ONRL (Office of Naval Research Labs) first developed the technology for 3D laser scanning on a much larger scale, and they in turn married the data to a much larger rapid prototyping system which essentially does the same thing only on a much larger scale with not so state of the art computers back then - although they were considered state of the art back in the day - resulting in much more time needed in order to produce a detailed copy of whatever it was copying and accuracy was not always consistent ...
There are approximately 25 different types of rapid prototyping/printing technologies, and one of the oldest is LOM otherwise known as "Laminated Object Manufacturing" which was first commercially available and trademarked by Helisys of Torrence, CA.
More recent technologies include selective laser sintering, Direct Metal Laser Sintering (DMLS), inkjet technologies, fused deposition modeling, Polyjet matrix and many variations. All of these technologies take a 3D model, compute cross-sections of that model, and then deposit the cross-sections sequentially on top of each other until the final geometry is achieved. Overhanging parts are supported by a second material in many cases or by the material in powdered form such as in the case of Selective Laser Sintering.
To visualize how 3D printing works, consider a coffee cup. If you were to slice the coffee cup into wafer-thin layer like you would meat on a slicing machine at a Deli and save each layer and then re-stack them in order, you would re-create the shape of the original object. 3D printing accomplishes this by deposition of very thin layers on top of each other from sliced 3D models or CAD data within a computer system.
Varying the layer thickness affects the model surface finish and other parameters including but not limited to mechanical properties. Many methods have been devised to improve surface finishes; these usually slow down the printing process.
Direct Digital Manufacturing UsageIn 2006 there were approximately 50 commercially viewable examples of 3D printing being used for tooling or intermediate parts. The technology is still new and its use is directly dependent on users' knowledge of engineering to design a part and effectively use the printing equipment. The growth of the market is nevertheless fast, and was estimated in 2006 to be as high as 35% annually.
The earliest use of the term Direct Digital Manufacturing surfaced around 2004 by Digital Reality, Inc. The company purportedly holds a patent pending on a process for Direct Digital Manufacturing they call Made-To-Order Digital Manufacturing Enterprise. The company filed a non-publication request on the patent application.
As other folks have previously posted, this technology has been around for quite some time now and has currently been scaled down in overall size enough so that it now can be taken advantage of for use in commercial applications... The computers used in these systems are faster and smaller and the software is more sophisticated and complex than the earlier versions resulting in greater accuracies & faster completion times... As Spock would say: "Fascinating!!!"
Respectfully,
Henry
