U.S. patent application number 10/232424 was filed with the patent office on 2004-03-04 for method and apparatus for transferring thin films from a source position to a target position.
This patent application is currently assigned to Celanese Ventures GmbH. Invention is credited to Courtois, Louise C., Derby, Stephen, Hoppes, Glen, Puffer, Raymond H. JR., Saunders, Glenn.
Application Number | 20040042789 10/232424 |
Document ID | / |
Family ID | 31977004 |
Filed Date | 2004-03-04 |
United States Patent
Application |
20040042789 |
Kind Code |
A1 |
Puffer, Raymond H. JR. ; et
al. |
March 4, 2004 |
Method and apparatus for transferring thin films from a source
position to a target position
Abstract
A method and apparatus for handling thin films, for example, for
handling and assembling membranes in fuel cell electrodes. The
apparatus includes a translatable vacuum table for mounting the
thin film, a perforated drum having a source of vacuum for removing
the thin film from the vacuum table, and a transfer assembly having
a perforated surface and a source of vacuum for transferring the
thin film from the perforated drum to a target location. When the
thin films are provided in containers, the apparatus may also
include means for opening the containers to access the thin film
within. Removal of the thin film from the transfer assembly may be
aided by a thin film release device, for example, a plurality of
moveable wires. The apparatus may be automated, for example, the
apparatus may included automated controllers and robotic arms to
facilitate the handling of thin film materials.
Inventors: |
Puffer, Raymond H. JR.;
(Watervliet, NY) ; Derby, Stephen; (Troy, NY)
; Saunders, Glenn; (East Greenbush, NY) ; Hoppes,
Glen; (Germansville, PA) ; Courtois, Louise C.;
(Granby, MA) |
Correspondence
Address: |
HESLIN ROTHENBERG FARLEY & MESITI PC
5 COLUMBIA CIRCLE
ALBANY
NY
12203
US
|
Assignee: |
Celanese Ventures GmbH
Frankfurt am Main
DE
|
Family ID: |
31977004 |
Appl. No.: |
10/232424 |
Filed: |
August 30, 2002 |
Current U.S.
Class: |
396/599 |
Current CPC
Class: |
H01M 8/1004 20130101;
B65H 29/241 20130101; B23K 26/40 20130101; B65H 3/10 20130101; B65H
29/38 20130101; B26D 7/1863 20130101; B65H 2301/4472 20130101; B01D
67/0097 20130101; B23K 2103/04 20180801; B65H 2406/33 20130101;
Y02E 60/50 20130101; B65H 2801/72 20130101; B01D 65/00 20130101;
B65H 5/222 20130101; B65H 5/04 20130101; B23K 2103/05 20180801;
B26F 1/40 20130101; B65H 2220/09 20130101; B23K 2103/50 20180801;
H01M 8/1086 20130101; B65H 29/46 20130101; B65H 2406/351 20130101;
Y02P 70/50 20151101; B65H 2301/4472 20130101; B65H 2220/01
20130101; B65H 2220/02 20130101 |
Class at
Publication: |
396/599 |
International
Class: |
G03D 017/00 |
Claims
1. A method for transferring a thin film from a source position to
a target position, the method comprising: positioning the thin film
in the source position; attaching the thin film to a first surface
in a first position; moving the first surface from the first
position to a second position wherein the thin film is removed from
the source position; transferring the thin film from the first
surface to a second surface, the second surface positioned in a
first position; moving the second surface from the first position
to a second position; and transferring the thin film from the
second surface to the target position.
2. The method as recited in claim 1, wherein the thin film is
provided in a container having a top and wherein the method further
comprises cutting the top of the container to provide access to the
thin film.
3. The method as recited in claim 2, wherein cutting the top of the
container further comprises cutting the thin film.
4. The method as recited in claim 1, wherein the source position
comprises a translatable position and wherein moving the first
surface comprises translating the source position.
5. The method as recited in claim 4, wherein moving the first
surface further comprises translating the source position toward
the first surface.
6. The method as recited in claim 1, wherein the first surface
comprises a perforated first surface operatively connected to a
source of vacuum and wherein attaching the thin film to the first
surface comprises exposing the thin film to the source of vacuum
via the perforated first surface.
7. The method as recited in claim 1, wherein the first surface
comprises an arcuate surface and wherein moving the first surface
comprises rotating the arcuate surface.
8. The method as recited in claim 1, wherein the second surface
comprises a perforated second surface operatively connected to a
source of vacuum and wherein transferring the thin film from the
first surface to the second surface comprises exposing the thin
film to the source of vacuum via the perforated second surface.
9. The method as recited in claim 8, wherein transferring the thin
film from the perforated second surface to the target position
comprises reducing the vacuum provided by the source of vacuum.
10. The method as recited in claim 1, wherein the second surface
comprises a thin film release mechanism and wherein transferring
the thin film from the second surface to the target position
comprises activating the thin film release mechanism.
11. The method as recited in claim 1, wherein the thin film
comprises a membrane.
12. The method as recited in claim 1, wherein the thin film
comprises a thin film provided in a viscous solution.
13. The method as recited in claim 12, wherein the viscous solution
comprises an acidic viscous solution.
14. The method as recited in claim 12, wherein the thin film
comprises a fuel-cell membrane.
15. An apparatus for transferring a thin film from a source
position to a target position, the apparatus comprising: means for
transferring the thin film from the source position to a first
surface in a first position; means for moving the first surface
wherein the thin film is transferred to a second position; means
for transferring the thin film from the first surface to a second
surface, the second surface in a first position; means for moving
the second surface from the first position to a second position;
and means for transferring the thin film from the second surface to
the target position.
16. The apparatus as recited in claim 15, wherein the thin film is
provided in a container having a top and wherein the apparatus
further comprises means for cutting the top of the container to
provide access to the thin film.
17. The apparatus as recited in claim 16, wherein the means for
cutting the top of the container comprises a die cutter having at
least one metallic blade.
18. The apparatus as recited in claim 15, wherein the source
position comprises a translatable surface.
19. The apparatus as recited in claim 18, wherein the translatable
surface is slidably mounted in a support frame.
20. The apparatus as recited in claim 18, wherein the translatable
surface is a perforated translatable surface operatively connected
to a source of vacuum.
21. The apparatus as recited in claim 15, wherein the first surface
comprises an arcuate surface.
22. The apparatus as recited in claim 21 wherein the arcuate
surface comprises a drum.
23. The apparatus as recited in claim 21, wherein the means for
moving the first surface comprises means for rotating the arcuate
surface.
24. The apparatus as recited in claim 21, wherein the arcuate
surface comprises a perforated arcuate surface and wherein the
means for transferring the thin film from the source position to
the perforated arcuate surface comprises a source of vacuum
operatively connected to the perforated arcuate surface.
25. The apparatus as recited in claim 15, wherein the second
surface comprises a perforated second surface and wherein the means
for transferring the thin film from the first surface to the second
surface comprises a source of vacuum operatively connected to the
perforated second surface.
26. The apparatus as recited in claim 25, wherein the means for
transferring the thin film from the second surface to the target
position comprises means for reducing the vacuum provided by the
source of vacuum to the perforated second surface.
27. The apparatus as recited in claim 15, wherein the means for
moving the second surface from the first position to a second
position comprises automated manipulators.
28. The apparatus as recited in claim 15, wherein the means for
transferring the thin film from the second surface to the target
position comprises a thin film release mechanism.
29. The apparatus as recited in claim 28 wherein the thin film
release mechanism comprises a plurality of wires.
30. The apparatus as recited in claim 15, wherein the thin film
comprises a membrane.
31. The apparatus as in claim 30, wherein the membrane comprises a
fuel cell membrane.
32. The apparatus as recited in claim 15, wherein the thin film
comprises a thin film provided in a viscous solution.
34. The apparatus as recited in claim 32, wherein the viscous
solution comprises an acidic viscous solution.
35. A method for feeding a fuel cell membrane to a fuel cell
electrode, the method comprising: positioning the fuel cell
membrane onto a vacuum table; attaching the fuel cell membrane to
an arcuate surface in a first position; rotating the arcuate
surface from the first position to a second position wherein the
fuel cell membrane is removed from the vacuum table; transferring
the fuel cell membrane from the arcuate surface to a transfer
surface, the transfer surface positioned in a first position;
moving the transfer surface having the fuel cell membrane from the
first position to a second position adjacent a fuel cell electrode;
and transferring the fuel cell membrane from the transfer surface
to the fuel cell electrode.
