Mitsubishi MH50D Spindle Repair

CHALLENGE

We received this Mitsubishi MH50D spindle in completely seized condition. Our initial inspection uncovered that the #1 front bearing had suffered catastrophic failure. Grease was largely gone from the quad set, and what was left was degraded by coolant and debris. The tooling taper ID was damaged, with poor tool contact & high runout. 100mm front and 75mm rear bearing journals & shoulders had high runout. Gripper fingers had significant wear on tool retention surfaces.  

SOLUTION

This repair required significant grinding work to bring this spindle back to spec. We performed a grind, chrome plate & finish grind process to the tooling taper ID, 100mm front, and 75mm rear bearing journals. A kiss grind to the bearing shoulders remedied high runout. We replaced ceramic bearings, Bellevilles, grippers, o-rings and assembly screws.