U.S. patent application number 14/152265 was filed with the patent office on 2014-05-08 for glass sheet separating device.
This patent application is currently assigned to Corning Incorporated. The applicant listed for this patent is Corning Incorporated. Invention is credited to Steven Edward DeMartino, Michael Albert Joseph, II.
Application Number | 20140123709 14/152265 |
Document ID | / |
Family ID | 41319793 |
Filed Date | 2014-05-08 |
United States Patent
Application |
20140123709 |
Kind Code |
A1 |
Joseph, II; Michael Albert ;
et al. |
May 8, 2014 |
GLASS SHEET SEPARATING DEVICE
Abstract
A scoreless separation device and method are described herein
for separating a glass sheet without needing to score the glass
sheet. In one embodiment, the device shears a stationary glass
sheet without needing to score the glass sheet. In another
embodiment, the device shears a moving glass sheet to remove outer
edges from the moving glass sheet without needing to score the
moving glass sheet.
Inventors: |
Joseph, II; Michael Albert;
(Corning, NY) ; DeMartino; Steven Edward; (Painted
Post, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Corning Incorporated |
Corning |
NY |
US |
|
|
Assignee: |
Corning Incorporated
Corning
NY
|
Family ID: |
41319793 |
Appl. No.: |
14/152265 |
Filed: |
January 10, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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12262800 |
Oct 31, 2008 |
8656738 |
|
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14152265 |
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Current U.S.
Class: |
65/97 ; 225/2;
225/96.5; 65/176 |
Current CPC
Class: |
C03B 33/033 20130101;
C03B 33/023 20130101; C03B 33/03 20130101; C03B 21/04 20130101;
Y10T 83/0207 20150401; Y02P 40/57 20151101; C03B 33/0215 20130101;
C03B 33/0235 20130101; Y10T 225/325 20150401; C03B 33/074 20130101;
B65H 2301/41487 20130101; Y10T 83/664 20150401; B65H 2801/61
20130101; Y10T 225/12 20150401 |
Class at
Publication: |
65/97 ; 65/176;
225/2; 225/96.5 |
International
Class: |
C03B 33/03 20060101
C03B033/03; C03B 33/023 20060101 C03B033/023 |
Claims
1-45. (canceled)
46. A method for producing a glass sheet, said method comprising
the steps of: causing the glass sheet to travel in a traveling
direction; separating the glass sheet which is moving using a
scoreless separation device which comprises a separation mechanism
that generates a stress profile within the moving glass sheet that
produces a crack in a predefined location within the moving glass
sheet to shear off an edge of the moving glass sheet; wherein after
the edge has been sheared off of the moving glass sheet, a
remaining portion of the moving glass sheet is curved away from the
traveling direction to a greater extent than is the sheared-off
edge; and winding the remaining portion of the moving glass sheet
onto a take-up roller.
47. The method of claim 46, wherein the separation device further
comprises a crack initiator that interfaces at the predefined
location of the moving glass sheet to initiate the crack which is
formed and then propagated along a desired path within the moving
glass sheet.
48. The method of claim 46, wherein the separation device further
comprises at least one pair of air bearings that direct the
sheared-off edge.
49. The method of claim 46, wherein the separation device further
comprises at least one pair of rollers that direct the sheared-off
edge.
50. The method of claim 46, wherein before the step of causing the
sheet to travel in a traveling direction, there are performed the
steps of: melting batch materials to form molten glass and
processing the molten glass to form the glass sheet; and drawing
the glass sheet.
51. The method of claim 46, wherein a thickness of the remaining
portion of the moving glass sheet is <100 microns.
52. The method of claim 46, wherein the separation device further
comprises a cutter which cuts or partially cuts a coating on the
moving glass sheet prior to shearing the edge from the moving glass
sheet
53. A glass manufacturing system comprising: a scoreless separation
device comprising a separation mechanism that generates a stress
profile within the moving glass sheet where the stress profile
produces a crack which is subsequently formed in a predefined
location within the moving glass sheet to shear off an edge of the
moving glass sheet; a conveyance mechanism having a travel path
extending in a traveling direction leading to the scoreless
separation device, and separate travel paths leading away from the
scoreless separation device, the conveyance mechanism configured so
that after the edge has been sheared off of the moving glass sheet,
a remaining portion of the moving glass sheet is curved away from
the traveling direction to a greater extent than is the sheared-off
edge; and a take-up roller on which there is wound the remaining
portion of the moving glass sheet.
54. The glass manufacturing system of claim 53, wherein the
separation device further comprises at least one pair of air
bearings that direct the sheared-off edge.
55. The glass manufacturing system of claim 53, wherein the
separation device further comprises at least one pair of rollers
that direct the sheared-off edge.
56. The glass manufacturing system of claim 53, wherein the
separation device further comprises a crack initiator that
interfaces with the moving glass sheet to initiate the crack which
is formed and then propagated along a desired path within the
moving glass sheet.
57. The glass manufacturing system of claim 53, further comprising,
upstream of the scoreless separation device: at least one vessel
for melting batch materials and forming molten glass; a forming
device for receiving the molten glass and forming a moving glass
sheet; and a pull roll assembly for drawing the moving glass
sheet.
