G-code: Difference between revisions

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{{other uses|G-code (disambiguation)|G programming language (disambiguation)}}
{{redirect|RS-274|the photoplotter format|Gerber format}}
{{OriginalMore researchfootnotes sectionneeded|date=January 20162025}}
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| name = G-code
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| issue = This article may require restoring an older revision.
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{{Infobox programming language
| name = G-code
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| developer = [[Electronic Industries Alliance|Electronic Industries Association]] (RS-274), [[International Organization for Standardization]] (ISO-6983)
| implementations = Numerous; mainly [[Siemens]] Sinumerik, [[FANUC]], [[Haas Automation|Haas]], [[Heidenhain]], [[Yamazaki Mazak Corporation|Mazak]], [[Okuma Corporation|Okuma]]
| dialects =
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'''G-code''' (abbreviation for '''geometric code'''; also called<ref>{{cite tech report |editor1-last=Barkmeyer |editor1-first=Edward J. |editor2-last=Hopp |editor2-first=Theodore H. |editor3-last=Michael J. |editor3-first=Pratt |editor4-last=Gaylen R. |editor4-first=Rinaudot |title=Background Study: Requisite Elements, Rationale, and Technology Overview for the Systems Integration for Manufacturing Applications (SIMA) Program |date=1995 |publisher=NIST Technical Series Publications |___location=Gaithersburg, MD, USA |pages=45 |edition=NIST Interagency/Internal Report (NISTIR) 5662 |url=https://nvlpubs.nist.gov/nistpubs/Legacy/IR/nistir5662.pdf}}</ref> '''RS-274''',<ref>{{cite book |title=EIA Standard RS-274-D Interchangeable Variable Block Data Format for Positioning, Contouring, and Contouring/Positioning Numerically Controlled Machines |date=February 1979 |publisher=Electronic Industries Association |___location=2001 Eye Street, NW, Washington, D.C. 20006 |url=https://search.worldcat.org/de/title/11135300 |ref=RS-274-D}}</ref> standardized today in '''ISO 6983-1'''<ref>{{cite tech report |editor1-last=Technical Committee ISO/TC 184/SC 1 |title=ISO 6983-1:2009 Automation systems and integration — Numerical control of machines — Program format and definitions of address words; Part 1: Data format for positioning, line motion and contouring control systems |date=December 2009 |publisher=International Standards Organization |___location=Geneva, Switzerland |url=https://www.iso.org/standard/34608.html |ref=ISO 6983:2009}}</ref>) is the most widely used [[computer numerical control]] (CNC) and [[3D printing]] [[programming language]]. It is used mainly in [[computer-aided manufacturing]] to control automated [[machine tool]]s, as well as for [[Slicer (3D printing)|3D-printer slicer applications]]. G-code has many variants.
'''G-code''' (also '''RS-274''') is the most widely used [[computer numerical control]] (CNC) and [[3D printing]] [[programming language]]. It is used mainly in [[computer-aided manufacturing]] to control automated [[machine tool]]s, as well as for [[Slicer (3D printing)|3D-printer slicer applications]]. The ''G'' stands for geometry. G-code has many variants.
 
G-code instructions are provided to a [[Programmable logic controller|machine controller]] (industrial computer) that tells the motors where to move, how fast to move, and what path to follow. The two most common situations are that, within a machine tool such as a [[Metal lathe|lathe]] or [[Milling (machining)|mill]], a [[cutting tool (machining)|cutting tool]] is moved according to these instructions through a toolpath cutting away material to leave only the finished workpiece and/or an unfinished workpiece is precisely positioned in any of up to nine axes<ref>Karlo Apro (2008). ''[https://books.google.com/books?id=Ws228Aht0bcC Secrets of 5-Axis Machining]''. Industrial Press Inc. {{ISBN|0-8311-3375-9}}.</ref> around the three dimensions relative to a toolpath and, either or both can move relative to each other. The same concept also extends to noncutting tools such as [[Forming (metalworking)|forming]] or [[Burnishing (metal)|burnishing]] tools, [[Gerber format|photoplotting]], additive methods such as [[3D printing]], and measuring instruments.
 