36. An apparatus for removing a fuel cell membrane from a container
and feeding the fuel cell membrane to an fuel cell electrode, the
apparatus comprising: a vacuum table for accepting the container
containing a fuel cell membrane, the container having a top; a die
cutter for cutting the top of the container; a rotatable drum
having a perforated outer surface; vacuum means for drawing at
least part of the fuel cell membrane from the container and on to
the perforated outer surface of the rotatable drum; means for
rotating the rotatable drum wherein the fuel cell membrane is
transferred from the vacuum table to the rotatable drum; a
perforated surface operatively connected to a source of vacuum for
drawing the fuel cell membrane from the rotatable drum to the
perforated surface; means for positioning the perforated surface
bearing the fuel cell membrane adjacent the fuel cell electrode;
and means for transferring the fuel cell membrane from the
perforated surface to the fuel cell electrode.
37. A thin film handling device comprising: a perforated surface
upon which the thin film is mounted; a plenum communicating with at
least some of the perforations in the surface; a vacuum operatively
connected to the plenum; and a means for moving the perforated
surface.
38. The thin film handling device as recited in claim 37, wherein
the perforated surface is an arcuate surface mounted for
rotation.
39. The thin film handling device as recited in claim 38, wherein
the means for moving the arcuate surface comprises means for
rotating the arcuate surface.
40. The thin film handling device as recited in claim 38, wherein
the perforated arcuate surface comprises a cylindrical drum.
41. The thin film handling device as recited in claim 40, wherein
the interior of the cylindrical drum provides the plenum to which
the vacuum is connected.
42. The thin film handling device as recited in claim 37 wherein,
the perforated surface is a planar surface.
43. The thin film handling device as recited in claim 37, wherein
the perforated surface comprises means for dislodging the thin film
from the surface.
44. The thin film handling device as recited in claim 43, wherein
the means for dislodging the thin film from the surface comprises
hydraulic means, pneumatic means, or mechanical means.
45. The thin film handling device as recited in claim 44, wherein
the mechanical means comprises a plurality of wires extending
across the surface and moveable relative to the surface.
46. A method for handling thin films comprising: providing a
perforated surface in a first position; providing a source of
vacuum operatively connected to the perforated surface; mounting
the thin film on the perforated surface by means of the source of
vacuum; and moving the surface from the first position to a second
position.
47. The method as recited in claim 46, wherein the surface is a
planar surface or an arcuate surface.
48. The method as recited in claim 47, wherein the surface
comprises an arcuate surface and wherein the arcuate surface
comprises the outer surface of a cylindrical drum.
49. The method as recited in claim 46, wherein moving the surface
comprises translating the surface in one or more directions.
50. The method as recited in claim 46, wherein moving the surface
comprises rotating the surface.
51. The method as recited in claim 46, further comprising
dislodging the thin film from the surface.
52. The method as recited in claim 51, wherein dislodging the thin
film from the surface comprises hydraulicly, pneumatically, or
mechanically dislodging the thin film from the surface.
53. The method as recited in claim 1, wherein the second surface
comprises a perforated second surface operatively connected to a
source of pressurized gas and wherein transferring the thin film
from the perforated second surface to the target position comprises
providing pressurized gas to thin film.
54. The apparatus as recited in claim 15, wherein the second
surface comprises a perforated second surface operatively connected
to a source of pressurized gas and wherein the means for
transferring the thin film from the second surface to the target
position comprises means for providing pressurized gas to thin
film.
55. The thin film handling device as recited in claim 37, further
comprising means for pressuring the plenum.
56. The method as recited in claim 10, wherein the thin film
release mechanism comprises a plurality of wires.
57. A method for handling a thin film, the thin film provided in a
container having a top and a bottom, the method comprising:
providing a first perforated surface, the first perforated surface
provided with a source of vacuum; mounting the container with the
thin film on the perforated surface by means of the source of
vacuum; severing the top of the container wherein the top of the
container can be displaced; displacing the top of the container;
providing a second perforated surface, the second perforated
surface provided with a source of vacuum; and transferring the thin
film from the first perforated surface to the second perforated
surface.
58. The method of claim 57, wherein displacing the top of the
container from the container comprises one of manually displacing
the top of the container and automatedly displacing the top of the
container.
59. The method of claim 57, wherein displacing the top of the
container comprises removing the top of the container.
60. The method of claim 57, further comprising moving the second
perforated surface having the thin film to a target location.
61. The method of claim 57, where in the method comprises a method
for handling fuel-cell membranes.
Description
TECHNICAL FIELD
[0001] This invention relates generally to apparatus and methods
used for handling thin films, for example, for transferring and
positioning thin films into assemblies utilizing the thin films.
Specifically, the present invention provides improved methods and
apparatus for transferring thin membranes, for example, fuel cell
membranes, during the assembly of devices containing membranes, for
example, fuel cell membrane-electrode assemblies.
BACKGROUND OF THE INVENTION
[0002] Thin film-like materials are handled in many different types
of industries, for example, in photographic and x-ray film
manufacture and processing, membrane manufacture and processing,
packaging, printing, and electronics, among others. The thin,
flexible, and often fragile nature of film-like materials typically
requires special considerations when handling these materials, for
example, to prevent tearing, distortion, and breakage, and to
ensure proper orientation and alignment during assembly.
[0003] One field in which the handling of thin film-like materials
is often problematic is the field of fuel cell membranes, for
example, during the handling and assembly of fuel cell membranes
into Membrane Electrode Units (or MEUs). A critical step in the
process of assembling an MEU is the removal of the membrane from
the container in which it is received from the membrane
manufacture. Fuel cell membranes are typically provided in plastic
bags, for example, polyethylene (PE) or polyester (PET) bags, and
are maintained in an acidic environment, for example, the membranes
are typically conditioned in a viscous acidic fluid for example,
viscous solution of phosphoric acid. The membranes are typically
removed from these bags and positioned, for example, under close
tolerances, for instance, within about 0.003 inches, onto target
electrode assemblies without excessive wrinkling or distortion of
the membrane. This removal from the container and positioning on
the electrode is typically hampered by the following factors: 1)
the membrane material is typically very thin (for example,
approximately 30-100 microns in thickness); 2) the membrane is
typically conditioned in a viscous solution of phosphoric acid and
water, that is, typically an 85% solution of phosphoric acid and
water; 3) the conditioned membrane material becomes very soft,
slippery, and easy to distort; and 4) the membrane typically grows
in all dimensions by approximately 20% during conditioning,
necessitating cutting of the membrane after it has been
conditioned.
[0004] Typically, according to the existing art, the handling and
processing of fuel cell membranes is performed manually. In
addition to the worker safety issues associated with frequent
exposure to the conditioning acid, the tasks become more difficult
as the size of the membrane increases. For example, for larger size
membranes, for instance those handled in the assembly of MEUs, at
least two workers are required to handle the membrane and place it
smoothly on, for example, a target electrode. This is a very
time-consuming task. In addition, because the conditioned membrane
is highly hydrophilic the membrane must be sealed between the
electrodes within a short period of time after being removed from
its plastic bag. Due to economic, safety and other reasons, there
is a need in the art to provide automated means for handling fuel
cell membranes.
SUMMARY OF THE INVENTION
[0005] The present invention provides methods and apparatus which
address many of the limitations of prior art methods and apparatus.
One aspect of the present invention is a method for transferring a
thin film from a source position to a target position, the method
comprising: positioning the thin film in the source position;
attaching the thin film to a first surface in a first position;
moving the first surface from the first position to a second
position wherein the thin film is removed from the source position;
transferring the thin film from the first surface to a second
surface, the second surface positioned in a first position; moving
the second surface from the first position to a second position;
and transferring the thin film from the second surface to the
target position. In one aspect of the invention, the thin film is
provided in a container having a top and wherein the method further
comprises cutting the top of the container to provide access to the
thin film. In another aspect of the invention, cutting the top of
the container further comprises cutting the thin film.
[0006] In another aspect of the invention, the source position
comprises a translatable position wherein attaching the thin film
to a first surface further comprises translating the source
position. In one aspect of the invention, the first surface
comprises a perforated first surface operatively connected to a
source of vacuum and wherein attaching the thin film to the first
surface comprises exposing the thin film to the source of vacuum
via the perforated first surface. In another aspect of the
invention, the first surface comprises an arcuate surface, for
example, a perforated drum, and wherein moving the first surface
comprises rotating the arcuate surface. In anther aspect of the
invention, the second surface comprises a thin film release
mechanism and wherein transferring the thin film from the second
surface to the target position comprises activating the thin film
release mechanism. The thin film may comprise a membrane, for
example, a fuel cell membrane, provided in a viscous acidic
solution.
