Editing Machine tool (section)

==Automatic control==
{{unreferenced section|date=March 2021}}
{{see also|History of numerical control}}
Machine tools can be operated manually, or under automatic control.<ref>{{Cite web|title=What is a CNC machine for natural stone?|url=https://www.thibaut.fr/en/what-is-a-cnc-machine-for-natural-stone/|access-date=2020-07-29|website=Thibaut|date=23 January 2020 |language=en}}</ref>  Early machines used [[flywheel]]s to stabilize their motion and had complex systems of gears and levers to control the machine and the piece being worked on.  Soon after World War II, the [[numerical control]] (NC) machine was developed. NC machines used a series of numbers punched on [[paper tape]] or [[punched card]]s to control their motion. In the 1960s, [[computers]] were added to give even more flexibility to the process. Such machines became known as [[computerized numerical control (CNC) machines]]. NC and CNC machines could precisely repeat sequences over and over, and could produce much more complex pieces than even the most skilled tool operators.{{Citation needed|date=March 2021}}

Before long, the machines could automatically change the specific cutting and shaping tools that were being used. For example, a [[drill]] machine might contain a magazine with a variety of [[drill bit]]s for producing holes of various sizes. Previously, either machine operators would usually have to manually change the bit or move the work piece to another station to perform these different operations. The next logical step was to combine several different machine tools together, all under computer control. These are known as [[machining center]]s, and have dramatically changed the way parts are made.{{Citation needed|date=March 2021}}