SUPERCALENDERS GO HIGH TECH WITH RAPID ADVANCES IN AUTOMATION AND QUALITY-CONTROL SYSTEMS

Supercalender operating parameters and their effect on different paper properties are the focus of this article. Paper profiles in the cross-machine direction are typically controlled through zone-controlled variable-crown rolls and zone steam showers. Some other means to affect the paper profiles-such as overhanging weight relieving and the frictionless stack concept-also are presented. In the past few years, American and European engineers have come up with more new developments for supercalenders than anytime in their history. The authors concentrate on describing some new computerized operator interface systems as well as closed-loop quality control systems for supercalenders. Several mill experiences with closed-loop control of caliper, gloss, and moisture are presented. This includes both uncoated and coated grades.