3D printing is an additive manufacturing technique which proceeds by adding materials, unlike techniques which proceed by withdrawal of materials. Milling is one example of these techniques in this latter group. 3D printing makes it possible to produce common objects, spare parts or prototypes intended for testing.
The starting point is a computer file representing the object in three dimensions, broken down into slices or chunks. This information is sent to a 3D printer which will manufacture by adding successive layers.
There are different 3D printing techniques, depending on the raw material used:
Fused deposition modelling (FDM): deposition by extrusion of a wire of ABS plastic or melted PLA;
Stereolithography Apparatus (SLA): elastomers or liquid thermosetting plastics are polymerized layer by layer by a laser;
Continuous Liquid Interface Production (CLIP): a liquid resin is polymerized by an ultraviolet laser in an environment where the oxygen level is controlled;
Selective Laser Sintering (SLS): Thermoplastics, metals or ceramics in the form of powder are sintered layer by layer by a laser;
Selective laser fusion or Selective Laser Melting (SLM): Metals, plastics and ceramics in the form of powder are melted layer by layer by a laser.