[Green background indicates common code used in Langmuir Systems plasma tables.]
(v1.6-af) The parenthesis indicate a comment ignored by g code.
(PS100) Langmuir’s FireControl uses this for Torch Height Control. The 100 in this example refers to 100 inches/minute torch speed.
Letters
| Variable | Description | Details |
|---|---|---|
| A,B, C | Absolute or incremental position of A, B or C axis (rotational axis around X axis) | Positive rotation is defined as a counterclockwise rotation looking from X positive towards X negative. |
| D | Defines diameter or radial offset used for cutter compensation. D is used for depth of cut on lathes. It is used for aperture selection and commands on photoplotters. | G41: left cutter compensation, G42: right cutter compensation |
| E | Precision feedrate for threading on lathes | |
| F | Defines feed rate | Common units are distance per time for mills (inches per minute, IPM, or millimeters per minute, mm/min) and distance per revolution for lathes (inches per revolution, IPR, or millimeters per revolution, mm/rev) |
| G | Address for preparatory commands | G commands often tell the control what kind of motion is wanted (e.g., rapid positioning, linear feed, circular feed, fixed cycle) or what offset value to use. |
| H | Defines tool length offset; Langmuir Systems uses to enable height adjustment; Incremental axis corresponding to C axis (e.g., on a turn-mill). | G43: Negative tool length compensation, G44: Positive tool length compensation; Langmuir Systems H0 Torch height control off, H1 Torch height control on |
| I | Defines arc center in X axis for G02 or G03 arc commands. Also used as a parameter within some fixed cycles. | The arc center is the relative distance from the current position to the arc center, not the absolute distance from the work coordinate system (WCS). |
| J | Defines arc center in Y axis for G02 or G03 arc commands. Also used as a parameter within some fixed cycles. | Same details as I above. |
| K | Defines arc center in Z axis for G02 or G03 arc commands. Also used as a parameter within some fixed cycles, equal to L address. | Same details as I above. |
| L | Fixed cycle loop count; Specification of what register to edit using G10 | Fixed cycle loop count: Defines number of repetitions ("loops") of a fixed cycle at each position. Assumed to be 1 unless programmed with another integer. Sometimes the K address is used instead of L. With incremental positioning (G91), a series of equally spaced holes can be programmed as a loop rather than as individual positions. |
| M | Miscellaneous function | |
| N | Line (block) number in program | Line (block) numbers: Optional, so often omitted. Necessary for certain tasks, such as M99 P address (to tell the control which block of the program to return to if not the default) or GoTo statements (if the control supports those). N numbering need not increment by 1 (for example, it can increment by 10, 20, or 1000) and can be used on every block or only in certain spots throughout a program. |
| O | Program name | |
| P | Serves as parameter address for various G and M codes | With G04, defines dwell time value. |
| Q | Peck increment in canned cycles | For example, G73, G83 (peck drilling cycles) |
| R | Defines size of arc radius, or defines retract height in milling canned cycles | For radii, not all controls support the R address for G02 and G03, in which case IJK vectors are used. For retract height, the "R level", as it's called, is returned to if G99 is programmed. |
| S | Defines speed, either spindle speed or surface speed depending on mode | Data type = integer. In G97 mode (which is usually the default), an integer after S is interpreted as a number of rev/min (rpm). In G96 mode (Constant Surface Speed or CSS), an integer after S is interpreted as surface speed—sfm (G20) or m/min (G21). See also Speeds and feeds. On multifunction (turn-mill or mill-turn) machines, which spindle gets the input (main spindle or subspindles) is determined by other M codes. |
| T | Tool selection | To understand how the T address works and how it interacts (or not) with M06, one must study the various methods, such as lathe turret programming, ATC (Automatic Tool Change, set by M06) fixed tool selection, ATC random memory tool selection, the concept of "next tool waiting", and empty tools. Programming on any particular machine tool requires knowing which method that machine uses. |
