Numerical control for machines .tools were introduced in 1950’s by Prof.John T Parsons. The first NC machine was built at the Massachusetts institute of Technology in 1953 by joint efforts of US Air Force, the MIT and parson’s cooperation. NC is control by numbers .NC is control recorded information called part program, which is set of coded instructions given as numbers for automatic control of am machine in a pre-determined sequence.
Numerical control can be defined as a technique of controlling a machine tool by the direct insertion of numerical data at some point of the system .The functions that are controlled on the machine tool are displacement of the slide members, spindle speeds ,tool selection etc.At first ,the numerical control was used to produce geocentrically complex parts ,but later used for added efficiency in medium batch production of turned and milled parts presently, Numerical control is employed in all sectors of production .
Rapid development in the field of electronics such as integrated circuit, large scale integrated circuits and development of minicomputer lead to the development of minicomputers based CNC systems. Further development and the electronic “chip” revolution have ushered in the current generation “compact and powerful” Microprocessor based CNC systems.
Development of computer numerically controlled (CNC) machines is an outstanding contribution to the manufacturing industries. It has made possible the automation of the machining process with flexibility to handle small to medium batch of quantities in part production.
Initially, the CNC technology was applied on basic metal cutting machine like lathes, milling machines, etc. Later, to increase the flexibility of the machines in handling a variety of components and to finish them in a single setup on the same machine, CNC machines capable of performing multiple operations