Computer numerical control: Difference between revisions

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{{Short description|Computer control of machine tools}}

{{Redirect-multi|Numerics2|CNC|numerics|the field of computer science|Numericalnumerical analysis|other uses}}

{{Redirect|CNC}}

{{Redirect|Numerics|the field of computer science|Numerical analysis}}

[[File:CNC machine.jpg|thumb|A CNC machine that operates on wood]]

[[File:Wheel Machining.jpg|thumb|CNC machines typically use some kind of coolant, typically a water-miscible oil, to keep the tool and parts from getting hot.]]

[[File:Cnc lathe.png|thumb|A CNC [[metal lathe]] with the door open.]]

'''Computer numerical control''' ('''CNC''') or '''CNC machining''' is the [[Automation|automated control]] of [[machine tool]]s by a computer. It is an evolution of '''numerical control''' ('''NC'''), where machine tools are directly managed by [[data storage media]] such as [[punched card]]s or [[punched tape]]. Because CNC allows for easier programming, modification, and real-time adjustments, it has gradually replaced NC as computing costs declined.<ref>{{cite web | url=https://www.pcmag.com/encyclopedia/term/numerical-control | title=Definition of numerical control }}</ref><ref>{{Cite web|title=What Is A CNC Machine? |url=https://cncmachines.com/what-is-a-cnc-machine|access-date=2022-02-04|website=CNC Machines }}</ref><ref>{{cite encyclopedia |last=Groover |first=Mikell P. |date=2024-10-28 |title=Automation - Numerical Control, Robotics, Manufacturing |url=https://www.britannica.com/technology/automation/Numerical-control#ref390752 |access-date=2025-03-18 |encyclopedia=[[Encyclopædia Britannica]]}}</ref>

A CNC machine is a motorized maneuverable tool and often a motorized maneuverable platform, which are both controlled by a computer, according to specific input instructions. Instructions are delivered to a CNC machine<ref>{{Cite web |date=2023-11-18 |title=CNC Laser Metal Cutting Machine {{!}} Metal Laser Cutter |url=https://dwcnclaser.com/metal-laser-cutter/ |access-date=2024-06-01 |website=https://dwcnclaser.com/ |language=en-US}}</ref> in the form of a sequential program of machine control instructions such as [[G-code]] and M-code, and then executed. The program can be written by a person or, far more often, generated by graphical [[computer-aided design]] (CAD) or [[computer-aided manufacturing]] (CAM) software. In the case of 3D printers, the part to be printed is "sliced" before the instructions (or the program) are generated. 3D printers also use G-Code.<ref name=":1">{{Cite web |last=3ERP |date=2022-06-24 |title=What is CNC Milling and How Does it Work: Everything You Need to Know - 3ERP |url=https://www.3erp.com/blog/cnc-milling-everything-you-need-to-know/ |access-date=20222025-0603-3018 |website=Rapid Prototyping & Low Volume Production |language=en-US3ERP}}</ref>

In [[machining]], '''numerical control''', also called '''computer numerical control''' ('''CNC'''),<ref>{{Cite web|title=What Is A CNC Machine? {{!}} CNC Machines|url=https://cncmachines.com/what-is-a-cnc-machine|access-date=2022-02-04|website=cncmachines.com}}</ref> is the [[automation|automated control]] of tools by means of a [[computer]]. It is used to operate tools such as [[drill]]s, [[lathe]]s, [[Milling (machining)|mills]], [[Grinding machine|grinders]], [[CNC router|routers]] and [[3D printer]]s. CNC transforms a piece of material ([[metal]], [[plastic]], wood, ceramic, stone, or composite) into a specified shape by following coded programmed instructions and without a manual operator directly controlling the machining operation.

A CNC machine is a motorized maneuverable tool and often a motorized maneuverable platform, which are both controlled by a computer, according to specific input instructions. Instructions are delivered to a CNC machine<ref>{{Cite web |date=2023-11-18 |title=CNC Laser Metal Cutting Machine {{!}} Metal Laser Cutter |url=https://dwcnclaser.com/metal-laser-cutter/ |access-date=2024-06-01 |website=https://dwcnclaser.com/ |language=en-US}}</ref> in the form of a sequential program of machine control instructions such as [[G-code]] and M-code, and then executed. The program can be written by a person or, far more often, generated by graphical [[computer-aided design]] (CAD) or [[computer-aided manufacturing]] (CAM) software. In the case of 3D printers, the part to be printed is "sliced" before the instructions (or the program) are generated. 3D printers also use G-Code.<ref name=":1">{{Cite web |last=3ERP |date=2022-06-24 |title=What is CNC Milling and How Does it Work: Everything You Need to Know - 3ERP |url=https://www.3erp.com/blog/cnc-milling-everything-you-need-to-know/ |access-date=2022-06-30 |website=Rapid Prototyping & Low Volume Production |language=en-US}}</ref>

CNC offers greatly increased productivity over non-computerized machining for repetitive production, where the machine must be manually controlled (e.g. using devices such as hand wheels or levers) or mechanically controlled by pre-fabricated pattern guides (see [[Pantograph#Milling machines|pantograph mill]]). However, these advantages come at significant cost in terms of both capital expenditure and job setup time. For some prototyping and small [[batch production|batch]] jobs, a good machine operator can have parts finished to a high standard whilst a CNC workflow is still in setup.

