U.S. patent application number 12/528789 was filed with the patent office on 2010-02-18 for web guide control, web processing apparatus and method for operating the same.
This patent application is currently assigned to APPLIED MATERIALS, INC.. Invention is credited to Stefan Hein.
Application Number | 20100038468 12/528789 |
Document ID | / |
Family ID | 38267575 |
Filed Date | 2010-02-18 |
United States Patent
Application |
20100038468 |
Kind Code |
A1 |
Hein; Stefan |
February 18, 2010 |
WEB GUIDE CONTROL, WEB PROCESSING APPARATUS AND METHOD FOR
OPERATING THE SAME
Abstract
A web guide control for guiding a web, the web guide control
having a first guide roller (201) and a second guide roller wherein
the first guide roller (201) comprises an adjustment unit (310),
the second guide roller comprises a tension measurement unit (300),
and the web guide control comprises a data connection for
supporting the adjustment unit with tension data from the tension
measurement unit.
Inventors: |
Hein; Stefan; (Blankenbach,
DE) |
Correspondence
Address: |
PATTERSON & SHERIDAN, L.L.P.
3040 POST OAK BOULEVARD, SUITE 1500
HOUSTON
TX
77056
US
|
Assignee: |
APPLIED MATERIALS, INC.
Santa Clara
CA
|
Family ID: |
38267575 |
Appl. No.: |
12/528789 |
Filed: |
February 28, 2008 |
PCT Filed: |
February 28, 2008 |
PCT NO: |
PCT/EP2008/052438 |
371 Date: |
October 16, 2009 |
Current U.S.
Class: |
242/419.8 |
Current CPC
Class: |
B65H 23/044 20130101;
B65H 2553/822 20130101; B65H 2301/5114 20130101; B65H 23/0204
20130101; B65H 2557/2644 20130101; B65H 23/1888 20130101 |
Class at
Publication: |
242/419.8 |
International
Class: |
B65H 23/02 20060101
B65H023/02; B65H 23/00 20060101 B65H023/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 28, 2007 |
EP |
07004189.2 |
Claims
1. A web guide control for guiding a web, the web guide control
having a first guide roller, and a second guide roller wherein the
first guide roller comprises an adjustment unit; the second guide
roller comprises a tension measurement unit wherein the first guide
roller is positioned downstream of the second guide roller with
respect to the web guiding direction; and the web guide control
comprises a data connection for supporting the adjustment unit with
tension data from the tension measurement unit.
2. The web guide control according to claim 1 wherein the tension
measurement unit comprises a first tension sensor positioned at a
first side of the second guide roller.
3. The web guide control according to claim 1 wherein the tension
measurement unit comprises a second tension sensor positioned at a
second side of the second guide roller.
4. The web guide control according to claim 1 wherein the
adjustment unit comprises a motor for moving the first guide roller
positioned at one side of the first guide roller.
5. The web guide control according to claim 1 wherein the
adjustment unit is controlled using a closed-loop controller and
the tension data is used as variable feedback signal.
6. The web guide control according to claim 5 wherein the
closed-loop comprises analogue electronics.
7. The web guide control according to claim 5 wherein the
closed-loop comprises digital electronics.
8. A web processing apparatus having at least one web guide control
for guiding a web, the web guide control having a first guide
roller, and a second guide roller wherein the first guide roller
comprises an adjustment unit; the second guide roller comprises a
tension measurement unit wherein the first guide roller is
positioned downstream of the second guide roller with respect to
the web guiding direction; and the web guide control comprises a
data connection for supporting the adjustment unit with tension
data from the tension measurement unit.
9. The web processing apparatus according to claim 8 wherein the
tension measurement unit comprises a first tension sensor
positioned at a first side of the second guide roller.
10. The web processing apparatus according to claim 8 wherein the
tension measurement unit comprises a second tension sensor
positioned at a second side of the second guide roller (202).
11. The web processing apparatus according to claim 8 wherein the
adjustment unit comprises a motor for moving the first guide roller
positioned at one side of the first guide roller.
12. The web processing apparatus according to claim 8 wherein the
adjustment unit is controlled using a closed-loop controller and
the tension data is used as variable feedback signal.
13. The web processing apparatus according to claim 12 wherein the
closed-loop comprises analogue electronics.
14. The web processing apparatus according to claim 12 wherein the
closed-loop comprises digital electronics.
15. The web processing apparatus according to claim 8, further
comprising a coating unit for coating the web.
