The spindle trips an overload alarm under cut, with the load meter spiking well above the normal range for the tool and material in use.
These are the failure paths we see most often on the Fanuc Robodrill for a spindle overload alarm condition. Likelihood reflects field frequency; First Check is what you can do remotely before sharing logs.
| Cause | Likelihood | First Check |
|---|---|---|
| Dull or wrong tool / excessive depth of cut for the material | High | Compare the actual tool, wear and DOC to the proven job sheet for that material |
| Spindle load parameter or gain set too low for the cut | Medium | Read the spindle load limit and the servo/axis load parameters against the build |
| Bearing preload loss or contamination raising mechanical load | Medium | Listen for a rising tone or heat at the nose and compare to a baseline run |
| Coolant or chip evacuation poor, packing the cut | Low–Medium | Check coolant flow and chip clearing at the contact point |
Work through these in order. Each step is something you can perform and report back on without opening the enclosure or swapping parts.
Run the same tool in air (no cut) and note the load meter. Then take a light cut and a normal cut, recording where the overload trips. The delta isolates tooling from mechanics.
Pull the exact alarm number and the spindle load-limit parameter. We compare it to the machine's proven baseline to see if it was lowered or drifted.
Confirm the tool is sharp, the correct geometry, and the depth of cut matches the job sheet. Most overloads on a Robodrill are process, not mechanical.
With the guard open and safe, spin the spindle and note any rising tone, vibration or nose heat. A mechanical bearing fault shows even without a cut.
Verify coolant pressure at the nozzle and that chips clear. Packed chips double the load and trip the alarm without any hardware fault.
A Robodrill spindle overload is most often process — tool, cut or coolant — and only sometimes mechanical. The air-run vs cut load comparison is the single most useful reading we can use remotely. Cross-reference the broader collections: Overload / over-current alarm · Spindle & cutting process.
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Rarely. We separate process overload from a bearing fault using the air-run load and noise. A spindle swap is the last step, not the first.
Not safely. Raising the limit hides a real mechanical or process problem and can damage the spindle. We address the cause first.
The alarm is in the Fanuc spindle loop. We review the load parameter and the cutting data together to decide.
Share the air-run vs cut load readings and the alarm number. We separate tooling from a bearing fault so you do not replace a healthy spindle.
Submit Your Case Connect With SpecialistsWe do not perform hardware repair, we do not replace parts, and we cannot promise a 100% resolution. Our role is limited to remote diagnostic and step-by-step guidance based on the information, photos and logs you share.
Another CNC axis/servo alarm needing log review.
A different cutting process with its own overload-style faults.
Full CNC troubleshooting collection.