Mazak HTC-400 Spindle Repair

The Mazak HTC-400 is a high speed CNC horizontal machining center.  It comes equipped with an oil mist lubricated and coupling driven spindle capable of running up to 10,000 rpm.

CHALLENGE

This Mazak HTC-400 spindle arrived to Northland Tool and Electronics in pretty rough condition.  After a complete breakdown and evaluation, we noted that the bearings failed from contamination.  The shaft taper was bell mouthed and worn and one of the drive dogs had some damage.  We also found that the gripper fingers showed some wear, more on one finger than the other which could affect test bar runout.  Lastly, the drawbar shaft had some wear and scoring, which can be smoothed to improve function.  No other dimensional deviations were noted for this repair.

SOLUTION

The following actions were performed on this Mazak HTC-400 spindle:

• Clean, inspect overall dimensions
• Grind, chrome plate, and finish grind the shaft taper
• Repair drive dog damage
• Replace bearings, bellevilles, o-rings, and gripper fingers

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.