| U | Also defines dwell time on some machines (instead of "P" or "X"). | In these controls, X and U obviate G90 and G91, respectively. On these lathes, G90 is instead a fixed cycle address for roughing. |
| V | Incremental axis corresponding to Y axis | |
| W | Incremental axis corresponding to Z axis (typically only lathe group A controls) | |
| X | Absolute or incremental position of X axis. | |
| Y | Absolute or incremental position of Y axis | |
| Z | Absolute or incremental position of Z axis | The main spindle's axis of rotation often determines which axis of a machine tool is labeled as Z. |
G codes
| Code | Description | Milling | Turning | Details |
|---|---|---|---|---|
| ( M ) | ( T ) | |||
| G00 | Rapid positioning | M | T | On 2- or 3-axis moves, G00 (unlike G01) traditionally does not necessarily move in a single straight line between start point and endpoint. It moves each axis at its max speed until its vector quantity is achieved. A shorter vector usually finishes first (given similar axis speeds). This matters because it may yield a dog-leg or hockey-stick motion, which the programmer needs to consider, depending on what obstacles are nearby, to avoid a crash. Some machines offer interpolated rapids as a feature for ease of programming (safe to assume a straight line). |
| G01 | Linear interpolation | M | T | The most common workhorse code for feeding during a cut. The program specs the start and endpoints, and the control automatically calculates (interpolates) the intermediate points to pass through that yield a straight line (hence "linear"). The control then calculates the angular velocities at which to turn the axis leadscrews via their servomotors or stepper motors. The computer performs thousands of calculations per second, and the motors react quickly to each input. Thus the actual toolpath of the machining takes place with the given feed rate on a path that is accurately linear to within very small limits. |
| G02 | Circular interpolation, clockwise | M | T | Very similar in concept to G01. Again, the control interpolates intermediate points and commands the servo- or stepper motors to rotate the amount needed for the leadscrew to translate the motion to the correct tooltip positioning. This process repeated thousands of times per minute generates the desired toolpath. In the case of G02, the interpolation generates a circle rather than a line. As with G01, the actual toolpath of the machining takes place with the given feed rate on a path that accurately matches the ideal (in G02's case, a circle) to within very small limits. In fact, the interpolation is so precise (when all conditions are correct) that milling an interpolated circle can obviate operations such as drilling, and often even find boring. Addresses for radius or arc center: G02 and G03 take either an R address (for the radius desired on the part) or IJK addresses (for the component vectors that define the vector from the arc start point to the arc center point). Cutter comp: On most controls you cannot start G41 or G42 in G02 or G03 modes. You must already have compensated in an earlier G01 block. Often, a short linear lead-in movement is programmed, merely to allow cutter compensation before the main action, the circle-cutting begins. Full circles: When the arc start point and the arc endpoint are identical, the tool cuts a 360° arc (a full circle). (Some older controls do not support this because arcs cannot cross between quadrants of the cartesian system. Instead, they require four quarter-circle arcs programmed back-to-back.) |
| G03 | Circular interpolation, counterclockwise | M | T | Same corollary info as for G02. |
| G04 | Dwell | M | T | Takes an address for dwell period (may be X, U, or P). The dwell period is specified by a control parameter, typically set to milliseconds. Some machines can accept either X1.0 (s) or P1000 (ms), which are equivalent. Choosing dwell duration: Often the dwell needs only to last one or two full spindle rotations. This is typically much less than one second. Be aware when choosing a duration value that a long dwell is a waste of cycle time. In some situations, it won't matter, but for high-volume repetitive production (over thousands of cycles), it is worth calculating that perhaps you only need 100 ms, and you can call it 200 to be safe, but 1000 is just a waste (too long). |
