3D printing is poised to disrupt nearly every industry, with applications ranging from replicating organs to constructing houses; however, MIT is looking even further into the future introducing the concept of 4D printing. Skylar Tibbits, an architect, artist, computer scientist and director of MIT’s Self-Assembly Lab, recently gave a talk at the TED conference describing what is being called 4D printing. 4D printing involves 3D printing objects that change after they have been printed. 4D printing is basically a self assembly process whereby printed material forms itself into another shape after being subjected to an energy source such as heat, electricity, light, sound, or as he showcased in his demonstration, by submersion in water.
The whole idea started with materials that react in predictable ways to energy sources. This concept has led to the development of a material that changes shape in “programmable” ways when submersed in water. The result is a 3D printable material that when dunked into a tank of water, changes itself into a recognizable shape. A single strand for example, suddenly comes to life and forms the word “MIT” in two dimensions, while another pulls itself into an open ended three dimensional cube. This seemingly magical act comes about by programming different parts of the material to respond as desired. The self-folding structures are first printed out as long strands made of two core materials in combination – a synthetic polymer that can expand to more that twice its volume in water, and another polymer that is rigid in water. By carefully combining the two materials using specific blueprints, the expansion of the water-absorbing substance drives the joints to move, creating a predetermined geometrical transformation. “This is a whole new idea of printing, where you don’t just print static objects; you print things that turn into other things,” explained Skylar Tibbits.
On a large scale, the devices would be useful in building underwater structures or structures in space; anywhere where having people assemble it by hand would be prohibitively expensive, difficult or impossible. Research also shows the potential of programmable materials in the future of manufacturing. This opens up the concept of “environmental manufacturing,” in which companies can take advantage of ambient sources of surrounding energy. However, right now the transformations only happen in one direction. Tibbits said a future step in his research would be to see if they could be reversed. If so, the systems could become self-sustaining in environments with cyclical or seasonal change. For example, instead of using pumps, pipes could expand and contract, in a process resembling peristalsis, to push water. Overall, 4D printing is part of a whole new science that may very well revolutionize the way things are made. 4D printing would be a way to extend the printing window to after the printer has done its work to allow for self-assembly of three-dimensional objects that are limited only by our imaginations.