Now that 3D printing has been around quite for a while, new technologies surrounding this disruptive technology are being developed. 4D printing or programmable matter is one such innovation which harnesses 3D printing to realise virtual information in the material world. Besides the three space dimensions, the fourth dimension referred in this term is time. 4D printing is the ability of an object to change the shape or form as a function of external influences. Flat and low-volume structures can be reprogrammed into desired forms after production depending on the requirement. New researches and innovations have proved that 3D printing has been instrumental in synthesizing such smart structures.
Currently the objects we see around us are quite fixed in their forms. But we have the possibility of changing their shapes and forms when we want them to, according to external factors like location, temperature, climate etc. A wrist watch is always a wrist watch. But imagine if it can assume a form of table clock at home and wrist watch on your hand! With novel technologies and adequate materials, such a form-changing structure can be developed to respond to influencing conditions. Self-assembly, disassembly, recycling: the possibilities are endless.
The savior: 3D Printing
Manufacturing such a structure with variable time-based properties is quite complicated with conventional manufacturing techniques. Even though adjustable elastomers and form changing mechanisms are known to mankind since centuries, the right technique to combine these two spheres was unknown until few decades. 3D printing has rightly addressed this challenge through its exclusive property of freedom of geometry. Multi-material 3D printing technology is used to build a structure with materials of different viscous, elastic, conducting, magnetic and optical properties. The component is built in one particular shape and is reoriented after printing based on external influences.
Load bearing 4D structure
Researchers at ETH Zurich have demonstrated one of the most recent explorations of synthesizing 4D structures using 3D printing. They designed reversible, deployable structures that have load bearing capacity, and multiple, predictable activated geometries. The speciality is that these structures were fabricated flat. Using multi-material 3D inkjet printing, they developed a unit actuator based on Von Mises Truss, and expanded into a full mechanism by hierarchical principles. The resultant structure possessed multiple equilibrium states and though initially flat, they were activated to 3D structures.
4D Printing applications
The applications for such form-changing structures are manifold. Space and aerospace are significant consumers as space constraint is a prime concern. Flat structures are transported to space and then realised into final shape. Medical applications are also being developed, such as systems for valve opening and closing. The Self-Assembly Lab in MIT developed a strangle strand that self-folds to the letters “MIT” when exposed to water, and a flat surface that folds into a cube. Aeroplane wings are also being discussed in this field. Wings that can change shape during flight to reduce air resistance are under research. 3D printed clothes, shoes and accessories are also being investigated to be able to adapt to user’s conditions. With more and more innovations in 3D printing, we can expect such “magical” objects to be on our shelves soon!
Image courtesy: ETH Zurich, MIT, Self Assembly Lab