| G05 P10000 | High-precision contour control (HPCC) | M | Uses a deep look-ahead buffer and simulation processing to provide better axis movement acceleration and deceleration during contour milling | |
| G05.1 Q1. | AI Advanced Preview Control | M | Uses a deep look-ahead buffer and simulation processing to provide better axis movement acceleration and deceleration during contour milling | |
| G06.1 | Non-uniform rational B-spline (NURBS) Machining | M | Activates Non-Uniform Rational B Spline for complex curve and waveform machining (this code is confirmed in Mazatrol 640M ISO Programming) | |
| G07 | Imaginary axis designation | M | ||
| G08 | Lookahead | M | On older versions, look-ahead. G08P1 = on, G08P0 = off. Newer systems use G05 | |
| G09 | Exact stop check, non-modal | M | T | The modal version is G61. |
| G10 | Programmable data input | M | T | Modifies the value of work coordinate and tool offsets[14][13] |
| G11 | Data write cancel | M | T | |
| G17 | XY plane selection | M | ||
| G18 | ZX plane selection | M | T | |
| G19 | YZ plane selection | M | ||
| G20 | Programming in inches | M | T | Somewhat uncommon except in USA and (to lesser extent) Canada and UK. However, in the global marketplace, competence with both G20 and G21 always stands some chance of being necessary at any time. The usual minimum increment in G20 is one ten-thousandth of an inch (0.0001"), which is a larger distance than the usual minimum increment in G21 (one thousandth of a millimeter, .001 mm, that is, one micrometre). This physical difference sometimes favors G21 programming. |
| G21 | Programming in millimeters (mm) | M | T | Prevalent worldwide. However, in the global marketplace, competence with both G20 and G21 always stands some chance of being necessary at any time. |
| G28 | Return to home position (machine zero, aka machine reference point) | M | T | Takes X Y Z addresses which define the intermediate point that the tool tip will pass through on its way home to machine zero. They are in terms of part zero (aka program zero), NOT machine zero. |
| G30 | Return to secondary home position (machine zero, aka machine reference point) | M | T | Takes a P address specifying which machine zero point to use if the machine has several secondary points (P1 to P4). Takes X Y Z addresses that define the intermediate point that the tooltip passes through on its way home to machine zero. These are expressed in terms of part zero (aka program zero), NOT machine zero. |
| G31 | Feed until skip function | M | Used for probes and tool length measurement systems. | |
| G32 | Single-point threading, longhand style (if not using a cycle, e.g., G76) | T | Similar to G01 linear interpolation, except with automatic spindle synchronization for single-point threading. | |
| G33 | Constant-pitch threading | M | ||
| G33 | Single-point threading, longhand style (if not using a cycle, e.g., G76) | T | Some lathe controls assign this mode to G33 rather than G32. | |
| G34 | Variable-pitch threading | M | ||
| 38.2 | Special subroutine | Langmuir Systems uses for Initial Height Sensing. This downward command causes motion until contact condition changes. |
||
| 38.4 | Special subroutine | Langmuir Systems uses for Initial Height Sensing. This upward command causes motion until contact condition changes. |
||
| G40 | Tool radius compensation off | M | T | Turn off cutter radius compensation (CRC). Cancels G41 or G42. |
| G41 | Tool radius compensation left | M | T | Turn on cutter radius compensation (CRC), left, for climb milling. |
| Milling: Given righthand-helix cutter and M03 spindle direction, G41 corresponds to climb milling (down milling). Takes an address (D or H) that calls an offset register value for radius. | ||||
| Turning: Often needs no D or H address on lathes, because whatever tool is active automatically calls its geometry offsets with it. (Each turret station is bound to its geometry offset register.) | ||||
