Catastrophic bearing failure was the main cause of this spindle malfunction Continue reading to learn how Northland Tool performed this repair and converted a Weiss GHK 176239 spindle from grease-injected to permanent grease lubrication……
Read MoreDaewoo L200A Spindle Repair
Our customer sent in this Daewoo Lynx 200A 5000 RPM lathe spindle which had seized. They indicated that the spindle had become very noisy, but then proceeded to run it for another two days. Our free evaluation showed that the grease lubricated bearings failed due to extreme coolant contamination, which likely occurred because a front cover drain had become completely blocked. We also discovered that the pulley ID and the pulley journal OD were both severely fretted. This damage was corrected by grinding, chrome plating & finish grinding the pulley journal and replacing the pulley. We replaced the pulley because you cannot G/P/G two mating surfaces.
This customer made two critical errors that lead to us rebuilding the spindle with new ABEC 7 class precision bearings. The first was not following a preventative maintenance schedule, which needed to include checking that front cover drain remained clear. Coolant will eventually get into your spindle, and it needs a way to get out. The second error was to ignore the signs of impending bearing failure, in this case the extremely loud noise during operation. Not heeding this increased the cost and lead time of the rebuild process. The customer could have also taken steps to check the operating temperature of the spindle, or even could have used vibration analysis to determine bearing condition.
CHALLENGE
- Spindle was seized incoming, bearings contaminated with coolant sludge, front cover drain was clogged.
- Pulley journal is fretted & has two undersized bands -37/-45µ, pulley ID is fretted & has two oversized bands +60/+70µ.
- Pulley nut has pre-existing punch marks from attempts at removal.
- OD lathe taper and face are very pitted, pre-existing tick mark on taper.
SOLUTION
The following actions were performed on this Daewoo L200A spindle:
- Clean, inspect overall dimensions.
- Replace bearings, drive pulley, pulley nut and o-rings.
- Grind / chrome plate / finish grind pulley journal.
- Kiss grind OD lathe taper and face – some pitting may remain.
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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