58. The glass manufacturing system of claim 53, wherein the
separation device further comprises a cutter which cuts or
partially cuts a coating on the moving glass sheet prior to
shearing the edge from the moving glass sheet.
Description
TECHNICAL FIELD
[0001] The present invention relates to a device and a method for
separating a glass sheet without needing to score the glass sheet.
In one embodiment, the device separates a stationary glass sheet
without needing to score the glass sheet. In another embodiment,
the device separates a moving glass sheet to remove outer edges
therefrom without needing to score the moving glass sheet.
BACKGROUND
[0002] Scoring devices such as diamond scribes, carbide scoring
wheels and laser scoring devices are commonly used today in the
glass industry to score a glass sheet so that the glass sheet can
be broken into a desired shape. The diamond scribes have been used
for over 100 years in the glass industry. The carbide scoring
wheels have been used in the glass industry for about 100 years
while the laser scoring devices have been used for about 30 years.
Unfortunately, these scoring devices damage the top surface of the
glass sheet which severely limits the edge strength of the
separated glass sheet. Accordingly, there is a need for a device
and method that can address this shortcoming and other shortcomings
which are associated with the scoring and separation of a glass
sheet. This need and other needs are satisfied by the present
invention.
SUMMARY
[0003] In one aspect, the present invention provides a device for
separating a stationary glass sheet where the device includes: (a)
a support plate; (b) a first stabilizing surface extending upward
from the support plate; (c) an anvil surface extending upward from
the support plate, where the glass sheet is located on top of the
support plate, the first stabilizing surface, and the anvil
surface; (d) a second stabilizing surface placed on top of the
glass sheet, where the second stabilizing surface is located on an
opposite side of the glass sheet when compared to the first
stabilizing surface and the anvil surface, where the second
stabilizing surface is located closer to the anvil surface than to
the first stabilizing surface; and (e) a stress surface placed on
the top of the glass sheet, where the stress surface is located
between the first stabilizing surface and the anvil surface both of
which are located on the opposite side of the glass sheet from the
stress surface, where the stress surface when moved towards the
glass sheet contacts the glass sheet closely adjacent to the anvil
surface to generate a stress profile within the glass sheet that
produces a crack in the glass sheet and separates the glass sheet
into two separate glass sheets. This is important because the
resulting quality of the separated edge on the glass sheet is
pristine and superior in finish and strength to the current scored
edge.
[0004] In another aspect, the present invention provides a
separation device for separating a moving glass sheet without
having to score the moving glass sheet. In an embodiment, the
separation device includes a separating mechanism (e.g., rolls,
tracks etc.) that generates a stress profile within the moving
glass sheet where the stress profile produces a crack in a
predefined location within the moving glass sheet to shear off at
least one edge of the moving glass sheet. This is important because
the resulting quality of the separated edge on the glass sheet is
pristine and superior in finish and strength to the current scored
edge.
[0005] In yet another aspect of the present invention there is
provided a glass manufacturing system (and corresponding method)
that includes the following: (a) least one vessel for melting batch
materials and forming molten glass; (b) a forming device for
receiving the molten glass and forming a moving glass sheet; (c) a
pull roll assembly for drawing the moving glass sheet; (d) a
scoreless separation apparatus for separating the moving glass
sheet, where the scoreless separating apparatus includes one or
more separation devices each of which includes: (i) a separation
mechanism (e.g., rolls, tracks etc.) that generates a stress
profile within the moving glass sheet where the stress profile
produces a crack which is subsequently formed in a predefined
location within the moving glass sheet to shear off an edge of the
moving glass sheet; (ii) at least two pairs of stabilizing rolls
that control a crack propagation wavefront after the crack is
formed within the moving glass sheet and also direct the
sheared-off edge away from a remaining portion of the moving glass
sheet; (iii) at least one pair of re-directing rolls that further
direct the sheared-off edge away from the remaining portion of the
moving glass sheet; (d) at least one sheet stabilizing device for
stabilizing the remaining portion of the moving glass sheet; and
(e) a take-up roller on which there is wound the remaining portion
of the moving glass sheet.
[0006] Additional aspects of the invention will be set forth, in
part, in the detailed description, figures and any claims which
follow, and in part will be derived from the detailed description,
or can be learned by practice of the invention. It is to be
understood that both the foregoing general description and the
following detailed description are exemplary and explanatory only
and are not restrictive of the invention as disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] A more complete understanding of the present invention may
be had by reference to the following detailed description when
taken in conjunction with the accompanying drawings wherein:
[0008] FIG. 1 is a perspective view of an exemplary device that can
be used to shear a stationary glass sheet in accordance with an
embodiment of the present invention;
[0009] FIGS. 2A-2C and 3A-3C diagrammatically illustrate different
views of how the device shown in FIG. 1 can be used to shear the
stationary glass sheet in accordance with an embodiment of the
present invention;
[0010] FIGS. 4A and 4B are two diagrams that respectively
illustrate the results of a two point bend test which was performed
on a scoreless separated glass sheet and a conventionally scored
glass sheet;
[0011] FIGS. 5-6 are graphs which indicate the stress results of
several scoreless separated glass sheets which had underwent the
two point bend test in accordance with an embodiment of the present
invention;
[0012] FIG. 7 is a schematic view of an exemplary glass
manufacturing system which utilizes a scoreless separating
apparatus to shear a moving glass sheet and remove outer edges
therefrom in accordance with an embodiment of the present
invention;
[0013] FIG. 8 is a perspective view illustrating in greater detail
the components of the scoreless separating apparatus shown in FIG.
