Some rollers can be tipped, usually by a screw adjustment. For process rollers, such as calendering, coating and printing, one motivation is to attempt to “level” the process so that the side-to-side variation is reduced. Another motivation is to scissor rollers, as is occasionally done on some calenders, to counter the frown-shaped tendency caused by roller deflection.

Adjustments such as this are a two-edged sword. A good operator might be able to take a marginal situation and tip it just enough so that the product becomes acceptable. Conversely, a not-so-good operator may ruin an otherwise acceptable web by misadjustment.

However, I will claim that success in applying process skew depends more on machine and measurement than on operator skills. If the adjustments on the machine are coarse, have backlash or have no precision zero, even the best operators will have trouble. If there is no trustworthy measurement of process results, such as coatweight, the best operator will be running blind. It would be like trying to keep a car on the road by listening for the left or right tire hitting the gravel on the side of the road.

Some idler or transport rollers can be skewed, for instance to compensate for a baggy lane. In printing, these devices may be used to stretch or skew one side of an image versus the other. In the case of baggy webs or printing, measurement of the results is visual. The bagginess of a web is far harder to see than a printing misregistration error. I can give other reasons that bagginess compensation may not be effective. The compensation would be most effective for a pure case of camber, where tension varies linearly across the width. Most baggy lanes are too narrow to be treated this way, even if they were conveniently located on one edge only. Also, so what if you did compensate at the skew position? It does nothing for the next span, because the bagginess will immediately spring back—as no permanent change has been made to the web.

Then there are the idler rollers mounting on springs or pivots that are somehow supposed to automatically compensate for a baggy edge. However, there is every web-handling reason to believe that these are nothing but evil. They are unstable and usually make the problem much worse than hard mounting a roller in dead-level alignment.

I cannot say whether or not your particular skewing position is a good idea. That is for you to judge. What I will say is that all of these devices misalign rollers, which we know is extremely risky in its own right. These risks include the uneven processing, wrinkling and apparent bagginess that skewing is supposed to correct in the first place.

Thus, the results had better outweigh the very real risks. Also, if you do skew, do it well. First, you need a quantitative measure of side-to-side results that is fast, fine and very trustworthy. Second, the movement should be adjustable with a micrometer. Thousandths of an inch at a time in the case of transport rollers, ten-thousands of an inch at a time in the case of a process roller. Third, there should be an aligned zero so that the operator can always come right back to dead-flat alignment when things are not going well.