Paper Machinery

Dynamics and Vibrations Group

Dynamics of paper machinery

Roller pair of a paper calender
Roller pair of a paper calender

Calendering is the last step in the production process of paper. Here, concerning appearance and printability, the needed surface properties are achieved. The operation is performed by passing the paper web through a nip between two rolls pressed against each other. There are different types of paper calenders varying in the number of nips.

In a current research project two phenomena which occur during the calendering process are investigated. The first phenomenon is called barring. Here, within days, corrugation occur on the rollers leading to short operating times. The second phenomenon is characterised by an instability of the whole paper calender. Thus very large vibration amplitudes arise in very short time resulting in poor surface quality of the paper.

The research especially focuses on the contact kinematics and the dynamical behavior of the calender. Therefore, different models for the description of the phenomena are derived and various simulations are performed, including:

  • the structural dynamics of the rollers,
  • the mechanisms in the contact zone,
  • and stability analyses with respect to the calender's dynamics.

Students who are interested in writing a thesis, a seminar paper or in doing an advanced design project about these topics, should not hesitate to contact one of the members of the group or Prof. Peter Hagedorn directly.