# 3D printing

> Making an object by stacking very thin layers of material, one on top of another.

- Level: Basic
- Topics: Hardware
- URL: https://tidbit.legios.com.ar/3d-printing/
- In Spanish: [Impresión 3D](https://tidbit.legios.com.ar/es/3d-printing/)

**3D printing** builds an object from a digital design by adding material in thin layers, each one a fraction of a millimeter thick, until the full shape appears. That is why it is also called **additive manufacturing**: instead of carving a block down (like a sculptor) or pouring into a mold, the printer only puts material where the object needs it.

The process starts with a 3D model, drawn in a design program or downloaded from a site that shares models. A program called a slicer cuts it into hundreds of horizontal layers and writes instructions for the printer. The most common home printers then melt a plastic thread, called filament, and trace each layer with a moving hot nozzle, like a very precise glue gun. Other types harden liquid resin with light for finer detail, or fuse metal powder with lasers for industrial parts.

Its strength is making one-off or custom pieces cheaply: a prototype before mass production, a replacement knob that is no longer sold, a hearing aid shaped to one person's ear, a dental aligner, a part for a rocket engine. Its weakness is speed. Printing a single object can take hours, so for making thousands of identical plastic pieces, a mold is still much faster and cheaper per unit.

## An analogy

Like building a cake out of very thin crepes stacked one on top of another, each crepe cut to the exact shape of that slice of the cake. Stack enough of them and you get any shape you want, even ones a mold could never make.

## Keep in mind

- Builds objects layer by layer from a digital 3D model.
- Home printers usually melt plastic filament; others use resin or metal powder.
- Great for prototypes, spare parts and custom pieces.
- Slow for mass production, where molds are still cheaper.

## Go deeper

- [3D printing on Wikipedia](https://en.wikipedia.org/wiki/3D_printing)