Tips

If you process papers, films, foils, woven and non-woven webs, the battle to fight web wrinkles is never ending. There are a multitude of anti-wrinkle systems to help with your fight. One highly effective anti-wrinkle system is the nip type anti-wrinkle device.

Nip type anti-wrinkle systems utilize short face nip roll assemblies, mounted on each edge of your web. Each of the nip roller assemblies "grab" the webs edges and are mounted at an angle to the web. Utilizing the web handling principal that a web will seek to be perpendicular to a roller in it's entry span to that roller, this type of anti-wrinkle system is a highly aggressive, adjustable (by adjusting the angle) and cost effective anti-wrinkle tool.

Here are some tips to get the most of this type of anti-wrinkle system:

• There is no wrap angle through the nip assemblies. The web must enter and exit on the same plane.
• Make sure both nip roller assemblies are aligned to each other, on the same plane as the web.
• Standard nip roller materials are one rubber covered roller and one metal roller per nip roller assembly. You can vary these materials. However, the web MUST be in traction with both nip roller assemblies for this anti-wrinkle system to be effective. One rubber roller is used for traction with its high coefficient of friction. The metal roller provides the pressure necessary to keep the web in contact with the rubber roller. It is possible to supply rollers with other materials if your application requires such consideration. Whatever materials are used must grip the web for this anti-wrinkle system to successfully eliminate wrinkles.
• The nip pressure in each nip roller assembly should be similar. Original models of this type of anti-wrinkle system include adjustable springs for nip pressure adjustment. The newest models of this type of anti-wrinkle device include pneumatic loading for nip pressure adjustment. Pneumatic loading allows for more accurate and more low to high range nip pressure adjustment.

• For delicate webs, always opt for the pneumatically loaded version.
• Pneumatically loaded nip type anti-wrinkle systems make threading the web through the assembly a breeze.
• The angle of each nip roller assembly should be similar. The basic model of nip type anti-wrinkle systems include single-bolt mounting, allowing for loosening the bolt and then angling the nip roller assembly, relative to the web. Adjustable mounting brackets are available that include easy, accurate (with indicator) angle adjustment. These brackets also make it easy to change web width. Investing in these brackets will ensure each nip roller assembly is angled the same amount with equal web edge engagement.

• Do not "over angle" each of the nip roller assemblies. A little angle removes A LOT of web wrinkles.
• This type of anti-wrinkle system works extremely well for most paper, film, woven and non-woven webs. Nip type anti-wrinkle systems are not the best choice for most foils.
• Sample testing and trial units are typically available to help with a buying decision.

As with any anti-wrinkle device, nip type anti-wrinkle systems are highly effective at removing web wrinkles when they are applied properly in the web processing application. Follow these tips to get the most from your nip type anti-wrinkle system.

If you are experiencing issues with web wrinkles or would like to discuss this article, feel free to contact Jeff Damour of Converter Accessory Corporation at jdamour@converteraccessory.com