text:
G-code
From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
For other uses, see G-code (disambiguation) and G programming language (disambiguation).
"RS-274" redirects here. For the photoplotter format, see Gerber format.
G-code
Paradigm
Procedural, Imperative
Designed by
Massachusetts Institute of Technology
First appeared
1950s (first edition)
Filename extensions
.mpt, .mpf, .nc and several others
Major implementations
many, mainly Siemens Sinumerik, FANUC, Haas, Heidenhain, Mazak. Generally there is one international standard—ISO 6983.
G-code (also RS-274), which has many variants, is the common name for the most widely used numerical control (NC) programming language. It is used mainly in computer-aided manufacturing to control automated machine tools.
G-code is a language in which people tell computerized machine tools how to make something. The "how" is defined by g-code instructions provided to a 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 lathe or mill, a 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 9 axis[1] around the 3 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 or burnishing tools, photoplotting, additive methods such as 3D printing, and measuring instruments.
Contents
1 Implementations
2 Specific codes
2.1 Letter addresses
2.2 List of G-codes commonly found on FANUC and similarly designed controls for milling and turning
2.3 List of M-codes commonly found on FANUC and similarly designed controls for milling and turning
3 Example program
4 Programming environments
5 Abbreviations used by programmers and operators
6 See also
6.1 Extended developments
6.2 Similar concepts
6.3 Concerns during application
7 References
8 Bibliography
9 External links
Implementations[edit]
The first implementation of a numerical control programming language was developed at the MIT Servomechanisms Laboratory in the late 1950s. In the decades since, many implementations have been developed by many (commercial and noncommercial) organizations. G-code has often been used in these implementations. The main standardized version used in the United States was settled by the Electronic Industries Alliance in the early 1960s.[citation needed] A final revision was approved in February 1980 as RS-274-D.[2] In other countries, the standard ISO 6983 is often used, but many European countries use other standards. For example, 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 differences of each manufacturer's product.
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.[3]
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 developed with CAD/CAM applications that can output the appropriate G-code called a post for a specific machine tool.
Some CNC machines use "conversational" programming, which is a 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.
G-code began as a limited language that lacked constructs such as loops, conditional operators, and programmer-declared variables with 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 PLC data, such as axis positioning data and tool data,[4] via variables used by NC programs. These constructs make it easier to develop automation applications.
Specific codes[edit]
G-codes, also called preparatory codes, are any word in a CNC program that begins with the letter G. Generally it is a code telling the machine tool what type of action to perform, such as:
Rapid movement (transport the tool as quickly as possible in between cuts)
Controlled feed in a straight line or arc
Series of controlled feed movements that would result in a hole being bored, a workpiece cut (routed) to a specific dimension, or a profile (contour) shape added to the edge of a workpiece
Set tool information such as offset
Switch coordinate systems
There are other codes; the type codes can be thought of like registers in a computer.
People have pointed out over the years that the term "G-code" is imprecise. It comes from the literal sense of the term, referring to one letter address and to the specific codes that can be formed with it (for example, G00, G01, G28). But every letter of the English alphabet is used somewhere in the language. Nevertheless, "G-code" is established as the common name of the language.
Letter addresses[edit]
Some letter addresses are used only in milling or only in turning; most are used in both. Bold below are the letters seen most frequently throughout a program.
Sources: Smid 2008;[5] Smid 2010;[6] Green et al. 1996.[7]
Variable
Description
Corollary info
A Absolute or incremental position of A axis (rotational axis around X axis) Positive rotation is defined as a counterclockwise rotation looking from X positive towards X negative.
B Absolute or incremental position of B axis (rotational axis around Y axis)
C Absolute or incremental position of C axis (rotational axis around Z axis)
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;
Incremental axis corresponding to C axis (e.g., on a turn-mill) G43: Negative tool length compensation, G44: Positive tool length compensation
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 corollary info 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 corollary info 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.
G10 use: Specification of what register to edit (work offsets, tool radius offsets, tool length offsets, etc.).
M Miscellaneous function Action code, auxiliary command; descriptions vary. Many M-codes call for machine functions, which is why people often say that the "M" stands for "machine", although it was not intended to.
N Line (block) number in program;
System parameter number to change using G10 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.
System parameter number: G10 allows changing of system parameters under program control.[8]
O Program name For example, O4501. For many years it was common for CNC control displays to use slashed zero glyphs to ensure effortless distinction of letter "O" from digit "0". Today's GUI controls often have a choice of fonts, like a PC does.
P Serves as parameter address for various G and M codes
With G04, defines dwell time value.
Also serves as a parameter in some canned cycles, representing dwell times or other variables.
Also used in the calling and termination of subprograms. (With M98, it specifies which subprogram to call; with M99, it specifies which block number of the main program to return to.)
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 (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 fixed tool selection, ATC random memory tool selection, the concept of "next tool waiting", and empty tools.[5] Programming on any particular machine tool requires knowing which method that machine uses.[5]
U Incremental axis corresponding to X axis (typically only lathe group A controls)
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 Until the 2000s, the V address was very rarely used, because most lathes that used U and W didn't have a Y-axis, so they didn't use V. (Green et al. 1996[7] did not even list V in their table of addresses.) That is still often the case, although the proliferation of live lathe tooling and turn-mill machining has made V address usage less rare than it used to be (Smid 2008[5] shows an example). See also G18.
W Incremental axis corresponding to Z axis (typically only lathe group A controls) In these controls, Z and W obviate G90 and G91, respectively. On these lathes, G90 is instead a fixed cycle address for roughing.
X Absolute or incremental position of X axis.
Also defines dwell time on some machines (instead of "P" or "U").
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.
List of G-codes commonly found on FANUC and similarly designed controls for milling and turning[edit]
Sources: Smid 2008;[5] Smid 2010;[6] Green et al. 1996.[7]
Note: Modal means a code stays in effect until replaced, or cancelled, by another permitted code. Non-Modal means it executes only once. See, for example, codes G09, G61 & G64 below.
Code
Description
Milling
( M )
Turning
( T )
Corollary info
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 end point. It moves each axis at its max speed until its vector quantity 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 M T 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 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 feedrate 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 tool tip 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 feedrate 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 fine 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 end point 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
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[9][8]
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 tool tip 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
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 has 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 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 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 vector from part zero to tool tip) 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. The 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.[8] The method to use depends on 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 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 systems M T 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.
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 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 cycle, for roughing (Z-axis emphasis) T
G72 Fixed cycle, multiple repetitive cycle, 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 chipbreaking 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 feed 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 toolholder 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)
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.
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 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
List of M-codes commonly found on FANUC and similarly designed controls for milling and turning[edit]
Sources: Smid 2008;[5] Smid 2010;[6] Green et al. 1996.[7]
Some older controls require M codes to be in separate blocks (that is, not on the same line).
Code
Description
Milling
( M )
Turning
( T )
Corollary info
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.[10] Many modern controls treat M02 as equivalent to M30.[10] See M30 for additional discussion of control status upon executing M02 or M30.
M03 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.
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) M T See comment above at M03.
M05 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.
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, ATC fixed tool selection, ATC random memory tool selection, the concept of "next tool waiting", and empty tools.[5]
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 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.
