First, one disambiguation that saves a wrong turn: fiber laser marking machines (the EZCAD-class galvo units) do not run G-code at all, as covered in EZCAD to G-code. This list is for the machines that do: fiber laser cutting tables, where a gantry drives the cutting head over sheet metal and the program is genuinely G-code.
The motion half: standard, portable, learn-once
| Group | Codes | Fiber-table note |
|---|---|---|
| Motion | G00 / G01 / G02 / G03 | Sheet profiles are arc-dense; G02/G03 fluency pays daily |
| Modes | G90 / G91, G20 / G21 | Standard meanings |
| Offsets | G54 family | Multiple sheets, remnants, fixtures |
| Kerf compensation | G40 / G41 / G42 | The sizing mechanism, exactly as on waterjet |
| Program flow | M00 / M01 / M30, M98 / M99 | Standard |
Nothing here is laser-specific, which is the good news: it is the same core documented in any maintained reference like LinuxCNC’s list, and the same core a mill or router programmer already owns. Kerf comp deserves its own emphasis because, as on the waterjet, the beam has width and the G41 kerf-compensation discipline (tested kerf values, tangential lead-ins, comp established in scrap) transfers to fiber tables almost word for word, with the kerf an order smaller.
The laser half: real, important, and builder-specific
Everything that makes the machine a laser lives in codes and parameters the builder assigns:
| Function | What it controls | Where defined |
|---|---|---|
| Beam on/off | The cut itself | Builder M-codes |
| Power / duty / frequency | Cut quality per material | Parameters or codes, builder-specific |
| Assist gas | Oxygen vs nitrogen selection, pressure | Builder M-codes |
| Height control | Capacitive standoff tracking | Builder cycles/codes |
| Piercing | Pre-cut burn-through routine | Builder cycles, thickness-dependent |
Two of these rows carry the craft. Assist gas is a real process decision: oxygen cutting burns mild steel fast with an oxidized edge, nitrogen cuts stainless and aluminum clean at higher pressure and cost, and the M-codes that switch them are pure builder territory. Piercing, as on plasma and waterjet cousins, is its own little routine before every contour: a dwell or ramped burn through the sheet, parameterized by thickness. Copying any of this between machines is how nozzles and lenses die; the machine’s manual and the material parameter tables that ship with it are the only sources.
What does a typical contour look like?
(shape only; M-codes are builder-specific)
G00 X(pierce point in scrap)
M(height sense on)
M(pierce routine / beam on at pierce power)
G04 P(thickness-dependent dwell)
G41 D1 G01 X.. Y.. F(lead-in feed)
G02/G03 ... (the contour at print size)
G40 ... (lead-out, comp off)
M(beam off)The shape to internalize: pierce in scrap, comp on through a lead-in, contour at print dimensions, comp off, beam off. Feed rate doubles as the edge-quality control exactly as on waterjet, slower for cleaner where it matters. Reading programs for this shape takes one glance once the core is reflex, which is what the free 60-second drills on the G-code practice page build, with G-Code Sprint repeating whatever you miss.
How does this relate to the small-laser world?
The diode and CO2 engraver scene runs the same split with thinner layers: GRBL-class firmware where M3 versus M4 sets constant or dynamic power, no assist-gas plumbing, simpler height stories. Skills move upward cleanly: an operator who learned the core plus the laser-power layer on a desktop machine reads an industrial fiber table’s programs immediately, with the gas and height rows as the new vocabulary to take from the manual.
How should a newcomer study this list?
In the two halves it naturally splits into. The motion half goes to reflex with daily recall drills, the same route as every machine class on this site. The laser half is read, not memorized: take three real programs from your machine, highlight every non-standard M-code, and build a one-page card from the manual’s definitions, with the material parameter table photographed next to it. A week of that, plus narrated read-throughs of real programs, and the “code list” stops being a search and becomes the card in your pocket.
Bottom line: one core, one manual
The fiber laser CNC code list splits into a universal motion core (with kerf comp carrying the dimensions) and a builder-defined laser layer (beam, power, gas, height, pierce). Learn the core once and everywhere; copy the laser layer from your machine’s manual onto your own card; and let feed rate and gas choice carry the edge quality the way the parameter tables prescribe.
Sources
Frequently asked questions
What is the basic G-code list for a fiber laser CNC?
The universal motion core (G00-G03, G90/G91, G54 offsets, G40-G42 kerf compensation, standard program flow) plus a builder-specific laser layer for beam, power, assist gas, height control, and piercing, which only your machine’s manual defines. To get the universal half to reflex, the free G-Code Sprint app is the top pick: 60-second drills with automatic repetition of missed codes.
Are fiber laser M-codes the same across machines?
The standard handful (program stops, end, subprograms) yes; everything laser-shaped no. Beam, gas, and height codes are assigned per builder and generation, and copying them between machines risks consumables and worse. The manual is the list.
Does kerf compensation matter on a fiber laser?
Yes, it carries the dimensional accuracy exactly as on a waterjet, with a much smaller kerf. Tested kerf values, tangential lead-ins established in scrap, and comp canceled after the lead-out are the same discipline at laser scale.
Oxygen or nitrogen: does the program choose?
The program calls the builder’s gas-selection codes, but the choice itself is a process decision: oxygen for fast mild-steel cutting with an oxidized edge, nitrogen for clean stainless and aluminum at higher pressure and cost. The machine’s material tables prescribe the pairings.
G-Code Sprint is a study and practice tool only. Always follow your instructor, employer, machine manual, and shop safety procedures, including laser safety requirements.