283

Review the program before the alarm line and verify G17, G18, or G19 is active before G41/G42 is commanded.

Check that the compensation move contains motion in both axes of the selected plane (e.g., G17 requires X and/or Y movement, not just Z).

Ensure the plane selection has not been inadvertently cancelled or changed between compensation activation and the current move.

If using rotation or tilted work plane commands (G68.2), verify the coordinate system transformation is correctly defined before applying compensation.

Mixing coordinate rotation and cutter compensation requires careful programming sequence

Verify that G41.1 or G42.1 blocks include valid I, J, K parameters defining the tool axis vector direction.

Check that the vector defined by I, J, K is not a zero-length vector (at least one component must be non-zero).

Confirm the vector values are appropriate for the surface being machined and the move contains valid X, Y, Z endpoint coordinates.

If CAM-generated, regenerate the toolpath with correct surface normal output options enabled and verify post-processor settings for 3D compensation format.

Post-processor configuration errors are common with 3D compensation

If using specialized drilling/milling cycles, verify all required geometry parameters are programmed according to Fanuc manual specifications for that cycle.

Check for conflicting or redundant geometry definitions that may confuse the normal direction calculation (e.g., multiple plane definitions).

Review parameters 19500-19599 (coordinate system and compensation settings) for any unusual values that might affect geometry interpretation.

Parameter changes should be documented and backed up before modification

Consult the specific Fanuc manual supplement for your control model and optional features to verify proper syntax for advanced functions being used.