16. A method for guiding a web comprising the steps of: adjusting
the position of a first guide roller by moving one side of the
first guide roller; measuring the tension of the web acting on a
second guide roller, thereby receiving measurement results, wherein
the measuring is undertaken upstream of the adjusting with respect
to the web guiding direction; and wherein adjusting is based on the
measurement results.
17. The method according to claim 16 wherein the measuring is
undertaken at a first side of a second guide roller and at a second
side of the second guide roller.
18. The method according to claim 16 wherein the adjusting is
undertaken at one side of the first guide roller.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to a web guide control and a
web processing apparatus. The present invention relates
particularly to a web guide control for compensating failures in
the raw material and/or the coiling installation and to a web
processing apparatus for coating web in vacuum installations. The
present invention also relates to a method for guiding a web and
particularly to a method for compensating failures in a web during
web guiding.
BACKGROUND OF THE INVENTION
[0002] Web handling is an important issue in installations for
processing continuous web. Therein, many coils handling hundreds of
metres or even kilometres of web have to be arranged and operated
in such a way that no damage such as crinkles, trumlines,
tear-offs, or the like occur in the web.
[0003] It is of course undesirable that failures occur during the
web processing such as the web coating. These failures may lead to
the total stop of production and/or to the rejection of parts or
the entire web treated. In other words, a web guiding malfunction
can be very expensive and time consuming.
[0004] In order to avoid malfunctions of a web processing apparatus
it is known in the art to provide each guide roll of the web
guiding apparatus with a specific tolerance. This way a difference
up to e.g. 0.02 mm in the web's thickness along the width of the
web can be handled. However, in installations with long coiling
length the addition of the guide roller bearing tolerances can
cause a tilted feeding in the installation. Further, in vacuum
applications very small deviations in thickness can cause
complications or failure which would not occur at ambient
pressure.
SUMMARY OF THE INVENTION
[0005] The problems in the state of the art are at least partly
overcome by the web guide control according to claim 1, the web
processing apparatus according to claim 10 and the method for
guiding a web according to claim 12. Further aspects, details and
advantages are apparent by the dependent claims, the description
and the accompanying drawings.
[0006] In view of the above, a web guide control for guiding a web
is provided. The web guide control includes two guide rollers, an
adjustment unit at the first guide roller, a tension measurement
unit at the second guide roller, and a data connection for
supporting the adjustment unit with tension data from the tension
measurement unit.
[0007] According to another aspect of the present invention a web
processing apparatus with at least one guide control as described
herein is provided.
[0008] According to another aspect of the present invention, a
method for guiding a web is provided. The method includes the steps
of adjusting the position of a first guide roller by moving one
side of the first guide roller and measuring the tension of the web
acting on a second guide roller, thereby receiving measurement
results, wherein adjusting is based on the measurement results.
[0009] A typical application of web processing apparatuses is the
high vacuum web film deposition. For instance, in these
applications a protective layer is deposited on a packaging
substrate like thin plastic, paper, or metal foil. Thin metal or
oxide films may be deposited on the packaging substrate for
creating a moisture or oxygen barrier promoting freshness and
extending the shelf life of the consumer products which use these
films.
[0010] A further application of a web processing apparatus is the
field of manufacturing electronic products. A conductive layer may
be deposited on the web serving as conductive coating in
applications such as capacitor and touch panels.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The above features and advantages of the present invention
will become more apparent from the following detailed description
of preferred embodiments thereof with reference to the attached
drawings in which:
[0012] FIG. 1 shows a schematic diagram of an embodiment of a web
processing apparatus according to the present invention.
[0013] FIG. 2 shows a schematic diagram in a cross-sectional view
of the web guide control system according to an embodiment of the
present invention.
[0014] FIG. 3 shows a schematic diagram in a plain section view of
the web guide control system according to another embodiment of the
present invention.
[0015] FIG. 4 shows a schematic diagram in a plain section view of
the web guide control system according to another embodiment of the
present invention.
[0016] FIG. 5 shows a flow chart of the method for guiding a web
according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0017] Reference will now be made in detail to the various
embodiments of the invention, one or more examples of which are
illustrated in the figures. Each example is provided by way of
explanation of the invention, and is not meant as a limitation of
the invention. For example, features illustrated or described as
part of one embodiment can be used on or in conjunction with other
embodiments to yield yet a further embodiment. It is intended that
the present invention includes such modifications and
variations.