7 in accordance with an embodiment of the present invention;
[0014] FIGS. 9A-9F are multiple diagrams illustrating the various
components associated with an exemplary dynamic separation device
which is part of the scoreless separating apparatus shown in FIG. 8
in accordance with an embodiment of the present invention; and
[0015] FIG. 10 is a diagram illustrating how the scoreless
separating apparatus can be configured to separate the edges from a
coated glass sheet in accordance with an alternative embodiment of
the present invention.
DETAILED DESCRIPTION
[0016] Referring to FIG. 1, there is shown a perspective view of an
exemplary device 100 that can be used to separate a stationary
glass sheet 102 in accordance with an embodiment of the present
invention. The exemplary device 100 includes an arbor press 104
which interfaces with a die set 106 that is used to support and
shear the glass sheet 102. The die set 106 includes a bottom
support platform 108 on top of which are placed multiple support
bars 110a, 110b and 110c (three shown). In addition, the die set
106 includes a glass support 112 that is placed on top of the
support bars 110a, 110b and 110c. The glass support 112 has
extending upward therefrom a stabilizing surface 114 and an anvil
surface 116 where the stabilizing surface 114 does not extend as
far up as the anvil surface 116 (see the expanded view).
Alternatively, the stabilizing surface 114 and the anvil surface
116 may be attached to the support bar 110b and then extend upward
through the glass support 112. The glass sheet 102 can be
positioned at a desired separating position on top of the glass
support 112 by using one or more micrometers 118a and 118b (for
example) or other suitable locating and alignment device such as an
electronically controlled linear actuator which can be programmed
to position the glass sheet 102 to the desired position.
[0017] The bottom support platform 108 has four alignment shafts
120 extending upward therefrom on top of which is placed a top
plate 122. The top plate 122 has a stress riser 124 movably fixed
thereto where the stress riser 124 can be moved in a downward
direction to interface with and shear the glass sheet 102. In this
example, the stress riser 124 is attached to a moveable arm 126 on
the arbor press 104 and a hand controller 128 is used to move the
moveable arm 126 and the attached stress riser 124 towards or away
from the glass sheet 102. The stress riser 124 has extending
downward therefrom a stress surface 130 which interfaces with and
shears the glass sheet 102 (see the expanded view). The stress
surface 130 is arranged and moves parallel to the anvil surface 116
and parallel to the glass sheet 102. Alternatively, the stress
surface 130 may be arranged and move downward at a slight angle to
the anvil surface 116 and the glass sheet 102, such that the stress
surface initially contacts the glass sheet at one edge of the sheet
only, such that the separation in the glass sheet starts at the one
edge and propagates across the glass sheet. If desired, the stress
riser 124 can have a score initiator 132 attached thereto which can
be used to score a side edge (or top edge) of the glass sheet 102.
In addition, the die set 106 includes a stabilizing surface 134
(stabilizing bar 134) which is placed on top of the glass sheet 102
at a location between the stress riser 124 and the micrometers 118a
and 118b. Alternatively, the stabilizing bar 134 does not need to
extend across the entire length of the glass sheet 102 but instead
can be placed on one or more of the edges of the glass sheet 102. A
detailed discussion about how the device 100 can be used to shear
the glass sheet 102 is provided next with respect to FIGS. 2 and
3.
[0018] Referring to FIGS. 2A-2C and 3A-3C, there are illustrated
different diagrammatic views of how the device 100 shown in FIG. 1
can be used to shear the glass sheet 102 in accordance with an
embodiment of the present invention. For clarity, only the glass
support 112, the stabilizing surface 114, the anvil surface 116,
the stress surface 130, the stabilizing surface 134 and the glass
sheet 102 are shown in these drawings to help explain the
separation operation of the device 100. FIGS. 2A and 3A illustrate
a first step during which the glass sheet 102 is placed in a
desired position on top of the glass support 112. The glass sheet
102 is placed on top of the stabilizing surface 114, the anvil
surface 116, and the glass support 112 while the stress surface 130
and the stabilizing surface 134 are placed on top of the glass
sheet 102. In one embodiment, the stabilizing surface 114, the
anvil surface 116, the stress surface 130 and the stabilizing
surface 134 could all have a rubber coating or plastic coating to
help prevent damaging the glass sheet 102. In addition, the
stabilizing surface 114, the anvil surface 116, the stress surface
130 and the stabilizing surface 134 are shown as being different
shapes so they could be any shape including, for example, a
spherical shape, an elliptical shape, a rectangular shape or a
square shape. In this embodiment, the anvil surface 116 and the
stress surface 130 are generally square shaped especially at their
respective facing adjacent edges 136 and 137 which are located
closely adjacent to each other in order to create a highly
localized stress in the glass sheet 102. The horizontal spacing
between the facing adjacent edges 136 and 137 of the anvil surface
116 and the stress surface 130 may increase with increasing
thickness of the glass sheet being separated. Plus, the edges of
surfaces 116 and 130 are relatively sharp to provide a well defined
stress field in the plane of separation on the glass sheet 102. It
is possible that other shapes, as mentioned previously, may work as
well. In this example, the glass sheet 102 had a starter score 202
located on the side edge thereof which was made by the score
initiator 132. If desired, the starter score 202 could have been
made by a laser (not shown). The starter score 202 is optional and
not required to shear the glass sheet 102. In the case of the glass
sheet 102 being coated with a polymer or rubber, cutting bars can
be used to help remove the coating prior to separating the glass
sheet 102.
