Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · CNC and machine tools

Computer numerical control (CNC)

Also known as: CNC control, Computerized numerical control

German: Computerized Numerical Control (CNC)

In machine tools, computer numerical control (CNC) is numerical control in which a built-in computer stores and interprets the part program and calculates the axis movements, so programs can be edited, stored and corrected at the machine.

  • CNC
  • Standards

In one sentence

Computer numerical control (CNC) uses a built-in computer to store and interpret part programs and to control the axes of a machine tool.

Example

A five-axis CNC milling machine reads the part program from its memory, interpolates the tool path and drives the servo axes and spindle accordingly.

How it applies

  • Engineering: A CNC combines the NC kernel (interpolation, axis control), a PLC part for machine logic such as tool changers and coolant, and an HMI. Machine builders adapt the PLC part and the parameters to the machine.
  • Operation: Operators load or write NC programs, set Tool offsets and Work offsets and run the machine in the operating modes the control provides.
  • Documentation: CNC documentation is split between the control vendor (programming and operating manuals) and the machine builder (machine-specific functions, M-codes, safety instructions). The Operating manual should say clearly which document governs which function and which control software version it describes.

CNC vs. NC

Early Numerical control (NC) read programs from punched tape and had hard-wired logic. CNC stores programs in memory and computes the path in software. Today almost every NC machine is a CNC machine, and the terms are often used interchangeably.

By knowledge.aitechdoc.world · Published September 26, 2026 · Last reviewed

Source: ISO 2806:1994, Industrial automation systems — Numerical control of machines — Vocabulary

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Knowledge and are not part of any standard.

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