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April 14, 2005
What's your favorite rough roller?
Handling smooth films or papers on smooth rollers is like driving through puddles of water with bald tires. You can do it slowly, but its hazardous at even moderate speeds.
Many converter never run into this problem. If you product is porous (like many nonwovens) or rough (like abrasive-coated papers), you have a way to prevent air lubrications. But if you run smooth, non-porous webs, you have to manage the lubricating air layer with roller roughness.
What is your favorite rough roller?
What do I like? I like roller surfaces that have a lot of little valleys, not a few big grooves. I like knurled, machined anodized aluminum rollers. I like plasma sputter surfaces. I like the "nubby" tape made by Tesa. All of these feature short distances from peak to valley. All have good wear characteristics, so they will last a long time.
An example of a knurled roller can be found at the Webex, Inc. website: http://www.webexinc.com/ms.html
I'd like to hear what your favorite is. -tjw
Posted by Tim Walker at April 14, 2005 12:55 PM
Comments
We solved some air lubrication problems on smooth 8" rolls by changing to a 200RA blasted surface anodized aluminum roll. The difference in traction was quite dramatic. Before, at 150ft/min, you could stop the roll by pressing your thumb against the end of the shaft -and this is a high wrap roll. Now, it's as if the web is geared to the roll surface. -and as far as our web is concerned, the roll texture is still smooth enough to not cause concerns around scratching or marring.
Posted by: T Higgins at October 26, 2005 01:54 PM
I agree with your comments on obtaining surface roughness via knurling, blasting or plasma coating, and grooving. But we also have issues regarding keeping rollers clean, and grooved or knurled rolls present a challenge. Any thoughts on this? What are your thoughts around elastomeric surfaces (can probably get higher coef. of friction, but more difficult to control roughness, except through grooving)?
Posted by: Claude Faulkner at November 2, 2005 06:39 AM
