An irresistible proposition….
TED professor Skylar Tibbits in his February, 2013 speech at the MIT Conference defined 4D printing as “The use of a 3D printer in the creation of objects which change/alter their shape when they are removed from the 3D printer. The objective is that objects made self-assemble when being exposed to air, heat or water, this is caused by a chemical reaction due to the materials utilised in the manufacturing process.”
In other words 4D printing is the method of 3D printing where there is an addition of the dimension i.e. time. Generally the input in 4D printer is a “smart material” that can be a hydrogel, a shape memory polymer or a printed active composites (PAC’s). These smart materials due to their material properties can be configured to specific shape when subjected to external stimuli like water, heat, pressure, temperature etc. The most popular technology being shape memory alloy, where a change of temperature triggers a shape change. Other successful approaches use electro-active polymers, pressurised fluids or gasses, chemical stimulus and even in response to light. In contrast to 3D printed objects that are rigid.
4D printed objects are dynamic and can undergo computational folding allowing objects larger than printers to be printed.
Hence using 4D printing and right material any transformable shape can be attained. As such kind of self-assembling non-living objects would have wide range of applications. It is noteworthy for businesses that use of multi-material shape memory polymers in 4D printing world can revolutionize the world of materials and industries.
In the 255th National Meeting & Exposition of the American Chemical Society (ACS) researchers presented the most powerful 4D printer. “We are on the cusp of creating a new generation of devices that could vastly expand the practical applications for 3D and 4D printing,” H. Jerry Qi, Ph.D., says. “Our prototype printer integrates many features that appear to simplify and expedite the processes used in traditional 3D printing. As a result, we can use a variety of materials to create hard and soft components at the same time, incorporate conductive wiring directly into shape-changing structures, and ultimately set the stage for the development of a host of 4D products that could reshape our world.”
Until now most of the commercial printers could print structures of a single material only. However the 4D printer built by Qi and his colleagues combines four different printing techniques, including aerosol, inkjet, direct ink write and fused deposition modelling. As a result Qi and his team have developed an all-in-one 4D printer that could print almost all practically possible complex structures in one go.
It can handle stiff as well as elastic materials including hydrogels, silver nanoparticle-based conductive inks, liquid crystal elastomers and shape memory polymers (SMPs). The researchers can also use the printer to project a range of white, gray or black shades of light to form and cure a component into a solid. This grayscale lighting triggers a crosslinking reaction that can alter the component’s behaviour, depending on the grayscale of shade shined on it. So, for example, a brighter light shade creates a part that is harder, while a darker shade produces a softer part. As a result, these components can bend or stretch differently than other parts of the 4-D structure around them. Since the printer integrates direct-ink-write method to produce a line of silver nanoparticle ink it can be used to print electric wires coated with plastic that encases the wire. Instead of running multiple processes say for electrical or plastic component this super-4D printer could use multiple materials to print an entire mobile phone, antenna or other electrical devices in a single manufacturing process.
4D printing can have various applications in the real-world depending on the smart material used and changes in environmental circumstances which act as stimuli:
- Architecture: Buildings delivered as flat pack could assemble and disassemble themselves under right stimuli. Smart valves, connections and self- healing pipes of a plumbing system that dynamically change their diameter in response to the flow rate and water demand.
- Clothing: Clothes and footwear which change their function according to environment and the wearer. Shoes that can become water-resistant or transform themselves according to the use required. Clothes that can cool/ insulate depending on the type of weather, change style/size/shape according to wearers need. Imagine your closet with a single pair of highly durable fabric that can be worn in several ways.
- Medical Applications: Creating drug capsules that release medicine at the first sign of an infection .Using body temperature as trigger for 3D printed skin grafts which can change with conditions. In bio components, artificial muscles, implants, prosthetics and stents that expand after being exposed to body heat.
- Home appliances: 4D printing flat-board self-assembling furniture that curl up into a chair or a refrigerator on external stimuli say heat stimuli applied by a home hair dryer. Home appliances and products that can adapt to heat or moisture to improve comfort or add new features to better working.
- Transport: Roads which self-heal potholes. Components and structures made of morphing materials that could change shape in response to environmental temperature, air pressure, rain or other factors.
- Aviation: In aeroplane wings which transform themselves according to the flow of air for better lift. 4D printed hinges, motors or hydraulic actuators which would make planes simpler and lighter in weight.
- Aerospace: In extreme environments, such as space. 4D printed transformable shape bridges, shelters or any kind of installations, as they would build up themselves or repair themselves in case of weather damage.
- This also opens up potential uses in biomedical devices, soft robotics, wearable sensors and shape-changing photovoltaic solar cells.
Undoubtly, the 4-D printing would completely reshape the world we live in… At Aspioneers, we say the change is indeed welcomed!!!….