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What do the program letters mean in CNC machining?

Jun 12, 2019

1. The meaning of the letters in the NC program

O: program number, set the program number

N: block number, set the program sequence number

G: Preparation function

X/Y/Z: size characters, axis movement instructions

A/B/C/U/V/W: additional axis movement command

R: arc radius

I/J/K: arc center coordinates (vector)

F: Feed, set the feed rate

S: spindle speed, set the spindle speed

T: tool function, set the tool number

M: Auxiliary function, on/off control function

H/D: tool offset number, set the tool offset number

P/X: Delay, set delay time

P: Program number command, set subprogram number (such as subroutine call: M98P1000)

L: Repeat, set the number of subroutines or fixed cycle repetitions (eg M98 P1000 L2, omitting L for L1)

P/W/R/Q: parameters, parameters used in the fixed cycle (eg: tapping G98/(G99)G84 X_ Y_ R_ Z_ P_ F_)

2. Common G code interpretation

G00: Positioning or fast moving

G01: Linear interpolation

G02: circular interpolation / helical interpolation CW

G03: Circular interpolation / spiral interpolation CCW

G04: dwell time or delay time

Such as: G04 X1000 (or G04 X1.0)

G04 P1000 means stay for 1 second

G09: Stop accurately or stop the inspection accurately (check if it is within the target range)

G10: Programmable data input

G17: Select XPYP plane XP: X axis or its parallel axis

G18: Select ZPXP plane YP: Y axis or its parallel axis

G19: Select YPZP plane ZP: Z axis or its parallel axis

G20: inch input

G21: mm input

G28: Return to reference point detection

Format: G91/(G90) G28 X__ Y__ Z__

Return to the reference point via the intermediate point X__ Y__ Z__ (absolute value / incremental value command)

G29: Return from the reference point

G91/(G90) G29 X__ Y__ Z__

An instruction to return to the target point X__ Y__ Z__ from the starting point through the reference point (absolute value/incremental value command)

G30 returns to the 2nd, 3rd, 4th reference point

G91/(G90) G30 P2 X__ Y__ Z__; return to the 2nd reference point

G91/(G90) G30 P3 X__ Y__ Z__; return to the 3rd reference point

G91/(G90) G30 P4 X__ Y__ Z__; return to the 4th reference point

X__ Y__ Z__: After the intermediate point position (absolute value / incremental value command)

G40: Tool radius compensation canceled

G41: Left tool radius compensation (tool is on the left along the feed direction)

G42: Right tool radius compensation (tool is on the right along the feed direction)

G43: Tool length compensation + direction

G44: Tool length compensation - direction

G49: Cancel tool length compensation

G50: Unscaled

G51: Scaling, format:

ON G51 X_ Y_ Z_ P_;

OFF G50

X_ Y_ Z_: Set the zoom center position

P: scaling, the range is 1-999999, can not be a decimal, if P800 represents a scaling of 0.8

G52: Setting the local coordinate system

G53: Select machine coordinate system

G54-G59: Select workpiece coordinate system 1-6

G60: Single direction positioning, eliminating the transmission gap (instead of G00), passing the target position and then returning to the target position

G61: Quasi-stop check mode, decelerate when the cutting feed approaches the target position and check the position tolerance range

G62: Automatic corner override

G63: Tapping method

G64: Normal cutting mode, the cutting feed does not decelerate when approaching the target position, and the cutting section does not decelerate between the segments.

G65: Macro program call

G66: Macro program modal call

G67: Macro program modal call canceled

G68: coordinate rotation, format:

G17: G68 X_ Y_ R_

G18: G68 X_ Z_ R_

G19: G68 Y_ Z_ R_

G69 coordinate rotation canceled

G73: Multi-stage drilling cycle

G74: Attacking the left-hand thread cycle

G76: fine boring cycle (directional eccentric retraction)

G80: Cancel the canned cycle

G81: Single stage drilling cycle

G82: Single-stage drilling cycle (to achieve bottom hole stop or delay)

G83: Multi-stage drilling cycle

G84: Attack right-hand thread

G85: boring cycle

G86: boring cycle

G87: ruminant cycle

G88: boring cycle

G89: boring cycle

G90: Absolute instruction

G91: Relative instructions

G92: Setting the workpiece coordinate system

G98: Return to the starting point when the fixed cycle is back

G99: Retraction point when the fixed cycle is retracted (R point is set in the canned cycle)

3. Common M code explanation

M00: The program stops unconditionally

M01: Program condition stops

M02: End of program

M03: Spindle forward rotation

M04: Spindle reversal

M05: Spindle stop

M08: open outside cold

M09: Turn off all cooling

M26: open inside cold

M30: The program ends and returns to the beginning of the program

M84: Check tray 1

M95: Check tray 2

M98: Calling a subroutine

M99 : Return to the main program

M135: Rigid tapping

M417: Machine tray 1 inspection

M418: Machine tray 2 inspection

M419: Machine tray check is over

M433: Tool Broken Tool Detection

M462: tray number transmission

4. Common arithmetic

Addition: #i=#j+#k

Subtraction: #i=#j-#k

Multiplication: #i=#j*#k

Division: #i=#j/#k

Sine: #i=SIN[#j]

Arcsine: #i=ASIN[#j]

Cosine: #i=COS[#j]

Inverse cosine: #i=ACOS[#j]

Tangent: #i=TAN[#j]

Anyway cut: #i=ATAN[#j]

Square root: #i=SQRT[#j]

Absolute value: #i=ABS[#j]

Rounding: #i=ROUND[#j]

Round up: #i=FIX[#j]

Take down: #i=FUP[#j]

Natural logarithm: #i=LN[#j]

Exponential function: #i=EXP[#j]

Or: #i=#jOR#k

XOR: #i=#jXOR#k

With: #i=#AND#k

Convert from BCD to BIN: #i=BIN[#j]

Convert from BIN to BCD: #i=BCD[#j]

5. Logical operators

EQ: equal

NE: Not equal

GT: greater than

GE: less than or equal to

LT: less than

6. Program transfer and loop

Unconditional transfer: GOTO

Conditional transfer: IF [conditional expression]

IF [conditional expression] GOTO n, if the condition is satisfied, jump to block n

IF [conditional expression] THEN, such as: IF [#I=#J] THEN #K=0

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