G-code is the language CNC machines use to operate, and understanding its most common commands is essential for beginners and seasoned machinists alike. These commands control the machine’s movements, functions, and tool actions. Let’s dive into 20 of the most frequently used G-code commands, what they do, and why they’re important.
1. G00 – Rapid Positioning
This command moves the tool quickly to a specified position without cutting. It’s used to save time when moving the tool across the workpiece.
Example:
G00 X10 Y20Moves the tool to X=10, Y=20 as fast as possible.
2. G01 – Linear Interpolation
Used for straight-line cutting at a specified feed rate.
Example:
G01 X10 Y10 F100Moves the tool to X=10, Y=10 at a feed rate of 100 units per minute.
3. G02 – Circular Interpolation (Clockwise)
Cuts a circular path in a clockwise direction.
Example:
G02 X20 Y20 I10 J0Cuts a clockwise arc to X=20, Y=20 with a center offset of I=10, J=0.
4. G03 – Circular Interpolation (Counterclockwise)
Cuts a circular path in a counterclockwise direction.
Example:
G03 X20 Y20 I10 J0Cuts a counterclockwise arc to X=20, Y=20 with a center offset of I=10, J=0.
5. G20 – Set Units to Inches
Sets the machine to use inches as the unit of measurement.
Example:
G20Switches to inch mode.
6. G21 – Set Units to Millimeters
Sets the machine to use millimeters as the unit of measurement.
Example:
G21Switches to millimeter mode.
7. G28 – Return to Home Position
Sends the tool to the machine’s predefined home position.
Example:
G28Moves the tool to the home position.
8. G90 – Absolute Positioning
Specifies that all coordinates are absolute, relative to the origin.
Example:
G90Ensures coordinates refer to the origin.
9. G91 – Incremental Positioning
Specifies that all coordinates are incremental, relative to the current position.
Example:
G91Switches to incremental mode.
10. G40 – Cancel Tool Radius Compensation
Disables any tool radius compensation that was previously applied.
Example:
G40Turns off tool radius compensation.
11. G41 – Tool Radius Compensation Left
Offsets the tool to the left of the programmed path to account for its radius.
Example:
G41 D1Activates left compensation using tool diameter 1.
12. G42 – Tool Radius Compensation Right
Offsets the tool to the right of the programmed path to account for its radius.
Example:
G42 D1Activates right compensation using tool diameter 1.
13. G17 – Select XY Plane
Specifies that cutting will take place in the XY plane.
Example:
G17Cuts are made in the XY plane.
14. G18 – Select ZX Plane
Specifies that cutting will take place in the ZX plane.
Example:
G18Cuts are made in the ZX plane.
15. G19 – Select YZ Plane
Specifies that cutting will take place in the YZ plane.
Example:
G19Cuts are made in the YZ plane.
16. G43 – Apply Tool Length Compensation
Adjusts for the length of the tool to ensure accurate machining.
Example:
G43 H1Applies tool length offset for tool number 1.
17. G49 – Cancel Tool Length Compensation
Disables any tool length compensation that was previously applied.
Example:
G49Turns off tool length compensation.
18. M03 – Spindle On (Clockwise)
Turns the spindle on in a clockwise direction.
Example:
M03Starts the spindle spinning clockwise.
19. M05 – Spindle Stop
Turns the spindle off.
Example:
M05Stops the spindle.
20. M06 – Tool Change
Initiates a tool change.
Example:
M06 T2Changes to tool number 2.
360 Key Takeaways
- G-code commands control every aspect of CNC machine operation, from movement to tool changes.
- Basic commands like G00, G01, and M03 are essential for getting started.
- Understanding G-code allows you to troubleshoot and customize programs for specific projects.
- Practice and experimentation are key to mastering G-code programming.
Conclusion
Learning G-code commands might seem challenging at first, but it’s a crucial step in becoming a confident CNC operator. Start by familiarizing yourself with these 20 common commands, and you’ll have a solid foundation to tackle more complex projects. Remember, practice makes perfect, so don’t hesitate to experiment and learn by doing.