[0019] FIGS. 2B and 3B illustrate a second step during which the
glass sheet 102 has a stress field generated therein by applying a
force F which is caused by moving the stress riser 124 and in
particular the stress surface 130 down onto the top of the glass
sheet 102. The stress field is generated and rises until the
starter score 202 opens and a crack travels the entire length of
the glass sheet 102. The starter score 202 helps ensure that the
separation is initiated at a desired location on the glass sheet
102. FIG. 2B also illustrates a photo of a side edge 204 of the
glass sheet 102 that was scored in a conventional manner,
[0020] FIGS. 2C and 3C illustrate a third step showing the desired
cut 206 in the glass sheet 102 and that the separation was
initiated in the desired location and propagated along a desired
path corresponding with the nearly symmetrical stress field located
within the glass sheet 102. The stress field was created by the
downward movement of the stress surface 130 onto the glass sheet
102. FIG. 2C also illustrates a photo of the edge 206 of the glass
sheet 102 that was formed by the downward movement of the stress
surface 130 on top of the glass sheet 102 (compare to FIG. 2B).
[0021] Referring to FIGS. 4A and 4B, there are two diagrams
respectively illustrating the results of a two point bend test that
was performed on a scoreless separated glass sheet 102 (FIG. 4A)
and a conventionally scored glass sheet 400 (FIG. 4B). The two
point bend test was used to evaluate the bending stress on a small
area of the glass sheets 102 and 400 which are the same except for
the way that they were separated. In this test, two plates 402 and
404 are used to compress each of the glass sheets 102 and 400.
Then, the distance between the two plates 402 and 404 is measured
when the glass sheets 102 and 400 break. This distance is inversely
proportional to the stress handling capability of the glass sheets
102 and 400 where the smaller the distance between the two plates
402 and 404 then the higher the resisting glass edge strength of
the glass sheets 102 and 400, In FIG. 4A, the scoreless glass sheet
102 had a relatively small radius when it was broken by the
compression of the two plates 402 and 404 which was indicative of a
glass edge strength of greater than 600 MPa. In FIG. 4B, the
conventionally scored glass sheet 400 had a relatively large radius
when it was broken by the compression of the two plates 402 and 404
which was indicative of a glass edge strength of about 200 MPa.
[0022] Referring to FIG. 5, there is illustrated a graph which
indicates that several tested glass sheets 102 which underwent the
aforementioned compression test had a stress handling capacity that
averaged 600-1000 MPa which is at least three times better on
average than the conventional carbide wheel scored glass sheets 400
(200 MPa) and the conventional laser scored glass sheets 400 (300
MPa) (note: the y-axis of the graph represents "probability" and
the x-axis represents "Stress MPa"). In this test, the glass sheets
102 where 100 .mu.m thick and the "diamond" in the graph indicates
a compression measurement and the "triangle" in the graph indicates
a tension measurement. The compression measurement indicates when
an inner portion 406 of the tested glass sheet 102 had broke due to
the compression of the blocks 402 and 404 (see FIG. 4A). The
tension measurement indicated when an outer portion 408 of the
tested glass sheet 102 had broke due to the compression of the
blocks 402 and 404 (see FIG. 4A).
[0023] Referring to FIG. 6, there is illustrated a graph which
indicates the stress results of several tested glass sheets 102
which had underwent the aforementioned compression test (note: the
y-axis of the graph represents "percent" and the x-axis represents
"2-Point Bend Strength (MPa)"). In this test, one set of tested
glass sheets 102 which had a laser scored edge 202 indicated by the
"circles" and the solid line in the graph had a stress handling
capacity on average of 609.8 MPa. Another set of tested glass
sheets 102 which did not have a scored edge 202 indicated by the
"squares" and the dashed line in the graph had a stress handling
capacity on average of 749.1 MPa. Yet another set of the tested
glass sheets 102 which had a mechanical scored edge 202 indicated
by the "diamonds" and the dotted-dashed line in the graph had a
stress handling capacity on average of 807.0 MPa. The glass sheets
102 where all about 100 .mu.m thick. A conclusion that can be made
by viewing these results is that_the scoreless method yields edge
strength and quality results which are far superior to the
traditional laser, scorewheel, or scribe methods. The lack of a
stress riser cut into the glass surface minimizes the potential for
micro-cracks and flaws associated with traditional contact and non
contact methods of glass scoring/separation.
