Quite often we come across news items concerned with developments in 3D technology. Research units across the world are exploiting the already existing technology to make it more flexible and useful.
Under such developments, one massive shift in the technology has been introduction of ‘4D Printing’. The concept of 4D technology was first introduced by a research team Led by Skylar Tibbits, Self-Assembly Lab Director at the Massachusetts Institute of Technology, and the firms Stratasys and Autodesk Inc.
The 4D technology came into existence as an advanced step to 3D technology when the research team was trying to create objects on 3D printers—objects that can be printed after adding the concept of ‘time’ (4th dimension) to the 3D printing process.
Incorporation of ‘time’ can be interpreted as a 3D object that is capable of shape shift when heated or cooled to a specific temperature, or subjected to different environmental conditions. This would require 4D printing techniques to create structures capable of acting (and reacting) in different ways to different stimuli- change shape and transform on their own (self-assembly).
Tibbits describes this technology in his Ted Talk as “Today at the micro- and nanoscales, there’s an unprecedented revolution happening. And this is the ability to program physical and biological materials to change shape, change properties and even compute outside of silicon-based matter. There’s even a software called cadnano that allows to design three-dimensional shapes like nano robots or drug delivery systems and use DNA to self-assemble those functional structures”.
The 4D assembly techniques allow physical materials to build themselves- this process is called self-assembly by which disordered parts assemble to form an ordered structure. This entire process is triggered through only local interaction such as changed surrounding environmental conditions like heat, shaking, pneumatics, gravity, magnetic coupled with smartly designed interactions for error correction- and ultimately allow the shapes to go from one state/shape to another.
One from many ways to implement the 4D technology is to use ‘Shape Memory Alloy’. As per Wikipedia, Shape Memory Alloy (also known as SMA, smart metal, memory metal, memory alloy, muscle wire, smart alloy) is an alloy that “remembers” its original shape. SMA has a special property that allows them to revert to their original shape after heating. This is possible due to their fully reversible crystal structure. Other successful techniques use electroactive polymers (polymers that exhibit a change in size or shape when stimulated by an electric field), pressurized fluids or gasses, chemical stimulus among others.
The ability to create technology which allows physical materials to build themselves—based on the orientation and location—opens up huge possibilities for product design. Research is being done to develop technology that can be adapted to metals and other materials. Industries such as manufacturing, packaging, and biomedical can be revolutionized and benefitted to a large extent.
Tibbits explains this as “In infrastructure, let’s just take one example. Take piping. In water pipes, we have fixed-capacity water pipes that have fixed flow rates, except for expensive pumps and valves. We bury them in the ground. If anything changes — if the environment changes, the ground moves, or demand changes — we have to start from scratch and take them out and replace them”. Manufacturing facilities can be made to be more flexible and challenges such as inefficiencies, energy consumption and excessive labor techniques can be tackled.
The application can be extended to transform many aspects of our daily lives as well including 4D printed clothing, medicine, smart cities, solar panels etc.
Future Possibilities of 4D technology is vast and its implications can revolutionize engineering!
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