Before we get to the printer, firstly, we need to build a 3D digital model of the object using CAD(computer-aided design) on computer and then “cut” the model into lots of 2D cross-sectional layers. After that, based on these sectional drawing data, the 3D printer can begin its work.

Its basic principle overlaps 2D printing as printing 2D cross-sectional layers is also necessarily involved in 3D printing process. But rather than using ink as raw material, 3D printing entails molten material, typically, a kind of thermoplastics ABS or solid powder, which hardens and sets reasonably quickly. Here we set ABS plastic 3D printing as an example. When printing, ABS plastic, looking like whiteish-yellow glue in its raw form, is extruded through a tiny nozzle and melted at print head. According to the 3D model drawing made before, with each cross-sectional layer drawing on computer, the print head prints one layer at a time; meanwhile, the plastic is steadily melting and depositing, and then these deposit layers will be fused together with adhesive or ultraviolet light, from the bottom up, until a 3D model is formed.

Not all ABS plastics are in the form of filament, some types of printer with small pellet; Plastic or powder are also not necessarily used since chocolate can be melted and turn solid as well when you cool them down.