The relevance of spindle orientation has increased as technology has advanced. Although 4- and 5-axis contour milling and CNC single-pointing have depended on spindle position encoders for decades, before the advent of widespread live tooling and mill-turn/turn-mill systems, it was not as often relevant in "regular" (non-"special") machining for the operator (as opposed to the machine) to know the angular orientation of a spindle as it is today, except in certain contexts (such as tool change, or G76 fine boring cycles with choreographed tool retraction). Most milling of features indexed around a turned workpiece was accomplished with separate operations on indexing head setups; in a sense, indexing heads were originally invented as separate pieces of equipment, to be used in separate operations, which could provide precise spindle orientation in a world where it otherwise mostly didn't exist (and didn't need to). But as CAD/CAM and multiaxis CNC machining with multiple rotary-cutter axes becomes the norm, even for "regular" (non-"special") applications, machinists now frequently care about stepping just about any spindle through its 360° with precision.
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).[10] 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.[10] 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 overide)
M49 Feedrate override NOT allowed M T Prevent MFO (manual feedrate overide). 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
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).
Example program[edit]
This is a generic program that demonstrates the use of G-Code to turn a 1" diameter X 1" long part. Assume that a bar of material is in the machine and that the bar is slightly oversized in length and diameter and that the bar protrudes by more than 1" from the face of the chuck. (Caution: This is generic, it might not work on any real machine! Pay particular attention to point 5 below.)
Sample
Block
Code
Description
% Signals start of data during file transfer. Originally used to stop tape rewind, not necessarily start of program. For some controls (FANUC) the first LF (EOB) is start of program. ISO uses %, EIA uses ER (0x0B).
O4968 (OPTIONAL PROGRAM DESCRIPTION OR COMMENT) Sample face and turn program. Comments are enclosed in parentheses.
N01 M216 Turn on load monitor
N02 G20 G90 G54 D200 G40 Inch units. Absolute mode. Activate work offset. Activate tool offset. Deactivate tool nose radius compensation.
N03 G50 S2000 Set maximum spindle speed in rev/min — This setting affects Constant Surface Speed mode
N04 T0300 Index turret to tool 3. Clear wear offset (00).
N05 G96 S854 M03 Constant surface speed [automatically varies the spindle speed], 854 sfm, start spindle CW rotation
N06 G41 G00 X1.1 Z1.1 T0303 M08 Enable cutter radius compensation mode, rapid position to 0.55" above axial centerline (1.1" in diameter) and 1.1 inches positive from the work offset in Z, activate flood coolant
N07 G01 Z1.0 F.05 Feed in horizontally at rate of 0.050" per revolution of the spindle until the tool is positioned 1" positive from the work offset
N08 X-0.016 Feed the tool slightly past center—the tool must travel by at least its nose radius past the center of the part to prevent a leftover scallop of material.
N09 G00 Z1.1 Rapid positioning; retract to start position
N10 X1.0 Rapid positioning; next pass
N11 G01 Z0.0 F.05 Feed in horizontally cutting the bar to 1" diameter all the way to the datum, 0.05in/rev
N12 G00 X1.1 M05 M09 Clear the part, stop the spindle, turn off the coolant
N13 G91 G28 X0 Home X axis — return the machine's home position for the X axis
N14 G91 G28 Z0 Home Z axis — return to machine's home position for the Z axis
N15 G90 Return to absolute mode. Turn off load monitor
N16 M30 Program stop, rewind to top of program, wait for cycle start
% Signal end of data during file transfer. Originally used to mark end of tape, not necessarily end of program. ISO uses %, EIA uses ER (0x0B).
Tool Path for program
Several points to note:
There is room for some programming style, even in this short program. The grouping of codes in line N06 could have been put on multiple lines. Doing so may have made it easier to follow program execution.
Many codes are "modal, meaning they remain effect until cancelled or replaced by a contradictory code. For example, once variable speed cutting (CSS) had been selected (G96), it stays in effect until the end of the program. In operation, the spindle speed increases as the tool nears the center of the work to maintain constant surface speed. Similarly, once rapid feed is selected (G00), all tool movements are rapid until a feed rate code (G01, G02, G03) is selected.
It is common practice to use a load monitor with CNC machinery. The load monitor stops the machine if the spindle or feed loads exceed a preset value that is set during the set-up operation. The jobs of the load monitor are various:
Prevent machine damage in the event of tool breakage or a programming mistake.
This is especially important because it allows safe "lights-out machining", in which the operators set up the job and start it during the day, then go home for the night, leaving the machines running and cutting parts during the night. Because no human is around to hear, see, or smell a problem such as a broken tool, the load monitor serves an important sentry duty. When it senses overload condition, which semantically suggests a dull or broken tool, it commands a stop to the machining. Technology is available nowadays to send an alert to someone remotely (e.g., the sleeping owner, operator, or owner-operator) if desired, which can allow them to come intercede and get production going again, then leave once more. This can be the difference between profitability or loss on some jobs, because lights-out machining reduces labor hours per part.
Warn of a tool that is becoming dull and must be replaced or sharpened. Thus, an operator tending multiple machines is told by a machine, essentially, "Pause what you're doing over there, and come attend to something over here."
It is common practice to bring the tool in rapidly to a "safe" point that is close to the part—in this case 0.1" away—and then start feeding the tool. How close that "safe" distance is, depends on the preference of the programmer and/or operator and the maximum material condition for the raw stock.
If the program is wrong, there is a high probability that the machine will crash, or ram the tool into the part, vice, or machine under high power. This can be costly, especially in newer machining centers. It is possible to intersperse the program with optional stops (M01 code) that let the program run piecemeal for testing purposes. The optional stops remain in the program but are skipped during normal running. Fortunately, most CAD/CAM software ships with CNC simulators that display the movement of the tool as the program executes. Nowadays the surrounding objects (chuck, clamps, fixture, tailstock, and more) are included in the 3D models, and the simulation is much like an entire video game or virtual reality environment, making unexpected crashes much less likely. Many modern CNC machines also allow programmers to execute the program in a simulation mode and observe the operating parameters of the machine at a particular execution point. This enables programmers to discover semantic errors (as opposed to syntax errors) before losing material or tools to an incorrect program. Depending on the size of the part, wax blocks may be used for testing purposes as well. Additionally, many machines support operator overrides for both rapid and feedrate that can be used to reduce the speed of the machine, allowing operators to stop program execution before a crash occurs.
For educational purposes, line numbers have been included in the program above. They are usually not necessary for operation of a machine, and increase file sizes, so they are seldom used in industry. However, if branching or looping statements are used in the code, then line numbers may well be included as the target of those statements (e.g. GOTO N99).
Some machines do not allow multiple M codes in the same line.
Programming environments[edit]
This section possibly contains original research. Please improve it by verifying the claims made and adding inline citations. Statements consisting only of original research should be removed. (January 2016) (Learn how and when to remove this template message)
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 editors, using colors and indents semantically [plus other features] to aid the user in ways that basic text editors can't. CAM packages are analogous to IDEs in general programming.)
Two high-level paradigm shifts have been (1) abandoning "manual programming" (with nothing but a pencil or text editor and a human mind) for CAM software systems that generate G-code automatically via postprocessors (analogous to the development of visual techniques in general programming), and (2) 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 approach in general). Macro (parametric) CNC programming uses human-friendly variable names, relational operators, 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 difference has many analogues, both from before the computing era and from after its advent, such as (1) creating text as bitmaps versus using character encoding with glyphs; (2) the abstraction level of tabulated engineering drawings, with many part dash numbers parametrically defined by the one same drawing and a parameter table; or (3) the way that HTML passed through a phase of using content markup for presentation purposes, then matured toward the CSS model. In all these cases, a higher layer of abstraction introduced what was missing semantically.
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. 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 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 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.[11] 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."[12] 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.[13][14] 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.
Making a living cutting parts on computer-controlled machines has been made both easier and harder by CAD/CAM software. Efficiently written G-code can be a challenge for CAM software. Ideally a CNC machinist should know both manual and CAM programming well, so that the benefits of both brute-force CAM and elegant hand programming can be used where needed. Many older machines were built with limited computer memory at a time when memory was very expensive; 32K was considered plenty of room for manual programs whereas modern CAM software can post gigabytes of code. CAM excels at getting a program out quick that may take up more machine memory and take longer to run. This often makes it quite valuable to machining a low quantity of parts. But a balance must be struck between the time it takes to create a program and the time the program takes to machine a part. It has become easier and faster to make just a few parts on the newer machines with lots of memory. This has taken its toll on both hand programmers and manual machinists. Given natural turnover into retirement, it is not realistic to expect to maintain a large pool of operators who are highly skilled in manual programming when their commercial environment mostly can no longer provide the countless hours of deep experience it took to build that skill; and yet the loss of this experience base can be appreciated, and there are times when such a pool is sorely missed, because some CNC runs still cannot be optimized without such skill.
