1. The code which controls the CNC machine.
CNC Programming
The code which controls the CNC machine.

2. CNC Programming
NC Code
Sample NC Part and Program
M Codes
G Code

3. NC Code Components
Lines of NC code contain instructions for the machine to follow.
Some of the instructions
prepare the machine
tell the machine where to send the tool
and control accessories on the machine.

4. NC Code Components Block Number (N) Preparatory Codes (G)
Is the line number within the program
Preparatory Codes (G)
Prepare the machine to perform an operation
Miscellaneous Codes (M)
Perform miscellaneous functions within the program

5. NC Code Components Primary X Motion (X)
Instructs the machine to move the tool to this X coordinate.
Primary Y Motion (Y)
Instructs the machine to move the tool to this Y coordinate.
Primary Z Motion (Z)
Instructs the machine to move the tool to this Z coordinate.

6. NC Code Components Circle Center X (I)
the X coordinate of the circle center for circular interpolation.
Circle Center Y (J)
the Y coordinate of the circle center for circular interpolation.

7. Preparatory: G-Codes
G90 - Absolute Coordinates – makes all coordinates relative to the origin
G91 – Incremental Coordinates – makes new coordinates relative to the last point.
G00 - Rapid Traverse (non-cutting move) – move the tool at the maximum rate of feed

8. Preparatory: G-Codes
G01 - Straight Line Interpolation – move the tool in a straight line to the desired coordinates
G02 - Circular Interpolation CW – move the tool in a clockwise direction through an arc
G03 – Circular Interpolation CCW – move the tool in a counter-clockwise direction through an arc

9. Preparatory: G-Codes
G04 - Dwell (wait) Pause between motions on all axis. Time in seconds - G04F2 - pause for 2 sec.
G05 - Pause - waits for user intervention.

10. Miscellaneous: M Codes
M02 - End of Program
M03 - Spindle on [speed to follow (e.g. S3000)]
M05 - Spindle off
M08/M09 Accessory 1 on/off
M10/M11 Accessory 2 on/off

11. Sample NC Program Block
N00 G90
BLOCK SEQUENCE #
PREP CODE – ABSOLUTE COORDINATES

12. Sample NC Program Block
N01 G01
PREP CODE – S.L. INTERPOLATION

13. Sample NC Program Block
N02 X.5 Y.5 Z0 F1
X COORDINATE
Y COORDINATE
Z COORDINATE
FEED RATE (IN/MIN)

14. SAMPLE PART ABSOLUTE COORD. A 0.5 0.5 B 0.5 1.5 C 0.875 1 D 1.25 1.5 E B C D E F H I
1.75 1

15. SAMPLE PROGRAM N00 G90 ;ABSOLUTE COORDINTAES
N01 G01 ;STRAIGHT LINE INTERPOLATION
N02 T1M06 ;LOAD TOOL 1
N03 M03 S3000 ;TURN SPINDLE ON TO 3000 RPM
N04 G00 X.5Y.5 ;RAPID TO POINT A
N05 G00 Z .1 ;RAPID TO .1 ABOVE PART
N06 Z-.0625F9 ;PLUNGE AT 9 IN/MIN.
N07 X.5Y1.5 ;MOVE TO B
N08 X.875Y1 ;MOVE TO C
N09 X1.25Y1.5 ;MOVE TO D
N10 X1.25Y.5 ;MOVE TO E
N11 Z.1 ;RETRACT CUTTING TOOL

16. Sample Program Continued
N12 G00 X1.75Y1.5 ;RAPID TO POINT F
N13 Z-.0625F9 ;PLUNGE AT 9 IN/MIN.
N14 X1.75Y.5 ;MOVE TO H
N15
N16 G03 X1.75Y1.5I1.75J1 ;CCW CIRCLE INTER.
;CUT THE ARC TO X1.75Y1.5
;WITH CIR CENTER AT X1.75Y1
N17 G01Z.1 ;RETRACT CUTTING TOOL
N18 M05 ;TURN OFF SPINDLE
N19 T00M06 ;UNLOAD CUTTING TOOL
N20 M02 ;END OF PROGRAM