[0018] FIG. 1 shows an embodiment of a web processing apparatus
where web guide control 10 according to the present invention is
implemented. The web processing apparatus comprises a web
processing unit 100 where a web 140 is fed to. Further, a web
storage unit 110 is shown where the web 140 is coiled. The web 140
enters the web processing unit 100 via the inlet port 120. The
processed web 150 is guided out of the web processing unit 100
through the outlet port 130. Some installations, in particular at
ambient pressure, do not use inlet or outlet port or other units
which would be denoted as such. Typically, the web processing unit
100 comprises one, two, three, or more web guide controls according
to the present invention for serial web processing. Synonyms to the
term "web" as used within the present application are strip,
flexible substrate or the like.
[0019] Typically, a web is a three dimensional solid body the
thickness of which is in the range up to 1 mm, more typically
between 1 .mu.m and 500 .mu.m, and the width of which is between 10
cm and 4.5 m, more typically between 30 cm and 3 m. In typical
embodiments, the length of a web is larger than 10 m. Typically, a
web consists of a continuous sheet of thin and flexible material.
Typical web materials are metals, plastics, paper, or the like.
[0020] According to an embodiment of the present invention, the web
140 is fed to the web processing unit 100 from a web supply.
Typically, the web supply is a web storage unit 110 where the web
is coiled. Typical lengths of the web on the coil are in the range
between 500 m and 50 km. In other embodiments, the web supply is
continuous e.g. from a section with or without an outlet port where
the web exits the section for being fed to the web processing unit
100 (not shown). Typical guiding velocities are in the range of
between 0.1 and 20 metre per second. Typically, different
processing steps are performed in the web processing unit 100 such
as cleaning, coating, cooling, heating, or structuring the web.
[0021] After the web has been processed in the web processing unit
100, the processed web 150 exits the web processing unit 100 at the
outlet port 130. Typically, the processed web 150 is fed to a
second processing unit or guided out for storage.
[0022] Typically, a web processing apparatus comprising one or more
web guide controls according to the present invention may be used
for guiding a web in various applications. This web processing
apparatus is particularly suitable for challenging webs such as a
metal web, in particular aluminium web, and thin plastic web. Thin
web in this context is meant to be understood as having a thickness
of between 1 .mu.m and 200 .mu.m, in particular between 30 .mu.m
and 140 .mu.m.
[0023] FIG. 2 shows a cross-sectional view of an embodiment of the
web guide control 10 of the present invention. The web guide
control 10 comprises a first guide roller 201 with its
corresponding shaft axis 205 and a second guide roller 202 with its
corresponding shaft axis 215. The web 140 is guided through the
first guide roller 201 and the second guide roller 202. The web 140
may be unprocessed or have already undergone one or more processing
steps. Typically the first guide roller 201 is positioned upstream
of the second guide roller 202. The terms "downstream" and
"upstream" within the present application are to be understood with
respect to the travelling direction of the web. The web guide
control 10 of the present invention is not exclusively limited to
the implementation in web processing apparatus. For example, the
web guide control can also be implemented in manufacturing plants
where web transport is required. In principal, it is also possible
to position the first guide roller 201 downstream of the second
guide roller 202.
[0024] According to the present invention the distance between both
shaft axes 205 and 215 can be adjusted to compensate for
transversal tension acting on the web travelling between both guide
rollers 201 and 202. To allow for compensation, the second guide
roller is equipped with a web tension measurement unit such as a
tension sensor. A tension sensor may be a piezoresistive or
piezoelectric tension sensor. Alternatively, the sensor may be
equipped with a hall element or a capacitor in order to determine
the tension. In other embodiments, both the first guide roller and
the second guide roller are equipped with tension measurement
units. According to an embodiment of the present invention which is
shown in the drawings, the web tension measurement unit is enclosed
in the second guide roller 202. Typically, the measurement sensor
is adapted for measuring tensions of between 0 and 400 N/m.
Typically this distance is adjusted using an adjustment unit placed
at one side of the first guide roller 201. The "side" of the roller
is to be understood as the position at or close to the end of the
roller or its axis. Typical diameters of guide rollers used in the
present invention are between 65 mm and 300 mm.
[0025] The advantage of using a two roller system for measurement
and adjustment instead of a single roller system is, for example, a
better handling of vibrations caused by the control loop.
[0026] In principle the adjustment unit may be applied for
alignment of the guide rollers required to avoid transversal
tension acting on the web. Typically the web guide control 10 of
the present invention is particularly useful for compensating
different coiling strengths at the guide rollers 201 and 202.