Abbreviations used by programmers and operators[edit]
This list is only a selection and, except for a few key terms, mostly avoids duplicating the many abbreviations listed at engineering drawing abbreviations and symbols (which see).
Abbreviation
Expansion
Corollary info
APC automatic pallet changer See M60.
ATC automatic tool changer See M06.
CAD/CAM computer-aided design and computer-aided manufacturing
CCW counterclockwise See M04.
CNC computer numerical control
CRC cutter radius compensation See also G40, G41, and G42.
CS cutting speed Referring to cutting speed (surface speed) in surface feet per minute (sfm, sfpm) or meters per minute (m/min).
CSS constant surface speed See G96 for explanation.
CW clockwise See M03.
DNC direct numerical control or distributed numerical control Sometimes referred to as "Drip Feeding" or "Drip Numerical Control" due to the fact that a file can be "drip" fed to a machine, line by line, over a serial protocol such as RS232. DNC allows machines with limited amounts of memory to run larger files.
DOC depth of cut Refers to how deep (in the Z direction) a given cut will be
EOB end of block The G-code synonym of end of line (EOL). A control character equating to newline. In many implementations of G-code (as also, more generally, in many programming languages), a semicolon (;) is synonymous with EOB. In some controls (especially older ones) it must be explicitly typed and displayed. Other software treats it as a nonprinting/nondisplaying character, much like word processing apps treat the pilcrow (¶).
E-stop emergency stop
EXT external On the operation panel, one of the positions of the mode switch is "external", sometimes abbreviated as "EXT", referring to any external source of data, such as tape or DNC, in contrast to the computer memory that is built into the CNC itself.
FIM full indicator movement
FPM feet per minute See SFM.
HBM horizontal boring mill A type of machine tool that specializes in boring, typically large holes in large workpieces.
HMC horizontal machining center
HSM high speed machining Refers to machining at speeds considered high by traditional standards. Usually achieved with special geared-up spindle attachments or with the latest high-rev spindles. On modern machines HSM refers to a cutting strategy with a light, constant chipload and high feedrate, usually at or near full depth of cut.[15]
HSS high speed steel A type of tool steel used to make cutters. Still widely used today (versatile, affordable, capable) although carbide and others continue to erode its share of commercial applications due to their higher rate of material removal.
in inch(es)
IPF inches per flute Also known as chip load or IPT. See F address and feed rate.
IPM inches per minute See F address and feed rate.
IPR inches per revolution See F address and feed rate.
IPT inches per tooth Also known as chip load or IPF. See F address and feed rate.
MDI manual data input A mode of operation in which the operator can type in lines of program (blocks of code) and then execute them by pushing cycle start.
MEM memory On the operation panel, one of the positions of the mode switch is "memory", sometimes abbreviated as "MEM", referring to the computer memory that is built into the CNC itself, in contrast to any external source of data, such as tape or DNC.
MFO manual feedrate override The MFO dial or buttons allow the CNC operator or machinist to multiply the programmed feed value by any percentage typically between 10% and 200%. This is to allow fine-tuning of speeds and feeds to minimize chatter, improve surface finish, lengthen tool life, and so on. The SSO and MFO features can be locked out for various reasons, such as for synchronization of speed and feed in threading, or even to prevent "soldiering"/"dogging" by operators. On some newer controls, the synchronization of speed and feed in threading is sophisticated enough that SSO and MFO can be available during threading, which helps with fune-tuning speeds and feeds to reduce chatter on the threads or in repair work involving the picking up of existing threads.[16]
mm millimetre(s)
MPG manual pulse generator Referring to the handle (handwheel) (each click of the handle generates one pulse of servo input)
NC numerical control
OSS oriented spindle stop See comments at M19.
SFM surface feet per minute See also speeds and feeds and G96.
SFPM surface feet per minute See also speeds and feeds and G96.
SPT single-point threading
SSO spindle speed override The SSO dial or buttons allow the CNC operator or machinist to multiply the programmed speed value by any percentage typically between 10% and 200%. This is to allow fine-tuning of speeds and feeds to minimize chatter, improve surface finish, lengthen tool life, and so on. The SSO and MFO features can be locked out for various reasons, such as for synchronization of speed and feed in threading, or even to prevent "soldiering"/"dogging" by operators. On some newer controls, the synchronization of speed and feed in threading is sophisticated enough that SSO and MFO can be available during threading, which helps with fune-tuning speeds and feeds to reduce chatter on the threads or in repair work involving the picking up of existing threads.[16]
TC or T/C tool change, tool changer See M06.
TIR total indicator reading
TPI threads per inch
USB Universal Serial Bus One type of connection for data transfer
VMC vertical machining center
VTL vertical turret lathe A type of machine tool that is essentially a lathe with its Z axis turned vertical, allowing the faceplate to sit like a large turntable. The VTL concept overlaps with the vertical boring mill concept.
See also[edit]
3D printing
Canned cycle
LinuxCNC - a free CNC software with many resources for G-code documentation
Extended developments[edit]
Direct Numerical Control (DNC)
STEP-NC
MTConnect
Similar concepts[edit]
Gerber file
Concerns during application[edit]
Cutter location, cutter compensation, offset parameters
Coordinate systems
References[edit]
Jump up ^ Karlo Apro (2008). Secrets of 5-Axis Machining. Industrial Press Inc. ISBN 0-8311-3375-9.
Jump up ^ EIA Standard RS-274-D Interchangeable Variable Block Data Format for Positioning, Contouring, and Contouring/Positioning Numerically Controlled Machines, 2001 Eye Street, NW, Washington, D.C. 20006: Electronic Industries Association, February 1979
Jump up ^ Martin., Libicki, (1995). Information Technology Standards : Quest for the Common Byte. Burlington: Elsevier Science. p. 321. ISBN 9781483292489. OCLC 895436474.
Jump up ^ "Fanuc macro system variables". Retrieved 2014-06-30.
^ Jump up to: a b c d e f g Smid 2008.
^ Jump up to: a b c Smid 2010.
^ Jump up to: a b c d Green 1996, pp. 1162–1226.
^ Jump up to: a b c Smid 2004, p. 61
Jump up ^ "FAQ's - At Your Service". atyourservice.haascnc.com. Retrieved 5 April 2018.
^ Jump up to: a b c d Smid 2010, pp. 29–30.
Jump up ^ MMS editorial staff (2010-12-20), "CAM system simplifies Swiss-type lathe programming", Modern Machine Shop, 83 (8 [2011 Jan]): 100–105. Online ahead of print.
Jump up ^ Smid 2008, p. 457.
Jump up ^ Lynch, Mike (2010-01-18), "When programmers should know G code", Modern Machine Shop (online ed.).
Jump up ^ Lynch, Mike (2011-10-19), "Five CNC myths and misconceptions [CNC Tech Talk column, Editor's Commentary]", Modern Machine Shop (online ed.).
Jump up ^ Marinac, Dan. "Tool Path Strategies For High Speed Machining". www.mmsonline.com. Retrieved 2018-03-06.
^ Jump up to: a b Korn, Derek (2014-05-06), "What is arbitrary speed threading?", Modern Machine Shop.
Bibliography[edit]
Oberg, Erik; Jones, Franklin D.; Horton, Holbrook L.; Ryffel, Henry H. (1996), Green, Robert E.; McCauley, Christopher J., eds., Machinery's Handbook (25th ed.), New York, NY, USA: Industrial Press, ISBN 978-0-8311-2575-2, OCLC 473691581.
Smid, Peter (2008), CNC Programming Handbook (3rd ed.), New York: Industrial Press, ISBN 9780831133474, LCCN 2007045901.
Smid, Peter (2010), CNC Control Setup for Milling and Turning, New York: Industrial Press, ISBN 978-0831133504, LCCN 2010007023.
Smid, Peter (2004), Fanuc CNC Custom Macros, Industrial Press, ISBN 978-0831131579.
External links[edit]
CNC G-Code and M-Code Programming
Tutorial for G-code
Kramer, T. R.; Proctor, F. M.; Messina, E. R. (1 Aug 2000), The NIST RS274NGC Interpreter – Version 3, NIST, NISTIR 6556
http://museum.mit.edu/150/86 Has several links (including history of MIT Servo Lab)
Complete list of G-code used by most 3D printers
Fanuc and Haas G-code Reference
Fanuc and Haas G-code Tutorial
show
v
t
e
Metalworking
hide
v
t
e
Machining and computing
Computer-aided
engineering
2.5D
CAD
CAM
G-code
Numerical control (NC and CNC)
Stewart platform
Drilling and
threading
Die head
Drill
Drill bit
Drill bit shank
Drill bit sizes
Drilling
List of drill and tap sizes
Tap and die
Tap wrench
Threading
Grinding and
lapping
Abrasive
Angle grinder
Bench grinder
Coated abrasives
Cylindrical grinder
Diamond plate
Flick grinder
Grinding
Grinding dresser
Grinding machine
Grinding wheel
Jig grinder
Lapping
Sanding
Sharpening stone
Spark testing
Surface grinder
Tool and cutter grinder
Machining
Boring
Broaching
Electrical discharge machining
Electrochemical machining
Electron beam machining
Endmill
Engraving
Facing
Hobbing
Jig borer
Machine tool
Machining
Metal lathe
Milling cutter
Milling machine
Pantograph
Photochemical machining
Planer
Reamer
Rotary transfer machine
Shaper
Turning
Ultrasonic machining
Machine tooling
Angle plate
Chuck
Collet
Fixture
Indexing head
Jig
Lathe center
Machine taper
Magnetic base
Mandrel
Rotary table
Wiggler
Terminology
Cutting fluid
Machining vibrations
Speeds and feeds
Swarf
Tolerance
Tool and die making
Tramp oil
Casting
Fabrication
Forming
Jewellery
Machining
Metallurgy
Smithing
Tools and terminology
Welding
Retrieved from "https://en.wikipedia.org/w/index.php?title=G-code&oldid=865094333"
Categories:
Computer-aided engineering
Domain-specific programming languages
Encodings
Metalworking
Hidden categories:
All articles with unsourced statements
Articles with unsourced statements from March 2010
Articles that may contain original research from January 2016
All articles that may contain original research
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Article
Talk
Variants
Views
Read
Edit
View history
More
Search
Navigation
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
Languages
Беларуская
Čeština
Dansk
Ελληνικά
Español
فارسی
Français
한국어
Hrvatski
Italiano
Қазақша
Nederlands
Polski
Português
Română
Русский
Српски / srpski
Türkçe
Українська
中文
11 more
Edit links
This page was last edited on 21 October 2018, at 17:50 (UTC).
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
Contact Wikipedia
Developers
Cookie statement
Mobile view
Enable previews

