Fryer TC-40V Spindle Repair

The Fryer TC-40V is a CNC vertical machining center.  It can come fitted with this grease lubricated and belt driven spindle capable of running up to 8,500 rpm.

CHALLENGE

This Fryer TC-40V spindle had bearings that were noisy when rotated by hand in assembly incoming.  We noted during disassembly that the rear shaft nut was difficult to remove from the shaft.  After completing the breakdown and evaluation, we found that the cages of the rear bearings were worn and had contaminated the bearing grease.  We then measured the critical surfaces and found a few unacceptable deviations.  First, the tooling 50 taper ID had poor tool contact and excessive runout >8µm.  Second, the 90mm front bearing journal had 6µm runout.  Lastly, the front shoulder had 4µm runout.  The drawbar and gripper fingers were also inspected and we found that the gripper fingers (collet) had significant wear on critical tool retention surfaces.  The retention nuts were also galled on the drawbar shaft and the shaft threads were damaged.

SOLUTION

The following actions were performed on this Fryer TC-40V spindle:

• Clean, inspect overall dimensions
• Rework the rear shaft nut
• Grind, chrome plate, and finish grind (GPG) the tooling taper
• GPG the 90mm front journal
• Kiss grind the front shoulder
• Replace all bearings, grippers, drawbar assembly, 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.