What does the command “M03” mean in a G-code program?

The command “M03” in a G-code program specifically instructs the CNC machine to start the spindle rotation in a clockwise direction. This command is essential for operations that require the spindle to be actively cutting material. When M03 is called, it activates the spindle motor and sets its rotation direction, which is critical for tasks such as milling or drilling, where the cutting tool needs to engage with the workpiece.

Understanding this command is vital for safe and proper machining operations, as it ensures that the spindle is ready for cutting before any movement commands are executed. Familiarity with spindle commands like M03 allows operators to sequence operations effectively, ensuring that the machine is configured correctly for the intended task.