key: html

type: local

value: div

attrs: id class

values: mw-page-base noprint

values: mw-head-base noprint

value: a

attrs: id class lang

values: firstHeading firstHeading en

values: siteSub noprint

attrs: class href

values: mw-jump-link #mw-head

values: mw-jump-link #p-search

attrs: href class title

values:
/wiki/G-code_(disambiguation)
mw-disambig
G-code (disambiguation)

attrs: role class

values:
note
hatnote navigation-not-searchable

attrs: href title

value: caption

value: th

value: td

value: tr

values: International Organization for Standardization

values: checkbox button toctogglecheckbox toctogglecheckbox display:none

values: This claim needs references to reliable sources. (March 2010)

values:
noprint Inline-Template Template-Fact
white-space:nowrap;

values: Edit section: List of G-codes commonly found on FANUC and similarly designed controls for milling and turning

values: Edit section: List of M-codes commonly found on FANUC and similarly designed controls for milling and turning

attrs: alt src width height class srcset data-file-width data-file-height

attrs: alt src width height srcset data-file-width data-file-height

values: plainlinks metadata ambox ambox-content ambox-Original_research

values:
/wiki/Small_and_medium_enterprises
mw-redirect
Small and medium enterprises

values: Edit section: Abbreviations used by programmers and operators

values: Engineering drawing abbreviations and symbols

values:
/wiki/Milling_machine
mw-redirect
Milling machine

values:
/wiki/High_speed_steel
mw-redirect
High speed steel

values:
/wiki/Universal_Serial_Bus
mw-redirect
Universal Serial Bus

values:
/wiki/Direct_Numerical_Control
mw-redirect
Direct Numerical Control

values:
/wiki/Gerber_file
mw-redirect
Gerber file

values: Edit section: Concerns during application

values:
nofollow
external text
//www.worldcat.org/oclc/895436474

values: -moz-column-width: 30em; -webkit-column-width: 30em; column-width: 30em; list-style-type: decimal;

values:
nofollow
external text
//www.worldcat.org/oclc/473691581

values:
nofollow
external text
//lccn.loc.gov/2007045901

values:
nofollow
external text
//lccn.loc.gov/2010007023

values:
nofollow
external text
http://gnipsel.com/linuxcnc/index.html

values:
nofollow
external free
http://museum.mit.edu/150/86

values:
nofollow
external text
http://reprap.org/wiki/G-code

values: Template talk:Metalworking navbox/mach (page does not exist)

values:
/wiki/Electron_beam_machining
mw-redirect
Electron beam machining

values: nowraplinks collapsible uncollapsed navbox-subgroup mw-collapsible mw-made-collapsible

values: nowraplinks hlist collapsible autocollapse navbox-inner mw-collapsible mw-made-collapsible mw-collapsed

values: navigation navbox Metalworking padding:3px

values: Category:All articles with unsourced statements

values: Category:Articles with unsourced statements from March 2010

values: Category:Articles that may contain original research from January 2016

values: Category:All articles that may contain original research

values: Discussion about edits from this IP address [ctrl-alt-n]

values: A list of edits made from this IP address [ctrl-alt-y]

values: You are encouraged to create an account and log in; however, it is not mandatory

values: You're encouraged to log in; however, it's not mandatory. [ctrl-alt-o]

values:
/wiki/G-code
View the content page [ctrl-alt-c]
c

values: Discussion about the content page [ctrl-alt-t]

values: p-namespaces navigation vectorTabs p-namespaces-label

values:
p-variants
navigation
vectorMenu emptyPortlet
p-variants-label

values:
/w/index.php?title=G-code&action=edit
Edit this page [ctrl-alt-e]
e

values: Past revisions of this page [ctrl-alt-h]

values: p-views navigation vectorTabs p-views-label

values:
p-cactions
navigation
vectorMenu emptyPortlet
p-cactions-label

values:
mw-wiki-logo
/wiki/Main_Page
Visit the main page

values:
/wiki/Main_Page
Visit the main page [ctrl-alt-z]
z

values: Featured content – the best of Wikipedia

values: Find background information on current events

values:
/wiki/Special:Random
Load a random article [ctrl-alt-x]
x

values: portal navigation p-navigation p-navigation-label

values: Guidance on how to use and edit Wikipedia

values: About the project, what you can do, where to find things

values: A list of recent changes in the wiki [ctrl-alt-r]

values: portal navigation p-interaction p-interaction-label

values: List of all English Wikipedia pages containing links to this page [ctrl-alt-j]

values: Recent changes in pages linked from this page [ctrl-alt-k]

values:
/wiki/Wikipedia:File_Upload_Wizard
Upload files [ctrl-alt-u]
u

values: A list of all special pages [ctrl-alt-q]

values: Permanent link to this revision of the page

values: Link to connected data repository item [ctrl-alt-g]

values: Printable version of this page [ctrl-alt-p]

values:
https://be.wikipedia.org/wiki/G-code
G-code – Belarusian
be
be
interlanguage-link-target

values:
interlanguage-link interwiki-be
display: none;

values:
interlanguage-link interwiki-cs
display: none;

values:
https://da.wikipedia.org/wiki/G-code
G-code – Danish
da
da
interlanguage-link-target

values:
interlanguage-link interwiki-da
display: none;

