What U need to work out is what came first....

IS the system unstable ie design error.

Or did the surface codntion cause excitation of the system.

U really need expert help with this issue and the OEM supplier should be consulted first.

U need to find the natural frequency of the whole system - complex work....from the base plates to the tire mounting and drum.

Then, U need to look at the input forces to the system eg pulsating torque spikes from the 2 drives, other forcing functions.

U can also take somne onsite vibration radings - do this over a speed range...

If the frequency of the (main) vibrations is the same but the ampliture changes with speed...then U have a natural frequency issue eg bell ringing.

If the frequency of the main vibration changes with the speed..then U have a forced vibration mode..this could be coming from the drive system or the condtion of the running surfaces.

What is the condtion of the tires/rollers - they must be almost perfect and kept that way - esp. at 8rpm...

Machining of tire is not good....better ways for tires, OK for rollers is done properly

Tire/roller maintenance must be done by experts who will guarantee the results.

Sounds like U may need to replace some parts - ensure that they are defect free with no casting holes and no weld repairs made.

Was the vibration present from startup??? When did it start??



Does the tire/rollers have a axial movement system to keep the running faces in good condtion??

Your problem creates a lot of questions whihc is really out of the scope of this forum....I hope that I have given U something to go on..

Cheers

James ■

Irfan,

It sounds as if your coating drum is vibrating excessively due to the reduced diameter of the drive tyres---

look at it this way-what you have done is reduced the elevation of the coating drum from the original centerline, this results in the drum still trying to track at its original elevation due to the rear of the drum in my opinion-thus the chatter from the drum-since you cut off more of the tyres the end of the drum has less are to contact thus the drum is essentially scraping against the new diameter of the tires since it does not have full contact with the drive tires.

my opinion lzaharis- if you have the time measure the distances and you should see a distance change it is just like trying to roll a perfect cone on the ground-it will try to go in a circle-in your case it is not as bad but still problematic ■

Irfan,

I do not have much info, but from what U have said, I would say that the condtion of the running surfaces is the cause of the problems..

do U have any casting defects or unsual markings on the running surfaces....

the tire grinding op. does not sound like to it was done correctly....grinding is supposed to improve the running....did they use a belt grinder, cone grinder or machine tool???

I hope that this helps....

Cheers

James ■

Irfan,

If the drive gear engagement is not bottom, you have a bearing or missalignment problem somewhere in the system.

For the data you provided, it also appears that the metal condition of the tyre is not very good.

Does the system vibrates when empty?

Look at the power draw of the drive motor... Does it vary according to the vibration cycle?

What is the condition of the gear reducer?

Good luck!



Antonio Reis

Vitrom Mfg Consultants

Your Process and Manufacturing Solutions

Phone: 209.834.1900

Fax: 209.834.1039

www.vitrom.com ■