Different coiling strength is most typically a result of different
thickness of the web along its width. This could result in tilted
feeding and, subsequently, varying contact between guiding rollers
and web which can go along with thermal complications. Typically
shorter distances of less than 1 m between the axis of adjacent
guide rollers are more critical to the proper handling of the
web.
[0027] In some embodiments of the present invention, the first
guide roller 201 and/or the second guide roller 202 are cooling or
heater rollers. Alternatively, or in addition, there might be
positioned a further cooling or heater guide roller in between the
first guide roller 201 and the second guide roller 202, upstream of
the first and second guide roller 201 and 202, or downstream of the
first and second guide roller. Other processing steps such as
cleaning or coating may be undertaken before, the first guide
roller, between the first guide roller and the second guide roller,
or after the second guide roller.
[0028] FIG. 3 shows a plain view of a typical embodiment of the
present invention. The different elements of this embodiment
forming part of the transversal web tension adjustment are shown in
the figure: an adjustment unit 310 at the first guide roller 201, a
web tension measurement unit 300 at the second guide roller 202,
and a data connection 330 between both guide rollers 201 and 202 to
supply tension data to the adjustment unit 310. Typically, the
first guide roller 201 is positioned upstream of the second guide
roller 202.
[0029] The data connection 330 is used to transmit information from
the measurement unit to the adjustment unit 310. The data
connection 330 can also be used to transmit information from the
adjustment unit 310 to an external interface. Typically this
interface consists of a personal computer which processes the data
from the adjustment unit 310. Also the interface can consist of an
analogue front panel comprising different element to tune the
adjustment unit 310, i.e. using different potentiometers, dials,
switches, and displays. Further, the interface can also consist of
a digital device including numeric pads, graphical display, text
commands, or a graphical user interface. Typically, all these
interfaces include different features such as controller function,
calibration of the system, compensation of ambient conditions, or
acquisition and recording of waveforms from the tension unit 300 or
the adjustment unit 310.
[0030] For connecting the data connection 330 to the different
devices, different port types are used. Typically, when serial
communication is used, the ports are RS232, RS422, RS485, or
universal serial bus (USB) ports. Typically, parallel communication
devices are used when communication between the data connection 330
and a computer is required. Most often used parallel communication
devices are DB-25, Centronics 36, SPP, EPP or ECP parallel ports.
The data connection 330 can be used to make the adjustment unit 310
compatible with transistor-transistor logic (TTL) or with
programmable logic controllers (PLC). Additionally the data
connection 330 can be used to connect the adjustment unit 310 with
a network.
[0031] According to an embodiment of the present invention the
tension acting on both shaft axes 215 and 216 of the second guide
roller 202 will be acquired separately. The acquired data will be
processed and sent to the adjustment unit 310 in the first guide
roller 201. The adjustment unit 310 adjusts the position of the
shaft axis at one side of the first guide roller 201. Thereby, the
distance between the shaft axes of the first guide roller and the
shaft axes of the second guide roller is adjusted. The adjustment
unit 300 is operated in order to equalize the tension measured
between the shaft axes at both sides of the second guide roller
202. It is, however, also possible to adjust the position of the
shaft axis on both sides of the first guide roller 201 (not shown
in drawings).
[0032] FIG. 4 shows a plain view of another embodiment of the web
guide control 10 of the present invention where the adjustment unit
consists of a rotating shaft axis 420 and a translation element
411. The web tension measurement units 300 are placed at the
bearings 431 and 432 of the second guide roller 202. Typically the
translation element 411 encloses a drive 410, such as a motor, and
a moving bearing 415 which can be displaced along the machine frame
452. The shaft axis 206 is attached to the moving bearing 415
enclosing the drive 410. The rotating shaft axis 420 encloses the
shaft axis 205 which is attached with rotational freedom to the
machine frame 451.
[0033] Different kind of motors can be used in the adjustment unit
of the present invention. At the first guide roller 201 the
distance between the bearings of the two guide rollers 201 and 202
can be adjusted on one side. In order to do so, a powered engine is
typically used. Typically, the drive for adjustment is either an
electrical or hydraulic motor according to the present invention.
The position of the moving bearing 415 of the first guide roller
201 is adjusted in such a way that both tension measurement sensors
in the second guide 202 roller face the same loading.
[0034] In typical embodiments of the present invention the web
tension measurement units consists of a transducer and a strain
gauge. Typically the transducer consists of a beam which stretches
or compresses in response to varying tensions. The strain gauge
measures the corresponding change in electrical resistance.
