Eurotech 730 SLY Spindle Repair

The Eurotech 730 SLY is a production CNC turning center.  It comes equipped with a grease lubricated and belt driven spindle capable of running up to 4,000 rpm.

CHALLENGE

This Eurotech 730 SLY spindle was nearly seized incoming.  Upon disassembly, we found that the spindle interior components, including shaft, were covered in rust.  The grease in all the bearings was completely washed out and the spindle interior is dry.  The inner bearing spacer spun on the shaft, resulting in damage to the spacer ID and both bearing journals.  We then measured the critical dimensions and found that the 110mm front and rear bearing journals were severely worn undersized. The front was +2/-60µm and the rear was +2/-70µm (ISO=±5.5µm).  No other significant dimensional deviations were noted (shaft taper/face, housing bores).

SOLUTION

The following actions were performed on this Eurotech 730 SLY spindle:

• Clean, inspect overall dimensions.
• Grind, chrome plate, and finish grind (GPG) the inner bearing spacer ID
• GPG both front and rear 110mm bearing journals
• Replace ceramic bearings, 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.