Note: Descriptions are shown in the official language in which they were submitted.
CA 02560723 2003-06-06
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CONSUMER PRODUCT WINDING CONTROL AND ADrtJSTMENT
FIELD OF THE INVENTION
A method and apparatus for winding sheets of material such as paper, film,
textile,
plastic, food, three-dimensionally shaped formed film and adhesive
combinations, or other
materials. The apparatus and method control the winding speed, winding tension
and/or the
winding density of the wound sheet of material.
BACKGROUND OF THE INVENTION
An important factor far determining the quality of a wound sheet of material
is the
winding speed. Generally, winding speed can be used to control the winding
tension and/or the
winding density. The winding speed is especially important for sheet materials
including filin
and adhesive combinations where the majority of the adhesive lies in the
recesses of the film.
Although various mechanisms and apparatuses have been proposed for winding and
unwinding
operations, problems have been presented in maintaining a uniform wound
product.
In various manufacturing operations for producing textiles, felts, papers,
films, etc., it is
necessary to wind a sheet of material into a roll. Where the sheet of material
is a uniform and
repeatable rolled consumer product, the roll may be referred to as a Iog.
Consumer product Logs
are often much smaller than the commercial rolls used in other applications.
Further, sheets of
material such as paper products or film-adhesive combinations may have little
or no tension
applied at certain points in the rolling process. It has been found that a
better, faster and more
repeatable control mechanism is possible through controlling the material log
speed with a
reference profile that is adjustable based upon measured process parameters.
Other winding systems are constrained by their design to rewinding relatively
large
commercial rolls used in subsequent processing for making finished product.
The prior art does
not provide a winding system as disclosed and claimed herein.
The winding quality and material properties such as thickness and appearance
are
strongly influenced by the tension that is present in the sheet of material
during the winding
operation. Despite the efforts to improve the winding of material, there
remains a need for
improvements in the speed, control, and effectiveness of devices for producing
wound consumer
logs of material.
Several patents describe alternative winding approaches for various purposes.
Such
efforts are described in U.S. Pat. No. 4,588,138, issued to Spencer, U.S. Pat.
No. 4,508,284
issued to Kataoka, U.S. Pat, No. 4,744,526 issued to Kremar, U.S. Pat. No.
5,611,500 issued to
CA 02560723 2003-06-06
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Smith, U.S. Pat. No. 3,934,837 issued to Keilhack, et al., U.S. Pat. No.
6,189,824 issued to
Stricker, U.S. Pat. No. 4,883,233 issued to Saukkonen, et al. and U.S, patent
6,189,825 issued to
Mathieu, et ai.
An object of the present invention is to provide a winding apparatus for
paper, textile,
plastic, or other sheets of material, which has advantageous winding
characteristics for consumer
size logs. Another object of the invention is to manufacture logs with a
smaller diameter
variation. It is also an object of the present invention to provide a log with
a more consistent
wind tension such that the force required to unwind the sheet of material from
the log is relatively
constant throughout the log. This is especially important for flm-adhesive
combinations where
the bonding of the sheets to one another inside the log can be a problem
Further objects,
features, and advantages of the invention will become apparent from the
detailed description that
follows.
SUM'.VIARY OF THE INVENTION
An object of the present invention is to provide a consumer product winding
control and adjustment.
The invention provides a method and apparatus for winding a sheet of material
such as
paper and film finished products using a reference profile, thereby improving
product quality,
manufacturing rate and reliability. Many commercial consumer product winding
systems may be
used including center winding systems, surface winding systems, and
translating systems. The
proposed method and apparatus are designed to provide improved consumer
product quality in
high-speed converting operations malting small, consumer size logs.
In one embodiment, the method includes using a winding apparatus to wind a
sheet of
material onto a core to form a Log. The material is wound into the log in
accordance with a
reference profile. A process parameter is measured to obtain at Least one
process para~ter
measurement. The reference profile is adjusted according to at least one
process parameter
measurement. The core has a variable rotational velocity during the winding
operation.
Preferably, the winding rotational velocity changes a minimum of about 400
revolutions per
minute between about 2 and about 35 machine degrees. More preferably, the
velocity change is a
decrease of about 400 revolutions per minute between about 2 and about 35
machine degrees.
In one embodiment, the winding apparatus includes a mandrel, a drive system, a
material
CA 02560723 2003-06-06
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handling system, an adjustable reference profile, and a process parameter
measuring device. A
core is removabIy disposed about the mandrel. The drive system drives the
mandrel, and winds
the sheet of material onto the core to form a log. .The material handling
system delivers the sheet
of material to the mandrel and/or core. Tn one embodiment, the reference
profile is the winding
speed in rotations per minute (RP1V)] vs. machine degrees. The process
parameter measuring
device measures at least one process parameter. In one embodiment, the process
parameter
measurements are taken at least once when a log is measured. The logs may be
measured at any
interval of logs.
In one embodiment, the process parameter measured is log diameter. The minimum
core
rotational velocity change during winding is about 400 revolutions per minute
between about 2
and about 35 machine degrees. Alternatively, the minimum core rotational
velocity change is 4%
in the first 10 revolutions after start of winding, or 8% in the first 20
revolutions, or I2% in the
fast 30 revolutions.
In accordance with another aspect of the invention, there is provided a method
of
using a winding apparatus, preferably a center winding apparatus, to wind a
sheet of
material onto a core to form a log, characterized in that the method comprises
the steps of
. . winding the sheet of material about the core in accordance with a
reference profile;
measuring a process parameter to obtain at least one process parameter
measurement;
providing a reference profile adjustment according to the at least one process
parameter
measure~nt, preferably wherein the reference profile adjustment is based upon
the process parameter measurement vs. a target process parameter; and
the core having a rotational velocity change of at least about 400 revolutions
per minute
between about 2 and about 35 machine degrees.
