OKK HP 500S Spindle Repair

The OKK HP 500S is a CNC horizontal machining center.  It comes equipped with a grease lubricated and coupling driven spindle capable of running up to 12,000 rpm.

CHALLENGE

This OKK HP 500S spindle had heavy contamination of the permanent grease in the front bearings.  There was also significant endplay due to loss of preload from the bearing failure.  We also found a cracked front labyrinth ring and tool drive keys.  The drawbar was inspected and we found low tool retention force and the drawbar assembly was difficult to remove with many cracked bellevilles.  There was significant wear in the tooling taper ID that was severely compromising tool contact.  Lastly, the shaft tail journal was damaged and worn significantly undersized by the drive coupling.

SOLUTION

The lead time on this rebuild was affected by the delivery time of the OEM parts needed (ring and keys.) While we awaited arrival of these parts, we completed the grind, chrome plate, and finish grind of the tail journal and the kiss grind of the taper. After a thorough cleaning of all components, we reassembled the spindle with all new precision bearings, Bellevilles, gripper balls, o-rings, and assembly screws.

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.