3D printing is a form of additive manufacturing technology where a three dimensional object is created by laying down successive layers of material. 3D printers are generally faster, more affordable, and easier to use than other additive manufacturing technologies. However, the term 3D printing is increasingly being used to describe all additive manufacturing processes. 3D printers offer product developers the ability to print parts and assemblies made of several materials with different mechanical and physical properties, often in a single build process. Advanced 3D printing technologies yield models that can serve as product prototypes.
Since 2003 there has been large growth in the sale of 3D printers. Additionally, the cost of 3D printers has declined.The technology also finds use in the fields of jewelry, footwear, industrial design, architecture, engineering and construction (AEC), automotive, aerospace, dental and medical industries, education, geographic information systems, civil engineering, and many others.
A large number of competing technologies are available to do 3D printing. Their main differences are found in the way layers are built to create parts. Some methods use melting or softening material to produce the layers, e.g. selective laser sintering (SLS) and fused deposition modeling (FDM), while others lay liquid materials that are cured with different technologies. In the case of laminated object manufacturing, thin layers are cut to shape and joined together.Each method has its advantages and drawbacks, and consequently some companies offer a choice between powder and polymer as the material from which the object emerges.Generally, the main considerations are speed, cost of the printed prototype, cost of the 3D printer, choice and cost of materials and colour capabilities.
One method of 3D printing consists of an inkjet printing system. The printer creates the model one layer at a time by spreading a layer of powder (plaster, or resins) and inkjet printing a binder in the cross-section of the part. The process is repeated until every layer is printed. This technology is the only one that allows for the printing of full colour prototypes. This method also allows overhangs.In digital light processing (DLP), a vat of liquid polymer is exposed to light from a DLP projector under safelightconditions. The exposed liquid polymer hardens. The build plate then moves down in small increments and the liquid polymer is again exposed to light. The process repeats until the model is built.
Standard applications include design visualization, prototyping/CAD, metal casting, architecture, education, geospatial, healthcare and entertainment/retail. Other applications would include reconstructing fossils in paleontology, replicating ancient and priceless artifacts in archaeology, reconstructing bones and body parts in forensic pathology and reconstructing heavily damaged evidence acquired from crime scene investigations.
More recently, the use of 3D printing technology for artistic expression has been suggested. Artists have been using 3D printers in various ways. During the 2011 London Design Festival, an installation, curated by Murray Moss and focused on 3D Printing, took place in the Victoria and Albert Museum (the V&A). The installation was called Industrial Revolution 2.0: How the Material World will Newly Materialise.
3D printing technology is currently being studied by biotechnology firms and academia for possible use in tissue engineering applications where organs and body parts are built using inkjet techniques. Layers of living cells are deposited onto a gel medium and slowly built up to form three dimensional structures. Several terms have been used to refer to this field of research: organ printing, bio-printing, and computer-aided tissue engineering, among others. 3D printing can produce a personalized hip replacement in one pass, with the ball permanently inside the socket, and even at current printing resolutions the unit will not require polishing.
Source : http://en.wikipedia.org/wiki/History_of_printing