In accordance with another aspect of the invention, there is provided a
winding
apparatus for winding a sheet of material, preferably film, food, nonwoven,
woven, or
combinations thereof, to meet a reference profile, the apparatus characterized
in that the
apparatus comprises:
a mandrel with a removable core disposed about the mandrel;
a material handling system for delivering the sheet of material to the core;
a drive system for rotating the mandrel and core, the drive system winding the
sheet of
material onto the core to form a log;
at least one process parameter measuring device to obtain at least one process
parameter
measurement, preferably obtainable at a frequency greater than about 10 times
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3a
per second, the at least one process parameter measurement being used to
adjust
the reference profile, preferably where the reference profile is adjustable at
a
frequency from about 1 time per minute to about SO times per second.
In accordance with another aspect of the invention, there is provided an
unwind
apparatus for unwinding a log of a sheet material, the unwinding apparatus
characterized
in that it comprises:
an unwind mandrel about which the log is placed;
a pull system for pulling the sheet of material off of the log in an unwind
direction;
at least one unwind measuring device, preferably an automated unwind measuring
device
to obtain at least one process parameter measurement, the process parameter
measurement being used to adjust a winding apparatus reference profile used to
subsequently manufacture a second log.
BRIEF DESCRIPTION OF TIC DRAW~TGS
The various advantages of the present invention will become apparent to
skilled artisans
after studying the following specification and by reference to the drawings in
which:
Figure 1 is- a generic graphical view of a speed reference profile;
Figure 2 is a perspective view of a log winding apparatus;
Figure 3 is a side view of one embodiment of the log winding apparatus;
Figure 5 is a plan view of a log unwinding apparatus;
Figure 4A is a plan top view of a three dimensional sheet;
Figure 4B is a plan side view of a three di~sional sheet;
Figure 6 is a plan view of a log unwinding apparatus with a nip roll.
Like elements may have like numbers in more than one drawing in order to
reduce the
number of different numerical identifiers used for a particular element.
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3b
DfiTAILED DESCRIPTION OF THE IrIVENTION
The present invention controls the wind characteristics of consumer logs
(logs) using at
least one measured process parameter to adjust a reference profile. The
reference profile reflects
a desired target process parameter value at a particular point in the process.
This reference
profile value is compared with a measured process parameter value. The
reference profile is used
to control at least one aspect of a wind apparatus or wind method. Further
process parameter
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measurements lead to further adjustments in the reference profile as necessary
to deliver the
desired consumer size wind of a sheet of material, called a log. The reference
profile adjustments
reduce the process parameter variation during and/or between log windings. The
adjustments can
also be used to control the internal tension and compressive forces between
the layers of sheet of
material in the log. Tntemal log tension control is particularly desirable for
film-adhesive
combinations.
Definitions
The terms used herein have the following meanings:
"Disposed" is used to mean that an elements) is formed or positioned in a
particular
place or position as a unitary structure. The element may be joined or not
joined to other
elements.
"Joined" encompasses configurations whereby an element is directly secured to
another
element by affixing the element directly to the other element, and
configurations whereby an
element is indirectly secured to another element by affixing the element to
intermediate
member(s), which in turn are affixed to the other element.
"Comprise," "comprising," and "comprises" are open ended terms that specify
the
presence of what follows e.g. a component, but does not preclude the presence
of other features,
elements, steps or components known in the art, or disclosed herein.
"Compression" refers to a load that tends to squeeze or press an article
together.
"Tension" refers to force tending to stretch or elongate an article.
"Sheet of material" refers to any flexible material that can be rolled into a
log.
Examples include film, aluminum foil, paper, cloth, food, wovens, scrims,
meshes, nonwovens,
combinations thereof and the like.
"Log" refers to an in process, near complete or completed wind of at least a
portion of a
sheet of material into a consumer size wind of material.
"Consumer size" refers to a size or configuration generally sold retail to the
public.
"Wind" refers to the rotational process of rolling a sheet of material into a
log.
"Core" refers to a component that remains with the log after winding and
provides
internal support.
"Caliper factor" refers to the theoretical spacing between sheet of material
winding
layers on a log. The Caliper Factor and/or log diameter measurements may be
used to influence
CA 02560723 2003-06-06
the instantaneous slope of the line 11 in Figure 1. The slope may change from
a fixed pivot point
on the line.
"Max line speed" refers to a scalar that moves the line 11 in Figure I
vertically without
changing the slope of the line.
"Robustness" refers to being insensitive to small changes, variations, or
inaccuracies.
"Machine degree" refers to specified equivalent portions of a repeating
winding cycle.
Any number of machine degrees may be used to represent equivalent intervals in
the wind cycle.
As used herein the basis for calculating machine degrees is that there are 360
equivalent machine
degrees in each wind region of the winding cycle. For example, a log with 720
revolutions per
Iog in the wind region would have the revolutions divided by 360 for two
revolutions per
machine degree. If a basis of 720 machine degrees were chosen than a point at
35 machine
degrees as defined herein (base 360) would correspond to a point at 70 machine
degrees with a
base 720.
The Reference Profile
For any given log product, there is at least one reference profile 70 for the
winding
process. Figure 1 shows a generic reference profile 70. The reference profile
70 is designed to
yield a log with desired properties. These log properties include a preferred
wind tension, log
diameter, and log material density. In one embodiment, the reference profile
70 provides a
relatively consistent in-wound tension and/or compression throughout the log.
This is provided
in part by properly locating or spacing each layer of paper or film throughout
the log.
The reference profile 70 may control the winding apparatus and/or one or more
components of the winding apparatus. For example, the reference profile 70 may
control the
sheet of material tension during winding, the wind speed, the length of
material being wound, the
core angular displacement, the drive system, the relationship between one or
more of these
parameters, or other winding measurement parameters.
