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Computer Numerical control (CNC) refers to the automation of machine tools in manufacturing
processes. The machines are controlled by computer software which carries out a series of
operations automatically. The first NC machines were built in the 1940s and 1950s. They are
used to cut and shape products, such as automobile parts that need precise specifications.
Parts must be carefully planned and prepared by CNC programmers. First they view the
three-dimensional computer aided designed part. Then they calculate where to cut, the speed
and shape and select the tools and materials. The CNC programmers translate the planned
machine operations into a set of instructions. These instructions are translated into a computer
aided manufacturing (CAM) program containing a set of commands for the machine. The
commands are a series of numbers which explains where to cut and the position of material.
The computer checks all the operations made by the machine tools.