Toyoda FH450S Spindle Repair

The Toyoda FH450S is a large CNC horizontal machining center.  It comes fitted with this oil mist lubricated and stator driven spindle capable of running up to 15,000 rpm.

CHALLENGE

Our customer sent in this Toyoda FH450S spindle with complaints of bearing noise.  The spindle was very difficult to spin by hand incoming and the field passed all electrical testing. The encoder sensor failed incoming testing and showed rub out damage on the sensor surface.  After completing disassembly we noted that there was a catastrophic failure of the rear roller bearing. The rolling elements had become misshapen and the cage was breaking down.  Looking at the taper, we noted the interior was heavily packed with rust and the face of the taper showed signs of rubout damage and transfer of material that got stuck.  The grippers were extremely difficult to remove and the post was damaged during breakdown.  We then measured the critical surfaces and found a couple unacceptable deviations.  First, the taper insert has poor contact and slightly high runout (4µ).  Second, the rear housing was on the very loose end of ISO (+1/+2µ, ISO is +2/-13) and should be brought back into a tighter spec.  Lastly, the seals in the actuator were showing signs of wear and the rotary union in the actuator was not springing properly and should be replaced.

SOLUTION

The following actions were performed on this Toyoda FH450S spindle:

• Clean, inspect overall dimensions
• Replace bearings, bolts, o-rings, and bellevilles
• Replace grippers, gripper post, rotary union, encoder, and seals
• Grind, chrome plate, and finish grind (GPG) 40 ID taper insert
• GPG the rear 90mm housing

RESULT

After reassembly of all components, adjusting bearing preload, and undergoing break-in and testing procedures, this spindle passed our final quality inspection before being returned to our customer with a 1-year warranty.