Akira Seiki Performa V4 XP Spindle Repair

The Akira Seiki Performa V4 XP is a CNC vertical machining center.  It comes equipped with a grease lubricated and pulley driven spindle capable of running up to 12,000 rpm.  Our customer requested that we repair this spindle and upgrade it to be able to run up to 15,000 rpm.

CHALLENGE

When this Akira Seiki Performa V4 XP spindle arrived to our facility, the first things we noted was that the bearings were noisy when rotated by hand.  During disassembly, we found that the drawbar retention nut was gauled to the spindle shaft and had to be cut off to continue.  After completing the breakdown and evaluation we found that the rear radial bearing suffered a catastrophic failure.  Some debris had contaminated the rear of the spindle and found its way into the bearing.  The critical dimensions were measured and we noted two issues.  First, the 50mm rear bearing journal was undersized -6/-8µ (ISO is ±4µ).  Second, the 80mm rear housing bore was damaged from the rear radial bearing outer race spinning freely.

SOLUTION

The following actions were performed on this Akira Seiki Performa V4 XP spindle:

• Clean, inspect overall dimensions
• Manufacture and install a new drawbar retention nut
• Grind, chrome plate, and finish grind the 50mm rear bearing journal & 80mm rear housing bore
• Upgrade bearings to ceramic angular contact quad set in front and high speed deep groove radial in rear to achieve 15k max rpm
• Replace bellevilles, 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.