Kitamura Mycenter HX1000i Rear roller failure
Kitamura Mycenter HX1000i, 8,000 RPM, oil mist lubrication, gear driven
Rear roller failure damaged the housing bore, flaking chrome in Big-Plus 50 taper
This spindle arrived at our facility seized because of a catastrophic failure of the rear roller bearing. When the cage that normally contains the rollers disintegrated, the crushed phenolic material migrated to the front of the spindle, contaminating the ceramic quad set. Another result of the rear roller failure was that several deep grooves were created in the rear housing bore as the destroyed bearing rotated. We also observed that the Big-Plus dual-contact tooling 50 taper ID was damaged, and that the face was worn down as well. In addition, we noted that the taper ID had been previously plated, and that the hard chrome was flaking where the ID had taken some hits.
We performed a precision grind, chrome plate & finish grind of the rear housing bore to remedy the damage from the bearing failure. We also did a grind/plate/grind of the 50 taper ID & kiss ground the face of the shaft to preserve the Big-Plus dual-contact functionality. When all components had been thoroughly cleaned, we reassembled the spindle with new bearings, setting the proper preload, and replaced the o-rings and assembly screws. Our final QC process included run up of the spindle with vibration & thermal analysis during the three hour test run. Unfortunately, we could not check tool retention force or trim balance the spindle because our customer was unable to provide us with the drawbar assembly, drive dogs & keyed drive gear.