040

Review the alarm line number and examine the programmed geometry at that block and the preceding 3-5 blocks.

Check the tool offset register (geometry or wear) being used and verify the total radius value against the smallest features in the programmed path.

Reduce the tool radius value in the offset register or modify the program to use a smaller tool if the current tool is physically too large.

If geometry cannot be changed, add intermediate points or increase radii in the part program to accommodate the tool radius.

Ensure part print tolerances are maintained when modifying programmed geometry

Locate the G41 or G42 activation block in the program at or before the alarm line number.

Verify that the G41/G42 block contains a G00 or G01 linear move (not G02/G03 arc) and that the move distance exceeds the tool radius value.

If necessary, add a longer linear approach move before the first compensated contour move, ensuring the distance is greater than the tool radius.

Check the G40 cancellation move uses a similar linear exit move of sufficient length before compensation is cancelled.

Never activate or cancel cutter compensation on an arc move

Identify sharp inside corners or acute angles in the programmed path near the alarm line, particularly angles less than 90 degrees.

Use EDIT or graphical simulation mode to verify the compensated tool path at the suspect geometry.

Ensure machine is in EDIT mode, not AUTO, when reviewing program

Modify the program to add a small radius or chamfer at sharp inside corners, or insert an intermediate point to break the acute angle.

Alternatively, check parameter 5006 (interference check type) settings - some Fanuc controls allow type B or C checking which may handle certain acute angles differently.

Changing interference parameters may affect all programs; consult machine builder documentation