The 3D printing technology was first introduced in the 80s, when the first 3D printer using stereolithography technique, was developed by Charles W. Hull. The 3D printing gained traction in the 90s onwards, though mainly applied in engineering, architecture and manufacturing.
 
3D printing can give shape to building materials normally available in powder forms. A digital 3D-model is required for creating an object through a 3D printer. This model can be made through different ways like, drawing it through computer-assisted design, scanning a set of 3D images, or through different software such as CAD. These sample designs are also available online. The digital 3D-model is usually saved in STL format and then sent to the printer. The process of printing is to print three-dimensional object layer-by-layer with a printer which is quite similar to inkjet printers. The most common filaments used to create 3D objects include PLA, ABS, Nylon, Carbon Fiber, TPU, Wood, Metal, Glow-in-the-dark, PVA and others.

Types of 3D printing:

Types of 3D printing or various 3D technologies include SLS (Selective Laser Sintering), FDM (Fused Deposition Modelling) and SLA (Stereolithography).
 

SLS (Selective Laser Sintering):

It is additive manufacturing (AM) technique in which the power source is usually the light which is then used to sinter powdered material (like nylon/polyamide). The laser automatically aims at the different points in space which is defined by a 3D model and binds the material together to create a solid structure. SLS is considered as new technology and is mainly used for fast prototyping and low volume production of parts. Production roles are increasing with new advancements and commercialisation of the technology.

FDM (Fused Deposition Modelling):

It is a 3D printing process which works on the continuous filament of thermoplastic material. This filament is provided through a large coil, and at the end of the coil, there is a moving, heated printer extruder head. The print head is used to make the printed shape, which works under computer control. The layers of the object are laid by the movement of extruder head in two dimensions, but it deposits one horizontal layer at a time when complete its movement. After the completion of one layer, the print head is then moved vertically by a small amount to begin a new layer. The thickness of the products made by FDM is about 100-20 Microns Layer thickness.
 

SLA (Stereolithography):

It is a form of 3D printing technology which also works in a layer by layer fashion but uses the photochemical processes to make various 3D objects. In the photochemical process, the light combines the chemical monomers, which in turn become polymers. These polymers then turn the 3D object int into a solid body. It is mainly used for creating models, prototypes, patterns, and production parts. The thickness of the products made by SLA is about 140-150 Microns Layer thickness.