Since the introduction of the CNC(Computer Numerical Control) machines back in 1940's by pioneer John T. Parson. CNC machines were commended for being fast,accurate and very consistent. The early technology, known then as simply Numerical Control, provided manufacturing with a way to replicate precise parts for variety of industries.
Starting in 1948, Parsons joined the U.S. Air force at an MIT laboratory to further develop Numerical control. The team behind numerical control developed a process to produce aircraft parts that required a high amount of precision, and took manual operators hours to work through.
While early NC systems were revolutionary, there was still room for improvement. Machine tools had to be programmed using a lengthy process, and errors were commonplace.
In 1959 when APT(Automatically Programmed Tools) was developed, Computer systems weren't mainstream yet, but technology was growing.Early NC machines could be programmed and controlled by small computers attached to each machine.
Currently, many CNC machine factories use Distributed Numerical Control (DNC), which allows the programmer to control several CNC units from a central computer. Many CNC units are built around software, and require significantly less training to operate.