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