WHQuiz Answer #2 - Crossweb Tension Variations

Published: February 21, 2012

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.