Heavy vibration in slitter line

Hi Frnds,

I am facing vibration issue in my slitter line, During running CR sheet vibrate heavily & due to that we are not able to run line more then 100 to 120 MPM.
I checked uncoiler, recoiler, slitter & deflector roll encoder & already changed uncoiler & recoiler encoder but no improvement found.
I also checked & found that in all 3 motors there is no hunting in load current during running line also MPM is showing correct on HMI.
Also checked all 3 motors & there encoder cable but everything is found ok.
Slitter line having control logix 5000 PLC & all DC motors controlled by power flex dc drive.
Plz suggest some solution.

Possibly you could hand tach all drive rolls, and verify that they are indeed running at a stable steady speed.
I've dealt with heavy vibration on a slitter machine before, from the unwind stand. Heavy rolls would vibrate due to a large mass of steel plates the mech engineers had added to beef up the unwind shafts mounts. It was a patch for poorly designed frame. This large mass at the end of a fulcrum created a harmonic vibrations at high rpm. At the time, I had to put in code to limit line speed as the unwind rpm would increase to stay out of the "danger zone". The point is that most likely you have a mechanical issue. You can't solve that with code. Get more sets of eyes and find where the problem is coming from and fix it.

What vibration frequency are you seeing? 1 Hz, 10 Hz, 100 Hz, 1000 Hz?

Keith

during running line sheet vibrates heavily.

If all drives are in sync you are probably experiencing resonance, you're hitting the natural frequency of the sheet. And like dcooper33 said you can't avoid that programmatically.

I've only worked with rolling knife slitters and fabrics so far, feed rate was never a problem there, the material would just ball up at the knife if the line speed was to high. Are you sure that your slitter can handle the feed rate?

Line maximum speed is 200 MPM & becoz of vibration we are running line upto 120-130 mpm.
When we run the line upto 60 mpm vibration is more & after that it stable slightly but again when we increase line speed beyond 130 mpm vibration increases & sheet vibrates heavily.
One observation was found in recoiler drive section that coupling between motor & gear box having play in its key way & also when we stand at recoiler gear box side heavy vibration feels, also gear box sound little abnormal found.