| G41 and G42 for milling have been partially automated and obviated (although not completely) since CAM programming has become more common. CAM systems let the user program as if using a zero-diameter cutter. The fundamental concept of cutter radius compensation is still in play (i.e., that the surface produced will be distance R away from the cutter center), but the programming mindset is different. The human does not choreograph the toolpath with conscious, painstaking attention to G41, G42, and G40, because the CAM software takes care of that. The software has various CRC mode selections, such as computer, control, wear, reverse wear, off, some of which do not use G41/G42 at all (good for roughing, or wide finish tolerances), and others that use it so that the wear offset can still be tweaked at the machine (better for tight finish tolerances). | ||||
| G42 | Tool radius compensation right | M | T | Turn on cutter radius compensation (CRC) right, for conventional milling. Similar info as for G41. Given righthand-helix cutter and M03 spindle direction, G42 corresponds to conventional milling (up milling) |
| G43 | Tool height offset compensation negative | M | Takes an address, usually H, to call the tool length offset register value. The value is negative because it will be added to the gauge line position. G43 is the commonly used version (vs G44). | |
| G44 | Tool height offset compensation positive | M | Takes an address, usually H, to call the tool length offset register value. The value is positive because it will be subtracted from the gauge line position. G44 is the seldom-used version (vs G43). | |
| G45 | Axis offset single increase | M | ||
| G46 | Axis offset single decrease | M | ||
| G47 | Axis offset double increase | M | ||
| G48 | Axis offset double decrease | M | ||
| G49 | Tool length offset compensation cancel | M | Cancels G43 or G44. | |
| G50 | Define the maximum spindle speed | T | Takes an S address integer, which is interpreted as rpm. Without this feature, G96 mode (CSS) would rev the spindle to "wide open throttle" when closely approaching the axis of rotation. | |
| G50 | Scaling function cancel | M | ||
| G50 | Position register (programming of the vector from part zero to tooltip) | T | Position register is one of the original methods to relate the part (program) coordinate system to the tool position, which indirectly relates it to the machine coordinate system, the only position the control really "knows". Not commonly programmed anymore because G54 to G59 (WCSs) are a better, newer method. Called via G50 for turning, G92 for milling. Those G addresses also have alternate meanings (which see). Position register can still be useful for datum shift programming. The "manual absolute" switch, which has very few useful applications in WCS contexts, was more useful in position register contexts because it allowed the operator to move the tool to a certain distance from the part (for example, by touching off a 2.0000" gage) and then declare to the control what the distance-to-go shall be (2.0000). | |
| G52 | Local coordinate system (LCS) | M | Temporarily shifts program zero to a new location. It is simply "an offset from an offset", that is, an additional offset added onto the WCS offset. This simplifies programming in some cases. A typical example is moving from part to part in a multipart setup. With G54 active, G52 X140.0 Y170.0 shifts program zero 140 mm over in X and 170 mm over in Y. When the part "over there" is done, G52 X0 Y0 returns program zero to normal G54 (by reducing G52 offset to nothing). The same result can also be achieved (1) using multiple WCS origins, G54/G55/G56/G57/G58/G59; (2) on newer controls, G54.1 P1/P2/P3/etc. (all the way up to P48); or (3) using G10 for programmable data input, in which the program can write new offset values to the offset registers.[13] The method to use depends on the shop-specific application. | |
| G53 | Machine coordinate system | M | T | Takes absolute coordinates (X, Y, Z, A, B, C) with reference to machine zero rather than program zero. Can be helpful for tool changes. Nonmodal and absolute only. Subsequent blocks are interpreted from the previously selected Work Coordinate System, G54 to G59, even if it is not explicitly programmed. |