[0024] Referring back to FIG. 1, a person skilled in the art will
appreciate that the device 100 is an off-line glass sheet
separation system that could be used by a glass manufacturer to
refine their processes that require off-production line separation
of glass sheets 102 (e.g., Liquid Crystal Display (LCD) substrates
102 or other substrates 102). In one embodiment, the device 100 has
metal bars 114, 116, 130 and 134 covered with rubber or plastic
that bend the thin glass sheet 102 such that a stress distribution
is formed within the thin glass sheet 102. When the stress reaches
a high enough level, it will initiate a crack at the high stress
region in the thin glass sheet 102. The resulting crack propagates
through the width of the thin glass sheet 102 until the stress is
relieved. Since, the thin glass sheet 102 is an amorphous material
with a very random atomic structure, it typically resists cutting
along a plane and instead tends to shatter or cracks form and move
in seemingly random directions. This does not happen in the present
invention because the device 100 has the stress surface 114 which
ensures that there is always a stress continuously applied to the
surface of the thin glass sheet 102 which maintains the stress
field or stress distribution and causes a crack propagation to
proceed in a desired direction along a predefined path on the thin
glass sheet 102 until the separation is complete.
[0025] The device 100 also has several other benefits, advantages
and features several of which are as follows (for example): [0026]
The device 100 can easily be adjusted such that different
configurations can be achieved by simply adding on, removing, or
adjusting various components to separate a thin glass sheet 102.
[0027] The greater bend strength in the separated glass sheets 102
is desirable when the glass sheets 102 are used to make thin
flexible displays. [0028] The device 100 reduces production costs
by increasing the yield of acceptable glass sheets 102 due to
having fewer glass edge related failures.
[0029] The device 100 enhances key substrate edge attributes in the
separated glass sheets 102 (see FIGS. 4-6). [0030] The device 100
can be easily modified such that a greater understanding about a
proposed scoreless separation technique can be achieved. [0031] The
device 100 reduces the risk associated with failures of glass
sheets 102 that are under high stress due to the substantially
stronger scoreless edges 206. [0032] The device 100 can separate
glass sheets 102 or other thin substrates which have a thickness of
<100 .mu.m. [0033] The device 100 can incorporate different
types of sensors including motion sensors, laser sensors, sonic
sensors etc. to determine the performance of the separation
equipment and the quality of the separated glass sheets 102. [0034]
The device 100 or versions thereof could easily be automated for
commercial production of glass sheets one example of which is
discussed below with respect to FIGS. 7-9. In another example, a
slot draw process provides a glass sheet at a given rate, The glass
sheet orientation is changed from vertical to horizontal by means
of a catinary. The glass sheet now traveling in the horizontal
plane is supported by rollers and is periodically nicked with a
starter score and hand broken by the operator. The operator's job
can be automated by a machine like device 100 with the addition of
a proximity sensor to indicate when the desired glass length has
been reached. This length would correspond to the position of the
starter score which is desirable for proper crack initiation. The
separator bars would be actuated at the desired time by a linear
actuator and closed loop control with the proximity sensor. In
conjunction with this action, a short throw, <100 mm, a
traveling anvil machine (TAM) mechanism could be employed to keep
the bars in the same relative position as the nicked glass
commensurate with the time required to initiate the separation. The
bars would then return to the same home position to await for the
next separation event.
[0035] Referring to FIG. 7, there is shown a schematic view of an
exemplary glass manufacturing system 700 which utilizes a scoreless
separation apparatus 702 to shear a moving glass sheet 705 and
remove outer edges 706a and 706b therefrom in accordance with an
embodiment of the present invention. As shown, the exemplary glass
manufacturing system 700 includes a melting vessel 710, a fining
vessel 715, a mixing vessel 720 (e.g., stir chamber 720), a
delivery vessel 725 (e.g., bowl 725), a forming vessel 730, a pull
roll assembly 735, the scoreless separation apparatus 702, a pair
of sheet stabilizer devices 740a and 740b, a take-up roller 745,
and a controller 150.
[0036] The melting vessel 710 is where the glass batch materials
are introduced as shown by arrow 712 and melted to form molten
glass 726. The fining vessel 715 (e.g., finer tube 715) has a high
temperature processing area that receives the molten glass 726 (not
shown at this point) from the melting vessel 710 and in which
bubbles are removed from the molten glass 726. The fining vessel
715 is connected to the mixing vessel 720 (e.g., stir chamber 720)
by a finer to stir chamber connecting tube 722. And, the mixing
vessel 720 is connected to the delivery vessel 725 by a stir
chamber to bowl connecting tube 727.
[0037] The delivery vessel 725 delivers the molten glass 726
through a downcomer 728 and an inlet 729 into the forming vessel
730 (e.g., isopipe 730). The forming vessel 730 includes an opening
736 that receives the molten glass 726 which flows into a trough
737 and then overflows and runs down two sides 738a and 738b before
fusing together at what is known as a root 739 (see also FIG. 8).
