| Machine Type | Typical Default (8901) | Common Problem | The "Better" Setting | Why It’s Better | |-------------|------------------------|----------------|----------------------|-------------------| | VMC (Vertical Mill) | 0 (1st axis = X) | Z-axis tapping on a VMC: X is irrelevant | (Z-axis as 3rd axis) | Direct sync between spindle and Z, eliminating following error from intermediate axes | | HMC (Horizontal Mill) | 1 (2nd axis = Y) | Tapping on B-axis rotated face | Dynamic (use macro to change) | Adapts to active tool axis (Z or Y) | | Lathe with C-axis | 0 (X) | Tapping off-center (C + Z) | 5 (Z-axis + C) | Synchronizes spindle rotation with Z feed AND C rotation simultaneously |
If you bypass the alarm, monitor the control unit's temperature closely. Heat is the #1 killer of CNC motherboards. fanuc parameter 8901 better
| Setting | Axis selected | |---------|----------------| | 0 | 1st axis (X) | | 1 | 2nd axis (Y) | | 2 | Not used (invalid) | | 3 | Not used | | 4 | 3rd axis (Z) | | 5 | 4th axis (A/B) | | Machine Type | Typical Default (8901) |