The Bridgeport Torq-Cut 22 is a smaller CNC vertical machining center. It comes fitted with a grease lubricated and belt driven spindle capable of running up to 7,500 rpm.
Read MoreMitsubishi MH-60 Spindle Repair
The Mitsubishi MH-60 is a CNC horizontal machining center. It comes fitted with an oil mist lubricated and stator driven spindle capable of running up to 6,000 rpm.
CHALLENGE
When this Mitsubishi MH-60 spindle arrived at Northland Tool and Electronics we completed a full breakdown and evaluation. Upon inspection we found a lot of dimensional deviations that will need to be addressed. First, the taper was very beat up and worn with several windows, 30-40 microns runout, and below gaugeline. Second, the gripper fingers were worn with a low drawbar pull force, at 3,600lbs (standard is 4,136-6,204lbs). The drive dogs were also worn and will need to be addressed. Third, the rear of the shaft had chrome chipping off at the two key ways and the rear journal was -8/-13 with a deep hole. (ISO is +3/+13) Fourth, the rront journal has 6-11 microns runout with light pre-existing score lines. Lastly, the housing has pre-existing light scratch marks and the front shaft nut spanner holes have pre-existing damage.
SOLUTION
The following actions were performed on this Mitsubishi MH-60 spindle:
- Clean, inspect overall dimensions
- Weld and machine drive dogs
- Grind, chrome plate, and finish grind the shaft taper, front journal, and rear journal
- Weld and machine front shaft spanner nuts
- Replace bearings with customer supplied bearings
- Replace grippers, bellevilles, screws, and o-rings
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.
DETAILED CAUSE OF FAILURE
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Repair History - Here are examples of similar spindle repairs that may contain additional information that will help you. If you have additional questions, please contact us.
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