Requirements for the Cross-Machine Direction Basis Weight Control of the Paper Web

Local deformation of the slice lip of the paper machine headbox is used throughout the paper industry to control the Cross-Machine Direction (CMD) basis weight. The properties of the slice transfer function for the control of the CMD basis weight are investigated. Requirements for the successful control of the basis weight in the cross direction are discussed, and typical results obtained with the OPTIPROFILE controller satisfying these requirements are presented. Results include applications from newsprint, coated fine paper, and supercalendered web offset.