What is 3D printing and how does it work?

3D printing or additive manufacturing is a process of making three-dimensional solid objects from a digital file. The creation of a 3D-printed object is achieved using additive processes. In an additive process, an object is created by laying down successive layers of material until the entire object is created. Each of these layers can be seen as a thinly sliced horizontal cross-section of the eventual object.
It starts with making a virtual design of the object that is to be created. This virtual design is made in a CAD (Computer Aided Design) file using a 3D-modeling program (for the creation of a totally new object) ... read more

History of 3-D Printing

The earliest use of additive manufacturing was in rapid prototyping (RP) during the late 1980s and early 1990s. Prototypes allow manufacturers a chance to examine an object's design more closely and even test it before producing a finished product. RP allowed manufacturers to produce those prototypes much faster than before, often within days or sometimes hours of conceiving the design. In RP, designers create models using computer-aided design (CAD) software, and then machines follow that software model to determine how to construct the object. The process of building that object by "printing" its cross-sections layer by layer became known as 3-D printing.

The earliest development of 3-D printing technologies happened at Massachusetts Institute of Technology (MIT) and at a company called 3D Systems. In the early 1990s, MIT developed a procedure it trademarked with the name 3-D Printing, which it officially abbreviated as 3DP. As of February 2011, MIT has granted licenses to six companies to use and promote the 3DP process in its products [source: MIT].

From building sites through science labs to hospitals, 3D printing is turning up in more places and creating objects on demand. But how to get from a design on a computer screen to something you can hold?

There are three different ways 3D printers work but they all rely on the printer converting a design into individual 2D slices which are then combined to make the final 3D object.

The first method uses a pool of chemicals that turns solid when light, typically a UV laser, is shone on to it. The laser moves across a thin layer of liquid, drawing the required design. Once the first layer is finished the resulting solid is lowered to allow a second thin layer of liquid to be deposited on its surface. The laser is then used to outline and solidify the design. More and more layers are built up until the final product is finished.

A second method uses molten ink (or even chocolate or cheese) that becomes solid when it emerges from the printer head. Designs are drawn out by the ink and again built up layer by layer until the final product is complete. A final method uses layers of powdered material, held together with glue or heated to fuse the powder together, to translate the design into reality.


At right is a mega-hamburger designed by a student with a lot of elements stacked on top of one another.

This video shows a simulation of how a 3D printer would be printing a 3D object from the bottom build plate. It shows the printing of the layers as the nozzle travels from bottom to top, depositing melted filament which will build up to form the 3D object. In order for the 3D printer to print the object, the design file is sliced in 2D layers by a slicing software so the 3D printer can be instructed where to deposit the layers of filaments on top of one another, eventually creating 3D object.

The checkered bottom is the build plate on which the object will be built up. The frame around the object represents the build volume, i.e. the biggest size that the 3D printer is capable of making, e.g. 5x5x5", 8x8x8" or 12x12x12",etc.