Leadwell MCV1100 Spindle Repair

The Leadwell MCV1100 is a larger CNC vertical machining center.  It comes equipped with a grease lubricated and belt driven spindle capable of running up to 6,000 rpm.

CHALLENGE

This Leadwell MCV1100 spindle arrived seized due to a catastrophic bearing failure of the #6 rear bearing. The rear housing cover had dried coolant residue all over it indicating it may have had a leaking rotary union that allowed coolant to get into the rear bearing and washed out the lubricating grease.  Deeper into the inspection we noted that the bearings 1-5 were also mostly washed out with very little to no grease left in them going from 5 being worse than 1. This is also a good indication that it was washed out from the rear.  Incoming drawbar force was low for a 50 taper, around 2,000lbs.  We noted that the gripper fingers had slight wear, but still look completely functional. After measuring the critical dimensions (bearing journals, housing, taper, etc.) we noted a few issues.  First, the rear housing was extremely worn out from running with such a deteriorated rear bearing, it measured +6/+170.  Second, the rear shaft journal is extremely worn out from running with such a deteriorated rear bearing, it measures -3/-12.  Lastly, the spindle came in missing the drive dogs and 3 rotating parts for the rear that will be needed for balancing.

SOLUTION

The following actions were performed on this Leadwell MCV1100 spindle:

• Clean, inspect overall dimensions.
• Grind, plate, and finish grind 140mm rear housing and 90mm rear shaft journal
• Replace bearings, bellevilles, and o-rings
• True up all spacer shoulders that were damaged
• Make a new rear shaft spacer

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.