Code

Description

Milling Turning (M) (T)

Corollary info

G00

Rapid positioning

On 2- or 3-axis moves, G00 (unlike G01) traditionally does not necessarily move in a single straight line between start point and end point. It moves each axis at its max speed until its vector is achieved. 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

The most common workhorse code for feeding during a cut. The program specs the start and end points, and the control automatically calculates (interpolates) the intermediate points to pass through that will yield a straight line (hence "linear"). The control then calculates the angular velocities at which to turn the axis leadscrews. The computer performs thousands of calculations per second. Actual machining takes place with given feed on linear path.

G02

Circular interpolation, clockwise

Cannot start G41 or G42 in G02 or G03 modes. Must already be compensated in earlier G01block.

G03

Circular interpolation, counterclockwise

Cannot start G41 or G42 in G02 or G03 modes. Must already be compensated in earlier G01block.

G04

Dwell

Takes an address for dwell period (may be X, U, or P). The dwell period is specified inmilliseconds.

G05P10000

High-precision contour control (HPCC)

Uses a deep look-ahead buffer and simulation processing to provide better axis movement acceleration and deceleration during contour milling

G05.1 Q1. Ai Nano contour control M

Uses a deep look-ahead buffer and simulation processing to provide better axis movement acceleration and deceleration during contour milling

G07

Imaginary axis designation

G09

Exact stop check

G10

Programmable data input

G11

Data write cancel

G12

Full-circle interpolation, clockwise

Fixed cycle for ease of programming 360 circular interpolation with blend-radius lead-in and lead-out. Not standard on Fanuc controls.

G13

Full-circle interpolation, counterclockwise

Fixed cycle for ease of programming 360 circular interpolation with blend-radius lead-in and lead-out. Not standard on Fanuc controls.

G17

XY plane selection

G18

ZX plane selection

On most CNC lathes (built 1960s to 2000s), ZX is the only available plane, so no G17 to G19codes are used. This is now changing as the era begins in which live tooling, multitask/multifunction, and mill-turn/turn-mill gradually become the "new normal". But the simpler, traditional form factor will probably not disappear just move over to make room for the newer configurations. See also V address.

G19

YZ plane selection

G20

Programming ininches

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 tenthousandth 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 inmillimeters (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)

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, M aka machine reference point) T

Takes a P address specifying which machine zero point is desired, if the machine has several secondary points (P1 to P4). 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.

G31

Skip function (used for probes and tool length measurement systems)

G32

Single-point threading, longhand style (if not using a cycle, e.g., G76)

Similar to G01 linear interpolation, except with automatic spindle synchronization for single-point threading.

G33

Constant-pitchthreading

G33

Single-point threading, longhand style (if not using a cycle, e.g., G76)

Some lathe controls assign this mode to G33 rather than G32.

G34

Variable-pitch threading

G40

Tool radius compensation M off

Cancels G41 or G42.

G41

Tool radius compensation

Milling: Given righthand-helix cutter and M03 spindle direction, G41 corresponds to climb milling (down

left

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.)

G42

Tool radius compensation M right

Similar corollary 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 negativebecause 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 positivebecause 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

G48

Axis offset double decrease

G49

Tool length offset compensation cancel

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

G50

Position register (programming of vector from part zero to tool tip)

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.

G52

Local coordinate system (LCS)

Temporarily shifts program zero to a new location. This simplifies programming in some cases.

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 as "back to G54" 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. 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 M systems

Up to 48 more WCSs besides the 6 provided as standard by G54 to G59. Note floating-point extension of G-code data type (formerly all integers). Other examples have also evolved (e.g.,G84.2). Modern controls have the hardware to handle it.

G70

Fixed cycle, multiple repetitive cycle, for finishing (including contours)

G71

Fixed cycle, multiple repetitive cycle, for roughing (Z-axis

emphasis)

G72

Fixed cycle, multiple repetitive cycle, for roughing (X-axis emphasis)

G73

Fixed cycle, multiple repetitive cycle, for roughing, with pattern repetition

G73

Peck drilling cycle for milling - high-speed (NO M full retraction from pecks)

Retracts only as far as a clearance increment (system parameter). For when chipbreaking is the main concern, but chip clogging of flutes is not.