== History ==
==Background and implementations==
The first implementation of a numerical control programming language was developed at the [[MIT Servomechanisms Laboratory]] in the 1950s. In the decades that followed, many implementations were developed by numerous organizations, both commercial and noncommercial. Elements of G-code had often been used in these implementations.<ref>{{cite book | last=Xu | first=Xun | date=2009 | url=https://www.google.com/books/edition/Integrating_Advanced_Computer_Aided_Desi/habcATPQWJ4C | title=Integrating Advanced Computer-aided Design, Manufacturing, and Numerical Control: Principles and Implementations | publisher=Information Science Reference | page=166 | isbn=9781599047164 | via=Google Books}}</ref><ref>{{cite book | last=Harik | first=Ramy | author2=Thorsten Wuest | date=2019 | url=https://www.google.com/books/edition/Introduction_to_Advanced_Manufacturing/O3h0EAAAQBAJ | title=Introduction to Advanced Manufacturing | publisher=SAE International | page=116 | isbn=9780768090963 | via=Google Books}}</ref> The first [[Technical standard|standardized]] version of G-code used in the United States, ''RS-274'', was published in 1963 by the [[Electronic Industries Alliance]] (EIA; then known as Electronic Industries Association).<ref>{{cite book | last=Evans | first=John M., Jr. | date=1976 | url=https://www.govinfo.gov/content/pkg/GOVPUB-C13-2ef4aaa5a150eedcb85a1e6985e90bfa/pdf/GOVPUB-C13-2ef4aaa5a150eedcb85a1e6985e90bfa.pdf | title=National Bureau of Standards Information Report (NBSIR) 76-1094 (R): Standards for Computer Aided Manufacturing | publisher=National Bureau of Standards | page=43}}</ref> In 1974, EIA approved ''RS-274-C'', which merged ''RS-273'' (variable block for positioning and straight cut) and ''RS-274-B'' (variable block for contouring and contouring/positioning). A final revision of ''RS-274'' was approved in 1979, as ''RS-274-D''.<ref>{{cite journal | last=Schenck | first=John P. | date=January 1, 1998 | url=https://link.gale.com/apps/doc/A20429590/GPS?sid=wikipedia | title=Understanding common CNC protocols | work=Wood & Wood Products | publisher=Vance Publishing | volume=103 | issue=1 | page=43 | via=Gale}}</ref><ref>{{citation| title = EIA Standard RS-274-D Interchangeable Variable Block Data Format for Positioning, Contouring, and Contouring/Positioning Numerically Controlled Machines |publisher = Electronic Industries Association |___location= Washington D.C. |date=February 1979}}</ref> In other countries, the standard ''[[International Organization for Standardization|ISO]] 6983'' (finalized in 1982) is often used, but many European countries use other standards.<ref>{{cite book | last=Stark | first=J. | author2=V.&nbsp;K. Nguyen | date=2009 | url=https://www.google.com/books/edition/Advanced_Design_and_Manufacturing_Based/RIgLRe12RD4C | chapter=STEP-compliant CNC Systems, Present and Future Directions | title=Advanced Design and Manufacturing Based on STEP | editor-last=Xu | editor-first=Xun | editor2=Andrew Yeh Ching Nee | publisher=Springer London | page=216 | isbn=9781848827394 | via=Google Books}}</ref> For example, ''[[Deutsches Institut für Normung|DIN]] 66025'' is used in Germany, and PN-73M-55256 and PN-93/M-55251 were formerly used in Poland.
 