The root 739 is where the two sides 738a and 738b come together and
where the two overflow walls of molten glass 726 rejoin (e.g.,
refuse) to form the glass sheet 705 before being drawn downward by
the pull roll assembly 735. The scoreless separation apparatus 702
shears the glass sheet 705 to remove the outer edges 706a and 706b
therefrom and form the glass sheet 705'. The sheared outer edges
706a and 706b are broken and collected within a pair of cullet bins
741a and 741b. The sheet stabilizer devices 740a and 740b direct
the remaining portion of the glass sheet 705' to the take-up roller
745. In this example, the controller 150 (e.g., computer 150) has a
memory 151 that stores processor-executable instructions and has a
processor 153 that executes the processor-executable instructions
to control the pull roll assembly 740, the scoreless separation
apparatus 702, the sheet stabilizer devices 740a and 740b and the
take-up roller 745.
[0038] Referring to FIG. 8, there is shown a perspective view
illustrating in greater detail several the scoreless separation
apparatus 702 and several other components of the exemplary glass
manufacturing system 700 shown in FIG. 7 in accordance with an
embodiment of the present invention. The scoreless separation
apparatus 702 includes two separation devices 703a and 703b, the
controller 150, and the cullet bins 741a and 741b. In operation,
the separation devices 703a and 703b each apply an external stress
to generate a stress profile within the moving glass sheet 705
where the stress profile produces a crack which is formed in a
predefined location within the moving glass sheet 705 to separate
and remove the outer edges 706a and 706b without needing to score
the glass sheet 705. Plus, the separation devices 703a and 703b
begin to curve the remaining portion of the glass sheet 705' and,
with the aid of the sheet stabilizers 740a and 740b, the remaining
glass sheet 705' can be rolled up on the take-up roller 745. The
remaining glass sheet 705' which in this example is less than 100
.mu.m thick has a two-point stress edge strength greater than 600
MPa which is a dramatic improvement over a conventionally scored
glass sheet which had a stress edge strength in the range of 300
MPa (see FIGS. 4-6). A detailed discussion about the different
components which are part of each exemplary dynamic separating
device 703a and 703b is provided below with respect to FIGS.
9A-9F.
[0039] Referring to FIGS. 9A-9F, there are multiple diagrams
illustrating the various components associated with the exemplary
dynamic separating device 703a (for example) in accordance with an
embodiment of the present invention. FIG. 9A is a diagrammatic left
side view of the separating device 703a which illustrates the glass
sheet 705 travelling through a series of rolls including a first
pair of rolls 902a and 902c, a second pair of rolls 904a and 904c,
a movable crack initiator 906, a third pair of rolls 908a and 908c,
a fourth pair of rolls 910a and 910c, and a fifth pair of rolls
912a and 912c. The exemplary separating device 703a also has the
glass sheet 705 travel through a first pair of air bearings 914a
and 914c (located between rolls 908a and 908c and rolls 910a and
910c), a second pair of air bearings 916a and 916c (located between
rolls 910a and 910c and rolls 912a and 912c), and a third pair of
air bearing 918a and 918c (located after rolls 912a and 912c).
[0040] In addition, the exemplary separation device 703a has
several other sets of rollers 902b and 902d, 904b and 904d, 908b
and 908d, and 910b and 910d which can not be seen in this
particular view but are respectively located adjacent to first pair
of rolls 902a and 902c, the second pair of rolls 904a and 904c, the
third pair of rolls 908a and 908c, the fourth pair of rolls 910a
and 910c, and the fifth pair of rolls 912a and 912c (see FIGS.
9B-9F). Likewise, the exemplary separation device 703a also
includes several other sets of air bearings 914b and 914d, 916b and
916d, and 918b and 918d which can not be seen in this particular
view but are respectively located adjacent to the first pair of air
bearings 914a and 914c, the second pair of air bearings 916a and
916e, and the third pair of air bearing 918a and 918c (see FIGS.
9C-9D).
[0041] In FIG. 9A, the controller 150 can interface with various
components like, for example, the drives, motors, solenoid valves,
air devices etc. . . . which operate the rolls 902a-902d,
904a-904d, 908a-908d, 910a-910d and 912a-912d, and the air bearings
914a-914d, 916a-916d and 918a-918d (see also FIG. 8). The
controller 150 can also interface with a variety of instruments
such as a pair of crack propagation scanners 920a and 920b, a pair
of sheet shape interferometers 922a and 922b, and a pair of thermal
scanners 924a and 924b to aid in the separation of the outer edge
706a from the moving glass sheet 705. The crack propagation
scanners 920a and 920b would be used to spot and track the crack at
different locations in the moving glass sheet 705. The sheet shape
interferometers 922a and 922b would be used to monitor the stress
profile at different locations in the moving glass sheet 705. The
thermal scanners 924a and 924b would be used to monitor the thermal
gradients at different locations in the moving glass sheet 705. The
function of these rolls 902a-902d, 904a-904d, 908a-908d, 910a-910d
and 912a-912d and the air bearings 914a-914d, 916a-916d and
918a-918d will be apparent after the discussion is completed about
the layout of these rolls 902a-902d, 904a-904d, 908a-908d,
910a-910d and 912a-912d, and the air bearings 914a-914d, 916a-916d
and 918a-918d.