As shown in Figure 1, the reference profile 70 may be a speed reference
pxofile 70 of the
log speed in revolutions per minute (RPM) at a specified machine degree (RPM
vs. machine
degree). The wind RPM is shown in Figure 1 as a percentage of the top motor
speed in the
winding process. Target speeds are established at multiple machine degrees in
the winding cycle.
To maximize accuracy there are preferably several speed reference points
spaced in equal
increments within each machine degree. For example, there may be 2048 speed
reference points
in each winding cycle, or approximately 5.689 points per machine degree. The
combination of
CA 02560723 2003-06-06
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speed v. machine degree provides the speed reference profile 70. The reference
profile 70 in
Figure 1 may have any shape needed to properly wind the sheet of material into
a log.
As shown in Figure 1, a pre-transfer region PT between about 260 degrees and
about 0
degrees represents the acceleration and deceleration period prior to winding
the log. At about 0
degrees, the mandrel/core and the sheet of material speeds are matched or
nearly matched as the
two are connected. The post winding PW region between about 360 degrees and
about 60
degrees represents the deceleration period after the log is complete and the
sheet of material feed
has been separated from the log. The wind region WR is between about 0 degrees
and about 360
degrees. This represents the period when the sheet of material is wound onto
the core to form a
log.
The reference profile 70 is designed to be adjustable and/or changed by
reference profile
adjustments. Reference profile adjustments may be made by changing the max
line speed and or
the caliper factor. The reference profile adjustments are made as needed and
indicated by
comparing actual process parameter measurements with theoretical or target
process parameters.
A control device may be used to adjust the reference profile 70 based upon
variations in
the measured process parameter. Preferably, the reference profile adjustments
are calculated by
computer and automatically updated. The difference between the measured and
target process
parameter data provides the primary input for calculating the reference
profile.
Data from the log being wound may be used to make reference profile
adjustments.
More preferably, the data from more than one log may be used to make reference
profile
adjustments. Generally, the measured process parameter vs. a target process
parameter
comparisons are made at selected points in the wind process. For example, a
process parameter
measurement could be the log diameter measured at one or more selected machine
degrees. The
process parameter measurement may be taken at a machine degree anywhere from
about 0 to
about 360 machine degrees. Preferably, the process parameter measurement may
be taken at
least once at anywhere from about 10 machine degrees to about 358 machine
degrees. More
preferably, the process parameter measurement may be taken at least once at
anywhere from
about 340 machine degrees to about 360 machine degrees. In one embodiment, one
measurement
on a log may be taken at about 356 degrees. If the log diameter is larger than
desired, the
winding speed and thus the winding tension may be increased to compress and
reduce the log
diameter during winding. Subsequent log diameters at the specified degree
location may be
measured to assess the effect of the reference profile 70 speed/tension
change.
The reference profile adjustments and process parameter measurements may be
made at
any frequency and at any interval. Frequency refers to the number of reference
profile
CA 02560723 2003-06-06
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adjustments and/or process parameter measurements made in a particular time
frame. Interval
refers to the number of logs manufactured between measurements. For example,
the process
parameter measurements may take about IS measurements per second for about 1
second at about
3 log intervals.
The frequency and interval of reference profile adjustments may be controlled
in part, by
how closely the process parameter measurements match the target process
parameters. Reference
profile adjustments in a well controlled system with minimal variation may be
infrequent. The
reference profile adjustments are calculated as needed at any point in the
manufacturing process.
Reference profile adjustments may be made as needed to maintain at least one
process parameter,
such as log diameter, within a desired variability. The reference profile 70
may be adjusted at a
frequency greater than about once per minute. The reference profile 70 may be
adjusted at a
frequency greater than about 10 times per second. The reference profile 70 may
be adjusted at a
frequency from about 1 time per minute to about 50 times per second.
The reference profile adjustment intervals may be any interval of logs as
needed to
maintain control of the manufacturing process. The reference profile 70 may be
adjusted
between logs such that the reference profile adjustment affects at least one
subsequently wound
log. The reference profile 70 may preferably be adjusted such that the
reference profile
adjustment affects at least the log being wound. Alternate reference profile
adjustment intervals
include about every log, about every other log, about every third to fifth
log, at least about every
sixth to tenth log, about every 100'a log, about every 1,OOOm log and the
like. The frequency and
or interval of reference profile adjustments are preferably made in accordance
with known
statistical process control techniques such as those disclosed in American
Society for Quality
Control (ASQC) document Z1.4-1993 "Sampling Procedures and Tables for
Inspection by
Attributes."
Generally, at least one process parameter measurement is used to calculate a
reference
profile adjustment. Therefore, it may be desirable for the frequency of
process parameter
measurements to equal or exceed the frequency of reference profile
adjustments. However, the
process parameter measurements may be obtained at any frequency. The process
parameter
measurement may be obtained at a frequency greater than about once per minute.
The process
parameter measurement may be obtained at a frequency greater than about 10
times per second.
The process parameter measurement may be obtained at a frequency from about 1
time per
minute to about 50 tunes per second.
The interval of measuring one or more process parameters may be any interval
of logs
needed to maintain control of the manufacturing process. Process parameter
measurement
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interval examples include about every log, about every other log, about every
third to fifth log, at
least about every sixth to tenth log, about every 100' log, about every 1,000'
log and the Like.
Exemplary intervals are also disclosed in ASQC document Z1.4-1993.
The reference profile need not be adjusted based on every individual process
parameter
measurement. One potential benefit of averaging or analyzing data vs.
responding to a single
measurement when adjusting the reference profile 70 is improved log
uniformity. Using an 8 log
moving average, a pilot test process was able to keep the log diameter within
a range of about
plus or minus (~ 1.5 millimeters (mm). Preferably, the log diameter variation
would be limited
to between about ~ 0.3 mm. A closed-loop algorithm for adjusting the reference
profile 70 using
an average of the log diameter measurements maintained a log diameter range of
about t 0.8 mm
over 120 consecutive logs. This was achieved by adjusting the caliper factor,
and/or the mar line
speed.