The first implementation of a numerical control programming language was developed at the [[MIT Servomechanisms Laboratory]] in the 1950s. In the decades that followed, many implementations were developed by numerous organizations, both commercial and noncommercial. Elements of G-code had often been used in these implementations.<ref>{{cite book | last=Xu | first=Xun | date=2009 | url=https://wwwbooks.google.com/books/edition/Integrating_Advanced_Computer_Aided_Desi/?id=habcATPQWJ4C | title=Integrating Advanced Computer-aided Design, Manufacturing, and Numerical Control: Principles and Implementations | publisher=Information Science Reference | page=166 | isbn=9781599047164978-1-59904-716-4 | via=Google Books}}</ref><ref>{{cite book | last=Harik | first=Ramy | author2=Thorsten Wuest | date=2019 | url=https://wwwbooks.google.com/books/edition/Introduction_to_Advanced_Manufacturing/?id=O3h0EAAAQBAJ | title=Introduction to Advanced Manufacturing | publisher=SAE International | page=116 | isbn=9780768090963978-0-7680-9096-3 | via=Google Books}}</ref> The first [[Technical standard|standardized]] version of G-code used in the United States, ''RS-274'', was published in 1963 by the [[Electronic Industries Alliance]] (EIA; then known as Electronic Industries Association).<ref>{{cite book | last=Evans | first=John M., Jr. | date=1976 | url=https://www.govinfo.gov/content/pkg/GOVPUB-C13-2ef4aaa5a150eedcb85a1e6985e90bfa/pdf/GOVPUB-C13-2ef4aaa5a150eedcb85a1e6985e90bfa.pdf | title=National Bureau of Standards Information Report (NBSIR) 76-1094 (R): Standards for Computer Aided Manufacturing | publisher=National Bureau of Standards | page=43}}</ref> In 1974, EIA approved ''RS-274-C'', which merged ''RS-273'' (variable block for positioning and straight cut) and ''RS-274-B'' (variable block for contouring and contouring/positioning). A final revision of ''RS-274'' was approved in 1979, as ''RS-274-D''.<ref>{{cite journal | last=Schenck | first=John P. | date=January 1, 1998 | url=https://link.gale.com/apps/doc/A20429590/GPS?sid=wikipedia | title=Understanding common CNC protocols | workjournal=Wood & Wood Products | publisher=Vance Publishing | volume=103 | issue=1 | page=43 | via=Gale}}</ref><ref>{{citation| title = EIA Standard RS-274-D Interchangeable Variable Block Data Format for Positioning, Contouring, and Contouring/Positioning Numerically Controlled Machines |publisher = Electronic Industries Association |___location= Washington D.C. |date=February 1979}}</ref> In other countries, the standard ''[[International Organization for Standardization|ISO]] 6983'' (finalized in 1982) is often used, but many European countries use other standards.<ref>{{cite book | last=Stark | first=J. | author2=V.&nbsp;K. Nguyen | date=2009 | url=https://wwwbooks.google.com/books/edition/Advanced_Design_and_Manufacturing_Based/?id=RIgLRe12RD4C | chapter=STEP-compliant CNC Systems, Present and Future Directions | title=Advanced Design and Manufacturing Based on STEP | editor-last=Xu | editor-first=Xun | editor2=Andrew Yeh Ching Nee | publisher=Springer London | page=216 | isbn=9781848827394978-1-84882-739-4 | via=Google Books}}</ref> For example, ''[[Deutsches Institut für Normung|DIN]] 66025'' is used in Germany, and PN-73M-55256 and PN-93/M-55251 were formerly used in Poland.
Extensions and variations have been added independently by control manufacturers and machine tool manufacturers, and operators of a specific controller must be aware of the differences between each manufacturer's product.
 
During the 1970s through 1990s, many CNC machine tool builders attempted to overcome compatibility difficulties by standardizing on machine tool controllers built by [[Fanuc]]. [[Siemens]] was another market dominator in CNC controls, especially in Europe. In the 2010s, controller differences and incompatibility arewere notmitigated aswith troublesomethe becausewidespread machiningadoption operations are usually developed withof CAD/CAM applications that canwere capable of outputting machine operations outputin the appropriate G-code for a specific machine through a software tool called a post-processor (sometimes shortened to just a "post").
One standardized version of G-code, known as ''BCL'' (Binary Cutter Language), is used only on very few machines. Developed at MIT, BCL was developed to control CNC machines in terms of straight lines and arcs.<ref>{{Cite book|url=https://books.google.com/books?id=GE8vBQAAQBAJ&q=binary+cutter+language+gcode&pg=PA321|title=Information Technology Standards : Quest for the Common Byte.|last=Martin.|first=Libicki|date=1995|publisher=Elsevier Science|isbn=9781483292489|___location=Burlington|pages=321|oclc=895436474}}</ref>
 
== Syntax ==
During the 1970s through 1990s, many CNC machine tool builders attempted to overcome compatibility difficulties by standardizing on machine tool controllers built by [[Fanuc]]. [[Siemens]] was another market dominator in CNC controls, especially in Europe. In the 2010s, controller differences and incompatibility are not as troublesome because machining operations are usually developed with CAD/CAM applications that can output the appropriate G-code for a specific machine through a software tool called a post-processor (sometimes shortened to just a "post").
 
