Web wrinkles can be difficult to eliminate, but with perseverance you can be successful.
Lead-in rollers cause a majority of wrinkles, especially as ink and paper lint build up.
Cleaning these rollers regularly will reduce or eliminate this problem. In any event, it is imperative that all ink rollers are cleaned before continuing to resolve any wrinkles that still exist. The lead-in roller bearing should also be checked. Any bearing with more than .002-inch movement should be replaced. An accumulation of several worn lead-in rollers will also cause web wrinkles.
Additionally, check the blankets to make sure they are properly installed and are in good condition. A blanket running partial rolls will pack down on one side, causing a wrinkle to occur whenever full rolls are used. Make sure they are parallel and packed properly.
Other causes of wrinkles include improperly set iron-to-iron or unit-to-unit or unit-to-folder misalignment.
If the unit is misaligned, then the angle bars will be out of alignment as well.
Web alignment, in other words, unit alignment, is based on the RTF, or roller top of former. Check the RTF bearing for wear.
If there is any wear at all the bearings should be replaced to ensure accurate alignment.
Checking the levels
To align your press, use a laser or optical transit. You can also use piano wire or a monofilament line to align the centerline of the press.
Machinist levels should be used to level all of the units to one another as well as to the folder. It is extremely important that the level and line are as close to perfect as possible in order to eliminate web wrinkles, ensure accurate print register and to eliminate driveline wear.
Don't forget to check the folders for worn nips, misaligned guide rollers, improper pin extension or other issues governing the angle of the folder board.
Web wrinkles can be difficult to diagnose because proper alignment involves so many components. Additionally, the very product you are trying to control - paper - is difficult to manage because of moisture content and other factors.
Some web wrinkles will come and go because of the quality of the product. You may notice fewer wrinkles from paper manufactured by a particular mill.
In most cases, any web wrinkle can be ironed out through the use of a perfectly aligned press and good, quality paper.
Frank Bourlon is the executive and training director for the Newspaper Production and Research Center. He can be reached at firstname.lastname@example.org or 405.524.7774.