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==History==

{{Main article|History of numerical control}}

The first CNCNC machines were built in the 1940s and 1950s, based on existing tools that were modified with motors that moved the tool or part to follow points fed into the system on [[punched tape]].<ref name=":1" /> These early [[servomechanism]]s were rapidly augmented with analog and digital computers, creating the modern CNC machine tools that have revolutionized machining processes.

== Today ==

Now the CNC in the processing manufacturing field has been very extensive, not only the traditional [[Milling (machining)|milling]] and [[turning]], other machines and equipment are also installed with the corresponding CNC, which makes the manufacturing industry in its support, greatly improving the quality and efficiency. Of course, the latest trend in CNC<ref>{{Cite web |last=CapableMaching |title=CNC Machining Industry: new & important trend |url=https://capablemachiningcapablemaching.com/cnc-machining-industry/ |website=}}</ref> is to combine traditional [[Machining|subtractive manufacturing]] with [[3D printing|additive manufacturing]] (3D printing) to create a new manufacturing method<ref>Chang Y C, Pinilla J M, Kao J H, et al. Automated layer decomposition for additive/subtractive solid freeform fabrication[C]. 1999 International Solid Freeform Fabrication Symposium, 1999.</ref> - hybrid additive subtractive manufacturing (HASM).<ref>{{Cite journal |last=W. Grzesik/ |date=2018 |title=HYBRIDHybrid ADDITIVEAdditive ANDand SUBTRACTIVESubtractive MANUFACTURINGManufacturing PROCESSES...Processes and Systems: A Review |url=https://bibliotekanauki.pl/articles/99525.pdf |journal=Journal of Machine Engineering |volume=18 |issue=4 |pages=5–24|doi=10.5604/01.3001.0012.7629 |doi-broken-date=1 July 2025 }}</ref> Another trend is the combination of [[Artificial intelligence|AI]], using a large number of [[sensor]]s, with the goal of achieving [[Flexible manufacturing system|flexible manufacturing]].<ref>L.C. Moreira, W. Li, X. Lu, M.E. Fitzpatrick Supervision controller for real-time surface quality assurance in CNC machining using artificial intelligence Comput. Ind. Eng., 127 (2019), pp. 158-168</ref>

==Examples of CNC machines==

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|-

| [[Electric discharge machining]] || (EDM), also known as spark machining, spark eroding, burning, die sinking, or wire erosion, is a manufacturing process in which the desired shape is obtained using electrical discharges (sparks). Material is removed from the workpiece by a series of rapidly recurring [[Electric current|current]] discharges between two electrodes, separated by a [[dielectric fluid]] and subject to an electric [[voltage]]. One of the electrodes is called the tool electrode, or simply the "tool" or "electrode", while the other is called the workpiece electrode, or "workpiece".

EDM can be broadly divided into "sinker" type processes, where the electrode is the positive shape of the resulting feature in the part, and the electric discharge erodes this feature into the part, resulting in the negative shape, and "wire" type processes. Sinker processes are rather slow as compared to conventional machining, averaging on the order of 100mm100 mm³/min,<ref>{{Cite journal |lastlast1=Klocke |firstfirst1=F. |last2=Schwade |first2=M. |last3=Klink |first3=A. |last4=Veselovac |first4=D. |date=2013-01-01 |title=Analysis of Material Removal Rate and Electrode Wear in Sinking EDM Roughing Strategies using Different Graphite Grades |url=https://www.sciencedirect.com/science/article/pii/S2212827113001534 |journal=Procedia CIRP |series=Proceedings of the Seventeenth CIRP Conference on Electro Physical and Chemical Machining (ISEM) |volume=6 |pages=163–167 |doi=10.1016/j.procir.2013.03.079 |issn=2212-8271|doi-access=free }}</ref> as compared to 8x10⁶8 million mm³/min for conventional machining, but it can generate features that conventional machining cannot. Wire EDM operates by using a thin conductive wire, typically brass, as the electrode, and discharging as it runs past the part being machined. This is useful for complex profiles with inside 90 degree corners that would be challenging to machine with conventional methods.

||

[[File:EDMWorkpiece.jpg|thumb|Sinker EDM. Electrolyte solution saturates the workpiece, and voltage is applied between the sinker, top, and workpiece, bottom.]]

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==Other CNC tools==

[[File:Cortadora Laser - FabLAB Newton.jpg|thumb|[[Laser cutter]] at a [[fab lab]]]]

Many other tools have CNC variants, including:

{{div col begin}}

* [[3D printing]]

* [[CNC riveting]]

* [[CNC router]]

* [[Canned cycle]]

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:[M16 Special tool call]

:[M19 Spindle orientate]

:[M29 DNC mode ]

:[M30 Program reset & rewind]

:[M38 Door open]

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==See also==

{{Portal|Manufacturing}}

*[[Automatic tool changer]]

*[[Binary cutter ___location]]

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*[[Robotics]]

*[[Touch probe]]

*[[Wireless DNC]]

*[[List of computer-aided manufacturing software]]

*[[List of 3D printing software]]

==References==

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* {{Smid2008}}

* Christopher jun Pagarigan (Vini) Edmonton Alberta Canada. CNC Infomatic, ''Automotive Design & Production''.

* [https://www.engtechgroup.com/cnc-machines-evolution/ The Evolution of CNC Machines (2018).] Retrieved October 15, 2018, from Engineering Technology Group

* Fitzpatrick, Michael (2019), "Machining and CNC Technology".