values:
https://el.wikipedia.org/wiki/G-code
G-code – Greek
el
el
interlanguage-link-target

values:
interlanguage-link interwiki-el
display: none;

values:
https://es.wikipedia.org/wiki/G-code
G-code – Spanish
es
es
interlanguage-link-target

values: Programmation de commande numérique – French

values:
https://ko.wikipedia.org/wiki/G-code
G-code – Korean
ko
ko
interlanguage-link-target

values:
https://hr.wikipedia.org/wiki/G_naredbe
G naredbe – Croatian
hr
hr
interlanguage-link-target

values:
interlanguage-link interwiki-hr
display: none;

values:
https://it.wikipedia.org/wiki/Codice_G
Codice G – Italian
it
it
interlanguage-link-target

values: Макропрограммалау – Kazakh

values:
interlanguage-link interwiki-kk
display: none;

values:
https://nl.wikipedia.org/wiki/G-code
G-code – Dutch
nl
nl
interlanguage-link-target

values:
interlanguage-link interwiki-nl
display: none;

values:
https://pl.wikipedia.org/wiki/G_code
G code – Polish
pl
pl
interlanguage-link-target

values:
interlanguage-link interwiki-pl
display: none;

values: Programarea mașinilor-unelte cu comandă numerică – Romanian

values:
interlanguage-link interwiki-ro
display: none;

values:
https://ru.wikipedia.org/wiki/G-code
G-code – Russian
ru
ru
interlanguage-link-target

values:
https://tr.wikipedia.org/wiki/G-kodu
G-kodu – Turkish
tr
tr
interlanguage-link-target

values:
https://uk.wikipedia.org/wiki/G-code
G-code – Ukrainian
uk
uk
interlanguage-link-target

values: mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-G-code rootpage-G-code skin-vector action-view


text:
Common snapping turtle
From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Common snapping turtle
Female searching for nest site
Conservation status