[0007] Another aspect of the invention is an apparatus for
transferring a thin film from a source position to a target
position, the apparatus comprising: means for transferring the thin
film from the source position to a first surface in a first
position; means for moving the first surface wherein the thin film
is transferred to a second position; means for transferring the
thin film from the first surface to a second surface, the second
surface in a first position; means for moving the second surface
from the first position to a second position; and means for
transferring the thin film from the second surface to the target
position. In one aspect of the invention, the thin film is provided
in a container having a top and wherein the apparatus further
comprises means for cutting the top of the container to provide
access to the thin film. In one aspect of the invention, the means
for cutting the top of the container comprises a die cutter having
at least one metallic blade. In another aspect of the invention,
the source position comprises a translatable surface, for example,
a translatable vacuum table. In one aspect of the invention, the
first surface comprises an arcuate surface, for example, perforated
drum, and wherein the means for moving the first surface comprises
means for rotating the drum. In one aspect of the invention, the
second surface comprises a perforated second surface and wherein
the means for transferring the thin film from the second position
to the second surface comprises a source of vacuum operatively
connected to the perforated second surface. In one aspect of the
invention, the thin film is a membrane, for example, a fuel cell
membrane provided in a viscous acidic solution.
[0008] A further aspect of the invention is a method for feeding a
fuel cell membrane to a fuel cell electrode, the method comprising:
positioning the fuel cell membrane onto a vacuum table; attaching
the fuel cell membrane to an arcuate surface in a first position;
rotating the arcuate surface from the first position to a second
position wherein the fuel cell membrane is removed from the vacuum
table; transferring the fuel cell membrane from the arcuate surface
to a transfer surface, the transfer surface positioned in a first
position; moving the transfer surface having the fuel cell membrane
from the first position to a second position adjacent a fuel cell
electrode; and transferring the fuel cell membrane from the
transfer surface to the fuel cell electrode.
[0009] A further aspect of the invention is an apparatus for
removing a fuel cell membrane from a container and feeding the fuel
cell membrane to a fuel cell electrode, the apparatus comprising: a
vacuum table for accepting the container containing a fuel cell
membrane, the container having a top; a die cutter for cutting the
top of the container; a rotatable drum having a perforated outer
surface; vacuum means for drawing at least part of the fuel cell
membrane from the container and on to the perforated outer surface
of the rotatable drum; means for rotating the rotatable drum
wherein the fuel cell membrane is transferred from the vacuum table
to the rotatable drum; a perforated surface operatively connected
to a source of vacuum for drawing the fuel cell membrane from the
rotatable drum to the perforated surface; means for positioning the
perforated surface bearing the fuel cell membrane adjacent the fuel
cell electrode; and means for transferring the fuel cell membrane
from the perforated surface to the fuel cell electrode.
[0010] A further aspect of the invention is a thin film handling
device comprising: a perforated surface upon which the thin film is
mounted; a plenum communicating with at least some of the
perforations in the surface; a vacuum operatively connected to the
plenum; and a means for moving the perforated surface. In one
aspect of the invention, the perforated surface is an arcuate
surface mounted for rotation and the means for moving the arcuate
surface comprises means for rotating the arcuate surface. In one
aspect of the invention, the perforated arcuate surface comprises a
cylindrical drum. In one aspect of the invention, the interior of
the cylindrical drum provides the plenum to which the vacuum is
connected. In another aspect of the invention, the perforated
surface is a planar surface. In another aspect of the invention,
the device, having either a planar or an arcuate surface, further
includes means for dislodging the thin film from the surface. For
example, the means for dislodging the thin film from the surface
may be hydraulic means, pneumatic means, or mechanical means. For
instance, in one aspect of the invention, the mechanical means for
dislodging the thin film may be a plurality of wires extending
across the surface and moveable relative to the surface. In another
aspect of the invention, the pneumatic means of dislodging the thin
film from the surface may comprise means for pressurizing the
plenum, for example, for a limited duration, to dislodge the thin
film from the surface. In one aspect of the invention, the thin
film comprises a membrane, for example, a fuel-cell membrane, but
any type of thin film may be handled by the invention.
[0011] A still further aspect of the invention is a method for
handling thin films comprising: providing a perforated surface in a
first position; providing a source of vacuum operatively connected
to perforated surface; mounting the thin film on the perforated
surface by means of the source of vacuum; and moving the surface
from the first position to a second position. The surface may be a
planar or arcuate surface, for example, the arcuate surface may be
the outer surface of a cylindrical drum. In one aspect of the
invention, moving the surface may comprise translating the surface
in one or more directions or rotating the surface. The method may
further comprise dislodging the thin film from the surface, for,
example, hydraulicly, pneumatically, or mechanically dislodging the
thin film from the surface. The method may comprise a method for
handling membranes, for example, fuel-cell membranes, but the
method may be used to handle any type of thin film.
[0012] A further aspect of the invention is a method for handling a
thin film, the thin film provided in a container having a top and a
bottom, the method comprising: providing a first perforated
surface, the first perforated surface provided with a source of
vacuum; mounting the container with the thin film on the perforated
surface by means of the source of vacuum; severing the top of the
container wherein the top of the container can be displaced;
displacing the top of the container; providing a second perforated
surface, the second perforated surface provided with a source of
vacuum; and transferring the thin film from the first perforated
surface to the second perforated surface. In one aspect of the
invention, the displacing the top of the container from the
container comprises one of manually displacing the top of the
container and automatedly displacing the top of the container. In
another aspect of the invention, displacing the top of the
container comprises removing the top of the container. In one
aspect of the invention, the method further comprises moving the
second perforated surface having the thin film to a target
location. As in the aspects above, this method may be a method for
handling fuel-cell membranes.
[0013] These and other embodiments and aspects of the present
invention as well as their advantages compared to the prior art
will become more apparent upon review of the attached drawings,
description below, and attached claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The subject matter which is regarded as the invention is
particularly pointed out and distinctly claimed in the concluding
portion of the specification. The invention, however, both as to
organization and method of practice, together with further objects
and advantages thereof, may best be understood by reference to the
following detailed descriptions of the preferred embodiments and
the accompanying drawings in which:
[0015] FIG. 1 is a perspective view of a thin-film handling system
according to one aspect of the present invention
[0016] FIG. 2 is a perspective view of a membrane storage container
that can be handled using handling system shown in FIG. 1 according
to one aspect of the invention.
[0017] FIG. 3 is a perspective view of the vacuum table assembly of
the thin-film handling system shown in FIG. 1 according to one
aspect of the invention.
[0018] FIGS. 4A and 4B illustrate a top view and a cross-sectional
view, respectively, of a die cutter according to one aspect of the
present invention.
[0019] FIG. 5 is a perspective view of the transfer drum assembly
of the thin-film handling system shown in FIG. 1 according to one
aspect of the invention.
[0020] FIG. 6 is top perspective view of the transfer plate
assembly of the thin-film handling system shown in FIG. 1 according
to one aspect of the invention.
[0021] FIG. 7 is bottom perspective view of the transfer plate
assembly of the thin-film handling system shown in FIG. 1 according
to one aspect of the invention.
[0022] FIG. 7A is a detailed view of one leading edge hole pattern
of the transfer plate assembly of FIG. 7 according to one aspect of
the present invention.
[0023] FIG. 7B is a detailed cross-sectional view of the perforated
surface shown in FIG. 7 according to one aspect of the present
invention.
[0024] FIG. 8 is perspective view of the vacuum plate assembly
shown in FIGS. 6 and 7 according to one aspect of the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] FIG. 1 illustrates a perspective view of a thin-film
handling system 10 according to one aspect of the present
invention. Though thin film-like materials having a broad range of
thicknesses may be handled by the present invention, the materials
handled by the present invention may have a thickness that ranges
from about 1 micrometer (about 0.00004 inches) to about 1
millimeter (about 0.040 inches) and typically may have a thickness
that ranges from about 25 micrometers (about 0.001 inches) to about
500 micrometers (about 0.020 inches). In one aspect of the
invention, the material handled by the present invention may have a
thickness between about 50 micrometers (about 0.002 inches) and
about 200 micrometers (about 0.008 inches).
