How Do 3D Printers Work?

3D printing (additive manufacturing) builds three-dimensional objects by depositing material layer by layer, rather than subtracting material from a block. The most common consumer technology is Fused Deposition Modelling (FDM): a thermoplastic filament (usually PLA or ABS) is heated to about 200 degrees Celsius and extruded through a nozzle that traces each layer pattern, building up the object typically in 0.1-0.3 mm layers. Stereolithography (SLA) uses a UV laser to cure liquid photopolymer resin, producing finer detail. Selective Laser Sintering (SLS) fuses powder (nylon, metal) with a laser, enabling strong functional parts. Metal 3D printing (Direct Metal Laser Sintering) can produce complex aerospace and medical components impossible to manufacture traditionally. The technology was invented by Chuck Hull in 1984 (he coined the term "stereolithography" and co-founded 3D Systems). Applications span prototyping, custom medical implants, aerospace components, architectural models, and consumer products.