| G54 to G59 | Work coordinate systems (WCSs) | M | T | Have largely replaced position register (G50 and G92). Each tuple of axis offsets relates program zero directly to machine zero. The Standard is 6 tuples (G54 to G59), with optional extensibility to 48 more via G54.1 P1 to P48. |
| G54.1 P1 to P48 | Extended work coordinate systems | M | T | Up to 48 more WCSs besides the 6 provided as standard by G54 to G59. Note the floating-point extension of the G-code data type (formerly all integers). Other examples have also evolved (e.g., G84.2). Modern controls have the hardware to handle it. |
| G61 | Exact stop check, modal | M | T | Can be canceled with G64. The non-modal version is G09. |
| G62 | Automatic corner override | M | T | |
| G64 | Default cutting mode (cancel exact stop check mode) | M | T | Cancels G61. |
| G68 | Rotate coordinate system | M | Rotates coordinate system in the current plane given with G17, G18, or G19. Center of rotation is given with two parameters, which vary with each vendor's implementation. Rotate with the angle given with argument R. This can be used, for instance, to align the coordinate system with a misaligned part. It can also be used to repeat movement sequences around a center. Not all vendors support coordinate system rotation. | |
| G69 | Turn off coordinate system rotation | M | Cancels G68. | |
| G70 | Fixed cycle, multiple repetitive cycle, for finishing (including contours) | T | ||
| G71 | Fixed cycle, multiple repetitive cycles, for roughing (Z-axis emphasis) | T | ||
| G72 | Fixed cycle, multiple repetitive cycles, for roughing (X-axis emphasis) | T | ||
| G73 | Fixed cycle, multiple repetitive cycle, for roughing, with pattern repetition | T | ||
| G73 | Peck drilling cycle for milling – high-speed (NO full retraction from pecks) | M | Retracts only as far as a clearance increment (system parameter). For when chip breaking is the main concern, but chip clogging of flutes is not. Compare G83. | |
| G74 | Peck drilling cycle for turning | T | ||
| G74 | Tapping cycle for milling, lefthand thread, M04 spindle direction | M | See notes at G84. | |
| G75 | Peck grooving cycle for turning | T | ||
| G76 | Fine boring cycle for milling | M | Includes OSS and shift (oriented spindle stop and shift tool off centerline for retraction) | |
| G76 | Threading cycle for turning, multiple repetitive cycle | T | ||
| G80 | Cancel canned cycle | M | T | Milling: Cancels all cycles such as G73, G81, G83, etc. Z-axis returns either to Z-initial level or R level, as programmed (G98 or G99, respectively). |
| Turning: Usually not needed on lathes, because a new group-1 G address (G00 to G03) cancels whatever cycle was active. | ||||
| G81 | Simple drilling cycle | M | No dwell built in | |
| G82 | Drilling cycle with dwell | M | Dwells at hole bottom (Z-depth) for the number of milliseconds specified by the P address. Good for when hole bottom finish matters. Good for spot drilling because the divot is certain to clean up evenly. Consider the "choosing dwell duration" note at G04. | |
| G83 | Peck drilling cycle (full retraction from pecks) | M | Returns to R-level after each peck. Good for clearing flutes of chips. Compare G73. | |
| G84 | Tapping cycle, righthand thread, M03 spindle direction | M | G74 and G84 are the righthand and lefthand "pair" for old-school tapping with a non-rigid toolholder ("tapping head" style). Compare the rigid tapping "pair", G84.2 and G84.3. | |
| G84.2 | Tapping cycle, righthand thread, M03 spindle direction, rigid toolholder | M | See notes at G84. Rigid tapping synchronizes speed and feeds according to the desired thread helix. That is, it synchronizes degrees of spindle rotation with microns of axial travel. Therefore, it can use a rigid tool holder to hold the tap. This feature is not available on old machines or newer low-end machines, which must use "tapping head" motion (G74/G84). | |
| G84.3 | Tapping cycle, lefthand thread, M04 spindle direction, rigid toolholder | M | See notes at G84 and G84.2. | |
| G85 | boring cycle, feed in/feed out | M | Good cycle for a reamer. | |
