Today’s Computer Numerically Controlled (CNC) machines have their origins in early numerically controlled (NC) machines, servomotor controlled tools able to machine precise shapes by following instructions fed into them on magnetic or paper tape or punch cards. The tapes or cards carried a series of points through which the controls would move, with the result that shapes could be machined with more precision than when the machines were operated by hand.At first the geometric calculations to generate the points required to generate different shapes had to be worked out by hand by hand, which was a time-consuming process. This was a time-consuming and sometimes imprecise process, but with the advent of computer-generated punch tapes in the mid 1950s the era of computer numerical control (CNC) had arrived.Computers were so much quicker and more efficient in performing the calculations required that in 1956 the US Air Force commissioned Douglas T. Ross to formulate a general programming language for numerical machine control that was based on points and lines. This language was developed into the Automatically Programmed Tools (APT) programming language, which was used to program CNC machines until the 1970s.In 1957 MIT researchers led a team aimed at developing a fully computerized numerical control system using the new APT programming language. By 1959 their work had resulted in the first product ever produced using computer-aided design and manufacturing – an aluminium ashtray.

As the price and size of computers fell during the 1960s it became cost-effective to replace the dedicated servo motors controlling CNC machines with minicomputers. In the 1970s, the development of microprocessors led to microprocessor-controlled CNC machines becoming more common, and today almost all CNC machines are controlled by microprocessors. Modern media like USB drives, floppy disks and local area networks have replaced punch tapes to some extent in modern CNC systems.

Modern precision machining has diversified from the spindle and cutting tool processes for which it was originally developed, and today CNC can be used for any processes that can be carried on machine tool motion platforms. These include lasing, welding, flame cutting, bending, spinning, pinning, gluing, fabric cutting, sewing, routing, and sawing.