What does “M05” signify in G-code?

The code "M05" in G-code is specifically used to stop the spindle from rotating. This command is crucial in CNC machining as it allows the operator to safely interrupt the spindle movement, which is necessary when changing tools or performing maintenance on the machine. When using M05, the command ensures that the spindle comes to a complete stop before any further actions, such as tool changes or movements, take place. Understanding this function is fundamental as it relates directly to the safe operation of CNC milling machines and contributes to the overall efficiency of machining processes.