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November 09, 2005
More on Rough Rollers
In a reply post to my question on 'What's your favorite rough roller?', the following questions were brought up:
'We 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)?'
In my experience, a shallow knurled roller, where the roller is knurled, re-ground to remove burrs and the tops of the knurled pyramids, then anodized (talking aluminum roller here), leaving a groove that is 0.010-0.020" deep and wide on a 10-20 pitch is fairly easy to clean. Lots of small grooves are better to reduce air lubrication than a few big grooves, plus shallower grooves (like from the knurling process described above) are easier to clean. (continued...)
Elastomeric roller surface, which often have a high coefficient of friction to many web materials, will still have air lubrication problems if they are too smooth. I agree, it is more difficult to dial in a roughness on a elastomeric roller. If the right elastomer is chosen, they surface may have high surface energy, making it difficult for comtaminate to stick to it and easier to clean without harsh solvents (take care to consult the elastomer care instruction regarding solvent contact).
Roller wraps are another inexpensive way to 'roughen' a roller. Wrap the roller with cheesecloth and another soft porous material. To 'clean' the roller, simply pull off a layer of wrap to expose a fresh fabric.
Keep your ideas coming. -tjw
Posted by Tim Walker at November 9, 2005 08:32 AM