G-code began as a limited language that lacked constructs such as loops, conditional operators, and programmer-declared variables with [[Natural language|natural]]-word-including names (or the expressions in which to use them). It was unable to encode logic but was just a way to "connect the dots" where the programmer figured out many of the dots' locations longhand. The latest implementations of G-code include macro language capabilities somewhat closer to a [[high-level programming language]]. Additionally, all primary manufacturers (e.g., Fanuc, Siemens, [[Heidenhain]]) provide access to [[programmable logic controller]] (PLC) data, such as axis positioning data and tool data,<ref>{{cite web |url-status=dead |archive-date=2014-05-03 |url=http://www.machinetoolhelp.com/Applications/macro/system_variables.html |title=Fanuc macro system variables |access-date=2014-06-30 |archive-url=https://web.archive.org/web/20140503030834/http://www.machinetoolhelp.com/Applications/macro/system_variables.html }}</ref> via variables used by NC programs. These constructs make it easier to develop automation applications.
Some CNC machines use "conversational" programming, which is a [[wizard (software)|wizard]]-like programming mode that either hides G-code or completely bypasses the use of G-code. Some popular examples are Okuma's Advanced One Touch (AOT), Southwestern Industries' ProtoTRAK, Mazak's Mazatrol, Hurco's Ultimax and Winmax, Haas' Intuitive Programming System (IPS), and Mori Seiki's CAPS conversational software.
 
== Extensions and variations ==
G-code began as a limited language that lacked constructs such as loops, conditional operators, and programmer-declared variables with [[Natural language|natural]]-word-including names (or the expressions in which to use them). It was unable to encode logic but was just a way to "connect the dots" where the programmer figured out many of the dots' locations longhand. The latest implementations of G-code include macro language capabilities somewhat closer to a [[high-level programming language]]. Additionally, all primary manufacturers (e.g., Fanuc, Siemens, [[Heidenhain]]) provide access to [[programmable logic controller]] (PLC) data, such as axis positioning data and tool data,<ref>{{cite web |url-status=dead |archive-date=2014-05-03 |url=http://www.machinetoolhelp.com/Applications/macro/system_variables.html |title=Fanuc macro system variables |access-date=2014-06-30 |archive-url=https://web.archive.org/web/20140503030834/http://www.machinetoolhelp.com/Applications/macro/system_variables.html }}</ref> via variables used by NC programs. These constructs make it easier to develop automation applications.
 
Extensions and variations have been added independently by control manufacturers and machine tool manufacturers, and operators of a specific controller must be aware of the differences between each manufacturer's product.
==Programming environments==
{{Original research section|date=January 2016}}
 
One standardized version of G-code, known as ''BCL'' (Binary Cutter Language), is used only on very few machines. Developed at MIT, BCL was developed to control CNC machines in terms of straight lines and arcs.<ref>{{Cite book|url=https://books.google.com/books?id=GE8vBQAAQBAJ&q=binary+cutter+language+gcode&pg=PA321|title=Information Technology Standards : Quest for the Common Byte.|last=Martin.|first=Libicki|date=1995|publisher=Elsevier Science|isbn=9781483292489978-1-4832-9248-9|___location=Burlington|pagespage=321|oclc=895436474}}</ref>
G-code's programming environments have evolved in parallel with those of general programming—from the earliest environments (e.g., writing a program with a pencil, typing it into a tape puncher) to the latest environments that combine CAD ([[computer-aided design]]), CAM ([[computer-aided manufacturing]]), and richly featured G-code editors. (G-code editors are analogous to [[XML editor]]s, using colors and indents semantically [plus other features] to aid the user in ways that basic [[text editor]]s can't. CAM packages are analogous to [[integrated development environment|IDEs]] in general programming.)
 