In one example, the process parameter measured is the log diameter. The
reference
profile 70 is for the drive system controlling the center wind. At least one
log diameter
measurement is compared to the target or theoretical log diameter for that
point in the winding
process. This comparison may be made at one or more points in the winding
process. The
difference between the measured and the target values at each point are then
used to generate a
modification to the reference profile 70 based upon a previously established
relationship or a
correction scale factor. The modified reference profile 70 is used for
subsequent log windings
until new measurements indicate further changes in the reference profile 70
are needed.
The Apparatus
One winding apparatus 200 embodiment may be a center winding apparatus as
shown in
Figure 2. The present invention can also be applied to any type of center,
turret, translating, non-
translating (stationary), rewinder-roll apparatus, or combination thereof. The
winding process
may operate at any rotational or translational operating speed. The
translationai and rotational
speeds may also vary during the winding process. Apparatuses that are
continuously translating
may also be used. One example of a continuously translating apparatus 200 is
U.S. Pat. No.
5,913,490 issued to McNeil et al.
As shown in Figure 2, the winding apparatus 200 is designed to wind at least
one log 30
of sheet of material 50. The apparatus 200 may include at least one drive
system 240, at least one
mandrel 280 with a mandrel radius 285 (Figure 3), at least one material
handling system 290, and
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at least one process parameter measuring device 246. A core 220 is designed to
be disposed
about the mandrel 280 for winding and removed with the log 30. The mandrel 280
supports the
core 220 and rotates to wind the sheet of material 50 about the core.
Generally, the core and
mandrel are associated with each other on the apparatus 200 such that they
have the same
rotational velocity (revolutions per minute or RPM) during the winding
process. The winding
apparatus 200 may also include at least one control means 243 for adjusting
the reference profile
70 (Figure 1) based upon the process parameter measuring device 246. In one
embodiment, the
control means 243 may be a computer connecting the process parameter measuring
device 246
with the drive system 240.
As shown in Figure 2, the drive system 240 may include at least one drive
motor 242,
drive controller 244, drive connector 245, and process parameter measuring
device 246. The
drive connector 245 may rotate and/or translate about a central axis 247
during the winding
process. Movement about the central axis 247 controls the translation. The
drive connector 245
may be used to connect the mandrel 280 with the drive system 240 and rotate
the mandrel. A
preferred embodiment is disclosed in U.S. Patent 5,913,490 issued to McNeil,
et al. The drive
system 240 may be connected and unconnected with the mandrel 280 as needed
when the
mandrels) 280 are rotated. The connection may be by any means lmown in the art
including but
not limited to, a belt, pulley, or chain. The drive system 240 is designed to
drive (rotate) the
mandrel and/or the sheet of matexial. The drive system 240 may also convey the
sheet of material
50 in a winding direction WD for winding onto the core 220 to form a log 30.
The drive system
240 may be controlled by the reference profile 70 (Figure 1). The drive system
240 may
preferably use a digital reference profile 70 for all measurement points
during the wind. The
drive system 240 may be adjusted by adjusting each digital reference
throughout the reference
profile 70. The drive system 240 may control the material handling system 290
and the supply of
the sheet of material 50. The drive system 240 may also control the mandrel
280 and the winding
of the sheet of material 50 onto the core 220.
As shown in Figure 2, the material handling system 290 feeds (delivers) the
sheet of
material 50 to the mandrel 280 and/or core for winding about the core 220. The
material
handling system 290 may be connected to the drive system 240 or operate
independently. A log
removal means 291 may be used to assist in the removal of the completed log 30
from the
apparatus 200.
The sheet of material SO is wound about the core 220 in a wind direction WD.
The
winding apparatus 200 may include a cantilever support (not shown) for one end
of the mandrel.
The mandrel 280 may also be supported by a removable support such as a
removable cupping
CA 02560723 2003-06-06
arm 260 which comes up to support the mandrel 280 during winding and is
separated from the
mandrel 280 after winding to remove the core 220 and finished log 30 from the
mandrel 280.
Figure 3 is a simplified side view of the apparatus 200. As shown in Figure 3,
the
mandrels) 280 rotate into position for winding about the central axis 247. The
mandrels 280
rotate in a rotational direction RD. A tensile load T on the sheet of material
50 during winding
may be maintained from about 0 Kilograms force (kgf) per linear centimeter
(cm) to about 0.2
kgf per linear cm (about 1 pound force per linear inch). The linear centimeter
of the sheet of
material SO is measured generally along the central axis 247, perpendicular to
the log diameter 36
measurement as shown in Figure 2. Preferably, the tensile load T on the sheet
of material SO
during winding may be maintained from about 0.001 Kilograms force (kgf) per
linear centimeter
(cm) to about 0.1 kgf per linear cm As shown in Figure 3, the tensile load T
and/or the size of
the log 30 may affect the compressive load C that may be created on each log
layer 35. A log
layer 35 is a generally circumferential wind of a sheet of material, which has
another sheet of
material wound under and/or above it on the log 30.
The process parameter measuring device 246 shown in Figure 3 is designed to
measure
process parameters including log diameter, machine degree, drive speed,
angular position of the
drive motor shaft, displacement of the drive motor shaft, the machine wind
cycle point, and
combinations thereof.
The apparatus 200 may also include other capabilities including a means for
perforating
the sheet of material, adding adhesive to the core, severing the sheet of
material after the desired
log is wound, loading the core on to the mandrel, delivering a leading portion
of the sheet of
material to the core, removing the wound log, moving the~mandrel supports
during winding, and
other means known in the art.
