Although the word "metamaterial" sounds fancy—and they do often have sci-fi properties like giving the world real-life transformers and invisibility cloaks—all it really means is a material designed or engineered to exhibit a property not seen in nature.
Usually, this is achieved by creating materials with a grid of precisely repeating cells too complicated to happen by chance. Such materials can be used to effect sound, electromagnetic radiation, and more, which is why they're of interest to industries like semiconductors and aerospace. But a metamaterial can also just be a dense network of origami-like folds that allows the material to move in interesting ways. Metamaterials don't have to be straight out of Asimov to be useful, as researchers at the Hasso-Plattner Institut have shown with a new technique that lets them 3D print simple machines out of a single block of material.
That's the principle Professor Patrick Paudisch of Hasso-Plattner's Human Computer Interaction Division is exploring, by way of 3D printing. His new "Metamaterial Mechanisms" are 3D printed blocks made up of standard filament that have moving parts, thanks to the way their composite cells have been organized. More specifically, his design uses something called "shear cells"—weaker, less densely-packed cells designed to deform when force is applied—to control directional movement and create simple 3D printed machines.
For example, the handle of Paudisch's metamaterial latch can be twisted to open a door, thanks to the way the dense placement of cells keeps the latch and handle rigid, while moving everything else. Nor does it end at door latches. Using the principles of cell shearing, Paudisch has 3D printed other metamaterial mechanisms, including a pair of pliers, a pantograph, and even a miniature version of one of Theo Jansen's Strandbeests, all with no or minimal post-printing assembly.
The holy grail of additive manufacturing is a way to 3D print machines without having to assemble them. Paudisch's Metamaterial Mechanisms take a clever step towards that goal, and better yet, one that can be put into practice by anyone with geometry skills strong enough to understand cell shearing. Read more about the research here.