Skewed Rolls for CD Uniformity
rolls must be ground with proper crown to exhibit a uniform nip pli
across the rolls. This will
in uniform paper bulk in CD, and the converted products, rolls or
folded, will be equally dense from one side to the other.
and Dewatering Rolls,
and Laminating Rolls,
and Texturizing Rolls.
the current crown and nip loading (pli), and relate it to the current
nip impressions in the middle and the ends.
the desired nip loading, and compute the new crown.
the degree of cosine curve for best fit.
case of skewed rolls, develop the skew vs. nip loading curve.
program computes the radial crown required on one of the rolls, the
mating roll is uncrowned. Alternatively, crown can be split in any
desired ratio between the rolls.
the offset at the support
bearings on each end of one of the rolls.
the optimal bearing location for rolls with internal bearings.
the effect of the varying thickness of rubber cover for a crowned roll,
and provides a crown correction equation.*
correction for existing crown when the nip impression is not uniform
computes the crown curve of rolls with a uniform wall thickness and
varying cover thickness as a result of crowning.*
is same as above but with rolls of varying wall thickness.*
solves the case for a 3-roll stack.*
drawing of the rolls.
impression taken in the middle should match that at the ends.
bulk profile of the paper should be fairly even in CD.
converted product density should be uniform.
have been calculated for a number of installations with satisfactory
the desired result is obtained on the first try.
For details on these items please refer to "Deformation of Contacting
Rollers with Compliant Coatings", by Balbir Singh, Ph.D. Thesis,
University of Pennsylvania, 1979.