According to the ASTM, additive manufacturing is a process used to assemble materials from 3D models, usually layer by layer and in opposition to substractive manufacturing, such as machining and cutting.
Additive manufacturing allows to build parts with less loss of material while also limiting the number of production steps. Additive manufactured parts do not need to be machined from a bulk block, there is no riser to be removed and it is not necessary to shape multiple preforms to obtain the final product. Usually, a final machining is necessary to obtain the desired surface finish.
