4D printing?

These days, 3D printing seems to be at the core of most new new research ventures, whether it's developing ways to print entire meals or recreating facial features to repair a patient's face.

But Skylar Tibbits wants to up the ante: He's hoping 4D printing will be the thing of the not-so-far future.

The name for his concept, Tibbits admits, was a bit lighthearted at first. At the Massachusetts Institute of Technology, Tibbits and researchers from the firms Stratasys and Autodesk Inc were trying to come up with a way of describing the objects they were creating on 3D printers—objects that not only could be printed, but thanks to geometric code, could also later change shape and transform on their own.

The name stuck, and now the process they developed—which turns code into "smart objects" that can self-assemble or change shape when confronted with a change in its environment—could very well pop up in a number of industries, from construction to athletic wear.

“Normally, we print things and we think they’re done,” Tibbits says. “That the final output and then we assemble them.  But we want them to be able to transform and change shape over time.  And we want them to assemble themselves.”

Tibbits, a research scientist at MIT, was given the go-ahead last year to establish what’s known as the university's Self-Assembly Lab.  The challenge was to see how smart researchers could make an object without relying on sensors or chips; how fluid they could make something without wires or motors.

As luck would have it, when Tibbits shared this dilemma with acquaintances at Stratasys, a leading 3D printing firm, they told him the company had developed a printing material that expands by 150 percent when placed in water.  It sounded promising. But the real question was how to bring precision to that transformation so an object could unfold, curl and form specific angles instead of just swelling up like a bloated sponge.

Tibbits’ answer:  Geometry.

With a 3D printer, an operator plugs in a virtual blueprint for an object, which the printer uses to construct the final product layer by layer. To make something "4D," though, Tibbits feeds the printer a precise geometric code based on the object's own angles and dimensions but also measurements that dictate how it should change shape when confronted with outside forces such as water, movement or a change in temperature.

In short, the code sets the direction, the number of times and the angles at which a material can bend and curl. When that object is confronted with a change in environment, it can be stimulated to change shape. Pipes, for instance, could programmed to expand or shrink to help move water; bricks could shift to accommodate more or less stress on a given wall.

Tibbits demonstrated the concept of 4D printing at a TED talk last year, during which he showed how a single strand of printed material could be programmed to fold, on its own, into the word  “MIT.”

PS:Since the fourth dimension is time 4-D printing is basically printing 3-D objects that change their shape with time

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