What is CNC Machining? CNC stands for Computer Numerical Control. CNC machining is the process of using pre-programmed computer software to dictate and control the movement and functionalities of a machine. Many industries use CNC machines, with the most saturation in metal and plastic production. Compared to manual machining, CNC machining is faster, more efficient, and more accurate. CNC machining is a subtractive manufacturing process, which means such machines typically employ computerized tools to remove layers of materials from a workpiece to produce a custom design part. You might think that the computer has always been an intrinsic part of CNC machines, but that?s not true. The first CNC machine was a mere machine with a metal frame. It was invented in 1751 and was developed later to become what it is now.