I have done many measurements on both hot and cold rolling (4 to 7 stands) mills, on both the work rolls, spindles, backup rolls and mill housing. Our investigations included chatter detection, gauge control, work roll condition, backup roll condition, spindle condition, motor condition etc. What would you like to know? C. Hugh
I want to measure the 7 thrust bearings on a hot rolling (7 stands) for morgoil.
To you have some examples, i means photos.
Where could i put the sensor, the best way ?
I have many years of experience measuring rolling mills. I can send you via email a detailed description of how to collect data. Send me a note if you would like see this description. wyndell@vibcons.com
The drive line (spindle) thrust bearing is typically located just before the drive motor(s) and inside the motor room which is a clean dry place (horray!), unless there is a gearbox which synchronizes the top and bottom roll speeds and is in the hot, oily, dirty, nasty and very wet area (boo!).
You did not say why you are measuring the thrust bearing, but these machines are typically low speed except for stand #7. This raises many more issues. Are you comparing stands? (different speeds, different products = hard to compare).
Are you interested in product quality? motor condition? gearbox condition?
If you are measuring a thrust bearing on the gearbox, then I would use stud mounted acceleometers on the bearings. If you are in the clean area, magnet mounts will be sufficient. If spindle thrust is a problem and you are more interested in the slow speed stands (#1 to 4), proximity sensors may be better.
I could be a little more helpful if you let me know what the measurements are for?
Taking your measurements under "no load" conditions will allow some comparison of the relative conditon of each of the 7 stands. However I think you will find that the levels are relatively low, and can be very dependant on the condition of the work rolls and the work roll coupling. You should compare measurements taken with accelerometers in 3 directions, and a single displacement measurement in the axial direction on the thrust bearing.
If you can, I would compare the loaded versus unloaded thrust levels. To do so you will have to schedule measuremtns with a large run of similar product so that you can move from stand to stand.
There will still be an issue of the varying stand speeds. One method I used was synchronous time averaging using a shaft trigger before and after the gearbox. I then compared the levels for all the stands.
