The American Society for Testing and Materials (ASTM) defines additive manufacturing as the “process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies, such as traditional machining.”
This is how it works: first you open a blueprint on your computer screen, then you press print. A machine builds up the object gradually, either by depositing material from a nozzle, or by selectively solidifying a thin layer of plastic or metal dust using tiny drops of glue or a tightly focused beam. Products are thus built up by progressively adding material, one layer at a time.
Additive manufacturing requires less workers than standard manufacturing, and because objects can be described in a digital file, they can be easier to pirate. Nevertheless, it has several advantages, such as reducing costs and waste, allowing the creation of parts in shapes that conventional techniques cannot achieve and enabling the production of a single item quickly and cheaply.
At the moment the process is possible only with certain materials (plastics, resins and metals) and with a precision of around a tenth of a millimetre. This new technique is being tried out only by a few academics and industrials, but it may change the world as deeply as the first mass production factory did.