Calendering Concept

Exciting new calender innovations are changing the way different paper grades are finished. They provide potential for more on-line capabilities than previously, as they can operate at faster speeds andstill produce papers with better surface and structural characteristics. Besides high-speed soft-nip calenders.Valmet has recently introduced and started up new Opti Load multinip calenders and Opti Dwelllong-nip calenders.A grade-by-grade vision of where the calendering process is heading gives a direction for conceptsand expected results. The grades discussed range from newsprint to uncoated woodfree and SCgradesas well as different coated papers.The new Opti Concept Paper Machine will utilize on-line calendering to a great extent. It is expected, however, that off-line calendering continues to be the primary concept of finishing most highendpaper grades, such as double-coated and triple-coated printing papers. It will be interesting to seehow quickly, and to what extent, the new long-nip calendering process is applied to finishing of certainuncoated mechanical and woodfree papers.