I was asked to explain CNC ...So here you go.

Computer Numeric Control (CNC)

Think of a modern day “connect the dot” game done by the computer. What that means is, the computer assigns a “numeric address” to every point along the line. When this is done just on the X/Y axis it's called "vectoring" ...from the Latin word "to follow" ...ya, whatever - I made that up.

Picture a 10 inch long straight line where the computer has assigned an address at points every 1 inch…no problem the computer has enough information to draw or cut that line with accuracy since it's only sending the cutting head one inch before it gives it more information. However, if that were a curved line, you would need to provide a greater resolution (more addresses) to form the curve in a smooth line…the more points, the smoother the curve.

From a manufacturing perspective vector CNC is used to laser plastic and metal parts, to water-jet parts, to route parts…..even the vinyl letters on your van door were done using this form of vector CNC.

http://video.google.com/videosearch?hl=en&q=CNC+engraving&um=1&ie=UTF-8&ei=VsHcSZH8BaDulQe-8fH0DQ&sa=X&oi=video_result_group&resnum=4&ct=title#

To complicate things a bit, we also use CNC equipment to make more "3D" style tools and molds used in production all the time. In this process we are using X/Y like before, but now we’re adding “Z” (x/y/z) effectively making the address a point in space instead of on a line like before. The CNC doesn’t care; as long as it has the ability to physically get to that point it could care less.

This time think of a human face. If we wanted to vector cut the outline, X/Y data would be fine. But…if you want to know the address of that point on the tip of the nose you need to have X/Y/Z data….because the tip of the nose is now a point in space and we have to tell the computer where to find it.

http://video.google.com/videosearch?hl=en&q=CNC+engraving&um=1&ie=UTF-8&ei=VsHcSZH8BaDulQe-8fH0DQ&sa=X&oi=video_result_group&resnum=4&ct=title#q=making+a+machine+part+on+a+cnc&hl=en&emb=0&start=10

CNC equipment is widely used in the manufacturing of parts for products. From engines to little doll parts at some point in the process there is likely a CNC being used to make a simple outline cut, or a more complicated "3D" part.