# computer numerical control

Also found in: Acronyms.

## computer numerical control

[kəm′pyüd·ər nü′mer·i·kəl kən′trōl]
(control systems)
A control system in which numerical values corresponding to desired tool or control positions are generated by a computer. Abbreviated CNC. Also known as computational numerical control; soft-wired numerical control; stored-program numerical control.

## Computer numerical control

The method of controlling machines by the application of digital electronic computers and circuitry. Machine movements that are controlled by cams, gears, levers, or screws in conventional machines are directed by computers and digital circuitry in computer numerical control (CNC) machines.

Computer numerical control provides very flexible and versatile control over machine tools. Most machining operations require that a cutting tool be fed at some speed against a workpiece. In a conventional machine such as a turret lathe, the turning tool is mounted on a slide with hand-operated infeed and crossfeed slides. The operator manually turns a crank that feeds the cutting tool into the workpiece (infeed) to the desired diameter. Another crank then moves the turning tool along the longitudinal axis of the machine and produces a cylindrical cut along the workpiece. The feed rate of the turning tool is sometimes controlled by selecting feed gears. These gears move the axis slide at the desired feed. A CNC machine replaces the hand cranks and feed gears with servomotor systems. See Servomechanism

Computer numerical controls allow the desired cut depths and feed rates to be “dialed in” rather than controlled by cranks, cams, and gears. This provides precise, repeatable machine movements that can be programmed for optimal speeds, feeds, and machine cycles. All cutting-tool applications, whether on a lathe, drill press, or machining center, have optimum speeds and feeds, which are determined by carefully weighing the economics of tool life, required production rates, and operator attentiveness. With computer numerical control these parameters are set once, and then they are repeated precisely for each subsequent machine cycle.

In computer-aided manufacturing (CAM), computers are used to assist in programming CNC machines. In sophisticated CNC manufacturing operations, machined parts are first designed on computer-aided-design (CAD) equipment. The same electronic drawing is then used to create the CNC part program automatically. A less advanced version of CAM is the use of high-level part programming languages to write part programs. See Computer-aided design and manufacturing

Computer numerical control machines are used mainly when flexibility is required or variable and complex part geometries must be created. They are used to produce parts in lot sizes of a few pieces to several thousand. Extremely large manufacturing lot sizes frequently call for more product-specific machines, which can be optimized for large production runs.

References in periodicals archive ?
Equipped with high precision Computer Numerical Control (CNC) machinery for punching, machines for bending and gasketing and in-house powder coating capabilities, the new sheet metal factory continues to strengthen Scientechnic's promise to deliver the highest quality sheet metal enclosures.
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Trinity Precision specialise in supplying exceptional quality Computer Numerical Control (CNC) machined parts to many different sectors such as oil and gas, automotive, sub-sea and Formula One.
At Blyth, a state of the art computer numerical control will allow Omega to produce a more diverse range of tools quicker and more efficiently than before.
However Damietta's long artisan heritage is now endangered due to the spread of the Computer Numerical Control (CNC) machine.
Benjamin Geskin, known for leaking smartphones, claimed&nbsp;on Twitter to have a computer numerical control (CNC) model of the upcoming device, and he posted pictures of the device Sunday.
Maker librarians from the US and Canada detail how to start a makerspace, including strategic planning, funding sources, starter equipment, space design, and safety guidelines, as well as teaching and learning opportunities makerspaces offer and how to encourage a diverse maker culture; key technologies and tools (3D printers, Raspberry Pi, Arduino, wearable electronics, Google Cardboard, hackerspace programs, computer numerical control, robotics, Legos, drones, and circuitry kits) and how to use them; and making makerspaces mobile, sustaining them, and their future in libraries.
The Maslow CNC is a revolutionary design in the world of CNC, or computer numerical control.
Engineering curriculum team leader John Markowycz said: "We have some really goodquality candidates who have applied for mechanical engineering apprenticeships which would cover traditional machining and more advanced manufacturing using CNC - Computer Numerical Control - machines.
Ethan is currently employed by Electroimpact, of Manor Lane, Hawarden as an apprentice Computer Numerical Control (CNC) machinist and won his gold medal in CNC Milling.
The company, originally founded as Specialty Blades in 1985 by engineer Martin Lightsey, was developed with the concept of combining computer numerical control and razor-blade sharpening technologies to address the needs of companies that required high-performance, custom-made blades.
GCMI houses design, material and mechanical engineering resources, such as high-end 3-D printing, extrusion and computer numerical control machines, capable of producing medical devices for development, pre-clinical testing and clinical studies.

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