[0026] Handling system 10 includes a film mounting table assembly
12, for example, a vacuum table assembly, a film transfer drum
assembly 14, and a film transfer plate assembly 16. In one aspect
of the invention, a thin film may be transferred from mounting
table assembly 12 to transfer plate assembly 16 via transfer drum
assembly 14; however, in another aspect of the invention, a thin
film may be manually transferred from mounting table assembly 12 to
transfer plate assembly 16. System 10 may be enclosed in an
enclosure 11, for example, an enclosure in which the temperature,
pressure, and humidity are controlled. A typical thin film that is
handled by system 10 is shown in FIG. 2, but is not shown in FIG.
1. Mounting table assembly 12 typically includes at least one thin
film mounting table 18, for example, a vacuum table having a
plurality of apertures 20 and a plenum 19 operatively connected to
a source of vacuum (not shown). Mounting table 18, in one aspect of
the invention, is slidably mounted wherein it is translatable, that
is, it is moveable in one or more directions. In the aspect of the
invention shown in FIG. 1, mounting table 18 is moveable in the
direction shown by double arrow 22. Mounting table assembly 12 is
disclosed in more detail in FIG. 3.
[0027] In FIG. 1, transfer drum assembly 14 comprises an arcuate
surface 24 for retaining and transferring a thin film from mounting
table assembly 12 to transfer plate assembly 16. Though in FIG. 1
arcuate surface 24 is a complete cylindrical drum 26, in one aspect
of the invention, arcuate surface 24 may be less than 360 degrees
in circumference, for example, an arcuate surface having an arcuate
length less than about 180 degrees or even less than about 90
degrees. In one aspect of the invention, surface 24 includes holes
or perforations 25 and the inside of drum 26 provides a plenum 27
which is operatively connected to a source of vacuum, for example,
via conduit 28. Perforations 25 are typically evenly distributed
across surface 24. Though a single row of perforations 25 is shown
in FIG. 1, surface 24 may include 2 or more rows of perforations
25. The presence of a vacuum on the inside of drum 26 and the
perforations 25 provides one means of retaining the thin film on
the surface 24. Further aspects of transfer drum assembly 14
according to the present invention are disclosed in detail in FIG.
5.
[0028] Also with reference to FIG. 1, film transfer plate assembly
16, which is also known as a vacuum chuck, according to one aspect
of the present invention comprises a surface 30, for example, a
flat surface, for transferring a thin film from the transfer drum
assembly 14 to a target location (not shown). For example, in one
aspect of the invention, a target location for the thin film is a
fuel cell membrane electrode assembly, though according to other
aspects of the present invention, other types of targets may be
used depending upon the type of thin film being handled. As will be
shown more clearly later, in one aspect of the invention, surface
30 is perforated and transfer plate assembly 16 includes a plenum
32 operatively connected to a source of vacuum, for example, via
support and conduit 34. Transfer plate assembly 16 is typically
mounted upon an automated position controller or robotic arm 18,
for example, a robotic arm of a SCARA-type robotic arm, such as, an
Adept Cobra 600 robotic arm, or its equivalent. Further aspects of
transfer plate assembly 16 according to the present invention are
disclosed in detail in FIGS. 6, 7, and 8.
[0029] One type of thin film that may be handled by system 10 shown
in FIG. 1 is shown in FIG. 2. FIG. 2 illustrates a perspective view
of a membrane storage container 40 having one or more membranes 42,
for example, one or more fuel cell membranes, for example, the
polybenzimidazole (PBI) film produced by the process disclosed in
U.S. Pat. No. 6,187,231 [assigned to Celanese Ventures GmbH] or its
equivalent. In one aspect of the invention, container 40 is a
plastic bag, for example, a polyethylene (PE) plastic bag, for
instance, a high-density polyethylene (HDPE) or a low-density
polyethylene (LDPE) plastic bag, or a polyester (PET) plastic bag.
Container 40 typically includes one or more sealed edges 41 and an
upper inside surface 43 and a lower inside surface 45. In one
aspect of the invention, container 40 is a plastic bag described in
U.S. Pat. No. 4,756,422 (reissued as U.S. Re-issued U.S. Pat. No.
RE34,929) and marketed under the trademark VacLoc FoodSaver bag by
the company Tillia, Inc., San Francisco, Calif. In one aspect of
the invention, container 40 contains a viscous fluid 44, for
example, an acidic solution that conditions membrane 42, for
instance, the acidic solution may contain phosphoric acid or its
equivalents. Viscous fluid 44 typically has a viscosity of at least
about 1.0 centipoise (cp), and in one aspect of the invention, the
viscosity of the fluid is between about 20 cp and about 70 cp, for
example, a viscosity of about 28 cp at a temperature of about 20
degrees C.
[0030] In one aspect of the invention, the inner surfaces 43, 45 of
container 40 exhibit "preferential sticking", that is, one surface
provides a greater adherence to thin film 42 than the other
surface. For example, when transferring thin film 42 from one
surface to another surface, in some aspects of the invention, it is
preferred that thin film 42 be easily released from one inner
surface 43, 45 of container 40 while being retained by the other
surface 43, 45. For instance, during transfer from mounting table
18 to arcuate surface 24 of drum assembly 14, according to one
aspect of the invention, thin film 42 preferably adheres more
strongly to top inner surface 43 and is transferred with top
surface 43 to the acuate surface 24 while lower inner surface 45
readily releases thin film 42 allowing thin film 42 to transfer to
arcuate surface 24 while lower inner surface 45 is retained on
mounting table 18. Preferential sticking may be provided by
differences in surface texture, for example, one surface may
provide a textured surface and the other surface may provide a
relatively smooth surface. Preferential sticking may also be
provided by different materials, for example, different polymers;
surface treatment or different surface treatment, for example,
etching, coating, burnishing, and the like; among other means. In
one aspect of the invention, the preferential sticking is a
function of the pH, viscosity, or chemistry of the viscous fluid 44
contained in container 40.
[0031] FIG. 3 illustrates a perspective view of the mounting table
assembly 12 shown in FIG. 1 for mounting thin films to be handled
by system 10 in FIG. 1. The thin films mounted on mounting table
assembly12, may be in a sealed container, such as container 40
shown in FIG. 2, or its equivalent, or the thin film may not be
stored in a container but laid directly on to mounting table
assembly 12. In one aspect of the invention, the thin film or its
container may be mounted manually on mounting table assembly 12; in
another aspect of the invention, mounting may be automated.
[0032] As shown in FIG. 3, in one aspect of the invention, mounting
table assembly 12 includes a vacuum table 50 having a plurality of
perforations 51 and a plenum or manifold 53. Perforations 51 are
typically distributed about surface 24, for example, evenly
distributed, though, in one aspect of the invention, perforations
51 may be randomly distributed about the surface of vacuum table
50. In one aspect of the invention, the spacing, location, and size
of perforations 51 are customized to the size and weight of the
container being handled by table 50 (for example, container 40 in
FIG. 2). In one aspect of the invention, perforations 51 are
circular perforations, but perforations 51 may assume any shape
including smooth shapes, such as oval or ellipsoidal, and polygonal
shapes, such as triangular, square, quadrilateral, and pentagonal,
among others. Perforations 51 may vary in size from about 0.04
inches to about 0.25 inches. Perforations 51 may comprise a single
row or multiple rows of perforations, for example, evenly-spaced or
non-evenly-spaced perforations. The perforations 51 in the multiple
rows may be aligned, uniformly staggered, non-uniformly staggered,
or randomly distributed. Perforations 51 may also be randomly
distributed about the surface of vacuum table 50 or may be equally
distributed, for example, equally spaced about the surface of
vacuum table 50. In one aspect of the invention, perforations 51
are about 1/8 of an inch (about 3.175 mm) in diameter and are
equally spaced on about 0.75 inch (about 19.05 mm) centers in both
the longitudinal and transverse directions. In one aspect of the
invention, one or more perforations 51 may be masked to limit the
amount of area of the container exposed to vacuum and thus limit
the "gripping" force on the container. In one aspect of the
invention, the size and location of perforations 51 are defined to
minimize or prevent perforations 51 from interfering with the
cutting blades during die cutting of the container positioned on
vacuum table 50, for example, to minimize or prevent perforations
51 from interfering with the cutting blades 64 of die cutter
assembly 60 shown in FIGS. 4A and 4B.
