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Web Lines: The Spin on Idler Roller Testing

(Web Lines)

May 31, 2008, ... the speed of your idler rollers to speed of your web or to a non-slipping roller such as a nipped or vacuum-assisted driven roller — is the acid test. If the roller isn't slipping, what could be wrong? ...

Web Lines: Thinking About New Equipment?

(Web Handling)

January 31, 2008, ... needs, including number of zones, preferred tension feedback by zone, and drive roller traction preferences. (I like to avoid nipped drive rollers). Include the proposed tension control plan in the specification ...

Get a Grip: Driving Your Web

(Archive)

December 31, 2007, ... for driving a web between tension zones include the following: Unnipped rollers Simple, usually with a larger wrap angle and high traction surface (rubber with a roughness or groove pattern). These ...

Parallel Protocol

(Web Handling)

December 31, 2007, ... each time.) Finally, rolls that can be nipped and are used to apply a layer of coating onto a substrate, as shown in Figure 5, can have misalignment problems that lead to uneven coating thickness. This ...

Baggy Webs: Part 4 Minimizing

(Archive)

July 31, 2007, ... you will almost assuredly see wrinkling at all your nipped processes. Nips are needed for many processes, such as coating, laminating, and calendering, but avoid nipped rollers for web handling only. Apply ...

Under Pressure (A Brighter Look)

(Archive)

May 31, 2007, ... of covering thickness and diameter on pressure. If you run your nipped process by load, which many people do, a lab machine with 0.25 in. of rubber on a 3-in. roller will create the same pressure as a ...

Under Pressure (Revisited...and Revised)

(Archive)

February 28, 2007, If I have any repeating theme to understanding web handling, it is to follow the stresses and strains. In nipped processes, you need to follow the compressive stress (aka pressure). Web Lines (Corrected ...

Reader's Choic

(Magazine)

February 28, 2007, ... adhesive and the second, equipped with take-up and take-off units, to apply foil. Foil is nipped with the sheet between the blanket and impression cylinders, while pressure transfers only the adhesive-coated ...

Web Tension: A Pop Quiz

(Web Lines)

September 30, 2006, ... won't need a tenfold tension increase. Step 3: Bonus round (possible 10 points) Do you prefer unnipped or vacuum drive rollers over nipped drive rollers? (1 point) Have you used the belt equation ...

CPP: Season Two

(Magazine)

September 30, 2006, ... on the hottest topic related to both winding and wrinkling: baggy webs. Learn how winding can create baggy webs; and how to measure and handle baggy webs — especially in nipped roller processes.  ...

Deflecting Nip Roller Problems?

(Magazine)

March 30, 2006, What causes nip roller deflection? How can you compensate for nip roller deflection? Web Lines X ’em out! Nipped rollers are vital to many web processes, including coating, laminating, embossing, calendaring, ...

Drawing Conclusions: Part II

(Magazine)

May 30, 2005, ... sections (presses, slitters, small-wrap over rollers, and unnipped pull rollers) and for low-modulus or easily yielding webs. Large draws are used for film orienting and for separation after sheeting. ...

Why Tension?

(Magazine)

January 30, 2005, ... will mean breaks at lower tensions. Too little tension is more difficult to define; it varies by your process needs. If your web needs to go through nipped rollers or lie flat through slitting, you ...

Reduce Web Nip Problems

(Magazine)

January 31, 2004, Web handling is about transport and delivery, getting from point A to point B, without damaging the product. It is relatively easy to move a web across a free span or over an unnipped roller, but getting ...

Winding Better Rolls

(Archive)

May 31, 2003, ... web's speed. Without a winding nip, the high- velocity air creates high pressure at the web-roll convergence. An unnipped web, which creates only low pressure (less than 1 psi), can be lifted by the air ...

Can't Touch This (Web): Part

(Magazine)

March 31, 2003, ... coated films into taffy, or worse yet, into rope. How will we isolate the high-low tension change with single-sided contact web? Wrap angle limits prevent significant unnipped tension change. Nipping ...

Five Questions and Answers on Lubrication

(Magazine)

September 30, 2002, ... roll. Air lubrication should be suspected when shifted layers increase with larger diameter, higher speed, lower tension, and smoother products. How is air lubrication prevented? For unnipped rollers, ...