What are the root cause for vibration in Rolling Slitter line

Hi,

I am facing vibration issue in my Cold rolled slitter line & I am not able to find out the root cause behind this problem.
Whenever line is running there is heavy vibration observed in sheet after 100 MPM of line speed.
Vibration is observed in recoiler section i.e between deflector roll & recoiler.

1. Recoiler gearbox gearing and/or bearings.

2. Recoiler brake drum/disk and/or liners.

3. Recoiler motor bearings (and/or commutator/brushes if DC driven)

4. Uncoiler bearings.

5. Uncoiler drive linkage/clutch.

6. Slitter foundation footings.

7. Recoiler speed/tension controls.

How long has the system been in place and how long has the vibration been there?
Has anything mechanically been done? repairs made / parts replaced?
any maintenance work done?

james

If you can find a way to measure the frequency that is dominant in your observed vibrations, this may point to things either rotating at a specific rpm, parts of a certain weight vibrating at their resonant frequency, or parts that can be regarded as considerable weight swinging back and forth slightly on a long and light arm where the weight+arm length combination determine the resonant frequency (think swing, or pendulum clock).

Find the dominant frequency or frequencies, then look for the parts that would rotate at a speed corresponding to that frequency. Find parts (or assemblies) with a weight that matches the resonant frequency. Determine valid combinations of arm length + weight that match the observed frequencies and then find matching parts in the construction (or product) that can swing on something that could be considered an arm of matching length.

hi

james
last year we upgraded our line from PLC 5 to control logix system.
& w.r.t to mechanical parts uncoiler input pinion shaft was changed & when it was damaged, also recoiler input shaft which also changed as its key way was partial damage after up gradation of line.
Vibration issue is generated between this period.
Presently one issue which we observed that recoiler gear box input bearing was heated & its not normal.
also recoiler diameter calculation is slightly fluctuation as some time its increasing & then decreases & then increasing.