When winding a laminated web of several different materials, to obtain the suggested maximum web tensions for laminated structures, simply add the maximum web tensions for each of the materials that have been laminated together (usually disregarding any coatings or adhesives) and apply the sum of these tensions as the maximum web tension for the laminate.
The winding tools to develop roll hardness are web tension, nip pressure (from a pressure or lay-on roll or winding drum) and winding torque from a center drive when center/surface winding film webs.
When winding elastic films, web tension is the dominant principle of winding used to control roll hardness.
1, the web tension is produced by the winding torque from a center drive.
The amount of starting and finishing web tension for a specific material often must be determined empirically.
The nip loading is less material dependent than web tension and will vary greatly with the material and the amount of roll hardness required.
As stated earlier, this torque is used to produce the web tension on center winders.
The web tension coming into the winder is independent of the winding tension produced from this torque.
Typically the winding tension starts at 25-50% greater than the incoming web tension.