Containerboard and printing paper wound-on-strain measurements on a pilot winder
Abstract
Wound-On-Strain (WOS) measurement arrangement was set up on a single drum pilot-winder in the Winding Research Center of Valmet Technologies Inc. in Finland. The measurement was implemented with two Laser Doppler Velocimeters (LDV) - one measuring the paper web speed at the roll surface in the unwind stand or wind up and the other from the free web between the unwind and wind up. The target was to assess the feasibility of these roll structure related measurements. The measurement set up where one LDV is in the unwind enables also the WOS measurement of rolls produced with other winders while the set up where the LDV is in the wind up is convenient for the winding parameter trials. Comparison of these two measurements should provide valuable information of the viscoelastic properties of the wound roll. The measurement set up will be presented in detail. The source and corrections of several error terms are discussed. WOS curves for containerboard rolls run with our customer's two-drum winder week earlier are presented. The influence of the web tension and nip load on WOS was studied. The influence of the nip load become clearly visible in the WOS while as in surface winding the changes in the tension did not become detectable in the WOS measurement. The measurement of several containerboard rolls wound in identical conditions resulted in very similar WOS curves. The WOS estimates obtained with the LDV measurement and with a Cameron Gap test were compared.
Citation
Jorkama, M., & Palo, P. (2015, June). Containerboard and printing paper wound-on-strain measurements on a pilot winder. Paper presented at the Thirteenth International Conference on Web Handling (IWEB), Stillwater, OK.