Process analysis of the boardmaking process based on thermography

Production of paperboard is a complex process. A large number of process parameters determine the product properties. The parameters fluctuate over time resulting in variations in product properties. Most of the product properties are regularly measured in order to control these properties. The standard measurement technology installed on the board machines is at present only capable to measure product variations on a minute scale. However, since about 1 year, Iggesund Paperboard has installed an infrared camera on one of its board machines. It measures temperature variations with a speed of up to 200 Hz. The web temperature correlated usually with web grammage and moisture. Analysis of the temperature variations can therefore easily detect process variation in the sub-second scale, which is very valuable for identify the root-cause of the process variations. The objective of this thesis work is to quantitatively evaluate the infrared imaging for the analysis and identification of different high frequency process variations. In addition, methods will be tested to identify rare, but large variations, such as wet spots in the web.

Combination of maintenance and process data for process analysis and optimisation

Production of paperboard is a complex process. A large number of process parameters determine the product properties. The parameters fluctuate over time resulting in varying product properties. These process fluctuations occur often at sub-minute frequencies which cannot be detected with the standard measurement technology of the board machine. During the production process, the condition of many roller bearings are continuously measured in order to early detect damages. Here, high frequency systems based on vibration analysis are used. In many positions on the board machine, the measured vibrations also give indications on process variations. The information on process variations is presently not used for process optimization. The objective of this thesis work is to evaluate different approaches to use vibration measurement in order to detect process variations. Different sections of the board machine will be investigated and the measured vibrations are analysed and interpreted from a process point of view. Correlations between vibrations measurements and process variations will be investigated.

Contact

Interested in any of the two proposed thesis projects? Please contact:

Hannes Vomhoff, Project manager & Product development, Holmen Iggesund Paperboard,
hannes.vomhoff@holmen.com
+46 70 379 17 15