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{{Short description|Computer control of machine tools}}
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▲{{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|
[[File:Cnc lathe.png|thumb|A CNC [[metal lathe]]
'''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 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
▲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 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
== 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://
==Examples of CNC machines==
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| [[Milling (machining)|Mill]] || Translates programs consisting of specific numbers and letters to move the spindle (or workpiece) to various locations and depths. Can either be a Vertical Milling Center (VMC) or a Horizontal Milling Center, depending on the orientation of the spindle. Many use [[G-code]]. Functions include: face milling, shoulder milling, tapping, drilling and some even offer turning. Today, CNC mills can have 3 to 6 axes. Most CNC mills require placing the workpiece on or in them and must be at least as big as the workpiece, but new 3-axis machines are being produced that are much smaller.||
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| [[Lathe]] || Cuts workpieces while they are rotated. Makes fast, precision cuts, generally using [[Cutting tool (machining)#Cutting tools with inserts (indexable tools)|indexable]] tools and drills. Effective for complicated programs designed to make parts that would be unfeasible to make on manual lathes. Similar control specifications to CNC mills and can often read [[G-code]]. Generally have two axes (X and Z), but newer models have more axes, allowing for more advanced jobs to be machined. Most modern lathes have live tooling, allowing for limited milling operations to take place without having to remove the part from the lathe spindle. Second operations can be completed by using a sub-spindle, which is co-axial to the main spindle, but faces the other direction. This allows the part to be removed from the main spindle, and for additional features to be machined in the back side of the part.||
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| [[Plasma cutter]] || Involves cutting a material using a [[plasma torch]]. Commonly used to cut steel and other metals, but can be used on a variety of materials. In this process, gas (such as [[compressed air]]) is blown at high speed out of a nozzle; at the same time, an electrical arc is formed through that gas from the nozzle to the surface being cut, turning some of that gas to [[Plasma (physics)|plasma]]. The plasma is sufficiently hot to melt the material being cut and moves sufficiently fast to blow molten metal away from the cut.|| [[File:CNC Plasma Cutting.ogv|thumb|CNC plasma cutting]]
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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 100 mm<sup>3</sup>/min,<ref>{{Cite journal |last1=Klocke |first1=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 |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 8 million mm<sup>3</sup>/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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| Multi-spindle machine || Type of [[Automatic lathe|screw machine]] used in mass production. Considered to be highly efficient by increasing productivity through automation. Can efficiently cut materials into small pieces while simultaneously utilizing a diversified set of tooling. Multi-spindle machines have multiple spindles on a drum that rotates on a horizontal or vertical axis. The drum contains a drill head which consists of several spindles that are mounted on [[ball bearing]]s and driven by [[gear]]s. There are two types of attachments for these drill heads, fixed or adjustable, depending on whether the center distance of the drilling spindle needs to be varied.<ref>{{Cite news|url=https://www.davenportmachine.com/multi-spindle-machines/|title=Multi Spindle Machines - An In-Depth Overview|work=Davenport Machine|access-date=2017-08-25|language=en-US}}</ref> ||
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| [[Water jet cutter]] || Also known as a "waterjet", is a tool capable of slicing into metal or other materials (such as [[granite]]) by using a jet of water at high velocity and pressure, on the order of 60,000 PSI, or a mixture of water and an [[abrasive]] substance, such as
▲|-
▲| [[Water jet cutter]] || Also known as a "waterjet", is a tool capable of slicing into metal or other materials (such as [[granite]]) by using a jet of water at high velocity and pressure, or a mixture of water and an [[abrasive]] substance, such as sand. It is often used during the fabrication or manufacture of parts for machinery and other devices. Waterjet is the preferred method when the materials being cut are sensitive to the high temperatures generated by other methods. It has found applications in a diverse number of industries from mining to aerospace where it is used for operations such as [[cutting]], shaping, [[carving]], and [[reaming]]. ||[[File:Waterjet cutting machine.jpg|alt=Thibaut Waterjet cutting machine|thumb|[[Water jet cutter|Waterjet]] cutting machine for all materials]]
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| [[Punch press]] || Used to rapidly punch holes and cut thin materials. Such as sheet metal, plywood, thin bar stock, and tubing. Punch presses are generally used when a CNC mill would be inefficient or unfeasible. CNC punch presses can come in the C frame, where the sheet material is clamped onto a machining table and a hydraulic ram pushes down on the material, or they can come in a portal frame variant where bar stock/tubing is fed into the machine.
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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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==Numerical precision and equipment backlash==
Within the numerical systems of CNC programming, the code generator can assume that the controlled mechanism is always perfectly accurate, or that precision tolerances are identical for all cutting or movement directions.
The high backlash mechanism itself is not necessarily relied on to be repeatedly precise for the cutting process, but some other reference object or precision surface may be used to zero the mechanism, by tightly applying pressure against the reference and setting that as the zero references for all following CNC-encoded motions. This is similar to the manual machine tool method of clamping a [[Micrometer (device)|micrometer]] onto a reference beam and adjusting the [[Vernier scale|Vernier]] dial to zero using that object as the reference.{{citation needed|date=November 2017}}
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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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*[[Part program]]
*[[Robotics]]
*[[
*[[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''.
* Fitzpatrick, Michael (2019), "Machining and CNC Technology".
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[[Category:Numerical control| ]]
[[Category:Articles containing video clips]]
[[fr:Machine-outil à commande numérique]]
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