CNC stands for Computer Numerical Control which has been used since the 1970's at the onset of computers. That is how it got its name, except that it was first called only NC or numerical control when it was first introduced.
All of this work is simplified for the operator by the CNC machine. The CNC machine is the equivalent to a CNC drill press. All the operator has to do is place the metal where it needs, activate the spindle and set the controls. It's very similar to the automated way of doing things. With CNC machines, you can program everything that an operator needs to do with conventional machine tools.
A CNC machine can also produce precise and consistent work pieces. After the programming controls have been set, the CNC machine is capable of producing thousands of identical pieces in a very short time. If you do it manually, this is almost impossible.
Because processes can be programmed, CNC machines are flexible. A program can be run for one piece and saved so that it can be used again when the piece is needed. These machines can also be set up quickly, which will allow you to meet your deadlines more efficiently. You are not sacrificing performance or quality just because you are trying to save money. These machines are often on the market even though they are still in use.