A 3D printer works by creating a three-dimensional object layer by layer from a digital design. The process begins with a 3D model created using computer- aided design (CAD) software or obtained via 3D scanning. This model is then sliced into very thin horizontal layers by specialized software called a slicer, which generates instructions (usually in G-code) that guide the printer on how to build the object
. The printer builds the object through additive manufacturing, meaning it adds material layer upon layer from the bottom up, unlike subtractive manufacturing which removes material
. The most common 3D printing method is Fused Deposition Modeling (FDM), where a thermoplastic filament (such as PLA or ABS) is fed into a heated nozzle, melted, and extruded onto a build platform layer by layer to form the shape
. Other technologies include stereolithography (SLA), which uses a laser to cure liquid resin into solid plastic, and selective laser sintering (SLS), which fuses powdered material with a laser
. During printing, the printhead moves precisely according to the sliced model instructions, depositing material only where needed. The first layer is critical and usually printed on a heated platform to ensure good adhesion. The printer may also add support structures for overhanging parts, which are removed after printing
. After printing, parts often undergo post-processing such as cleaning off uncured resin, removing supports, or additional curing to enhance mechanical properties
. The final object can be used as is or further finished by machining, painting, or assembly. In summary, a 3D printer transforms a digital 3D design into a physical object by successively laying down thin layers of material- plastic, resin, or powder-guided by computer instructions until the complete shape is formed