[0042] Referring to FIG. 9B, there is a top view of the exemplary
dynamic separating device 703a which shows the first pair of rolls
902a and 902e and their adjacent rolls 902b and 902d through which
travels the moving glass sheet 705. As shown, rolls 902a and 902b
each have a curved surface 950a and 950b (e.g., high temperature
silicon 950a and 950b) and their opposing rolls 902c and 902d each
have a flat surface 950c and 950d (e.g., high temperature silicon
950c and 950d). The rolls 902c and 902d are also tiltable with
respect to their corresponding opposing rolls 902a and 902b. For
instance, rolls 902c and 902d can be tilted at an angle o of
anywhere between 0.degree.-5.degree.. In this example, roll 902e is
not tilted with respect to roll 902a but roll 902d is tilted about
2.5.degree. with respect to toll 902b. Thus, rolls 902a and 902c
help stabilize the outer edge 706a of the moving glass sheet 705
while the curved roll 902b and tilted roll 902d interface with the
moving glass sheet 705 to generate a stress profile within the
moving glass sheet 705 (note: the bending of the glass sheet 705
shown in the diagram has been enhanced). If desired, the rolls
902a-902d can incorporate temperature control mechanisms such as
channels 952 (for example) within which a fluid can flow to control
the temperature of the respective surfaces 950a-950d. In this
example, rolls 904a-904d which can not be seen in this figure would
be setup and function like rolls 902a-902d to help generate the
desired stress profile in the moving glass sheet 705.
Alternatively, one or more pair of tracks (or some other mechanism)
could be used instead of rolls 902a-902d and 904-904d through which
would pass the moving glass sheet 705 where one of the tracks would
have a protrusion extending therefrom which interfaces with the
moving glass sheet 705 to generate the desired stress profile
within the glass sheet 705 where the stress profile produces a
crack which is formed in a predefined location within the moving
glass sheet 705 to shear off the outer edge 706a of the moving
glass sheet 705.
[0043] Referring to FIG. 9C, there is a front view of the exemplary
dynamic separation device 703a which shows rolls 902a, 902b, 904a,
904b, 908a, 908b, 910a, 910b, 912a and 912b, the crack initiator
906, and air bearings 914a, 914b, 916a, 916b, 918a and 918b. This
figure also shows the high stress regions 954, a bow wave 956, a
scoreless wave front 958, low stress regions 960, and the
separation line 962 (or crack 962) present in the moving glass
sheet 705 when the dynamic separation device 703a is operating to
shear off the outer edge 706a of the moving glass sheet 705. The
separation line 962 (or crack 962) can be created by the
positioning of rolls 902b and 902d and the crack initiator 906 (if
used) can be moved to interface at a predefined location of the
moving glass sheet 705 to help initiate the crack 962 which when
formed is propagated along a desired path within the moving glass
sheet 705.
[0044] Referring to FIGS. 9D and 9E, there are respectively shown a
left side view and a top view of the rolls 908a-908d through which
travel the sheared-off outer edge 706a and the remaining portion of
the glass sheet 705'. In particular, the stabilizing rolls
908a-908d help control the scoreless wave front 958 (crack
propagation wavefront 958) after the crack 962 is formed within the
moving glass sheet 705 and also direct the sheared-off outer edge
706a away from the remaining portion of the glass sheet 705'. As
shown in FIG. 9E, the first pair of stabilizing rolls 908a and 908c
includes roll 908a which has a hard cover 964a (high durometer) and
roll 908c has a soft cover 964b (low durometer) between which
passes the sheared-off outer edge 706a. The second pair of
stabilizing rolls 908b and 908d includes roll 908b which has a soft
cover 964c (low durometer) and roll 908d has a hard cover 964d
(high durometer) between which passes the remaining portion of the
moving glass sheet 705'. The soft covers 964b and 964c on rolls
908b and 908c are pliable and deform when they interface with the
corresponding hard covers 964a and 964d on rolls 908a and 908d
which results in re-directing the sheared-off outer edge 706a away
from the remaining portion of the glass sheet 705'. The glass sheet
705' has relatively strong edges (e.g., 600 MPa or greater) which
enables the glass sheet 705' to be rolled into a relatively small
diameter on the take-up roll 745.
[0045] Referring to FIG. 9F, there is a left side view of rolls
908a-908d, 910a-910d and 912a-912d and air bearings 914a-914d,
916a-916d and 918a-918d through which pass the sheared-off outer
edge 706a and the remaining portion of the glass sheet 705'. As
discussed above, the stabilizing rolls 908a-908d direct the
sheared-off edge 706a away from the remaining portion of the glass
sheet 705'. The other rolls 910a-910d and 912a-912d and the air
bearings 914a-914d, 916a-916d and 918a-918d further help direct the
sheared-off edge 706a away from the remaining portion of the glass
sheet 705'. In particular, rolls 910a, 910c, 912a and 912c and air
bearings 914a, 914c, 916a, 916c, 918a and 918c are positioned to
direct the sheared-off outer edge 706a towards the cullet bin 741a
(see FIG. 8). In contrast, rolls 910b, 910d, 912b and 912d and air
bearings 914b, 914b, 916b, 916b, 918b and 918b are positioned to
direct the remaining portion of the glass sheet 705' to the sheet
stabilizer devices 740a and 740b and the take-up roller 745 (see
FIG. 8).
