How does the 'feed hold' function affect the CNC program execution, and when is it appropriate to use it?

The 'feed hold' function on a CNC machine temporarily pauses the execution of the CNC program, stopping all axis movements. When the feed hold button is pressed, the machine decelerates to a controlled stop, and the program execution is suspended at the current block. The spindle typically continues to rotate, and coolant flow may continue, depending on the machine's configuration. Pressing the cycle start button after activating feed hold resumes the program execution from the point where it was paused. The feed hold function is appropriate to use in several situations. First, it is used for inspection. To visually inspect the workpiece or the cutting tool during the machining process. This allows the operator to check for any problems, such as excessive tool wear or chip buildup, without stopping the program entirely. Second, it is used for adjustments. To make minor adjustments to the cutting parameters, such as the feedrate or spindle speed, during the machining process. This allows the operator to optimize the cutting conditions for improved performance. Third, it is used to avoid collisions. To stop the machine quickly if a potential collision is detected. This gives the operator time to assess the situation and take corrective action. Fourth, it is used for troubleshooting. To stop the machine to investigate a potential problem, such as an unusual noise or vibration. This allows the operator to diagnose the problem and take corrective action before it causes further damage. Feed hold should not be used in situations where stopping the machine abruptly could damage the workpiece or the cutting tool. For example, stopping in the middle of a threading operation could damage the threads. Also, feed hold is not a replacement for the emergency stop button. The emergency stop button should be used in situations where there is an immediate danger to personnel or equipment.