Least Concern (IUCN 3.1)[1]
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Tetrapodomorpha
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Family: Chelydridae
Genus: Chelydra
Species: C. serpentina
Binomial name
Chelydra serpentina
(Linnaeus, 1758)
Native range map of C. serpentina
Synonyms
Testudo serpentina
Linnaeus, 1758
Chelydra serpentina
— Schweigger, 1812
The common snapping turtle (Chelydra serpentina) is a large freshwater turtle of the family Chelydridae. Its natural range extends from southeastern Canada, southwest to the edge of the Rocky Mountains, as far east as Nova Scotia and Florida. The three species of Chelydra and the larger alligator snapping turtles (genus Macrochelys) are the only extant chelydrids, a family now restricted to the Americas. The common snapping turtle, as its name implies, is the most widespread.[2]
The common snapping turtle is noted for its combative disposition when out of the water with its powerful beak-like jaws, and highly mobile head and neck (hence the specific name serpentina, meaning "snake-like"). In water, they are likely to flee and hide themselves underwater in sediment. Snapping turtles have a life-history strategy characterized by high and variable mortality of embryos and hatchlings, delayed sexual maturity, extended adult longevity, and iteroparity (repeated reproductive events) with low reproductive success per reproductive event. Females, and presumably also males, in more northern populations mature later (at 15–20 years) and at a larger size than in more southern populations (about 12 years). Lifespan in the wild is poorly known, but long-term mark-recapture data from Algonquin Park in Ontario, Canada, suggest a maximum age over 100 years.[3]
Contents
1 Anatomy and morphology
2 Ecology and life history
3 Systematics and taxonomy
4 Behavior
5 Captivity
6 Invasive species
7 In politics
8 As food
9 Conservation
10 References
11 External links
12 Further reading
Anatomy and morphology[edit]
Close-up in Taum Sauk Mountain State Park
Head
Skull
Illustration from Holbrook's North American Herpetology, 1842
C. serpentina has a rugged, muscular build with a ridged carapace (upper shell), although ridges tend to be more pronounced in younger individuals. The carapace length in adulthood may be nearly 50 cm (20 in), though 25–47 cm (9.8–18.5 in) is more common.[4] C. serpentina usually weighs 4.5–16 kg (9.9–35.3 lb). Per one study, breeding common snapping turtles were found to average 28.5 cm (11.2 in) in carapace length, 22.5 cm (8.9 in) in plastron length and weigh about 6 kg (13 lb).[5] Males are larger than females, with almost all animals weighing in excess of 10 kg (22 lb) being male and quite old, as the species continues to grow throughout life.[6] Any specimen above the aforementioned weights is exceptional, but the heaviest wild specimen caught reportedly weighed 34 kg (75 lb). Snapping turtles kept in captivity can be quite overweight due to overfeeding and have weighed as much as 39 kg (86 lb). In the northern part of its range, the common snapping turtle is often the heaviest native freshwater turtle.[7]
Ecology and life history[edit]
Common habitats are shallow ponds or streams. Some may inhabit brackish environments, such as estuaries. Common snapping turtles sometimes bask—though rarely observed—by floating on the surface with only their carapaces exposed, though in the northern parts of their range, they also readily bask on fallen logs in early spring. In shallow waters, common snapping turtles may lie beneath a muddy bottom with only their heads exposed, stretching their long necks to the surface for an occasional breath (their nostrils are positioned on the very tip of the snout, effectively functioning as snorkels). Snapping turtles consume both plant and animal matter, and are important aquatic scavengers, but they are also active hunters that prey on anything they can swallow, including many invertebrates, fish, frogs, reptiles (including snakes and smaller turtles), unwary birds, and small mammals. In some areas, adult snapping turtles can be incidentally detrimental to breeding waterfowl, as they will occasionally take ducklings and goslings but their effect on such prey is frequently exaggerated.[8]
A snapping turtle's eggs
Common snapping turtles have few predators when older, but eggs are subject to predation by crows, mink, skunks, foxes, and raccoons. As hatchlings and juveniles, most of the same predators will attack them as well as herons (mostly great blue herons), bitterns, hawks, owls, fishers, bullfrogs, large fish, and snakes.[7] There are records during winter in Canada of hibernating adult common snapping turtles being ambushed and preyed on by northern river otters.[6] Other natural predators which have reportedly preyed on adults include coyotes, black bears, alligators and their larger cousins, alligator snapping turtles.[9] Large, old male snapping turtles have very few natural threats due to their formidable size and defenses, and tend to have a very low annual mortality rate.[6]
These turtles travel extensively over land to reach new habitats or to lay eggs. Pollution, habitat destruction, food scarcity, overcrowding, and other factors drive snappers to move; it is quite common to find them traveling far from the nearest water source. Experimental data supports the idea that snapping turtles can sense the Earth's magnetic field, which could also be used for such movements (together with a variety of other possible orientation cues).[10][11] This species mates from April through November, with their peak laying season in June and July. The female can hold sperm for several seasons, using it as necessary. Females travel over land to find sandy soil in which to lay their eggs, often some distance from the water. After digging a hole, the female typically deposits 25 to 80 eggs each year, guiding them into the nest with her hind feet and covering them with sand for incubation and protection. Incubation time is temperature-dependent, ranging from 9 to 18 weeks. In cooler climates, hatchlings overwinter in the nest. The common snapping turtle is remarkably cold-tolerant; radiotelemetry studies have shown some individuals do not hibernate, but remain active under the ice during the winter.[12] Hibernating snapping turtles do not breathe for, in the northern part of their range, more than six months since ice covers their hibernating site. These turtles can get oxygen by pushing their head out of the mud and allowing gas exchange to take place through the membranes of their mouth and throat. This is known as extrapulmonary respiration. If they cannot get enough oxygen through this method they start to utilize anaerobic pathways, burning sugars and fats without the use of oxygen. The metabolic by-products from this process are acidic and create very undesirable side effects by spring, which are known as oxygen debt.[13] Although designated as "least concern" on the IUCN redlist, the species has been designated in the Canadian part of its range as "Special Concern" due to its life history being sensitive to disruption by anthropogenic activity.[14]
Systematics and taxonomy[edit]
Currently, no subspecies of the common snapping turtle are recognized.[15] The former subspecies osceola is currently considered a synonym of serpentina, while the other former subspecies Chelydra rossignonii[16] and Chelydra acutirostris are both recognized as full species.[15][17]
Behavior[edit]
In their environment, they are at the top of the food chain, causing them to feel less fear or aggression in some cases. When they encounter a species unfamiliar to them such as humans, in rare instances, they will become curious and survey the situation and even more rarely may bump their nose on a leg of the person standing in the water. Although snapping turtles have fierce dispositions,[18] when they are encountered in the water or a swimmer approaches, they will slip quietly away from any disturbance or may seek shelter under mud or grass nearby.[19] However, common snapping turtles can be very aggressive if restrained or approached on land, and have a bite powerful enough to mutilate human fingers.
Captivity[edit]
The common snapping turtle is not an ideal pet. Its neck is very flexible, and a wild turtle can bite its handler even if picked up by the sides of its shell. The claws are about as sharp as those of dogs, but cannot be trimmed as can dog claws. Despite this, a snapping turtle cannot use its claws for either attacking (its legs have no speed or strength in "swiping" motions) or eating (no opposable thumbs), but only as aids for digging and gripping. Veterinary care is best left to a reptile specialist. A wild common snapping turtle will make a hissing sound when it is threatened or encountered; however, when in the water and unprovoked, they are fairly docile towards humans.
It is a common misconception that common snapping turtles may be safely picked up by the tail with no harm to the animal; in fact, this has a high chance of injuring the turtle, especially the tail itself and the vertebral column.[20] Lifting the turtle with the hands is difficult and dangerous. Snappers can stretch their necks back across their own carapace and to their hind feet on either side to bite. When they feel stressed, they release a musky odor from behind their legs.
It may be tempting to rescue a snapping turtle found on a road by getting it to bite a stick and then dragging it out of immediate danger. This action can, however, severely scrape the legs and underside of the turtle and lead to deadly infections in the wounds. The safest way to pick up a common snapping turtle is by grasping the carapace above the back legs. There is a large gap above the back legs that allows for easy grasping of the carapace and keeps hands safe from both the beak and claws of the turtle. It can also be picked up with a shovel, from the back, making sure the shovel is square across the bottom of the shell. The easiest way, though, is with a blanket or tarp, picking up the corners with the turtle in the middle.
Snapping turtles are raised on some turtle farms in China.[21]
Invasive species[edit]
In recent years in Italy, large mature adult C. serpentina turtles have been taken from bodies of water throughout the country. They were most probably introduced by the unwise release of pets. In March 2011, an individual weighing 20 kg (44 lb) was captured in a canal near Rome;[22] another individual was captured near Rome in September 2012.[23] In Japan, the species was introduced as an exotic pet in the 1960s; it has been recorded as the source of serious bite injuries. In 2004 and 2005, some 1000 individuals were found in Chiba Prefecture, making up the majority of individuals believed to have been introduced.[24]
In politics[edit]
Political cartoon depicting merchants attempting to dodge the "Ograbme"
The common snapping turtle was the central feature of a famous American political cartoon. Published in 1808 in protest at the Jeffersonian Embargo Act of 1807, the cartoon depicted a snapping turtle, jaws locked fiercely to an American trader who was attempting to carry a barrel of goods onto a British ship. The trader was seen whimsically uttering the words "Oh! this cursed Ograbme" ("embargo" spelled backwards). This piece is widely considered a pioneering work within the genre of the modern political cartoon.[citation needed]
