Matsuura RA-2G Spindle Repair

The Matsuura RA-2G is a CNC vertical machining center.  It comes fitted with a grease lubricated and coupling driven spindle that is capable of running up to 15,000 rpm.

CHALLENGE

Our customer sent in this Matsuura RA-2G spindle due to it suffering a crash and noisy bearings.  When it arrived at our facility the fist thing we noted was that the spindle felt slightly rough and sounded loud when spun by hand.  After breaking down the spindle and a full evaluation, we noted that the grease in all the bearings was slightly degraded.  The front bearing pair had brownish particulate contaminant and feel very scratchy by hand.  The front of spindle suffered very high heat damage causing #1 bearing outer race to spin and fret the front housing bore ID.
There was also some raised material on the front shaft OD.  We also noted that the retention nut on the drawbar became locked up when attempting to remove it. There was some rubbing damage on the ID of the spacer as well as the OD of the drawbar and OD of the retention nut.  Lastly, the 2 crush pins that lock the drawbar components together sheared during removal.  No other dimensional deviations were noted for this repair.

SOLUTION

The following actions were performed on this Matsuura RA-2G spindle:

• Clean, inspect overall dimensions
• Replace bearings, o-rings, Crush Pins, and assembly screws
• Kiss grind the taper ID and shaft OD
• Clean up damaged drawbar components and shaft OD

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.