[0046] Referring now to FIG. 10 there is a left side view
illustrating how the scoreless separating apparatus 703a can be
further configured to separate the edge 706a from a moving coated
glass sheet 705 in accordance with an alternative embodiment of the
present invention. In this embodiment, a polymer coating 1002 is
applied to one or both sides of the glass sheet 705 by rollers
1004a and 1004b. Alternatively, the glass sheet 705 can be coated
by means of rolled sheet, pre-cut sheets, or a spray or dip
coating. The coating 1002 may be formed of a polymer, plastic, or
rubber-like. The separation of the coating 1002 or partial cutting
of the coating 1002 is required in order to be able to physically
separate the glass sheet 705. For instance, the coating 1002 can be
partially cut or separated from the glass sheet 702 by cutting
blades 1006a and 1006b or other means such as mechanical contact
cutters, stationary or rolling knives, or non-contact laser
cutting, micro-flame, pneumatic jet, hot gas jet (e.g., argon gas)
chemical jet, water jet. As shown, the partial cut of the coating
1002 can be achieved by attaching the mechanical cutters 1006a and
1006b to force feedback controls (e.g., springs 1008a and 1008b)
that prevent excessive cutting force. This partial cut weakens the
coating 1002 sufficiently so that the coating 1002 is easily broken
when the glass bead portion 706a is separated from the body of the
glass sheet 102 by means of the previously described rollers
910a-910d and rollers 912a-912d. The partial cut is desirable since
it prevents mechanical cutters 1006a and 1006b from contacting the
glass sheet 705 which may be harmful to the surface of the glass
sheet 705.
[0047] In view of the foregoing discussion, it should be
appreciated that an exemplary glass manufacturing system 700 which
implements glass separation method in accordance with an embodiment
of the present invention would include following: (a) least one
vessel 710, 715, 720 and 725 for melting batch materials and
forming molten glass (step 1); (b) a forming device 730 for
receiving the molten glass and forming a moving glass sheet 705
(step 2); (c) a pull roll assembly 735 for &awing the moving
glass sheet 705 (step 3); (d) a scoreless separation apparatus 702
for separating the moving glass sheet 705 (step 4), where the
scoreless separating apparatus 702 includes one or more separation
devices 703a and 703b each of which includes: (i) a separation
mechanism (e.g., rolls 902a-902d and 904a-904d, tracks etc.) that
generates a stress profile within the moving glass sheet 705 where
the stress profile produces a crack 962 which is subsequently
formed in a predefined location within the moving glass sheet 705
to shear off an edge 706a and 706b of the moving glass sheet 705;
(ii) a crack initiator 906 (optional) that interfaces at the
predefined location of the moving glass sheet 705 to initiate the
crack 962 which is formed and then propagated within the moving
glass sheet 705; (iii) at least two pairs of stabilizing rolls
908a-908d that control a crack propagation wavefront 958 after the
crack 962 is formed within the moving glass sheet 705 and also
direct the sheared-off edge 706a or 706b away from a remaining
portion of the moving glass sheet 705; (iv) at least one pair of
re-directing rolls 910a-910d and 912a-912d that further direct the
sheared-off edge 706a and 706b away from the remaining portion of
the moving glass sheet 705; (v) at least one pair of air bearings
914a-914d, 916a-916d and 918a-918d that further direct the
sheared-off edge 706a and 706b away from the remaining portion of
the moving glass sheet 705; (e) one or more sheet stabilization
devices 740a and 740b to stabilize the remaining portion of the
moving glass sheet 705' (step 5); and (f) a take-up roller 745 on
which there is wound the remaining portion of the moving glass
sheet 705' (step 6).
[0048] In addition, the scoreless separation apparatus 702 may also
includes a controller 150 that interfaces with one or more crack
propagation scanners 920a and 920b, sheet shape interferometers
922a and 922b, and thermal scanners 924a and 924b, and then
controls the separation devices 703a and 703b to shear off the
outer edges 706a and 706b of the moving glass sheet 705. An
advantage of this scoreless separation method is that the sheared
glass sheet 705' has considerably stronger edges when compared to
conventional scored glass sheets and as such can be rolled into a
relatively small diameter on the take-up roller 745. Plus, LCD and
other brittle materials in various configurations, i.e. portrait,
landscape, rolled, catinary, can be separated using this scoreless
separation technology.
[0049] A person skilled in the art should readily appreciate that
any type of glass manufacturing system that draws molten glass to
make a glass sheet can also incorporate and use the scoreless
separation apparatus 702 of the present invention. In fact, the
scoreless separation apparatus 702 could be used to score other
types of materials in addition to a glass sheet such as for example
a plexi-glass sheet, LCD substrate etc. . . . Accordingly, the
scoreless separation apparatus 702 of the present invention should
not be construed in a limited manner.
[0050] Although several embodiments of the present invention have
been illustrated in the accompanying Drawings and described in the
foregoing Detailed Description, it should be understood that the
invention is not limited to the embodiments disclosed, but is
capable of numerous rearrangements, modifications and substitutions
without departing from the spirit of the invention as set forth and
defined by the following claims.
* * * * *