NUMERICALLY CONTROLLED MACHINES

Before the development of CAD, the manufacturing world adopted tools controlled by numbers and letters for manufacturing complex shapes in an accurate and repeatable manner. During 1950s, these numerically controlled (NC) machines used the existing technology of paper tapes with regularly spaced holes punched in them to feed numbers into controller machines that were wired to the motors positioning the work on machine tools. The electro-mechanical nature of the controllers allowed digital technologies to be easily incorporated as they were developed. In late 1960s, NC machining centres were commercially available, incorporating a variety of machining processes and automatic tool changing. Such tools were capable of doing work on multiple surfaces of a work piece, moving the work piece to positions programmed in advance and using a variety of tools — all automatically. What is more, the same work could be done over and over again with extraordinary precision and a very little additional human input. NC tools immediately raised automation of manufacturing to a new level once feedback loops were incorporated. What finally made NC technology enormously successful was the development of the universal NC programming language called automatically programmed tools (APT).