Re: Difference between CNC technology for manufacturing & NC machinesIn a Numerical Control machine, the program is fed to the machine through magnetic tapes or other such media.
The original NC machines were essentially basic machine tools which were modified to have motors for movement along the axes. In a Computer Numerical Controlled machine, the machines are interfaced with computers. This makes them more versatile in the sense that, suppose a change in dimension of a part is required.

In a NC machine, you would have had to change the program in the tape and then feed it to the machine again. But in a CNC machine, you just change a variable in the computer and your modification is done!!