There are many characteristics in your machine, which will cause wrinkles as well. Here are some things for which to look:
- Idler roll buckling or deflection (figure 7) will cause wrinkles because the web will actually deflect out of its normal running plane at different intervals across the web width. This out of plane condition will occur wherever the greatest amount of deflection (usually the center) is in the idler roll. When roll deflection occurs, webs will wrinkle because they will compress toward the deflection point.
- Air entrainment in webs (figure 8) as they flow over rolls will cause wrinkles. Air entrainment will create slippage between the web and the roll face. If this slippage occurs, then the web is not in traction with the roll. For the web handling principal, that a web will seek to be perpendicular to a roll in the entry span to that roll, to effect web behavior, it must be in traction with the roll. If the web is not in traction with a roll, it can wander or stay aligned with that roll to which it is not perpendicular. Webs that wander will wrinkle because the web will move to be perpendicular to the next roll with which it has traction. This movement to remain perpendicular will cause a strain on the web. Air entrainment problems can be detected by viewing idler rolls that stop rotating during the converting process. Also, if wear spots are seen across idler roll faces, air entrainment is probably the problem. Machinists’ bluing dye can be applied to idler rolls where air entrainment is suspect to detect wear spots.
- Material roll buckling or deflection (figure 9). If the parent roll deflects on its support mechanism (air shaft, mechanical chucks or core cones mounted on a simple steel through shaft) then compressive forces will cause the material roll to buckle and wrinkle before the web enters the converting process.
Jeff Damour
Converter Accessory Corporation
201 Alpha Road
Wind Gap PA 18091
800-433-2413
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