G74

Peck drilling cycle for turning

G74

Tapping cycle for milling, lefthand thread, M04 spindle direction

G75

Peck grooving cycle for turning

G76

Fine boring cycle for milling

G76

Threading cycle for turning, multiple repetitive cycle

G80 Cancel canned cycle M T

Milling: Cancels all cycles such as G73, G83, G88, 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

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.

G83

Peck drilling cycle (full retraction from pecks)

Returns to R-level after each peck. Good for clearing flutes of chips.

G84

Tapping cycle,righthand thread,M03 spindle direction

G84.2

Tapping cycle, righthand thread,M03 spindle direction, rigid toolholder

G90

Absolute programming

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 Zare 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)

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 Zare the absolute addresses. On these lathes, G90 is a fixed cycle address for roughing.

G92 Position register (programming of vector from part zero to tool tip) M T (B)

Same corollary 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.

G92

Threading cycle, simple cycle

T (A)

G94

Feedrate per minute

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

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 inG21 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 M canned cycle

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

G99

Feedrate per revolution (group type A)

T (A)

Feedrate per revolution is G95 on group type B.

[edit]List

of M-codes commonly found on Fanuc and similarly designed controls

Code

Description

Milling Turning (M) (T)

Corollary info

M00

Compulsory stop

Non-optionalmachine will always stop upon reaching M00 in the program execution.

M01

Optional stop

Machine will only stop at M01 if operator has pushed the optional stop button.

M02

End of program

No return to program top; may or may not reset register values.

M03

The speed of the spindle is determined by the address S, in surface feet per minute. Theright-hand rule can be used to determine which direction is clockwise and which direction is counter-clockwise. Spindle on (clockwise M rotation) T Right-hand-helix screws moving in the tightening direction (and right-hand-helix flutes spinning in the cutting direction) are defined as moving in the M03 direction, and are labeled "clockwise" by convention. The M03 direction is always M03 regardless of local vantage point and local CW/CCW distinction.

M04

Spindle on (counterclockwise rotation) Spindle stop

M M

T T

See comment above at M03.

M05 M06

Automatic tool change (ATC)

Many lathes do not use M06 because the T address itself indexes the turret. Programming on any particular machine tool requires knowing which method that machine uses. 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, T (someATC fixed tool selection, ATC random memory tool selection, times) the concept of "next tool waiting", and empty tools. These concepts are taught in textbooks such as Smid,[1] and online multimedia (videos, simulators, etc); the latter are usually paywalled to pay back the costs of their development. They are used in training classes for operators, both on-site and remotely (e.g., Tooling University).

M07 M08 M09 M10 M11 M13

Coolant on (mist) Coolant on (flood) Coolant off Pallet clamp on Pallet clamp off

M M M M M

T T T For machining centers with pallet changers For machining centers with pallet changers 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. Spindle orientation is more often called within cycles (automatically) or during setup (manually), but it is also available under program control via M19. The abbreviation OSS (oriented spindle stop) may be seen in reference to an oriented stop within cycles.

Spindle on (clockwise rotation) and coolant M on (flood)

M19 Spindle orientation M T

M21 M21 M22 M22 M23 M23 M24 M30 M41 M42 M43 M44 M48 M49

Mirror, X-axis Tailstock forward Mirror, Y-axis Tailstock backward Mirror OFF Thread gradual pullout ON Thread gradual pullout OFF

M T M T M T T T T T T T M T This rule is also called (automatically) within tapping cycles or single-point threading cycles, where feed is precisely correlated to speed. Same with spindle speed override and feed hold button. Also empty spindle. For machining centers with pallet changers T Takes an address P to specify which subprogram to call, for example, "M98 P8979" calls subprogram O8979. 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

End of program with M return to program top Gear select - gear 1 Gear select - gear 2 Gear select - gear 3 Gear select - gear 4 Feedrate override allowed Feedrate override NOT allowed

M52 M60 M98 M99

Unload Last tool from M spindle Automatic pallet change (APC) Subprogram call M M

Subprogram end

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).