numerical control

numerical control: see computer-aided manufacturing.

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numerical control

  (NC)

Control of a system or device by direct input of data in the form of numbers, letters, symbols, words, or a combination of these forms. It is a principal element of computer-integrated manufacturing, particularly for controlling the operation of machine tools. NC is also essential to the operation of modern industrial robots. The two basic types of NC systems are point-to-point, in which a device is programmed to perform a series of motions with fixed starting and stopping points, and continuous-path, in which a point-to-point programmed device has sufficient memory to be “aware” of its former actions and their results and to act in accordance with this information.

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numerical control

A category of automated machine tools, such as drills and lathes, that operate from instructions in a program. Numerical control (NC) machines are used in manufacturing tasks, such as milling, turning, punching and drilling. Both NC and CNC (computerized NC) are used to describe this category.

First-generation machines were hardwired to perform specific tasks or programmed in a very low-level machine language. Today, they are controlled by microprocessors and are programmed in high-level languages, such as APT and COMPACT II, which automatically generate the tool path (physical motions required to perform the operation).

The term was coined in the 1950s when the instructions to the tool were numeric codes. Just like the computer industry, symbolic languages were soon developed, but the original term remained.