Typically, the measurement performed by the strain gauge is
amplified and converted to a voltage or current for further
processing. In general, the web tension measurement units enclose
an analogue or digital front end, for further processing of the
tension measurement. Typically, the web tension measurement units
are aligned in order to maximize the measurement of the tension in
the travelling direction of the web between the first and the
second guide rollers. Typically, the web tension measurement units
are mounted in the guide rollers using different options, i.e.,
between pillow blocks, using cantilevered brackets, using securing
via a flange or clamp, using studs, or threaded into
through-holes.
[0035] FIG. 5 shows a signal flow chart for the web guide control
system according to an embodiment of the present invention, which
includes a closed-loop controller based on a negative feedback 500
of the transversal tension measurement. The closed-loop system
maintains an output of the controlled system, e.g. the feedback
signal 533, equal to a setpoint 534 value by using previous values
of the feedback signal 533 and a control signal 532 fed to the
controlled system which is an output of the controller itself. The
main elements of the flow chart are a controller 501 and a web
guide system 502 constituting the web guide control 10 according to
the present invention. The tension difference between both sides of
the second guide roller 202 is the feedback signal 533. Typically,
the setpoint 534 at the controller of the present invention has a
null value in order to compensate for tension differences which
correspond to transversal tensions acting on the web. Therefore, in
typical embodiments of the present invention, the error 531 of the
controller exactly corresponds to the tension difference
measurement, i.e. the feedback signal 533. In typical embodiments
of the present invention the controller compensates deviations from
zero of the error 531 using the adjustment unit 310. Typically,
this error 531 compensation translates to a distance adjustment of
the shaft axes 205 and 215 at one side of both guide rollers 201
and 202. Therefore, the control signal 532, e.g. the controller
output, typically corresponds to the distance between the shaft
axes at one side of both guide rollers 201 and 202.
[0036] In principle, different control approaches can be
implemented in the controller 501. Typically, a linear control
approach is implemented in the controller 501 choosing from:
proportional, integral and derivative (PID) control; proportional
and integral (PI) control; proportional and derivative (PD)
control; and proportional (P) control. However, also other advanced
controls using non-linear control approaches may be implemented in
embodiments of the present invention, e.g. adaptive gain, dead-time
compensation, fuzzy logic, neural networks, or feed-forward
control. Controllers implemented in the present application can be
analogue or digital interfaces including compatibility with
transistor-transistor logic (TTL). Typically, digital interfaces
works in a discrete manner where the values for the adjustment unit
are refreshed after a certain and fixed time period .DELTA.t. Other
special features can be present in controllers of the present
invention such as self-tuning, signal computation or filtering, or
built-in indicators.
[0037] As illustration of the functioning of a controller according
to an embodiment of the present invention, in the following the
implementation of a discrete PID controller is described. The
feedback signal at a given control step i corresponds to the
difference between both tension measurements T.sub.i.sup.215 and
T.sub.i.sup.216. Typically, for embodiments corresponding to the
present invention, the setpoint is kept at zero since the
controller has to compensate for transversal forces acting on the
web, i.e. the tension at both sides of the second guide roller 202
should be equal. Therefore, the error signal at a given processing
step i corresponds to
E.sub.i=T.sub.i.sup.215-T.sub.i.sup.216.
The PID controller calculates the output value D.sub.i+1 by
using:
D.sub.i+1=D.sub.i+K.sub.pE.sub.i+K.sub.d(E.sub.i-E.sub.i-1),
where the first term corresponds to the integral part of the
controller, the second to the proportional, and the third to the
derivative. K.sub.p is the proportional band and K.sub.d is the
derivative gain. Typically, values of D.sub.i+1-D.sub.i other than
zero correspond to a variation in the position at one side of the
first guide roller 201. In other embodiments of the present
invention, this corresponds to the signal for operation of the
drive 410 at the adjustment unit in the first guide roller 201.
[0038] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to make and use the invention. While the
invention has been described in terms of various specific
embodiments, those skilled in the art will recognize that the
invention can be practiced with modification within the spirit and
scope of the claims. Especially, mutually non-exclusive features of
the embodiments described above may be combined with each other.
The patentable scope of the invention is defined by the claims, and
may include other examples that occur to those skilled in the art.
Such other examples are intended to be within the scope of the
claims of they have structural elements that do not differ from the
literal language of the claims, or if they include equivalent
structural elements with insubstantial differences from the literal
languages of the claims.
* * * * *