FFF (Fused Filament Fabrication)
A filament of plastic material is pushed towards a heated mobile head which melts and extrudes the filament depositing it, layer by layer, in the desired shape.
SLA | LCD | DLP (photopolymerization)
A vat contains a liquid resin capable of polymerizing when exposed to light. A laser, an LCD display, or a projector solidify the resin according to the section of the piece to be made.
SLS (Selective Laser Sintering)
A laser beam sinters powder particles which can be polymer or composite based.