Most web-related CD tension variations are characterized by appearing throughout the web line, then changing CD position or disappearing with changes in input material.
Solutions to CD tension variations from web variations:
Most web bagginess is a permanent dimensional variation in the web. However, temporary bagginess may be induced by uneven heating or moisture changing process or conditions, then disappear when temperature and humidity are well controlled.
More on reducing bagginess and camber in 1B Baggy and Cambered Webs
Ensure temperature uniformity (or reduced variation) of heating and cooling processes.
Ensure uniform absorption of heat or moisture in web.