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Web handling and winding specialist Timothy J. Walker has 25+ years of experience in the field. He is President of TJWalker+Assoc. and has helped over 100 companies in processes involving paper, film, and foil-based manufacturing...more

WHQuiz Answer #2 - Crossweb Tension Variations

 

WebHandlersQuiz 2: Tension Control – Name three causes of tension variations across the web’s width (i.e. things would create a loose edge or center)?

Answer to WHQuiz#2

  • Roller variations, including: misalignment (level or tram), deflection, diameter variations vs. width.
  • Crossweb dimensional variations, either permanent (bagginess or skew) or temporary (from temperature or moisture variations)
  • Splicing misalignments

Bonus Question: How do you know which you have?

  • Roller variations will create a local bagginess that will not appear throughout the process or correspond to the splice as it passes through the process.
  • Permanent web bagginess and skew will be seen throughout the web lines, possibly changing in magnitude and location as a roll unwinds and commonly changing from input roll to input roll. Temporary dimensional variations from temperature or moisture will occur where the process or environment induced these changes.
  • Splice-related bagginess will be temporary as the splice passes through the equipment and quickly disappear after the splice goes by.

Be warned: These tension variations causes can occur simultaneously.

More on this topic was covered in this archived Web Lines column:

What Is the Right Tension? (Dec. 2009)

If you missed it, here are all 20 questions in my Web Handler's Quiz


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