Computer Aided Manufacture (CAM)
CAM uses computers to automatically control the machinery performing various manufacturing processes.
Computer Numerical Control (CNC): A CAM technology using computers to control cutting machines such as milling machines to cut specified three-dimensional shapes. CNC has been used since the early 1970s. You'll notice the milling maching in the photo (left) is a 4-Axis machine that removes material via its milling spindle to create a 3-dimensional model.
Another popular technology associated with CAM is 3D printing. A layer manufacturing technology in which the layers are formed by using a printhead-like device to distribute an adhesive to bond the surface of a powder in the desired shape. (photo right)
This process uses stereolithography technology to slice a computer model into hundreds or thousands of very thin slices that the printer will build layer upon layer until the piece is complete.
Similarly, another technology that relies on stereolithography to create models is based upon the principle of Photopolymerisation.
A photopolymer is a polymer that changes its properties when exposed to light, often in the ultraviolet spectrum.
Like a 3D printer these machines create a model layer by layer until complete. The resolution for this process is higher and is often the choice for intricate or very fine designs.(polymer models left)
A 3D printer builds the layers on top of each other starting with a baseplate. A machine that uses photopolymers builds the model upside down with each layer emerging from a pool of polymer.
There are advantages and disadvantages for each of these technologies. Cost and speed can play a vital role role in selecting which technology to use for each design. A very simple but larger design may work more efficiently with a CNC mill where a very intricate pattern may be best for a photopolymer.
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Watch the Video (3min)Gemological Institute of America