[0033] Plenum 53 is typically operatively connected to a source of
vacuum (not shown). In one aspect of the invention, vacuum table 50
is supported by a support structure 52 which in turn is slidably
mounted on a frame 54. The vacuum in plenum 53 retains the thin
film on vacuum table 50 and minimizes the undesirable movement of
the thin film, for example, unwanted lateral movement of the thin
film or the thin film container during the handling or separation
process. In addition, in one aspect of the invention, the vacuum in
plenum 53 ensures that the bottom layer of a container remains in
place as the top layer of the container and the thin film, for
example, membrane, are "peeled off" of the bottom of the
container.
[0034] Support structure 52 is typically mounted to frame 54 by
means of low friction bearings 55, for example, ball or roller
bearings or low-friction bearing surfaces. In one aspect of the
invention, support structure 52 is slidably mounted to frame 54 by
low friction bearings 55, for example, recirculating-ball-type
linear bearings mounted for translation on precision-ground shafts.
One such bearing mounting that can be used for the present
invention is a bearing arrangement referred to as a "Thompson
slide".
[0035] In one aspect of the invention, vacuum table 50 is
translatable, for example, capable of reciprocating motion in the
direction of double arrow 56. The movement of vacuum table 50 may
be automated, for example, in one aspect of the invention, the
movement of vacuum table 50 is controlled by a motor, for example,
a stepper motor or a servo-motor, and appropriate controls and one
or more drive means. In one aspect of the invention shown in FIG.
3, the movement of vacuum table 50 is controlled by a stepper motor
(not shown) mounted to motor mount 57. The motor may be coupled to
a drive means, for example, a drive means comprising one or more
ball screws 58, though in other aspects of the invention other
types of drive mechanisms may be used. In one aspect of the
invention, an encoder (not shown) may be used on the drive motor
shaft or drive means to provide position feedback to a motion
controller (not shown), for example, an Adept motion
controller.
[0036] According to one aspect of the invention, handling system 10
shown in FIG. 1 is used to handle thin films, for example,
membranes and the like, which are provided in sealed containers or
bags, for example, container 40 shown in FIG. 2. In one aspect of
the present invention, the container holding the thin film contains
an acidic solution. In order to handle such thin films, the
container holding the then film is typically severed, cut, or
otherwise opened to allow access to the thin film inside. In
addition, some types of membranes being handled according to the
present invention, for example, fuel-cell-type membranes, "grow"
approximately 20% to 25% during conditioning in the acid-filled
bag. In order to insure that the thin film is of the desired size,
the thin film is cut to size after it has been conditioned.
Typically, this may be the only way that the thin film, for
example, the membrane, maintains its desired size.
[0037] In one aspect of the invention, any conventional means of
opening the container holding the thin film may be used. The
container may be cut by hand or through automated means.
[0038] In another aspect of the invention, the container holding
the thin film is opened and the thin filmed accessed by means of a
die cutter assembly 60, shown in FIGS. 4A and 4B. FIG. 4B is a
cross sectional view of die cutter 60 taken through the view lines
4B-4B shown in FIG. 4A. In one aspect of the invention, die cutter
60 includes a support block 62, for example, a wooden support block
62, and at least one metallic cutting blades 64 mounted in the
support block 62. According to one aspect of the invention, die
cutter 60 is positioned over a thin film container, for example,
container 40 in FIG. 2, and compressed against the container to
sever at least part of the container. The at least one metallic
cutting blades are preferably acid resistant, for example, in one
aspect of the invention, metallic cutting blades 64 may be titanium
cutting blades or stainless steel cutting blades, for example, ASTM
304 or 316 stainless steel cutting blades, or their equivalents. In
another aspect of the invention, the one or more metallic cutting
blades 64 may also be a hardened steel, such as S-7 hardened steel,
which may be coated with an acid resistant coating, for example, a
titanium nitride coating. In one aspect of the invention, one or
more cutting blades 64 may be machined from a solid block of
material, for example, electro-discharged machined (EDM), laser
cut, or water-jet cut from a stainless steel (for example, 310 or
316 stainless steel), titanium, or hardened steel (such as S-7
hardened steel treated with an acid-resistant coating). In one
aspect of the invention, one or more cutting blades 64 may be
machined from a solid block of material wherein the remaining
material provides support block 62, that is, cutting blades 64 and
support block 62 may be fabricated as a single integral part. In
one aspect of the invention, die cutter assembly 60 includes a
plurality of resilient blocks 66, for example, rubber blocks, that
are used to insure that the thin film and or container are ejected
from the die cutter assembly 60 following cutting. In one aspect of
the invention, resilient blocks 66 comprise one or more resilient
sheets or boards, that may partially cover or entirely cover the
surface of support block 62.
[0039] In one aspect of the invention, die cutter assembly 60 is
mounted on a means for compressing the die cutter assembly 60
against a surface, for example, a hydraulic press. The means for
compressing the die cutter assembly 60 may comprise means for
compressing die cutter assembly 60 upon a container containing a
thin film, for example, a membrane.
[0040] In one aspect of the invention, die cutter assembly 60 is
positionable, for example, by manual or automated means. In one
aspect of the invention, die cutter 60 is positionable over a
container holding a thin film, such as container 40 in FIG. 2, for
example, while container 40 is positioned on mounting table
assembly 12 (see FIG. 1). For example, in one aspect of the
invention, die cutter assembly 60 is positionable by means of an
automated controller and a hydraulic press. In another aspect of
the invention, die cutter assembly 60 is positioned and compressed
upon a container holding a thin film before it is placed on
mounting table 12.
[0041] In one aspect of the invention, at least one cutting blade
64 severs only the top cover of the container holding the thin film
while leaving the thin film and bottom cover of the container
essentially intact. In another aspect of the invention, at least
one cutting blade 64 severs the top cover of the container and the
thin film within the container, that is, to effect a "kiss cut",
and the bottom cover of the container remains essentially intact.
In another aspect of the invention, at least one cutting blade 64
severs the top cover of the container, the thin film within the
container, and the bottom cover of the container, that is, all
sides of the container and its contents are severed. In another
aspect of the invention, at least three cutting blades 64 are used
in die cutter assembly 60, for example, a leading edge and two
sides edges of container 40 are severed. In another aspect of the
invention, at least four cutting blades 64 are used in die cutter
assembly 60.
[0042] FIG. 5 illustrates a perspective view of the transfer drum
assembly 14 shown in FIG. 1. Transfer drum assembly 14 is used to
peel the thin film, or the top of the container and the thin film,
from the mounting table assembly 12 and transfer the thin film to a
location where the thin film can be transferred to transfer plate
assembly 16. As noted with respect to FIG. 1, transfer drum
assembly 14 typically comprises an arcuate surface 24. Though in
FIG. 5 arcuate surface 24 is a complete cylindrical drum 26, in one
aspect of the invention, arcuate surface 24 may be less than 360
degrees in circumference. For example, surface 24 may comprise the
surface of a segment of a cylinder, or some other curved surface,
for example, a non-cylindrical curved surface, may be used. In one
aspect of the invention, surface 24 includes holes or perforations
25, for example, one or more rows of perforations 25, and the
inside of drum 26 provides a plenum or manifold 27 which is
operatively connected to a source of vacuum, for example, via
vacuum inlet 29. In one aspect of the invention, the source of
vacuum is operatively connected to plenum 27 via a hollow drive
shaft, for example, shaft 68 discussed below and appropriate rotary
seals. The source of vacuum typically provides between about 0.1
kiloPascals (kPa) (about 0.03 inches of Hg) to about 33.8 kPa
(about 10 inches of Hg) of vacuum in plenum 27. The level of vacuum
provided in plenum 27 may be monitored and regulated to control the
gripping force applied to the thin film materials being
handled.
[0043] Perforations 25 are typically distributed about surface 24,
for example, evenly distributed, though, in one aspect of the
invention, perforations 25 may be randomly distributed about
surface 24. In one aspect of the invention, the spacing, location,
and size of perforations 25 are customized to the size and weight
of the material being handled. In one aspect of the invention, as
shown in FIG. 5, perforations 25 are circular perforations, but
perforations 25 may assume any shape, including smooth shapes, such
as oval or ellipsoidal, and polygonal shapes, such as triangular,
square, quadrilateral, and pentagonal, among others. Perforations
25 may vary in size from about 0.04 inches to about 0.125 inches.
