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November 18, 2005
Got Wrinkles?
Please post your questions or comments on wrinkles here.
I tend to divide wrinkles into four types, each with a characteristic shape and mechanism (see extended comments)
Shear wrinkles:
diagonal troughs, wrinkles will 'walk' across the roller, caused by a shearing stress in the web, often associated with pull the web one directions (left or right), reduced by both long and short span lengths.
Tracking wrinkles:
chevron or inwardly points troughs from both sides, wrinkles will usually have a preferred crossweb position (no real 'walking', maybe some wandering), caused by both sides of the web tracking toward the web's center, reduced by short spans, increased with long spans.
Expansion wrinkles:
A specific wrinkle case from a web expanding while in contact with a roller (due to tension decrease, thermal expansion, moisture related width growth), many small wrinkles, may not cause creasing, may be reduce by spreading the web upstream of the problem roller.
Feed variations wrinkles:
generally crossweb wrinkles, baggy web folding over at a nip point (main reason I avoid nips), laminater buckling at small radius rollers.
Posted by Tim Walker at November 18, 2005 09:35 AM
Comments
During winding I have noticed that diagonal ripples don't turn into wrinkles on product until a certain diameter size for LDPE, why is this? Also, the wrinkles appear to be from the center to one edge of the log, could this be an alignment issue?
Posted by: Drew at May 18, 2007 11:50 AM
Since this is on the different types of wrinkles, I have a question about this. I have a client that prints wide webs, 124", and thru the accumulator the web folds in on itself just on one end. What could cause this?
Posted by: Ron Turner at October 3, 2007 12:48 PM
