Chevalier 3060VMC Spindle Repair

The Chevalier 3060VMC is a large CNC vertical machining center.  It comes fitted with a grease lubricated and pulley driven spindle capable of running up to 6,000 rpm.

CHALLENGE

This Chevalier 3060VMC spindle arrived at Northland Tool and Electronics for a full breakdown and evaluation.  The first thing we noted that the bearings felt very rough when rotated by hand incoming.  Upon inspection, we noted that the grease in the rear bearing pair was washed out, causing failure.  The tooling taper ID was bell mouthed and pockmarked, with poor tool contact.  We then measured the critical dimensions and found a few issues to address.  First, the shaft was bent 32µ at the rear bearing shoulder.  Second, the 80mm drive pulley journal OD was worn undersized -15/-19µ.  Third, the gripper assembly (collet) was loose on the drawbar incoming and the fingers have excessive wear on critical surfaces.  Lastly, the 125mm rear housing ID was lightly fretted from the failed rear bearings, but still within ISO.  We will polish and use it as is.

SOLUTION

The following actions were performed on this Chevalier 3060VMC spindle:

• Clean, inspect overall dimensions.
• Machine spindle shaft to reduce runout from bend at rear
• Grind, chrome plate, and finish grind the tooling taper ID
• GPG the 80mm drive pulley journal OD
• Replace all bearings, bellevilles, grippers, 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.