Calendering involves high pressure loading, requiring roll deflection compensation and control. Pyradia uses software modeling to establish deflection and selecting the best suited deflection control method, whether roll skewing, roll bending, or roll crowning. Roll crowning consist of grinding the calender rolls with a fix profile, ideal for applications dedicated to a single process where loading is constant. Roll skewing pivots on of the rolls versus the other to even the gap without affecting deflection. Roll bending consist of applying a force to the rolls, either positive or negative, depending on whether their surface are over or under crowned versus the applied loading. Secondary bearings are mounted outboard of the main bearings, and hydraulic cylinders apply a force to these bearings, using the main bearings as pivot points to bend the calender roll.
Calenders can be equipped several optional systems, such as preheating of the material or thickness gauging system for automatic, closed loop control of gap opening and loading force. Pyradia also developed proprietary servo-hydraulic solution for controlling gap positioning within few microns and adjusting it on the fly at full line speed and full loading.
With over 50 years of experience, extensive process knowledge, modeling software and pilot equipment, Pyradia engineers will analyse your specifications and recommend the ideal production line configuration for optimal process efficiency.
