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It begins with a digital 3d model

The 3d printing process begins with a digital 3d model, generated either on a piece of software known as Computer Aided Design, CAD for short, or using a 3d scanning system to scan a 3 dimensional model of a solid physical object.  The CAD software is readily available from many suppliers and is used extensively in the Engineering design process in design offices throughout the world.  3d scanning technology is less prevalent however, is ever increasingly becoming common for transferring solid objects into 3d computer models.


“Slicing” the 3d Model

The 3d computer model is then transferred into a second piece of software for Computer Aided Manufacture, CAM for short.  Traditionally this software converts the physical dimensions of an object into a set of coordinates that can be used by a manufacturing process to manufacture the object.  In the case of 3d printing the CAM software “slices” the object into hundreds of horizontal slices, each just a few micrometres thick (Note: 1 micrometre = one thousandth of a mm or 0.001mm).  The first slice is then “printed” in a 3d printer and the second slice is then “printed” on top of the first.  Each successive slice is then printed on top of the previous slice and, in doing so, a 3 dimensional object is “printed”.  Each slice is bonded to the previous slice in some way, with different 3d printing processes using different methods to achieve this bonding.


3d printing is Additive Manufacturing, not Subtractive Manufacturing

3d printing is sometimes referred to as additive manufacturing because the object is “additively” built i.e., it is built up by adding one layer on top of the other.  Many traditional manufacturing methods are subtractive technologies in that they start with a solid block of a material and subtract or remove material, by milling, cutting, drilling or similar processes, to achieve the final object.  Subtractive methods produce a significant amount of expensive waste product because the raw material, which is often expensive in its bar or block form, is turned into waste product in the form of swarf, and disposed of with little or no cost being recoverable.  3d printing on the other hand, only uses the correct amount of material required to produce the part with almost no waste product, saving significant cost.