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Refining our rules of thumb

Lynch, Ronald
Rules of thumb are common in web handling for good reasons. Many of the theories of web behavior are still under investigation and often are complex and a function of properties that are difficult to measure. Because of this, we rely on simple rules of thumb to estimate what are acceptable tensions in a web path. To be safe, these rules of thumb are often very conservative. As we push webs to run faster and more efficiently, we need to refine these rules to meet the new challenges. I wouldn't want to fly in an airplane that was designed with rules of thumb developed years ago for other materials, and I wouldn't want a converting line designed the same way. This paper goes beyond rules of thumb and presents several factors that can help us understand what tensions are right for our webs. It also identifies some area where the knowledge gaps still need to be filled.