CNC
CNC stands for Computer Numerical Control. A CNC is a computer that powers a machine tool by reading G-code machining instructions. (G-code is the basic programming language of CNC machining world.) Guided by the CNC, the machine tool shapes a workpiece by selectively removing metal.
Basic Movements
A CNC controller can give a machine tool a variety of instructions. At the simplest level, the CNC controller moves a cutting tool from one point to the other using the Cartesian coordinate system. Lathes are programmed horizontally or vertically in the X- or Y- axis (below). Milling machines can also be programmed in the Z-axis.
By combining many incremental G-code movements, the CNC can move a cutting tool in a smooth path like an arc. (Many recent CNC controllers can interpolate a horizontal circular arc as a single instruction--- making the programmer’s task much easier.)
Changing Tools - Automatically
A complex machining operation requires multiple tools. This is a snap for a CNC controller, as it automates tool changes. Machine tools come equipped with magazines that contain different tools. When a new tool is needed to continue an operation, the CNC controller tells the machine to retrieve the new tool from the magazine. (The G-code instruction for a tool change is M06)
