Principle of layer based technology:

The principle of layer based technology is to compose a 3D physical object called ‘part’ from many layers of (mostly) equal thickness.
This ‘part’ or ‘model’ initially generated using a 3D CAD system, can be fabricated directly without the need for process planning and any cutters, tooling or fixtures specific to object geometry.
Each layer is contoured according to the corresponding 3D data set and put on the top of the preceding one.

Terms of Reference of additive manufacturing:

3D 3D Manufacturing [Stereolithography]

AM Additive Manufacturing [Additive layer manufacturing, Additive Oriented Manufacturing]

SFF Solid Freedom Fabrication

LM Layer Manufacturing [Layer Based Manufacturing, Layer Oriented Manufacturing]

DM Digital Manufacturing [Digital mock-up]

RP Rapid Prototyping/ Tooling/ Manufacturing [Direct manufacturing, Direct tooling ]

History of additive manufacturing started in the 1980's in Japan: in 1981 ‘Hideo Kodama’ developed a layer-by-layer approach for manufacturing, using a photosensitive resin that was polymerized by UV light.

In 1986 ‘Charles Hull’ filed the first patent for stereolithography (SLA), then he founded a company 3D systems. In 1988 the first commercial SLA 3D printer, the SLA-1, was released by his company. He also developed the .stl file format. the file that 3D printers most commonly use today.

In 1988, ‘Carl Deckard’ at the University of Texas filed the patent for selective laser sintering (SLS) Technology.This system fused powders, instead of liquid, using a laser.

Fused Deposition Modeling (FDM) also called Fused Filament Fabrication was also patented around the same time by ‘Scott Crump’.

In the 90’s many companies and startups began popping up and experimenting with the different Additive Manufacturing. Technologies.

In 2005 open source (and online libraries) changed the game of 3D printing giving people more access to this technology. ‘Dr Adrian Bowyer’ created the rep-rap project, which was an open- source initiative to create a 3D printer that could build another 3D printer or objects.

so originally created with rapid prototyping as the goal. it has evolved over the years, now more and more companies integrated additive manufacturing into their product development design and production process.