Perforations 25 may comprise a single row or multiple rows of
perforations, for example, evenly-spaced or non-evenly-spaced
perforations. The perforations 25 in the multiple rows may be
aligned, uniformly staggered, non-uniformly staggered, or randomly
distributed. Perforations 25 may also be randomly distributed about
surface 24 or may be equally axially-spaced or equally
circumferentially spaced, or both. In one aspect of the invention,
perforations 25 are about 1/8 of an inch (about 3.175 mm) in
diameter and are equally axially spaced on about 1.125 inch (about
28.575 mm) centers and equally circumferentially spaced on about
1/2 inch (about 12.7 mm) centers. In one aspect of the invention,
the leading edge of perforations 25 on surface 24 (that is, the
perforations nearest table 12 by which the surface 24 first
"grasps" the thin film on table 12) may have a different pattern of
perforations than the remainder of the perforated surface 24 of
drum 26. For example, the leading edge of perforations 25 may have
a higher density of holes, for example, a large open area, than the
remainder of the perforations. These perforations 25 positioned
toward the leading edge may be of uniform size and distribution or
of non-uniform or varying size and distribution. In one aspect of
the invention, perforations 25 along the leading edge are about 1/8
inch (about 3.175 mm) in diameter and are spaced on 1/4 inch (6.35
mm) centers, that is, more closely spaced than the perforations
described above and thus providing more open area than the
perforations discussed above. Those of skill in the art will
recognize that many hole sizing and spacings may be used to effect
the desired transfer of the thin film.
[0044] In one aspect of the invention, drum 26 is rigidly mounted
to drive shaft 68 which is mounted for rotation in bearings 70
which are supported by support plates 72 having, for example, one
or more gussets 73. Support plates 72 may be mounted by means of
adjusting screws 82 to allow for adjustment of the standoff
distance between vacuum table 50 and drum 26 to account for
differences in the thickness and flatness of the thin film material
being handled. Transfer drum assembly 14 may also be mounted on
translatable mounts, for example, bearings or rollers, wherein
transfer drum assembly 14 may be positionable, either manually or
automatedly, in assembly 10, for example, by means of automated
controllers and positioning means.
[0045] Though many conventional drive means may be used to rotate
drum 26, in one aspect of the invention, drum 26 is driven by motor
74, for example, a stepper motor, having a drive sheave 76 which
drives a belt 78, for example, a v-belt or timing belt. Belt 78
rotates sheave 80 mounted on shaft 68 to rotate drum 26. In one
aspect of the invention, the drive means reciprocally rotates drum
26; in another aspect, the drive means rotates drum 26 in one
direction. According to other aspects of the invention, drum 26 may
be driven by any other conventional drive means, including and not
limited to, a direct drive motor, chains and sprockets, gears,
etc., among others means.
[0046] According to one aspect of the invention, the speed of drum
26 is monitored and controlled to allow drum 26 to be rotated in
approximate synchronization with the lateral movement of vacuum
table 50 and transfer plate assembly 16. In one aspect of the
invention, an encoder (not shown) is located on the shaft of drive
motor 74 and the encoder is used to provide position feedback of
speed or orientation of drum 26 to a motion controller (not
shown).
[0047] According to one aspect of the invention, the rotational
velocity of drum 26 relative to the speed of vacuum table 50
optimizes the thin film transfer process by controlling the
positional accuracy of the transfer. The controlling of the thin
film transfer helps minimize wrinkling or other distortion of the
thin film as it is being transferred from the vacuum table 50 to
drum 26 and from drum 26 to transfer plate assembly 16. In one
aspect of the invention, drum 26 initially rotates so that the drum
surface 24 moves at essentially the same speed as vacuum table 50.
This insures that the thin film material is securely held by drum
26 and the thin film material achieves an initial separation from
vacuum table 50. In another aspect of the invention, as drum 26 and
vacuum table 50 continue to move, the speed of drum 26 is increased
slightly (for example, at least about 1% to about 100%) compared to
the speed of vacuum table 50 to allow the thin film material to be
transferred under a slight tension, thereby minimizing any wrinkles
or other distortion in or damage to the thin film material during
transfer. For example, in one aspect of the invention, the table 50
travels at a linear speed of about 1 inch per second and drum 26
rotates at about 10 degrees per second, which (for the size of the
drum 26 used) corresponds to a tangential velocity of drum 26 of
about 1.87 inches per second. In this aspect of the invention, the
speed of drum 26 is about 87% faster than the speed of table
50.
[0048] FIG. 6 illustrates a top perspective view of the transfer
plate assembly 16 shown in FIG. 1. FIG. 7 illustrates a bottom
perspective view of transfer plate assembly 16 shown in FIG. 1.
Transfer plate assembly 16 is also referred to as the "vacuum chuck
assembly". As noted with respect to FIG. 1, according to one aspect
of the present invention, transfer plate assembly 16 is used to
remove a thin film material, for example, a membrane, from the
transfer drum 26 and transfer the thin film material to a target
location (not shown), for example, to an assembly into which a
membrane is to be installed. In one aspect of the invention, in
which the thin film material is stored in a container, for example,
a plastic bag 40 shown in FIG. 2, transfer plate assembly 16 is
used to remove the thin film material from transfer drum 26 while
leaving one layer of the container on transfer drum 26. In this
aspect of the invention, the layer of the container is held onto
the surface 24 of transfer drum 26 by vacuum.
[0049] As most clearly shown in FIG. 7, transfer plate assembly 16
includes at least one surface 30, for example, a horizontal flat
surface, having a plurality of holes, perforations, or apertures
31. The number, size, and location of holes 31 in surface 30 may be
varied or adjusted to accommodate different sizes and shapes of
thin films, for example, different shapes of membranes. Holes 31
are typically distributed about surface 30, for example, evenly
distributed, though, in one aspect of the invention, holes 31 may
be randomly distributed about surface 30. In one aspect of the
invention, the spacing, location, and size of holes 31 are
customized to the size and weight of the material being handled. In
one aspect of the invention, as shown in FIG. 7, holes 31 are
circular holes, but holes 31 may assume any shape, including smooth
shapes, such as oval or ellipsoidal, and polygonal shapes, such as
triangular, square, quadrilateral, and pentagonal, among others.
Holes 31 may vary in size from about 0.04 inches (about 1 mm) to
about 0.125 inches (3.125 mm). Holes 31, similar to perforations
25, may comprise a single row or multiple rows of perforations, for
example, evenly-spaced or non-evenly-spaced perforations. Holes 31
in the multiple rows may be aligned, uniformly staggered,
non-uniformly staggered, or randomly distributed. Holes 31 may also
be randomly distributed about surface 30 or may be equally spaced
on surface 30. In a typical aspect of the invention, holes 31 are
about 0.051 inches (about 1.29 mm) in diameter and are equally
spaced on about 1/2 inch (about 12.7 mm) centers in rows equally
spaced on about 1/2 inch (about 12.7 mm) centers. In one aspect of
the invention, the leading edge of holes 31 on surface 30 (that is,
the holes nearest drum 26 by which the surface 30 first "grasps"
the thin film on drum 26) may have a different pattern of holes
than the remainder of the pattern of holes in surface 30 of
transfer plate assembly 16. For example, the leading edge of
perforations 31 may have a higher density of holes, for example, a
large open area, than the remainder of the holes. These holes 31
positioned toward the leading edge may be of uniform size and
distribution or of non-uniform or varying size and distribution.
According to one aspect of the invention, holes 31 along the
leading edge of surface 30 may comprise one or more rows of larger
holes. According to another aspect of the invention, holes 31 along
the leading edge of surface 30 may comprise staggered rows of holes
of varying diameter. For example, in one aspect of the invention
shown in FIG. 7A the one or more rows of larger holes along the
leading edge of surface 30 may comprise rows of smaller holes 31A
alternating with larger holes 31B. For example, holes 31A may have
a diameter of about 0.04 inches (about 1 mm) and holes 31B may have
a diameter of about 0.06 inches (about 1.5 mm). In this aspect of
the invention, holes 31A may be equally-spaced on 1/8 inch centers
(about 3.127 mm), for example, in the vertical direction shown in
FIG. 7A, and equally-spaced on about 1/4 inch (about 6.254 mm)
centers, for example, in the horizontal direction of FIG. 7A. Large
holes 31B may be equally-spaced on about 1/4 inch (about 6.254 mm)
centers. Holes 31A and 31B may also be unequally spaced.
