Tissue360 - Spring/Summer 2018 - 31
Ensuring Rolls Run Right
FPInnovations Roll Testing Facility has provided a new opportunity
for mills to improve their tissue making and converting operations.
FPInnovations developed its Roll
Testing Facility (RTF) about 15 years ago to
look at non-uniformity of paper rolls. One
objective was to see if the root causes of problems seen in the pressroom, such as bagginess,
could be explained.
"We developed a tool to look at tension,
moisture, paper properties, and roll structure
quality to troubleshoot the problems with rolls
rejected by pressrooms," explains Frédéric
Parent, research leader, web performance.
An important step in its evolution came in
2015 when a rebuild of the equipment allowed
the RTF team to look at low basis weight paper
rolls such as tissue (all grades).
As tissue is very weak, the RTF had to be
able to reduce considerably the draw tension.
A new distributed control system included
the modification of the tension beam to avoid
tears and breakage.
"We recognized the decrease in demand
for paper testing," Parent adds. "At the same
time, we saw the need in tissue testing, for
example, uniformity as well as problems seen
in embossing such as wrinkles. We are doing
what we always did, but for tissue. We're taking all the knowledge we learned from paper
roll testing and applying it to tissue."
This is not to say that the RTF has turned its
back on other paper. "We are able to go from
liner to tissue to flexible packaging, any web
(including aluminum foil and plastic film),
The major challenge the RTF team faced at
the beginning was the inherent weakness of
tissue, particularly one-ply bathroom tissue.
"But now we can do it," Parent says.
Analyzing strength uniformity (m-factor) is
a useful tool in troubleshooting web breaks
in tissue converting. In describing the work
done at the RTF, Parent and co-authors
Nina Deng, André Ménard, Jean-Francois
Rousseau, Javad Saberian, Jimmy Jong, and
Xuejun Zou wrote: "Low strength uniformity
T .. pp I
* Is I
100 tensile tests were done on each tissue roll at 1 m
interval in MD
* The average tensile strength and strength uniformity, m-
factor were calculated according to Wiebull distribution
entails that there is a greater number of weak
areas in the tissue; when the weak areas meet
tension variations on the converting line,
the risk for web breaks greatly increases.
M-factor analysis consists in measuring the
variations of MD tensile for a certain tissue
length, and then calculates through software
the Weibull modulus of the tensile distribution. The higher the Weibull modulus (or
m-factor), the higher the strength uniformity
and lower the risk of having web breaks."
In North America, softness is key.
Therefore, hardwood pulp is a desired furnish. But, with a higher amount of hardwood
pulp, customers were facing runnability
issues because of the loss in strength. This
was happening at the converters as well as
"Therefore, we need to get that perfect balance," Parent says. "The industry is trying to
get a more uniform product to be able to add
more hardwood pulp."
Tissue360º SPRING/SUMMER 2018