In 2006, the snapping turtle was declared the state reptile of New York by a sweeping vote of the New York Legislature after being popularly chosen by the state's public elementary school children.[25]
As food[edit]
The common snapping turtle is a traditional ingredient in turtle soup; consumption in large quantities however can become a health concern due to potential concentration of toxic environmental pollutants in the turtle's flesh.[26]
Conservation[edit]
The species is currently classified as Least Concern by the IUCN, but has declined sufficiently due to pressure from collection for the pet trade and habitat degradation that Canada and several U.S. states have enacted or are proposing stricter conservation measures.[1] In Canada, it is listed as 'Special Concern' in the Species at Risk Act in 2011 and is a target species for projects that include surveys, identification of major habitats, investigation and mitigation of threats, and education of the public including landowners. Involved bodies include governmental departments, universities, museums, and citizen science projects.[27]
References[edit]
^ Jump up to: a b van Dijk, P.P. (2012). "Chelydra serpentina ". IUCN Red List of Threatened Species. 2012: e.T163424A97408395. Retrieved 4 December 2017. CS1 maint: Uses authors parameter (link)
Jump up ^ Ernst, C.H. (2008). "Systematics, Taxonomy, and Geographic Distribution of the Snapping Turtles, Family Chelydridae". In A.C. Styermark; M.S. Finkler; R.J. Brooks. Biology of the Snapping Turtle (Chelydra serpentina). Johns Hopkins University Press. pp. 5–13.
Jump up ^ "COSEWIC Assessment and Status Report on the Snapping Turtle Chelydra serpentina" (PDF).
Jump up ^ Wilson, D.E.; Burnie, D., eds. (2001). Animal: The Definitive Visual Guide to the World's Wildlife. London and New York: Dorling Kindersley (DK) Publishing. 624 pp. ISBN 978-0-7894-7764-4.
Jump up ^ Iverson, J.B.; Higgins, H.; Sirulnik, A.; Griffiths, C. (1997). "Local and geographic variation in the reproductive biology of the snapping turtle (Chelydra serpentina)". Herpetologica 53 (1): 96-117.
^ Jump up to: a b c Brooks, R.J.; Brown, G.P.; Galbraith, D.A. (1991). "Effects of a sudden increase in natural mortality of adults on a population of the common snapping turtle (Chelydra serpentina)". Canadian Journal of Zoology 69 (5): 1314-1320.
^ Jump up to: a b Virginia Herpetological Society: Eastern Snapping Turtle Chelydra serpentina serpentina
Jump up ^ Hammer, D.A. (1972). Ecological relations of waterfowl and snapping turtle populations. Ph.D. dissertation, Utah State University, Salt Lake City, UT. 72 pg.
Jump up ^ Ernst, C.H., & Lovich, J. E. (2009). Turtles of the United States and Canada. Baltimore: Johns Hopkins University Press.
Jump up ^ Landler, Lukas; Painter, Michael S.; Youmans, Paul W.; Hopkins, William A.; Phillips, John B. (2015-05-15). "Spontaneous Magnetic Alignment by Yearling Snapping Turtles: Rapid Association of Radio Frequency Dependent Pattern of Magnetic Input with Novel Surroundings". PLOS ONE. 10 (5): e0124728. doi:10.1371/journal.pone.0124728. ISSN 1932-6203. PMC 4433231. PMID 25978736.
Jump up ^ Congdon, Justin D.; Pappas, Michael J.; Krenz, John D.; Brecke, Bruce J.; Schlenner, Meredith (2015-02-27). "Compass Orientation During Dispersal of Freshwater Hatchling Snapping Turtles (Chelydra serpentina) and Blanding's Turtles (Emydoidea blandingii)". Ethology. 121 (6): 538–547. doi:10.1111/eth.12366. ISSN 0179-1613.
Jump up ^ US Army Corps of Engineers, Engineer Research and Development Center, Environmental Laboratory: Common Snapping Turtle (Chelydra serpentina)
Jump up ^ Edqvist, ULf. "Tortoise Trust Web - Conservation and Ecology of Snapping Turtles". www.tortoisetrust.org. Retrieved 3 April 2018.
Jump up ^ COSEWIC. "Species Profile - Snapping Turtle". Species At Risk Public Registry. Government of Canada. Retrieved 24 February 2012.
^ Jump up to: a b Rhodin, Anders G.J.; van Dijk, Peter Paul; Iverson, John B.; Shaffer, H. Bradley (2010-12-14). Turtles of the world, 2010 update: Annotated checklist of taxonomy, synonymy, distribution and conservation status (PDF). Chelonian Research Monographs. 5. p. 000.xx. doi:10.3854/crm.5.000.checklist.v3.2010. ISBN 978-0965354097. Archived from the original (PDF) on 2010-12-15.
Jump up ^ van Dijk, P.P.; Lee, J.; Calderón Mandujano, R.; Flores-Villela, O.; Lopez-Luna, M.A.; Vogt, R.C. (2007). "Chelydra rossignoni". IUCN Red List of Threatened Species. Version 2008. International Union for Conservation of Nature. Retrieved 2009-05-04.
Jump up ^ Chelydra, Reptile Database
Jump up ^ Snapping Turtle, Encyclopedia.com
Jump up ^ Common Snapping Turtle, Nature.ca
Jump up ^ Indiviglio, Frank (2008-06-24). "Handling Snapping Turtles, Chelydra serpentina, and Other Large Turtles". That Reptile Blog. That Pet Place. Retrieved 2008-07-20.
Jump up ^ Fang Anning (方安宁), "“小庭院”养殖龟鳖大有赚头" (Small-scale turtle farming may be very profitable). Zuojiang Daily (左江日报) (with photo)
Jump up ^ "Una "azzanatrice" catturata fuori Roma". (March 17, 2011). Corriere della Sera. Milan.
Jump up ^ "Tartaruga azzannatrice presa nel Tevere - Photostory Curiosità - ANSA.it". www.ansa.it. Retrieved 3 April 2018.
Jump up ^ Desaki, Yotaro (5 August 2014). "Invasive snapping turtles on the rise in Chiba, other areas". thejapantimes news. Retrieved 15 May 2017.
Jump up ^ Medina, Jennifer (2006-06-23). "A Few Things Lawmakers Can Agree On". N.Y./Region. New York Times. Retrieved 2008-07-20.
Jump up ^ "Common Snapping Turtle: Interesting Facts". Department of Energy and Environmental Protection, State of Connecticut. DEEP (ct.gov). 8 November 2016. Retrieved 7 October 2017.
Jump up ^ Environment and Climate Change Canada (2016). Management Plan for the Snapping Turtle (Chelydra serpentina) in Canada [Proposed] (PDF). Species at Risk Act Management Plan Series. Ottawa: Ottawa, Environment and Climate Change Canada.
External links[edit]
Wikispecies has information related to Chelydra serpentina
Wikimedia Commons has media related to Chelydra serpentina.
The Snapping Turtle Page - www.chelydra.org
Video: How to Help a Snapping Turtle Cross a Road, Toronto Zoo
Snapping Turtle, Reptiles and Amphibians of Iowa
Further reading[edit]
Behler JL, King FW (1979). The Audubon Society Field Guide to North American Reptiles and Amphibians. New York: Alfred A. Knopf. 743 pp. ISBN 0-394-50824-6. (Chelydra serpentina, pp. 435–436 + Plates 322-324).
Conant R (1975). A Field Guide to Reptiles and Amphibians of Eastern and Central North America, Second Edition. Boston: Houghton Mifflin Company. xviii + 429 pp. + Plates 1-48. ISBN 0-395-19979-4 (hardcover), ISBN 0-395-19977-8 (paperback). (Chelydra serpentina, pp. 37–38 + Plates 5, 11 + Map3).
Goin CJ, Goin OB, Zug GR (1978). Introduction to Herpetology, Third Edition. San Francisco: W.H. Freeman and Company. xi + 378 pp. ISBN 0-7167-0020-4. (Chelydra serpentina, pp. 122, 142, 258).
Linnaeus C (1758). Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, diferentiis, synonymis, locis. Tomus I. Editio Decima, Reformata. Stockholm: L. Salvius. 824 pp. (Testudo serpentina, new species, p. 199). (in Latin).
Smith HM, Brodie ED Jr (1982). Reptiles of North America: A Guide to Field Identification. New York: Golden Press. 240 pp. ISBN 0-307-13666-3. (Chelydra serpentina, pp. 38–39).
Zim HS, Smith HM (1956). Reptiles and Amphibians: A Guide to Familiar American Species: A Golden Nature Guide. New York: Simon and Schuster. 160 pp. (Chelydra serpentina, pp. 19, 24, 155).
show
v
t
e
Turtle family Chelydridae
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Family: Chelydridae
Genus
Species of the family Chelydridae
Chelydra
Central American snapping turtle
Common snapping turtle
South American snapping turtle
Macrochelys
Alligator snapping turtle
Apalachicola snapping turtle
Suwannee snapping turtle
show
v
t
e
Extant turtle taxonomy
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Subclass: Anapsida
Order: Chelonii or Testudines
Suborder
Superfamily
Family
Subfamily
Genus
Cryptodira
Chelydridae
Chelydra
Macrochelys
Chelonioidea
Cheloniidae
Carettinae
Caretta
Lepidochelys
Cheloniinae
Chelonia
Eretmochelys
Natator
Dermochelyidae
Dermochelys
Kinosternoidea
Dermatemydidae
Dermatemys
Kinosternidae
Kinosterninae
Kinosternon
Sternotherus
Staurotypinae
Claudius
Staurotypus
Testudinoidea
Emydidae
Deirochelyinae
Chrysemys
Deirochelys
Graptemys
Malaclemys
Pseudemys
Trachemys
Emydinae
Clemmys
Emys
Glyptemys
Terrapene
Geoemydidae
Geoemydinae
Batagur
Cuora
Cyclemys
Geoclemys
Geoemyda
Hardella
Heosemys
Leucocephalon
Malayemys
Mauremys
Melanochelys
Morenia
Notochelys
Orlitia
Pangshura
Sacalia
Siebenrockiella
Vijayachelys
Rhinoclemmydinae
Rhinoclemmys
Platysternidae
Platysternon
Testudinidae
Aldabrachelys
Astrochelys
Chelonoidis
Chersina
Cylindraspis
Geochelone
Gopherus
Homopus
Indotestudo
Kinixys
Malacochersus
Manouria
Psammobates
Pyxis
Stigmochelys
Testudo
Trionychia
Carettochelyidae
Carettochelys
Trionychidae
Cyclanorbinae
Cyclanorbis
Cycloderma
Lissemys
Trionychinae
Amyda
Apalone
Chitra
Dogania
Nilssonia
Palea
Pelochelys
Pelodiscus
Rafetus
Trionyx
Pleurodira
Chelidae
Chelinae
Acanthochelys
Chelus
Mesoclemmys
Phrynops
Platemys
Rhinemys
Chelodininae
Chelodina
Elseya
Elusor
Emydura
Flaviemys
Myuchelys
Pseudemydura
Rheodytes
Hydromedusinae
Hydromedusa
Pelomedusidae
Pelomedusa
Pelusios
Podocnemididae
Erymnochelys
Peltocephalus
Podocnemis
Phylogenetic arrangement based on turtles of the world 2012 update: annotated checklist. Extinct turtles not included.
Portal Book See also List of Testudines families
Taxon identifiers
Wikidata: Q289435
Wikispecies: Chelydra serpentina
ADW: Chelydra_serpentina
ARKive: chelydra-serpentina
EoL: 795409
EPPO: KHELSE
Fossilworks: 105357
GBIF: 2441905
iNaturalist: 39682
IRMNG: 11043640
ITIS: 173752
IUCN: 163424
NBN: NHMSYS0000080223
NCBI: 8475
Species+: 67966
Retrieved from "https://en.wikipedia.org/w/index.php?title=Common_snapping_turtle&oldid=866342506"
Categories:
IUCN Red List least concern species
Invasive reptile species
Chelydra
Turtles of North America
Fauna of the Great Lakes region (North America)
Reptiles of the United States
Reptiles of Ontario
Living fossils
Reptiles described in 1758
Hidden categories:
CS1 maint: Uses authors parameter
Articles with 'species' microformats
All articles with unsourced statements
Articles with unsourced statements from February 2010
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Article
Talk
Variants
Views
Read
Edit
View history
More
Search
Navigation
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
In other projects
Wikimedia Commons
Wikispecies
Languages
العربية
Български
Català
Cebuano
Čeština
Deutsch
Español
Esperanto
Euskara
فارسی
Français
한국어
Hrvatski
Italiano
עברית
Lietuvių
Magyar
Nederlands
日本語
پنجابی
Polski
Português
Русский
Slovenčina
Suomi
Svenska
Tsetsêhestâhese
Українська
Tiếng Việt
Winaray
粵語
中文
23 more
Edit links
This page was last edited on 29 October 2018, at 19:40 (UTC).
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
Contact Wikipedia
Developers
Cookie statement
Mobile view
Enable previews

