The famous Star Trek TV series features a device called the Replicator that recreates any object. Formally, we are talking about a kind of three-dimensional printing - just such a kind of it was recently mastered at the University of Berkeley. It is based on laser processing of a photosensitive polymer to quickly create objects of arbitrary shape.
A typical 3D printer applies the working substance layer by layer, performing thousands of small operations, which takes a lot of time - hours, and sometimes days. The "replicator" is designed differently, its principle of operation is similar to the operation of an MRI scanner. Rays with energy pass through the object, marking obstacles in their path, which are lined up in a model of the internal structure of the object. This image consists of dozens of "shots" taken from different angles and put together.
The replicator uses a ready-made model and a working area in the form of a transparent cylinder filled with a photosensitive polymer, a kind of synthetic resin. The projector shoots light beams in a pattern that matches the image of the object at a specific angle, and the resin hardens under the influence of light at the desired points. By turning the container with the polymer, one can successively form a three-dimensional clot inside it, repeating the original model.
The advantage of this 3D printing method is speed - one palm-sized figure only takes a few minutes of work. The product does not differ in high strength or plasticity, but this technology is suitable for the production of implants. So far, only small items can be made, but the production is waste-free - the remains of the liquid polymer are merged for reuse. And this is important, because the resin itself is not cheap, and therefore the technology is not yet ready for the needs of mass production.