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 MoreMatsuura RA-4G Spindle Repair
The Matsuura RA-4G is a large CNC vertical machining center. It comes standard with a grease lubricated and coupling driven spindle capable of running up to 8,000 rpm.
CHALLENGE
The interior of this spindle was contaminated with coolant throughout, which definitely contributed to the complete failure of the rear tapered rear roller bearing. Also, the 140mm rear housing was determined to be worn oversized 0/+6µ. ISO for this housing with a tapered roller is +3/-15µ, but should be on the tight side of spec for proper loading of that bearing type. Debris from the failure of the roller cage also caused severe damage to the labyrinth spacer located in front of the bearing.
We also determined that the ID & face of the 50 taper were worn with some damage resulting in poor tool contact and excessive runout >8µ. The gripper fingers showed evidence of uneven wear, and the drawbar shaft had heavy chatter wear on the OD from the action of the drawbar spring.
SOLUTION
The following actions were performed on this Matsuura RA-4G spindle:
- Clean all parts of the spindle
- Replace all bolts, o-rings, and bellevilles
- Replace gripper fingers
- Replace bearings
- Grind, plate, and finish grind (GPG) the rear housing
- GPG the drawbar shaft and the ID of the 50 taper
- Kiss grind the taper face
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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Spindle contamination is a critical issue that can significantly impact the performance and longevity of your machinery.
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