Consumer size logs are generally much smaller than commercial size rolls.
Consumer
logs may include finished products with log diameters less than about 50 cm,
log diameters less
than about 25 cm, andlor log diameters from about 5 cm to about 35 cm.
Consumer logs may
weigh less than about S kg, weigh less than about 3 kg, and/or weigh from
about 50 g to about 2
kg.
Industrial winding operations for relatively large rolls of wound material
generally
operate at a slower winding speed than the present invention with winding
times of S-60 minutes
per commercial roll vs. 1-3 seconds per log for a consumer product. In one
embodiment of the
present invention, the core rotational velocity change during winding is at
least about 400
revolutions per minute between about 2 and about 35 machine degrees. The
ability to rapidly
change the winding speed, combined with. the method and apparatus herein
disclosed is designed
CA 02560723 2003-06-06
11
to enable faster manufacturing speeds, the processing of thicker webs, and
more accurate and/or
consistent consumer product log winding. The core rotational velocity is
measured as core RPM
and is independent of any translational velocity of the core about the central
axis 247.
Alternatively, when winding a log the core revolutions per minute (RPM) may
decrease at least
about 4 percent (%) in the first 10 revolutions of the log winding, or
preferably 8% in the first 20
revolutions of the log winding, or more preferably 12% in the first 30
revolutions of the log
winding. These core rotational velocity changes are typical for efficient
consumer product log
manufacturing but too rapid for industrial sized winding operations. The speed
of consumer
product winding is one reason that rapid measurements and reference profile 70
adjustments are
preferred.
The prior art has a high ratio of wound sheet of material inertia relative to
the drive's
own inertia. Drive inertia includes all the driven mass of the apparatus 200.
This includes the
drive connectors) 245, the mandrels) 280, and the like. Processes where the
sheet of material
inertia is greater than the drive inertia are easier to control during the
winding process. A typical
wound sheet of material (log) to drive inertia ratio in the prior art is 50-
5,000 while the log to
drive inertia ratio for finished consumer products may vary from about 0.01 to
about 0.8. For
consumer products, the drive inertia is generally at least about twice that of
the log inertia,
resulting in a log to drive inertia ratio of less than about 0.5.
The winding apparatus 200 shown in Figure 2 can be used independently or in
conjunction with other components, which control the material tension, and/or
the material feed
speed to the winding system. The winding apparatus 200 can also be used in
conjunction with
upstream operations, which control material properties relevant to winding
such as thickness,
tensile strength, and stretch. Apparatus 200 allows the sheet of material 50
to wind under more
uniform tension, thereby improving log 30 quality by providing more consistent
log
diameter/compressibility and less variation on slit ends due to neck down
associated with
machine direction MD tension changes. Losses in manufacturing are also
minimized. Improved
sheet of material control reduces the unintended winding speed fluctuations
that may break the
sheet of material as it is wound, or result in unmarketable product. Avoiding
these problems can
allow higher manufacturing speeds and efficiencies.
The Process Parameter Measuring Device
The process parameter measuring device 246 in Figure 2 and Figure 3 may
measure
and/or record data from any point in the winding process. The process
parameter measuring
device may be attached to the apparatus 200 or mounted independently. In one
embodiment the
CA 02560723 2003-06-06
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process parameter measuring device 246 may move or translate to track with the
moving or
translating log 30 during winding. The process parameter measuring device 246
may sense
and/or measure a log diameter 36 on the core 220 at one or more machine
degrees during the
winding process.
As shown in Figure 2 and Figure 3, the process parameter measuring device 246
may be
connected with a control means 243 for controlling the drive system 240. The
drive system 240
may in turn control the winding or unwinding speed of the apparatus 200.
As shown in Figure 3, the control means 243 may automatically control a log
diameter 36
of finished product logs 30 at the winder, and/or sheet of material tension T.
The process
parameter measuring device 246 data may be correlated with the desired
finished product
characteristics and an appropriate correction can be made to the reference
profile 70 as needed to
improve the quality of the finished log 30.
The process parameter data may be any variable that affects the winding
quality and/or
manufacturing rate of production. Many variables affect the wind quality and
manufacturing
rate/reliability. These include raw material changes such as caliper, caliper
compressibility,
moisture content due to raw material supply or environment, and upstream
process changes such
as increased emboss efficiency over time. These variables cannot typically be
controlled within
the time period associated with a winding cycle or even several consecutive
winding cycles.
Therefore, they must be corrected for in the reference profile 70. A timely
correction of the
reference profile 70 is designed to include measuring one or more critical
process parameters
during the wind and/or soon enough thereafter to allow timely intervention and
adjustment of the
reference profile 70.
One such process parameter that may be used to adjust the reference profile 70
is log
diameter 36 at intervals throughout the winding process. Figure 3 shows the
log diameter 36.
The log diameter increases until the log is complete and a final log diameter
may be obtained. It
has been found that there is a strong correlation between the log winding
speed, winding tension,
and the diameter of the log at various incremental points in the winding
process. A system has
thus been developed to accurately measure log diameter 36 and log diameter
changes at one or
more points during the winding process. Alternatively, a system has also been
developed to
accurately measure the log diameter 36 at many points throughout the wind
shortly after winding
is complete by unwinding a wound product log 30.
For example, a log diameter control algorithm compares the measured log
diameter 36 at
a point in the process with a target value. The mandrel speed reference
profile is then
CA 02560723 2003-06-06
13
manipulated via the Caliper Factor parameter to keep the log diameter 36 at a
target value. The
present invention may maintain log diameter at a set point about ~- 0.8 mm
If the process parameter measuring device 246 shows that the diameter of a
winding log
is off the target value, a change may be made to the reference profile 70. The
reference profile
70 change will automatically yield small adjustments to the mandrel drive
speed and reduce the
measured log diameter variation from the desired target log diameter value in
the present, or
subsequentlogs.
