Fanuc Alarm 460 — What It Means
Alarm 460 on a Fanuc CNC means the spindle load exceeded the permissible limit. This can happen because of an aggressive cut, dull tooling, a seized spindle component, or a problem in the spindle drive system.
Common Causes
- Tool is dull or chipped. Cutting force rises sharply and drives spindle load up.
- Feed or depth of cut is too aggressive. The program is demanding more torque than the spindle can safely deliver.
- Spindle bearings are failing. Heat and drag increase spindle motor current.
- Gearbox or belt drive problem. Mechanical drag upstream of the spindle creates overload.
- Spindle drive or cooling issue. An overheated drive can behave unpredictably and trip load alarms.
Step-by-Step Fix {#fix}
- Check the tool first. Replace dull or damaged tooling before chasing electrical faults.
- Reduce feed and depth of cut. If the alarm disappears, the issue is process load, not machine failure.
- Run the spindle unloaded at several RPMs. If load is high with no tool cutting, the issue is mechanical or electrical.
- Listen for bearing noise. Growling, heat, or vibration points to spindle bearing failure.
- Inspect belts or gearbox if equipped. A seized idler or tight gearbox raises load dramatically.
- Check spindle drive cooling. Dirty filters or failed cooling fans can cause drive overheating and nuisance overload trips.
Parts Often Needed
| Part | Notes |
|---|---|
| Spindle bearings | Amazon | Replace if heat or noise is present |
| Toolholder / cutting tool | Amazon | Dull tools are the simplest fix |
| Drive cooling fan | Amazon | Check spindle drive cabinet airflow |
| Belt set | Amazon | Replace if glazed, cracked, or over-tensioned |
When to Call a Pro
If spindle load is high with no cutting load, the machine likely needs spindle service, drive diagnostics, or both. Continuing to run it risks spindle damage.