OT0500

Release Overtravel

Hold the overtravel release button (if equipped) and jog the affected axis in the negative direction using the manual jog mode until the alarm clears.

Move slowly to avoid overshooting in the opposite direction.

Ensure no personnel or tools are in the machine's path while jogging.

Review Active Program

Access the CNC control panel, navigate to the active program, and inspect the G-code for any commands that move the axis beyond the positive limit. Look for absolute positioning (G90) or incorrect incremental moves (G91).

Use the simulation mode if available to visualize the tool path without moving the machine.

Do not edit programs without proper documentation to avoid unintended consequences.

Test with Dry Run

Run the program in dry run mode (without cutting) at a reduced feed rate to observe if the axis approaches the limit again. Adjust the program coordinates if necessary.

Set a temporary soft limit in the parameters to prevent recurrence during testing.

Ensure the workpiece and tools are clear during dry run to prevent accidental damage.

Release Overtravel

Hold the overtravel release button and jog the axis in the negative direction to clear the limit switch and reset the alarm.

Note the current position display to understand how far past the limit the axis traveled.

Keep hands clear of moving parts while jogging the axis.

Check Work Offset Values

Navigate to the offset screen on the CNC control and verify the values for the active work offset (e.g., G54). Compare them to the setup sheet or intended workpiece zero point.

Document the current offset values before making changes for easy rollback if needed.

Incorrect offset adjustments can lead to crashes; double-check calculations.

Verify Tool Length Offsets

Inspect the tool offset table for the active tool to ensure the length compensation is correct. Re-measure the tool if necessary using a tool setter or manual method.

Use a consistent reference point for tool measurement to avoid discrepancies.

Ensure the machine is in a safe state before accessing tools or setters.

Release Overtravel

Press and hold the overtravel release button while jogging the axis in the negative direction to move it away from the limit switch.

Listen for the click of the limit switch disengaging as you jog away.

Avoid excessive force on the axis to prevent mechanical damage.

Inspect Limit Switch

Locate the positive overtravel limit switch for the affected axis (refer to machine manual for exact location). Check for physical damage, debris, or misalignment that could cause false triggering.

Use compressed air to clean around the switch if debris is present.

Power down the machine before inspecting hardware to avoid electrical hazards.

Test Switch Functionality

Use a multimeter to test the continuity of the limit switch in both engaged and disengaged positions. Alternatively, monitor the input status on the CNC diagnostic screen while manually actuating the switch.

Replace the switch if it shows inconsistent readings or fails to respond.

Ensure proper lockout/tagout procedures are followed during testing.

Release Overtravel

Hold the overtravel release button and jog the axis in the negative direction to clear the alarm and move away from the limit.

Record the current position before moving to compare with expected values.

Ensure the workspace is clear of obstructions before jogging.

Re-Home the Machine

Initiate the homing sequence for all axes as per the machine manual to reset the reference position. Observe if the affected axis homes correctly without triggering the alarm.

Check for smooth motion during homing; jerky movement may indicate encoder issues.

Do not interrupt the homing sequence as it may cause further misalignment.

Verify Home Position Parameters

Access the machine parameters related to home position or reference point (consult the FANUC parameter manual). Compare the stored values with factory settings or previous backups.

Save a backup of current parameters before making changes.

Incorrect parameter changes can disable machine functions; proceed with caution.

Release Overtravel

Hold the overtravel release button and carefully jog the axis in the negative direction to move it away from the limit switch.

Move in small increments to detect any resistance or unusual noise.

Stop immediately if significant resistance is felt to avoid motor damage.

Inspect Axis for Obstructions

Visually inspect the axis travel path, including ways, ball screws, and guides, for debris, tools, or material buildup that could obstruct movement.

Use a flashlight to check hard-to-see areas along the axis path.

Power down the machine and follow lockout/tagout procedures before inspection.

Check for Binding or Wear

Manually move the axis (if possible) or jog at low speed to feel for binding or uneven resistance. Inspect linear guides and ball screws for wear or lack of lubrication.

Apply manufacturer-recommended lubricant if guides appear dry, but avoid over-lubrication.

Do not force movement if binding is severe; consult a technician for disassembly.