Other process parameter measurements that may be measured include log
diameter, log
diameter versus winding time, log diameter versus length of material on the
log, the summation
of the tension measured during winding, the average of the tension during
winding or
combinations thereof. These measurements may be used to determine what
reference profile
adjustments should be made. Figure 1 has a reference profile of speed vs.
machine degrees.
Those parameters may be adjusted by changing the caliper factor and/or the max
line speed.
Measurin Sg ensors
The process parameter measuring device 246 may include one or more sensors.
The
sensors) may be contact and/or non-contact sensors. Contact sensors include
rollers, stress-
strain gauges, micrometers, and the like. Non-contact sensors include lasers,
ultrasonic devices,
optical devices, LEDs, combinations thereof, and the like. The number of data
points sampled
per wound log 30 can be anywhere from one to a thousand or more, depending on
the level of
variation incurred, the required resolution, and the capability of the
measuring device. The data
points may be taken from one or several logs 30. The sampling data can be used
as is or
converted to a control number by using a variety of mathematical functions
such as averages,
means, standard deviations, sums and the like. Other approaches include simple
subtraction of
actual from theoretical to more sophisticated feed forward logic, Laplace
transforms, differential
equations, and the like.
Pilot Converting Line log diameter may be measured using a non-contacting
Charge
Coupled Device laser sensor available from Keyence~, model LK-503. The non-
contacting
approach eliminates the possibility of snagging the sheet of material 50 and
creating sheet breaks.
The charge coupled device laser sensor provides highly accurate and repeatable
measurements.
Contacting measurement devices, such as linear variable differential
transformers may not
provide the same level of reliability and repeatability. On the Pilot
Converting Line, the LK-503
sensor may be used in "high precision" mode, meaning it has a 200 mm
measurement range with
micron resolution, and it never physically touches the surface of the winding
log. Avoiding
CA 02560723 2003-06-06
14
contact with the log and sheet of material may be especially important when
the process is being
run at the high speeds needed to economically produce a consumer product. A
user interface was
installed on the Pilot Converting Line operator interface station. This user
interface provides a
"window" to the log diameter control system. It gives the operators the
ability to monitor the
diameter control system, make set point changes, and change the mode of the
diameter controller.
These changes can be made manually or preferably automatically by computer
control.
In one embodiment the process parameter measuring device 246 may comprise a
non-
contacting laser sensor available from Keyence~, model LK-503. A process
parameter
measuring device 246 comprising a non-contacting laser sensor has been tested
in two locations
under the winding apparatus 200 as shown in Figure 2 and Figure 3. The process
parameter
measuring device 246 was mounted beneath the apparatus 200. As shown in Figure
3, the
process parameter measuring device 246 was fixed in place and aimed at a log
30 dwell position
38, allowing it to see valid data for approximately 1/3 of each 360°
wind cycle or from about 120
to about 240 machine degrees. The dwell position 38 is the point in the wind
process where the
mandrel is no longer translating but stationary while winding. The process
parameter measuring
device 246 was later moved to a second location under the bedroll assembly.
The process
parameter measuring device 246 was fixed in place and aimed at the chop-off
position. The
chop-off position is near the end of the winding cycle when the sheet of
material is cut. A
portion of the sheet of material may continue to be wound. A log diameter 36
measurement was
taken once for each log wind cycle, at approximately 356 machine degrees.
In a more preferred embodiment, the Keyence~ laser sensor can be aimed at the
start of
wind position and then continuously articulated to aim at the center of the
winding log until the
winding cycle is completed. A second sensor system can be used with the first
sensor system.
The second sensor may be aimed at the winding start position while the first
sensor system is
aimed at the log completion position, and vice versa as needed. The completion
position is at
about 360 machine degrees and coincides with the end of the log winding. Two
or more sensors
may be used to ensure no winding measurements are missed on consecutive logs
30 that are at
different positions (e.g. translating) in the wind cycle.
The sensors may measure distance using triangulation principles. A
semiconductor laser
beam is reflected off the target surface and passes through a receiver lens
system. The beam is
focused on a charge-coupled device sensing array. The charge-coupled device
detects the peak
value of the light quantity distribution of the beam spot for each pixel
(individual charge coupled
device sensing element) within the area of the beam spot and determines the
precise target
position. As the target displacement changes relative to the sensor head, the
reflected beam
CA 02560723 2003-06-06
position changes on the charge coupled device array. These positional changes
are analyzed by
the controller that resolves positional changes as small as 50.0 microns.
Charge-coupled device
technology has a discrete sensing element design, and precisely determines the
peak value of the
beam spot light distribution and will accurately measure the target's position
to 50.0 microns.
The non-contacting Keyence~ laser sensor may be connected to the control means
243
by any means known in the art. One example is a IO m extension cable available
tom
Keyence~, model LK-C10. The control means 243 may be a Keyence~, model LK-2503
controller. The control means 243 may be DIN-rail mounted. The control means
243 may be
powered by a Siemens 24VDC power supply. The power supply may also be mounted
on a DIN-
rail. The control means 243 may broadcast a tlOV signal on terminals 13 and
14. This signal
corresponds to the laser's 250 mm to 450 mm measurement range in "high
precision" mode. The
signal may be transmitted to an AutoMax Analog Input Card (570409) in AutoMax
Rack A02,
Slot 07. The signal may be transmitted on Belden-M 8770 3018 shielded cable.
This is
3-conductor wire, but only two of the three leads are required. The shield
wire is terminated at
the field termination cabinet for the AutoMax Rack A02. The AutoMax Analog
Input Card uses
12-bit A/D conversion. This yields a resolution of 1.92 mils or a diameter
resolution of 3.84
mils.
