ABSTRACT
Web wrinkles may be the result of more than one problem. They may be coming from roller misalignment or web skew, or some combination of problems. The roller where the wrinkle is observed may not even be the one causing the problem. An easy approach to narrow the possibilities on most converter machines is to reverse the payoff direction of the supply roll on the machine. If the wrinkles change their angled direction toward the other end of the roller, then the problem is most likely base web skew. If the wrinkles remain in the same location and are similar to what they were before the supply roll direction change, then the following problem(s) may exist:
• Roller misalignment • A web-treatment problem, such as nonuniform coating thickness • A web distortion problem due to applied heat and/or nonuniform
cooling transversely across the web
Base web skew and possible ways to correct it are discussed in Chapter 1. Skew specifications should be established when the web material is acquired. See the method outlined on page 10 to set up skew specifications. Also, Figure 1.7 shows how to measure skew for these specifications.
