Manufacturing Flexible Packaging

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Basics of Web Processes

This chapter summarizes common components of web-based processes. These processes involve long thin strips (“webs”) of various materials rolled onto a cylindrical core with length approximately equal to the width of the stip. The rolls will later be unwound for their eventual use. The mechanics of winding and unwinding observe very basic principles of physics. Tension, nip pressure, and torque are the physical forces used to control webs during various manufacturing processes. Understanding specific flexible packaging manufacturing processes requires at least a semiquantitative appreciation of the meaning and interactions of these forces. Industry measures including “yield” and “basis weight” must also be understood for ...