Some CNC machines use "conversational" programming, which is a [[wizard (software)|wizard]]-like programming mode that either hides G-code or completely bypasses the use of G-code. Some popular examples are Okuma's Advanced One Touch (AOT), Southwestern Industries' ProtoTRAK, Mazak's Mazatrol, Hurco's Ultimax and Winmax, Haas' Intuitive Programming System (IPS), and Mori Seiki's CAPS conversational software.
Two high-level paradigm shifts have been toward:
 
# abandoning "manual programming" (with nothing but a pencil or text editor and a human mind) for [[:Category:Computer-aided manufacturing software|CAM software]] systems that generate G-code automatically via postprocessors (analogous to the development of [[Visual programming language|visual]] techniques in general programming)
# abandoning hardcoded constructs for parametric ones (analogous to the difference in general programming between hardcoding a constant into an equation versus declaring it a variable and assigning new values to it at will; and to the [[object-oriented programming|object-oriented]] approach in general).
 
Macro (parametric) CNC programming uses human-friendly variable names, [[relational operator]]s, and loop structures, much as general programming does, to capture information and logic with machine-readable semantics. Whereas older manual CNC programming could only describe particular instances of parts in numeric form, macro programming describes abstractions that can easily apply in a wide variety of instances.
 
The tendency is comparable to a computer programming evolution from [[low-level programming language]]s to [[High-level programming language|high-level ones]].{{Citation needed|date=January 2022}}
 
[[STEP-NC]] reflects the same theme, which can be viewed as yet another step along a path that started with the development of machine tools, jigs and fixtures, and numerical control, which all sought to "build the skill into the tool." Recent developments of G-code and STEP-NC aim to build the information and semantics into the tool. This idea is not new; from the beginning of numerical control, the concept of an end-to-end CAD/CAM environment was the goal of such early technologies as [[DAC-1]] and [[APT (programming language)|APT]]. Those efforts were fine for huge corporations like GM and Boeing. However, [[small and medium enterprises]] went through an era of simpler implementations of NC, with relatively primitive "connect-the-dots" G-code and manual programming until CAD/CAM improved and disseminated throughout the industry.
 
== See also ==
 
* [[3D printing]]
* [[Canned cycle]]
* [[CoordinateDirect systemNumerical Control]]
* [[Cutter ___location]]
* [[Direct Numerical Control]] (DNC)
* [[Drill file (disambiguation)]]
* [[Gerber file]]
* [[HP-GL]]
* [[KUKA Robot Language]]
* [[LinuxCNC]]
* [[List of computer-aided manufacturing software]]
* [[MTConnect]]
* [[RAPID]]
* [[Slicer (3D printing)]]
* [[STEP-NC]]
* [[STL (file format)]]
 
== References ==
{{Reflist}}
 
{{refs}}
 
== Bibliography ==
 
* {{MachinerysHandbook25e}}
* {{Smid2008}}
* {{Smid2010}}
* {{Citation |last=Smid |first=Peter |year=2004 |title=Fanuc CNC Custom Macros |publisher=Industrial Press |url=https://books.google.com/books?id=YKvH-zYd3VwC&pg=PR11 |isbn=978-08311315790-8311-3157-9 |postscript=.}}
 
== External links ==
 
* [http://carlsonmfg.com/cnc-g-code-m-code-programming CNC G-Code and M-Code Programming]
* {{Citation |last1=Kramer |first1=T. R. |last2=Proctor |first2=F. M. |last3=Messina |first3=E. R. |title=The NIST RS274NGC Interpreter – Version 3 |date=1 Aug 2000 |id=NISTIR 6556 |journal=[[NIST]] |url=https://www.nist.gov/manuscript-publication-search.cfm?pub_id=823374 |ref=none}}
* http://museum.mit.edu/150/86 {{Webarchive|url=https://web.archive.org/web/20160319102859/http://museum.mit.edu/150/86 |date=2016-03-19 }} Has several links (including history of MIT Servo Lab)
* [http://reprap.org/wiki/G-code Complete list of G-code used by most 3D printers] at reprap.org
* [http://www.cnccookbook.com/CCCNCGCodeList.html Fanuc and Haas G-code Reference]
* [http://www.cnccookbook.com/CCCNCGCodeCourse.htm Fanuc and Haas G-code Tutorial]