| In some cases good for single-point boring tool, although in other cases the lack of depth of cut on the way back out is bad for surface finish, in which case, G76 (OSS/shift) can be used instead. | ||||
| If need dwell at hole bottom, see G89. | ||||
| G86 | boring cycle, feed in/spindle stop/rapid out | M | Boring tool leaves a slight score mark on the way back out. Appropriate cycle for some applications; for others, G76 (OSS/shift) can be used instead. | |
| G87 | boring cycle, backboring | M | For backboring. Returns to initial level only (G98); this cycle cannot use G99 because its R level is on the far side of the part, away from the spindle headstock. | |
| G88 | boring cycle, feed in/spindle stop/manual operation | M | ||
| G89 | boring cycle, feed in/dwell/feed out | M | G89 is like G85 but with dwell added at bottom of hole. | |
| G90 | Absolute programming | M | T (B) | Positioning defined with reference to part zero. |
| Milling: Always as above. | ||||
| Turning: Sometimes as above (Fanuc group type B and similarly designed), but on most lathes (Fanuc group type A and similarly designed), G90/G91 are not used for absolute/incremental modes. Instead, U and W are the incremental addresses and X and Z are the absolute addresses. On these lathes, G90 is instead a fixed cycle address for roughing. | ||||
| G90 | Fixed cycle, simple cycle, for roughing (Z-axis emphasis) | T (A) | When not serving for absolute programming (above) | |
| G90.1 | Absolute arc programming | M | I, J, K positioning defined with reference to part zero. | |
| G91 | Incremental programming | M | T (B) | Positioning defined with reference to previous position. |
| Milling: Always as above. | ||||
| Turning: Sometimes as above (Fanuc group type B and similarly designed), but on most lathes (Fanuc group type A and similarly designed), G90/G91 are not used for absolute/incremental modes. Instead, U and W are the incremental addresses and X and Z are the absolute addresses. On these lathes, G90 is a fixed cycle address for roughing. | ||||
| G91.1 | Incremental arc programming | M | I, J, K positioning defined with reference to previous position. | |
| G92 | Position register (programming of vector from part zero to tool tip) | M | T (B) | Store information in computer memory locations (register). Same info as at G50 position register. |
| Milling: Always as above. | ||||
| Turning: Sometimes as above (Fanuc group type B and similarly designed), but on most lathes (Fanuc group type A and similarly designed), position register is G50. | ||||
| G93 | Inverse feed time | M (with radial axes) | Means the move should be completed in [1/F number] minutes. An F number is required on all lines with G1, G2, G3 movements when in G93 mode.[15] Used to translate distance-per-time to rotary axes. | |
| G94 | Feedrate per minute | M | T (B) | On group type A lathes, feedrate per minute is G98. |
| G94 | Fixed cycle, simple cycle, for roughing (X-axis emphasis) | T (A) | When not serving for feedrate per minute (above) | |
| G95 | Feedrate per revolution | M | T (B) | On group type A lathes, feedrate per revolution is G99. |
| G96 | Constant surface speed (CSS) | T | Varies spindle speed automatically to achieve a constant surface speed. See speeds and feeds. Takes an S address integer, which is interpreted as sfm in G20 mode or as m/min in G21 mode. | |
| G97 | Constant spindle speed | M | T | Takes an S address integer, which is interpreted as rev/min (rpm). The default speed mode per system parameter if no mode is programmed. |
| G98 | Return to initial Z level in canned cycle | M | ||
| G98 | Feedrate per minute (group type A) | T (A) | Feedrate per minute is G94 on group type B. | |
| G99 | Return to R level in canned cycle | M | ||
| G99 | Feedrate per revolution (group type A) | T (A) | Feedrate per revolution is G95 on group type B. | |
| G100 | Tool length measurement | M |
M Codes
| Code | Description | Milling | Turning | Details |
|---|---|---|---|---|
| ( M ) | ( T ) | |||
| M00 | Compulsory stop | M | T | Non-optional—machine always stops on reaching M00 in the program execution. |
| M01 | Optional stop | M | T | Machine only stops at M01 if operator pushes the optional stop button. |