The Sheet of Material
The Sheet of Material 50 being wound can be any flexible material that can be
rolled
into a log. Sheet of Material 50 examples include any film, metal foil, paper,
cloth, food, woven,
scrim, mesh, nonwoven, combination thereof and the like. Single or multiple
layers within the
sheet of material structure are contemplated, whether co-extruded, extrusion-
coated, laminated,
or combined by other known means.
Useful films include, but are not limited to, polyethylenes (PE) (including
high density
polyethylene, HDPE, low density polyethylene, LDPE and linear low density
polyethylene,
1 T T~PE), polypropylene (PP), polyethylene terephthalate (PET), polyvinyl
chloride (PVC),
polyvinylidene chloride (PVDC), ethylene vinyl acetate (EVA), latex
structures, nylon, surlyn,
mixtures thereof, and the like. A preferred resin is a blend of EVA and
polypropylene. Any film
may be used including thermoplastic non-resilient flexible film. Perforated or
porous films may
also be used as a sheet of material.
As shown in Figure 4A and Figure 4B, the sheet of material 50 may be a three-
dimensionally shaped formed film. Three-dimensionally shaped formed films may
have a film
thickness 650 of from about 0.0001 inch (0.1 mil) to about 0.009 inches (9
mil), preferably about
CA 02560723 2003-06-06
16
0.5 mil to about 6 mils, more preferably about 3-5 mils. A preferred sheet of
material 50 includes
an adhesive material. The adhesive material may be applied to a first surface
57, a second
surface 59, or to both surfaces of the sheet of material 50. The three-
dimensional film first
surface 57 may comprise a plurality of recessed pressure sensitive adhesive
sites 56 and a
plurality of collapsible protrusions 55. The protrusions serve as stand-offs
to prevent premature
sticking of the adhesive sites to a target surface until a force sufficient to
collapse at least a
portion of the collapsible protrusions 55 has been applied to the second
surface 59.
As shown in Figure 3, the log layer 35 compressive force C is preferably less
than the
force sufficient to collapse more than about 30% of the collapsible
protrusions 55 in a log layer
35. More preferably, the Iog layer 35 compressive force C is less than the
force sufficient to
collapse more than about 20% of the collapsible protrusions 55 in a log layer
35.
A preferred three-dimensional film having an adhesive applied on one surface
for use as
the sheet of material 50 is described in U.S. Patent No. 5,871,607 issued to
Hamilton et al., U.S.
Patent No. 5,662,758 issued to Hamilton et al., U.S. Patent No. 5,968,633
issued to Hamilton et
al., and U.S. Patent No. 5,965,235 issued to McGuire et al.
The sheet of material 50 may come in a large roll as shown in Figure 2 and
Figure 3. The
sheet of material may be wound about multiple cores as necessary to complete
consumer sized
logs.
An On Line Example
A method of using the winding apparatus 200 shown in Figure 2 to wind a sheet
of
material 50 onto a core 220 to form a log 30 may include winding the sheet of
material 50 to form
the Iog 30 in accordance with a reference profile 70 shown in Figure 1. At
least one process
parameter may then be measured to obtain at least one process parameter
measurement. The
reference profile 70 may then be adjusted according to the at least one
process parameter
measurement.
In one example shown in Figure 3, the process parameter measuring device 246
measures
the log diameter 36 and the data is incorporated into a log diameter control
program in an
existing control means 243. The algorithm starts by computing a theoretical
sheet caliper based
on the log diameter set point entered at the operator interface. At every
processing cycle, the
theoretical sheet caliper, sheet count, sheet length, and/or current machine
position are used to
calculate a theoretical log diameter. For example, if a process parameter is
sampled at a machine
position of 356 degrees, and the ideal caliper is 22.89 mils (0.581406 mm) for
an 11 inches long
(279.4 mm), 72 sheet count product, the theoretical diameter will be
calculated as 5.08 inches
CA 02560723 2003-06-06
17
(129.032 rnm). rf the machine position is at chop-off, or 360 degrees, the
theoretical diameter
will be 5.10 inches (129.54 mm).
The log diameter control program uses data from the process parameter-
measuring device
246 to adjust the reference profile 70 (Figure I) as needed. The log diameter
control pxogram
monitors the machine position and incorporates the measured diameter data from
the process
parameter measuring device 246 as soon as a machine degree position reaches a
dexined value.
ht this example, the value chosen was 356°. The measured diameter is
subtracted from the
theoretical diameter as calculated above, and any difference results in an
error that is assessed by
the control means 243. In the present example, a configurable four-point
moving average block
was used to assess the error. The output of the moving average is then used to
calculate a "trim"
value for the existing caliper factor parameter, if the average falls outside
a user definable
preconfigured control limit. A control limit of 25 mils L+0.635 mm) was used
in this example. In
this example, the minimum value for this caliper factor "trim' is 0. l mil.
(0.00254 mm). The
trim value is subtracted from (or added to) the nominal caliper factor setting
to change in the
reference profile 70. The control means 243 then changes the process by
directing a change to
the mandrel rotational velocity. Tn this embodiment, the log diameter control
algorithm may take
the form of an integral-only controller. The 25 mil (~0.635 mm) preconfigured
control limit
helps reduce and/or prevent controller oscillations at steady-state operation.
Such oscillations
may result from the fact that caliper factor changes can only occur in 0.1 mil
increments or
larger. This corresponds very approximately to roll diameter changes of 10
mils (0.010" or 0.254
mm).
Once a control move has occurred, the process may continue and repeat
adjustments as
necessary until the average measured error is within the user definable
preconfigured control
limit. Once the average error is inside the user definable preconfigured
control limit, the log
diameter control program will cease manipulation of caliper factor, but will
continue to monitor
the average error. Control activity will resume if the average error exceeds
the preconfigured
control limit.
