Okuma MX-55VB Spindle Repair

The Okuma MX-55VB is a 5-axis CNC machining center.  It can come equipped with this grease lubricated and stator driven spindle capable of running up to 6,000 rpm.

CHALLENGE

When this Okuma MX-55VB spindle arrived at Northland Tool and Electronics, we noted right away that it spun freely but the bearings felt worn when spun by hand.  The target wheel had high run out incoming, but after completing the disassembly the tail had good run out.  We also noted that the rear roller was heavily contaminated with oil and the grease was washed out.  All the bearings in the front were also heavily contaminated with oil and washed out.  We then measured the critical dimensions and found a few issues.  First, the ID Taper had high run out and poor tool contact.  Second, the rear roller bearing shoulder had high run out.  Lastly, we noted that there was no draw bar sent in with the spindle.  No other dimensional deviations were noted for this repair.

SOLUTION

The following actions were performed on this Okuma MX-55VB spindle:

• Clean, inspect overall dimensions
• Replace bolts, bearings, and o-rings
• Grind, chrome plate, and finish grind the ID 50 taper
• Kiss grind the rear straight bore roller journal shoulder

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.