| M02 | End of program | M | T | Program ends; execution may or may not return to program top (depending on the control); may or may not reset register values. M02 was the original program-end code, now considered obsolete, but still supported for backward compatibility. Many modern controls treat M02 as equivalent to M30. See M30 for additional discussion of control status upon executing M02 or M30. |
| M03 | Torch Fire or Spindle on (clockwise rotation) | M | T | The speed of the spindle is determined by the address S, in either revolutions per minute (G97 mode; default) or surface feet per minute or [surface] meters per minute (G96 mode [CSS] under either G20 or G21). The right-hand rule can be used to determine which direction is clockwise and which direction is counter-clockwise. |
| M04 | Spindle on (counterclockwise rotation) | M | T | See comment above at M03. |
| M05 | Torch off or Spindle stop | M | T | |
| M06 | Automatic tool change (ATC) | M | T (some-times) | Many lathes do not use M06 because the T address itself indexes the turret. |
| M07 | Coolant on (mist) | M | T | |
| M08 | Coolant on (flood) | M | T | |
| M09 | Coolant off | M | T | |
| M10 | Pallet clamp on | M | For machining centers with pallet changers | |
| M11 | Pallet clamp off | M | For machining centers with pallet changers | |
| M13 | Spindle on (clockwise rotation) and coolant on (flood) | M | This one M-code does the work of both M03 and M08. It is not unusual for specific machine models to have such combined commands, which make for shorter, more quickly written programs. | |
| M19 | Spindle orientation | M | T | |
| M21 | Mirror, X-axis | M | ||
| M21 | Tailstock forward | T | ||
| M22 | Mirror, Y-axis | M | ||
| M22 | Tailstock backward | T | ||
| M23 | Mirror OFF | M | ||
| M23 | Thread gradual pullout ON | T | ||
| M24 | Thread gradual pullout OFF | T | ||
| M30 | End of program, with return to program top | M | T | Today, M30 is considered the standard program-end code, and returns execution to the top of the program. Most controls also still support the original program-end code, M02, usually by treating it as equivalent to M30. Additional info: Compare M02 with M30. First, M02 was created, in the days when the punched tape was expected to be short enough to splice into a continuous loop (which is why on old controls, M02 triggered no tape rewinding). The other program-end code, M30, was added later to accommodate longer punched tapes, which were wound on a reel and thus needed rewinding before another cycle could start. On many newer controls, there is no longer a difference in how the codes are executed—both act like M30. |
| M41 | Gear select – gear 1 | T | ||
| M42 | Gear select – gear 2 | T | ||
| M43 | Gear select – gear 3 | T | ||
| M44 | Gear select – gear 4 | T | ||
| M48 | Feedrate override allowed | M | T | MFO (manual feedrate override) |
| M49 | Feedrate override NOT allowed | M | T | Prevent MFO (manual feedrate override). This rule is also usually called (automatically) within tapping cycles or single-point threading cycles, where feed is precisely correlated to speed. Same with SSO (spindle speed override) and feed hold button. Some controls are capable of providing SSO and MFO during threading. |
| M52 | Unload Last tool from spindle | M | T | Also empty spindle. |
| M60 | Automatic pallet change (APC) | M | For machining centers with pallet changers | |
| M88 | Internal cooling on | M | (also known as high pressure cooling on) | |
| M89 | Internal cooling off | M | (also known as high pressure cooling off) | |
| M98 | Subprogram call | M | T | Takes an address P to specify which subprogram to call, for example, "M98 P8979" calls subprogram O8979. |
| M99 | Subprogram end | M | T | Usually placed at end of subprogram, where it returns execution control to the main program. The default is that control returns to the block following the M98 call in the main program. Return to a different block number can be specified by a P address. M99 can also be used in main program with block skip for endless loop of main program on bar work on lathes (until operator toggles block skip). |
| M100 | Clean Nozzle | Some 3d printers have a predefined routine for wiping the extruder nozzle in the X and Y direction often against a flexible scraper mounted to the dump area. |