[0050] Surface 30 may be made from a metallic, or non-metallic
material, for example, a transparent plastic material such as
polycarbonate, polypropylene, polyethylene, or like materials. As
most clearly shown in FIG. 6, transfer plate assembly 16 also
includes a vacuum plate assembly 93 having a manifold or plenum 32.
A perspective view of vacuum plate assembly 93 is shown in FIG. 8.
Plenum 32 is operatively connected to a source of vacuum (not
shown), for example, via hoses or conduits 34 and 35 connected to
vacuum connectors 87, 89, respectively. The source of vacuum
typically provides between about 0.1 kPa (about 0.03 inches of Hg)
to about 33.8 KPa (about 10 inches of Hg) in plenum 32. The level
of vacuum provided in plenum 32 may be monitored and regulated to
control the gripping force applied to the thin film materials being
handled. Holes or apertures or perforations 31 penetrate surface 30
and are exposed to the vacuum in plenum 32. According to one aspect
of the present invention, thin films are retained on surface 30 by
means of a vacuum drawn through holes 31. Transfer plate assembly
16 may also include one or more air hoses 34, 35, or a separate
hose (not shown) for providing a flow of pressurized gas, for
example, pressurized air at a pressure between about 0 psig and
about 90 psig, to plenum 32. Transfer plate assembly 16 may also
include a coupling 94, for example, a quick-disconnect coupling
having mating connectors 94A and 94B, for connecting and detaching
transfer plate assembly 16 from support 106, for example, for
mounting to a robotic arm (not shown). When mounting adapter 94
comprises a pneumatically controlled quick-disconnect coupling, the
coupling may be actuated by mean of pressurized air introduced via
hoses 90, 92 to actuate connectors 94A and 94B, respectively.
According to one aspect to the invention, thin films are detached
from surface 30 by a flow of pressurized gas from plenum 32 through
holes 31. The pressurized gas supply and vacuum may be monitored
and regulated by means of appropriate pressure and flow control
means (not shown), for example, pressure gages or pressure taps and
flow valves and valve controllers.
[0051] With reference to FIG. 6, plenum 32 of vacuum plate assembly
93 may be made from a metallic or non-metallic material, for
example, a transparent plastic material such as polycarbonate,
polypropylene, polyethylene, or like materials. Plenum 32 may
include one or more internal baffles 84 to isolate different
regions of plenum 32, for example, to isolate regions operatively
connected to the source of vacuum provided by conduits 34 and 35,
or further conduits (not shown). For example, in one aspect of the
invention, vacuum plate assembly 93 comprises multiple, separate
plenums (for example, 2 or more plenums, or 4 or more plenums) at
least some of which may be provided with a source of vacuum or
pressurized gas. The flow of pressurized gas to or the exposure to
vacuum of the individual plenums may be individually controlled and
monitored to provide flexibility in retaining and deflecting thin
films from perforated surface 30. In the aspect of the invention
shown in FIGS. 6 and 7, vacuum plate 93 is mounted in support frame
86, for example, a metallic or non-metallic support frame 86.
Support frame 86 provides a mounting for wires 96 (discussed below
with respect to FIG. 7). Support frame 86 deflects (that is,
translates) relative to vacuum plate 93 and, in one aspect of the
invention, movement of support from 86 may be guided by vacuum
plate 93, for example, guided by the sides of vacuum plate 93.
Support frame 86 may include a plurality of threaded fasteners 88,
for example, hex-head cap screws. Threaded fasteners 88 may be used
to retain support frame 86 (and wires 96) in a retracted or raised
position relative to vacuum plate 93.
[0052] As shown in FIG. 6, in one aspect of the invention, transfer
plate assembly 16 having vacuum plate 93 may be mounted to robotic
arm 18 (see FIG. 1) or other positioning system by means of
mounting adapter 94. Mounting adapter 94 may be attached to an
automated position controller or a robotic arm 18 (see FIG. 1), for
example, a robotic arm of a SCARA-type robotic arm, such as, an
Adept Cobra 600 robotic arm, or its equivalent. According to one
aspect of the invention, arm 18 is used to position transfer plate
assembly 16 at least adjacent to transfer drum 26 and then adjacent
to a target location (not shown), for example, an assembly onto
which the thin film is to be placed. In one aspect of the
invention, machine vision is used to accurately guide the robot arm
18 to place the thin film on the target location. In one aspect of
the invention, the positioning of transfer plate assembly 16 is
effected manually.
[0053] As shown most clearly in FIG. 7, in one aspect of the
invention, transfer plate assembly 16 includes a plurality of wires
96 which extend across surface 30 and assist in the removal of the
thin film from surface 30 of vacuum plate assembly 93. Wires 96 are
typically metallic wires, for example, wires made from 304 or 316
stainless steel and have a diameter of between about 0.010 inches
(about 0.25 mm) and about 0.125 inches (about 3.175 mm). Wires 96
typically extend across support frame 86 and are retained by
conventional mechanical fasteners 98, 100, for example, cap screws.
Wires 96 may be interlaced or woven to provide as uniformly planer
wire interface as possible. In one aspect of the invention,
fasteners 100 are adjustable tensioning screws used to vary the
tension in wires 96, for example, in one aspect of the invention,
wires 96 are retained at one end by socket-head cap screws 98 and
at the other end by adjustable tensioning screws 100. In one aspect
of the invention, as shown in FIG. 7B, surface 30 may include
shallow grooves or recesses 33 into which wires 96 are imbedded or
retracted below the surface 30 to ensure contact between the thin
film and surface 30. Grooves or recesses 33 may be equally spaced
from holes 31 and have depths and widths at least equal to or
slightly greater than the diameter of the wires 96. This ensures
that wires 96 are recessed below surface 30, for example, are not
exposed above surface 30 to contact the thin film. The recesses or
grooves 33 in surface 30 may be fashioned in a criss-crossing grid
patterned, for example, machined into surface 30.
[0054] In one aspect of the invention, when the transfer plate
assembly 16, having a thin film (not shown) on surface 30 (for
example, held by means of vacuum) is positioned above the desired
location, the vacuum is reduced or shut off and the thin film is
allowed to fall under the force of gravity into the desired
location. If the surface tension between the thin film and surface
30 (for example, due to the presence of a viscous liquid in which
the thin film is immersed) is too strong to overcome gravity stream
of gas, for example, a low pressure, high volume stream of gas
(typically air), may be applied to the vacuum plate assembly 93,
for example via hoses 34, 35 to dislodge the thin film from surface
30. (Though in one aspect of the invention hoses 34, 35 provide
both pressurized gas and vacuum, in another aspect of the
invention, pressurized gas and vacuum may be provided by separate
hoses.) However, as a further aid in releasing the thin film from
surface 30, surface 30 may be moveable relative to wires 96 to
force the thin film from surface 30. In one aspect of the
invention, vacuum plate assembly 93 is moveable relative to support
frame 86 and means are provided for deflecting vacuum plate
assembly 93 relative to support frame 86, or vice versa, to
dislodge the thin film from surface 30. For example, as the vacuum
plate assembly 93 having surface 30 is deflected from support frame
86 having wires 96, the thin film is more easily separated from
wires 96 by gravity, since there is typically insufficient surface
contact area between wires 96 and the thin film to allow the thin
film to adhere to wires 96.
[0055] According to one aspect of the invention support frame 86
having wires 96 may be deflected relative to vacuum plate assembly
93 by means of some form of manual, electrical, mechanical, or
electromechanical means, for example, hydraulically, pneumatically,
or magnetically. In one aspect of the invention, the deflection of
support frame 86 is effected electro-mechanically by
solenoid-controlled rods, also known as "shot pins". The deflection
of support frame 86 relative to vacuum plate 93 may be effected by
some form of cam or detent, for example, a spring-loaded detent,
which limits the range of deflection of frame 86 or plate 93. The
deflection of support frame 86 may also be limited by a mechanical
stops.
[0056] As shown in FIG. 8, stops 104 on vacuum plate assembly 93
may limit how far the vacuum, plate 93 can be displaced relative to
support frame 86. In one aspect of the invention, about 0.25 inches
to about 0.50 inches of relative displacement between vacuum plate
assembly 93 and support frame 86 is provided. As shown in FIG. 8,
vacuum plate assembly 93 may include locating pin blocks 108 which
cooperate with removable pins or threaded fasteners (not shown) to
allow for easy registration of the vacuum plate assembly 93 with
the target location.
