Mott Children’s Hospital developed an airway splint using 4D printing. This splint stops the baby’s airway from collapsing as it expands when the child grows. The splint was created for use in the neonatal intensive care unit to help babies until their airways are strong enough to support themselves. The University of Wollongong in Australia has developed a 4D printed water valve with the help of printed hydrogel ink. The hydrogel ink has the feature to react to high temperatures rapidly. The designed water valve closes itself when hot water is poured on it and widens when the temperature goes down. 4D printing can further be in the healthcare industry to make stents placed into blood vessels, prosthetic limbs, and self-folding proteins.