G-code: Difference between revisions

Revision as of 14:53, 27 December 2022

Revision as of 14:53, 27 December 2022

Line 471:

[[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.

Any machine tool with a great number of axes, spindles, and tool stations is difficult to program well manually. It has been done over the years, but not easily. This challenge has existed for decades in CNC screw machine and rotary transfer programming, and it now also arises with today's newer machining centers called "turn-mills", "mill-turns", "multitasking machines", and "multifunction machines". Now that [[Computer-aided technologies|CAD/CAM]] systems are widely used, CNC programming (such as with G-code) requires CAD/CAM (as opposed to manual programming) to be practical and competitive in the market segments these classes of machines serve.<ref name="MMS_2010-12-20_CAM_Sys">{{Citation |last=MMS editorial staff |date=2010-12-20 |title=CAM system simplifies Swiss-type lathe programming |journal=Modern Machine Shop |volume=83 |issue=8 [2011 Jan] |pages=100–105 |url=http://www.mmsonline.com/articles/cam-system-simplifies-swiss-type-lathe-programming |postscript=.}} ''Online ahead of print.'' }}</ref> As Smid says, "Combine all these axes with some additional features, and the amount of knowledge required to succeed is quite overwhelming, to say the least."<ref name="Smid2008p457">{{Harvnb|Smid|2008|p=457}}.</ref> At the same time, however, programmers still must thoroughly understand the principles of manual programming and must think critically and second-guess some aspects of the software's decisions.

Since about the mid-2000s, it seems "the death of manual programming" (that is, of writing lines of G-code without CAD/CAM assistance) may be approaching. However, it is currently only in ''some'' contexts that manual programming is obsolete. Plenty of CAM programming takes place nowadays among people who are rusty on, or incapable of, manual programming—but it is not true that ''all'' CNC programming can be done, or done ''as well'' or ''as efficiently'', without knowing G-code.<ref name="Lynch_MMS_2010-01-18">{{Citation |last=Lynch |first=Mike |date=2010-01-18 |title=When programmers should know G code |journal=Modern Machine Shop |edition=online |url=http://www.mmsonline.com/columns/when-programmers-should-know-g-code |postscript=.}}</ref><ref name="Lynch_MMS_2011-10-19">{{Citation |last=Lynch |first=Mike |date=2011-10-19 |title=Five CNC myths and misconceptions [CNC Tech Talk column, Editor's Commentary] |journal=Modern Machine Shop |edition=online |url=http://www.mmsonline.com/columns/five-cnc-myths-and-misconceptions |postscript=. |access-date=2011-11-22 |archive-url=https://web.archive.org/web/20170527082655/http://www.mmsonline.com/columns/five-cnc-myths-and-misconceptions |archive-date=2017-05-27 |url-status=dead }}</ref> Tailoring and refining the CNC program at the machine is an area of practice where it can be easier or more efficient to edit the G-code directly rather than editing the CAM toolpaths and re-post-processing the program.