[0057] As also shown in FIG. 8, vacuum plate assembly 93 typically
includes at least one vacuum port 110 and 112 into which vacuum
connectors 87 and 89 (see FIG. 6) can be inserted. Vacuum plate
assembly 93 also typically includes some form of support mounting
114 for attaching mounting adapter 94 (see FIG. 6) to vacuum plate
93. For example, mounting support 114 may be suitable mounting for
a pneumatically operated quick disconnect actuated by pressurized
air (typically, about 70 to about 90 psig) supplied via hoses 90,
92.
[0058] According to one aspect of the invention, thin films, for
example, the thin film 42 shown in FIG. 2, may be handled in the
following fashion. First, though thin film 42 may be removed from
container 40 (for example, plastic bag 40) prior to placing film 42
onto surface 18 of vacuum table assembly 12, in one aspect of the
invention, bag 40 containing thin film 42 is placed on table
assembly 12 without being opened or cut. Either prior to placing
bag 40 onto surface 18 or soon thereafter, a source of vacuum to
table assembly 12 is activated to produce a vacuum in plenum 19
whereby bag 40 is retained on surface 18. Bag 40 may be opened
manually or by positioning and compressing die cutter 60 (see FIGS.
4A and 4B) onto bag 40. As described above, in one aspect of the
invention, the four blades 64 of die cutter 60 may effect a "kiss
cut" wherein the top of bag 40 and thin film 42 are severed by
blades 64, but the bottom of bag 40 is not severed by blades 64.
Die cutter 60 may be positioned and compressed manually or by means
of automated actuators, for example, by means of an automatic
controller and, for example, a hydraulic press.
[0059] In one aspect of the invention, top of bag 40 may be removed
from table assembly 12 manually, that is, by an operator, and thin
film 42 can be picked up from table assembly 12 by transfer plate
assembly 16 and transferred by transfer plate assembly 16 to a
desired location. However, in another aspect of the invention, the
top of bag 40 and thin film 42 may be removed from table assembly
12 and transferred to transfer plate assembly 16 by means of
transfer drum assembly 14. In this aspect of the invention, after
removing die cutter 60 from bag 40, surface 18 having severed bag
40 is then moved, for example, by manual or automated means, toward
transfer drum assembly 14, for example, as indicated by double
arrow 22 in FIG. 1. Prior to or at the same time as bag 40 on table
assembly 12 approaches the surface 24 of drum 26, the source of
vacuum to plenum 27 is activated, and a vacuum is drawn through
holes 25 in surface 24. According to the present invention, when
bag 40 is positioned adjacent to holes 25, sufficient vacuum is
drawn through holes 25 wherein at least the leading edge of the top
of bag 40 and the leading edge of thin film 42 are drawn to and
retained onto surface 24. In one aspect of the invention, the
mounting of drum 26 may not be fixed, but may allow for at least
some deflection of drum 26, for example, vertical deflection,
whereby surface 24 is moved, for example, momentarily, closer to
the top of bag 40 to facilitate retention of the top of bag 40 and
thin film 42 on surface 24. Drum 26 is then rotated, for example,
in clock-wise direction as viewed from the right-hand side of drum
26 in FIG. 1. According to this aspect of the invention, the speed
and direction of rotation of drum 26 and the speed and direction of
translation of table assembly 12 are such (for example, in the same
direction, though they may move in opposite directions) that the
rotation of drum 26 "peels" the top of bag 40 and thin film 42 away
from table assembly 12 while the bottom of bag 40 is retained on
table assembly 12. The retention of the thin film 42 on drum 26 may
be aided by adhesion between the top of bag 40 and thin film 42 due
to surface tension. This surface tension may be enhanced by the
presence of a viscous fluid, for example, the viscous fluid in
which thin film 42 may be treated. As noted earlier, this peeling
of the top of bag 40 and thin film 42 away from the bottom of bag
40 may be facilitated by the preferential sticking of thin film 42
to the top of bag 40. This preferential sticking may be effected by
one or more of the means discussed above.
[0060] The rotation of drum 26 and the translation of table
assembly 12 is continued until the top of bag 40 and film 42 are
removed from table assembly 12. Upon removal of bag 40 and film 42,
table assembly 12 may be returned to its original source or
mounting position and, after removal of the waste bag material,
await acceptance of the next bag 40 and thin film 42. The waste bag
material may be removed from table assembly 12 manually or by
automated means.
[0061] According to the present invention, the rotation of drum 26
is continued until the position of the top of bag 40 and film 42
approaches transfer plate assembly 16. The rotation of drum 26 may
continue in the same direction (for example, clockwise as viewed
from the right side of FIG. 1) as when film 42 is removed from
table assembly 12, or in the opposite direction. For example, drum
26 may be rotated in a reciprocating fashion wherein the drum
"rocks" back and forth when transferring film 42 from table
assembly 12 to transfer table assembly 16.
[0062] Prior to or just when bag 40 and film 42 approach transfer
table assembly 16, a source of vacuum is introduced to plenum 32 of
transfer table assemble 16. The vacuum in plenum 32 draws a vacuum
through perforations 31 (see FIG. 7) wherein thin film 42 is drawn
to and attached to surface 30 of transfer table assembly 16.
According to the invention, the vacuum maintained in plenum 27 of
drum 26 and the vacuum drawn in plenum 32 of transfer table
assembly 16 are sufficient so that thin film 42 is drawn to and
attached to surface 30, but the top of bag 40 is retained on
surface 24 of drum 26. Though In one aspect of the invention drum
26 and surface 30 are stationary during the transfer of thin film
42, in another aspect of the invention, the removal of thin film 42
from surface 24 may be effected while surfaces 24 and 30 are in
motion, or when either surface 24 or surface 30 is in motion. For
example, the location of transfer table assembly 16 may be
controlled whereby the leading edge of thin film 42 is grasped by
surface 30 as drum 26 is moving and the leading edge of thin film
42 approaches surface 30. When both drum 26 and transfer table
assembly 12 are in motion during transfer of thin film 42 to
surface 30, the direction of motion of drum 26 and surface 30 is
typically the same, though the surfaces may move in opposite
directions. When surface 30 includes wires 96 (see FIG. 7) for
releasing thin film 42, wires 96 are typically retracted to avoid
hindering transfer of film 42 to surface 30. After thin film 42 is
removed from surface 24, drum 26 may be rotated back into position
and, after removal of the waste bag material, positioned to accept
and retain the next thin film. Again, the waste bag material may be
removed from drum 26 manually or by automated means.
[0063] According to the invention, after thin film 42 is retained
on the surface 30 of transfer table assembly 16, transfer table
assembly 16 may be moved and positioned over the target location,
for example, positioned over an electrode assembly. The movement of
transfer table assembly 16 may be effected manually or by means of
automated controllers, for example, by means of robotic arm 18 (see
FIG. 1). As noted above, the positioning of transfer table assembly
16 may be aided by the use of machine vision and appropriate
positioning software.
[0064] Upon proper positioning of thin film 42 over its target
position, the vacuum in plenum 32 may be reduced or eliminated
wherein thin film 42 may fall under the force of gravity into place
on the target position. If the force of gravity is insufficient to
dislodge thin film 42, displacement of thin film 42 from surface 30
may be encouraged by introducing pressurized air (or other gases,
such as nitrogen) supplied via conduits 34 and 35 to plenum 32
and/or deflecting surface 30 relative to wires 96 as discussed
above. Upon completion of the transfer of thin film 42 to its
target position, transfer table 16 may be returned to transfer drum
14 to receive the next thin film 42. This process may be repeated
continuously or intermittently.
[0065] As noted above, the handling of thin films according to the
present invention may be effected manually, automatically, or by a
combination of the two. Appropriate automated controllers, for
example, computerized controllers, may be used to optimize the
translations, rotations, positioning, vacuums, gas pressures and
flows, and related parameters of one or more of the components of
the system shown in FIG. 1.
[0066] The invention described above and in the attached claims
provides improved means for handling thin film materials, for
example, during the insertion of thin film materials into
assemblies containing thin film materials. In one aspect of the
invention, thin film materials provided in sealed containers in
corrosive environments are more readily manipulated to eliminate
the need for human handling. In another aspect of the invention,
the assembly of fuel-cell type membranes into fuel cell electrodes
is automated and facilitated.
[0067] While the invention has been particularly shown and
described with reference to preferred aspects and embodiments, it
will be understood by those skilled in the art that various changes
in form and details may be made to the invention without departing
from the spirit and scope of the invention described in the
following claims.
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