Matsuura H.Max-500 Spindle Repair

The Matsuura H.Max-500 is a very large CNC horizontal machining center.  It comes standard with an oil mist lubricated and coupling driven spindle capable of running up to 15,000 rpm.

CHALLENGE

This Matsuura H.Max-500 spindle was sent in to Northland Tool and Electronics for a full evaluation.  Upon disasssembly we noted that the #1 bearing failed from coolant contamination and does not feel smooth when spun by hand.  The front cover was packed with coolant sludge and had a large cosmetic dent but we will use as is.  Gripper fingers were worn and will need to be replaced.  We then measured the critical dimensions (bearing journals, housing, taper, etc.) and found a few issues to note.  First, the front housing was oversized +12/+15µ where the bearing locates.  Second, the OEM stamped ‘ground to +9µ’ (ISO is +/-9µ), but there is no visible fretting of the bearing and this deviation is not a cause of failure, we will use as is.  Third, the shaft taper has 6-14µ runout with visible windows and poor contact, also light face wear.  Lastly, the drive coupling had 150µ runout at the bent rear shaft nipple.

SOLUTION

The following actions were performed on this Matsuura H.Max-500 spindle:

• Clean, inspect overall dimensions
• Kiss grind shaft BT-40 taper, customer indicated that they do not use Big-Plus tooling
• Replace bearings, drive coupling, grippers, and ferrules
• Replace oil lines, push-connect fittings, spiral wire wrap, 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.