PAPER CURL MILL WISE
The Problem of PAPER CURL
Making a quality sheet of paper is hard enough, and paper curl doesn’t make it any easier
CHARLES GREEN and JIM ATKINS
aking a quality sheet of paper can be hard enough, but one problem that can make it almost impossible is paper curl. Curl affects almost every grade of paper and board. It causes paper jams in printer/copiers, print register problems in newspaper presses, and combined board warp (curl) issues for corrugators (Figure 1). As a papermaker, curl can be particularly frustrating because a sheet
that appears to be flat “as manufactured” may curl quite badly in the customer’s converting operation. Addressing curl problems requires that we look at our process and the very structure of paper to find out why curl is occurring. And it is very often the case that “the lack of information is all-pervasive; every link in the production and logistics chain can make a difference.”1 Each problem is usually a unique combination of paper properties and end-use conditions.
Figure 1. Twist warp of corrugated board due to fiber alignment problems.
Paper360º JANUARY/FEBRUARY 2012
Table of Contents for the Digital Edition of Paper360 - January/February 2012