Fanuc Spindle Motors and Mechanical Spindles
Spindle repair on a Fanuc machine covers two separate units with their own failure modes and their own repair steps. The Fanuc spindle motor turns the spindle and sends speed and position feedback to the spindle amplifier through its encoder. The mechanical spindle carries the tool or chuck on its own set of precision bearings inside the spindle housing of the machine.
Mechanical spindle rebuilders replace the bearings, seals, and O-rings and sleeve or machine worn housings back to OEM specs. Spindle motor rebuilders replace encoders, rebuild bearings, rewind stators, and balance the shaft. Each listing on this page shows the spindle repair categories published by that shop.
Fanuc Spindle Repair Shops
Lakeside CNC Electronics
Addison, IL
Brands: Fanuc
Midwest CNC Services
Waterloo, IA
Brands: Fanuc
Motor City Spindle Repair
Dearborn, MI
Brands: DMG Mori, Fanuc, Haas, Makino, Mazak, Okuma
MRO Electric and Supply
Raleigh, NC
Brands: Fanuc
Northline Industrial
Redford, MI
Brands: Fanuc, Makino, Okuma
Repair Zone
Bay City, MI
Brands: Fanuc
Servotech, Inc.
Middletown, CT
Brands: Fanuc
T.I.E. Industrial (FanucWorld)
La Vergne, TN
Brands: Fanuc, Okuma
Tri Star CNC Services, LLC
McHenry, IL
Brands: Fanuc
Compare Fanuc Spindle Repair Shops
This table lists turnaround, warranty, and evaluation terms from each shop's published information.
| Shop | Repair type | Turnaround (business days) | Warranty (months) | Free evaluation | Rush service |
|---|---|---|---|---|---|
| Lakeside CNC Electronics | Ship-in repair | 2-3 | 12 | Yes | Yes |
| Motor City Spindle Repair | Ship-in repair | 5-15 | 12 | Yes | Yes |
| MRO Electric and Supply | Ship-in repair | 2-3 | 12 | Not listed | Not listed |
| Northline Industrial | Ship-in and on-site | Not listed | 12 | Yes | Not listed |
| Repair Zone | Ship-in repair | Not listed | 12 | Not listed | Yes |
| Servotech, Inc. | Ship-in repair | 5 | 12 | Not listed | Yes |
| T.I.E. Industrial (FanucWorld) | Ship-in repair | Not listed | 12 | Not listed | Not listed |
| Tri Star CNC Services, LLC | Ship-in and on-site | Not listed | 12 | Not listed | Not listed |
Common Fanuc Spindle Failures
Bearing wear in a spindle shows up as radial play, thermal drift, and vibration at higher spindle speeds. Worn bearings add friction and can trip the SP9056 spindle motor overheat alarm on the CNC screen. A cooling fan with failed bearings or windings cuts off the airflow over the spindle motor and leads to the same overheat condition.
The encoder often fails first on a Fanuc spindle motor and degrades over time with heat exposure. Encoder trouble brings up speed deviation and speed feedback alarms like SP0741 and SP9043 on the CNC screen. Bad cables, loose connectors, and a wrong encoder air gap produce the same alarms and deserve a check ahead of any encoder replacement.
Motor Fault or Amplifier Fault
A spindle overcurrent alarm can start in the spindle amplifier or in the spindle motor and needs a check on both sides. On the amplifier side the usual causes include a failed IGBT or gate driver in the spindle amplifier module. On the motor side a seized bearing, a winding short to ground, or a power lead short to ground can trip the same alarm.
Turning the spindle by hand with the power off and locked out gives a quick read on bearing condition. A check of the power leads and motor windings for a short to ground rules the motor in or out ahead of an amplifier repair. An alarm code on the spindle amplifier display points the technician to the amplifier side of the fault.
What a Spindle Motor Rebuild Covers
A Fanuc spindle motor rebuild starts with an evaluation and a deep cleaning of the motor. The technician then examines each component and replaces or rebuilds the failed parts back to OEM specs. Fanuc spindle motors run on special high-speed bearings unique to the OEM and get new high-speed bearings in a rebuild.
Low imbalance on a spindle motor protects bearing life and the finish on machined parts. Rebuilders tune vibration levels on the fully assembled motor and set the final balance at that stage. Load testing comes last and runs the rebuilt motor on a spindle amplifier ahead of shipment.
Checks During and After a Rebuild
Some rebuilders inspect the spindle encoder on every Fanuc motor and replace a degraded encoder ahead of an actual failure. This step heads off a second failure soon after the motor’s return to service. Encoder installation also calls for special equipment and an exact alignment of the encoder to the motor poles.
A runout check at the spindle nose cold and again hot at running speed verifies a rebuilt mechanical spindle. Drift out of spec on a recent rebuild can point to reused bearings from the prior rebuild. A call to the shop behind that earlier rebuild belongs ahead of a second teardown.