The program may be written such that if the operator deactivates the log
diameter
control, the accumulated caliper factor change will be reset to zero and the
mandrel speed
reference tables will be recalculated based on the original, nominal caliper
factor value. The
program may alternatively integrate some, if not all, of the accumulated
caliper factor change into
a "new" nominal caliper factor value for the initial reference profile 70 for
use in subsequent
operations.
CA 02560723 2003-06-06
18
Off Line Measurements
Figure 5 shows an unwind apparatus 300 for unwinding a log 330 of a sheet of
material
350 and taking at least one process parameter measurement. The unwind
apparatus may also
measure at least one process parameter measurement having a correlation to the
reference profile
70. For example, the unwinding force throughout the log 330 as it is unwound
may be measured.
This process parameter measurement data has been found to have a strong
correlation with the
winding diameter, winding speed, and wind tension. This process parameter
measurement data
may then be used as desired to adjust the reference profile 70 of a winding
apparatus used to
subsequently manufacture logs. An unwind apparatus 300 may be used to unwind
any sheet of
material 350 including those previously disclosed. Unwind measurements are
particularly useful
for consumer products where the consumer will be removing the product from the
log 330. One
such product includes a film coated with a pattern of adhesive where the
unwind tensions may be
different from the wind tensions. The unwind apparatus 300 may also be used
for measuring the
log diameter 336 of the log 330 at different points in the winding process. As
the log 330 is
unwound the sheet of material 350 is removed and the remaining log diameter
336 can be related
to a particular machine degree or coordinated with the known length of sheet
of material 350
remaining an the log 330.
As shown in Figure 5, the unwind apparatus 300 for unwinding a log 330 of a
sheet of
material 350 may include, a pull system 340, an unwind mandrel 380 about which
the log is
placed, and at least one unwind measuring device 346. The pull system 340 is
used to pull the
sheet of material 350 off the log 330 in an unwind direction UD. The unwind
mandrel 380 has an
unwind nnandrel radius 385. The log 330 is placed on the unwind mandrel 380
for unwinding. A
portion of the sheet of material 350 is attached to the pull system 340. The
pull system 340 pulls
the sheet of material 350 off the log 330 while the unwind measuring device
346 obtains at least
one process parameter measurement.
At least one unwind measuring device 346 is designed to measure any desired
process
parameter. The unwind measuring device 346 measures at least one process
parameter, at least
once, as the pull system 340 pulls the sheet of material 350 of the log 330 in
an unwind direction
UD. Process parameter measurements may include log diameter, unwind speed,
angular position
of the unwind motor shaft, displacement of the unwind shaft, the machine
unwind cycle point,
machine degrees, pull speed, pull tension (force), pull angle, log diameter
versus unwinding time,
log tension required to unwind the Iog, log diameter versus length of material
on the log, the
summation of the tension measured during unwinding, the average of the tension
during
unwinding and combinations thereof.
CA 02560723 2003-06-06
19
In one embodiment shown in Figure 6, the unwind apparatus 600 pull system 340
includes at least one nip roll 345 with a nip shaft 349 and nip circumference
347. The pull
system 340 may also include a second nip roll 344. The nip roll 345 is
designed to be rotated and
unwind the material 350 from the log 330. The nip roll 345 has a nip
circumference 347 and acts
with the second nip roll 344 to rotate and unwind the sheet of material 350
from the log 330 in
the unwind direction UD. The nip roll 345 rotates in a rotational direction
RD1. The second nip
roll 344 rotates in a second rotational direction RD2. The log 330 is unwound
in a third
rotational direction RD3. A proximity sensor 366 may be located on the nip
roll shaft 349 to
measure log rotation. The sensor 366 measures the nip roll 345 rotation and,
since the nip
circumference 347 is loaown, the length of sheet unwound for each log
revolution can be
calculated. Successive diameter measurements can then emulate the unwind log
diameter 336 at
various points (e.g. machine degrees) in the winding process. Alternatively, a
laser triangulation
system or other lmown device can be used to measure the unwind log diameter
336 directly in the
off line system.
As shown in Figure 6, the unwind measuring device 346 may include having the
sheet of
material 350 routed over an idler roller 360 located between the log 330 and
the nip roll 345.
Two guide rollers 362 may be used with the idler roller 360. The idler roller
360 may be ..
mounted on load cells 361, which can measure the force exerted within the
unwind direction UD
of the sheet 350 to pull the sheet 350 off the log 330. The unwind direction
UD may also be
laiown as the machine direction. The nip roll 345 can then be rotated in
rotational direction RD1
to unwind the sheet 350 from the log 330. The proximity sensor 366 can measure
the log 330
rotations and determine the unwinding force vs. the position in the log 330.
The unwinding force
profile is then compared to the reference profile 70 and correction factors
may then be calculated
and fed back into the winding apparatus drive controller. This provides a
means to maintain
more consistent forces between adjoining sheet of material 350 layers through
the log 330,
thereby improving the ease and uniformity of dispensing (unrolling) product
from the log 330.
if the process parameter measurement is taken off line by unwinding and
measuring a
sample log 330, the system can be manual or automated. Preferably, the unwind
measuring
device is automated. An automated unwind measuring device would include
gathering the
unwind measuring device process parameter measurements and changing the
reference profile
used in a winding apparatus without the need for operator data entry or
calculations. The
apparatus and methods herein disclosed are designed to provide accurate data
quickly that
correlated well with production results and other lab tests previously used.
CA 02560723 2003-06-06
While particular embodiments of the present invention have been illustrated
and
described, it would be obvious to those skilled in the art that various other
changes and
modifications can be made without departing from the spirit and scope of the
invention. 1t is
therefore intended to cover in the appended claims all such changes and
modifications that are
within the scope of this invention.
