Avoid winder vibration with modern software and hardware tools

Despite the development of structural and control automation for winders, vibration problems in the winding process have not been totally solved. As a matter of fact, certain paper grades, which were not prone to winder vibration in the past, are today. This is not because winder manufacturers have not studied the vibration problems in the pulp and paper industry. The problem is that paper grades are developing such that paper surface and compressibility properties are favorable to deformation and slippage. These are common root causes of vibration problems.

A deformed roll will experience excessive vibration in certain frequency zones.

Other causes for vibration include:

• poor winder alignment
• poorly balanced winder drums
• incorrect spreading
• misalignment of slitters with cores
• inconsistent diameter cores
• not winding a set with good wound-in tension
• not using a hydraulic direct acting rider roll

There are several hardware and software solutions for winder vibration, using modern technology. A few are mentioned below...

Hardware solutions

Using winder drums of higher bending stiffness and very small dynamic run-outs can reduce vibration levels. Those properties will both reduce the nip load fluctuations and prevent irreversible deformation from taking place. Modern rider roll hydraulics (4-way valve configurations) have also proven to be an effective tool in reducing winder vibration and, in extreme cases, preventing roll throw outs.

Software solution

Vibration can also be controlled by adjusting the winder speed to avoid resonance rotation frequencies. The winding system, including both the winding set and the winder, has a resonance. This resonance must not coincide with rotating frequency for any length of time.Experienced winder operators have done this for years, but modern winder automation allows this to be done automatically as well.

Automated winder controls can quickly drop roll rotation speeds through the danger zone.

In some cases, it has been possible to eliminate, or at least reduce, the vibration by optimizing the running parameters for each particular grade of paper. Practically speaking, this means that the winding parameters are selected to produce soft winding.

For more information on how to control winder vibration, contact your Valmet representative.