values: mw-page-base noprint

values: mw-head-base noprint

values: firstHeading firstHeading en

values: siteSub noprint

values: mw-jump-link #mw-head

values: mw-jump-link #p-search

value: p

attrs: colspan style

value: img

attrs: href class

values:
/wiki/Least_Concern
mw-redirect
Least Concern

attrs: alt src width height data-file-width data-file-height

values: font-size:smaller; float:right; padding-right:0.4em; margin-left:-3em;

values: min-width:15em; text-align: center; background-color: rgb(235,235,210)

values: text-align: left; width: 200px; font-size: 100%

values: checkbox button toctogglecheckbox toctogglecheckbox display:none

values:
/wiki/Northern_river_otter
mw-redirect
Northern river otter

values:
/wiki/Egg_(biology)
mw-redirect
Egg (biology)

values:
/wiki/Chelydra_rossignonii
mw-redirect
Chelydra rossignonii

values:
/wiki/Chelydra_acutirostris
mw-redirect
Chelydra acutirostris

values:
/wiki/Turtle_farm
mw-redirect
Turtle farm

values:
/wiki/Political_cartoon
mw-redirect
Political cartoon

values: This claim needs references to reliable sources. (February 2010)

values:
noprint Inline-Template Template-Fact
white-space:nowrap;

values:
/wiki/New_York_Legislature
mw-redirect
New York Legislature

values: Category:CS1 maint: Uses authors parameter

values:
nofollow
external text
//www.worldcat.org/issn/1932-6203

values:
/wiki/PubMed_Identifier
mw-redirect
PubMed Identifier

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/25978736

values:
nofollow
external text
//doi.org/10.1111%2Feth.12366

values:
nofollow
external text
//www.worldcat.org/issn/0179-1613

values: International Union for Conservation of Nature

values: -moz-column-width: 30em; -webkit-column-width: 30em; column-width: 30em; list-style-type: decimal;

values:
nofollow
external text
http://www.chelydra.org

values:
/wiki/Herbert_S._Zim
mw-redirect
Herbert S. Zim

values:
*_Kingdom:_Animalia_
*_Phylum:_Chordata_
*_Class:_Reptilia_
*_Order:_Testudines_
*_Suborder:_Cryptodira_
*_Family:_Chelydridae

values: nowraplinks hlist collapsible autocollapse navbox-inner mw-collapsible mw-made-collapsible mw-collapsed

values:
*_Kingdom:_Animalia
*_Phylum:_Chordata
*_Class:_Reptilia
*_Subclass:_Anapsida
*_Order:_Chelonii_or_Testudines

values:
/wiki/Suborder_(biology)
mw-redirect
Suborder (biology)

values:
/wiki/Superfamily_(zoology)
mw-redirect
Superfamily (zoology)

values: Dermatemydidae row navbox-group width:10em

attrs: alt src title width height srcset data-file-width data-file-height

values: nowraplinks hlist collapsible collapsed navbox-inner mw-collapsible mw-collapsed mw-made-collapsible

values:
Taxon_identifiers
row
navbox-group
width:1%;text-align: left;

values:
nofollow
external text
http://eol.org/pages/795409/overview

values:
nofollow
external text
https://gd.eppo.int/taxon/KHELSE

values: Global Biodiversity Information Facility

values:
nofollow
external text
https://www.gbif.org/species/2441905

values:
nofollow
external text
https://www.inaturalist.org/taxa/39682

values: National Center for Biotechnology Information

values: Category:IUCN Red List least concern species

values: Category:Fauna of the Great Lakes region (North America)

values: Category:Articles with 'species' microformats

values: Category:All articles with unsourced statements

values: Category:Articles with unsourced statements from February 2010

values: Discussion about edits from this IP address [ctrl-alt-n]

values: A list of edits made from this IP address [ctrl-alt-y]

values: You are encouraged to create an account and log in; however, it is not mandatory

values: You're encouraged to log in; however, it's not mandatory. [ctrl-alt-o]

values:
/wiki/Common_snapping_turtle
View the content page [ctrl-alt-c]
c

values: Discussion about the content page [ctrl-alt-t]

values: p-namespaces navigation vectorTabs p-namespaces-label

values:
p-variants
navigation
vectorMenu emptyPortlet
p-variants-label

values: Past revisions of this page [ctrl-alt-h]

values: p-views navigation vectorTabs p-views-label

values:
p-cactions
navigation
vectorMenu emptyPortlet
p-cactions-label

values:
mw-wiki-logo
/wiki/Main_Page
Visit the main page

values:
/wiki/Main_Page
Visit the main page [ctrl-alt-z]
z

values: Featured content – the best of Wikipedia

values: Find background information on current events

values:
/wiki/Special:Random
Load a random article [ctrl-alt-x]
x

values: portal navigation p-navigation p-navigation-label

values: Guidance on how to use and edit Wikipedia

values: About the project, what you can do, where to find things

values: A list of recent changes in the wiki [ctrl-alt-r]

values: portal navigation p-interaction p-interaction-label

values: List of all English Wikipedia pages containing links to this page [ctrl-alt-j]

values: Recent changes in pages linked from this page [ctrl-alt-k]

values:
/wiki/Wikipedia:File_Upload_Wizard
Upload files [ctrl-alt-u]
u

values: A list of all special pages [ctrl-alt-q]

values: Permanent link to this revision of the page

values: Link to connected data repository item [ctrl-alt-g]

values: Printable version of this page [ctrl-alt-p]

values: portal navigation p-wikibase-otherprojects p-wikibase-otherprojects-label

values: سلحفاة نهاشة شائعة – Arabic

values: Кайманова костенурка – Bulgarian

values:
interlanguage-link interwiki-bg
display: none;

values:
interlanguage-link interwiki-ca
display: none;

values:
interlanguage-link interwiki-ceb
display: none;

values:
interlanguage-link interwiki-cs
display: none;

values:
interlanguage-link interwiki-eo
display: none;

values:
interlanguage-link interwiki-eu
display: none;

values: لاک‌پشت گازگیر معمولی – Persian

values:
interlanguage-link interwiki-fa
display: none;

values:
interlanguage-link interwiki-ko
display: none;

values:
interlanguage-link interwiki-it
display: none;

values: צב נשכן מצוי – Hebrew

values:
interlanguage-link interwiki-he
display: none;

values:
interlanguage-link interwiki-lt
display: none;

values:
interlanguage-link interwiki-hu
display: none;

values: Каймановая черепаха – Russian

values:
interlanguage-link interwiki-sk
display: none;

values:
interlanguage-link interwiki-fi
display: none;

values:
interlanguage-link interwiki-sv
display: none;

values:
interlanguage-link interwiki-chy
display: none;

values: Кайманова черепаха – Ukrainian

values:
interlanguage-link interwiki-uk
display: none;

values:
interlanguage-link interwiki-vi
display: none;

values:
interlanguage-link interwiki-war
display: none;

values:
interlanguage-link interwiki-zh-yue
display: none;

values: All languages (initial selection from common choices by you and others)

values: /static/images/wikimedia-button-1.5x.png 1.5x, /static/images/wikimedia-button-2x.png 2x

values: /static/images/poweredby_mediawiki_132x47.png 1.5x, /static/images/poweredby_mediawiki_176x62.png 2x

values:
suggestions
display: none; font-size: 13px;

values: mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-Common_snapping_turtle rootpage-Common_snapping_turtle skin-vector action-view