U.S. patent application number 13/721557 was filed with the patent office on 2013-08-29 for methods of finishing a sheet of material with magnetorheological finishing.
The applicant listed for this patent is Aric Bruce Shorey, Daniel Duane Strong. Invention is credited to Aric Bruce Shorey, Daniel Duane Strong.
Application Number | 20130225049 13/721557 |
Document ID | / |
Family ID | 49003358 |
Filed Date | 2013-08-29 |
United States Patent
Application |
20130225049 |
Kind Code |
A1 |
Shorey; Aric Bruce ; et
al. |
August 29, 2013 |
Methods of Finishing a Sheet of Material With Magnetorheological
Finishing
Abstract
Methods of finishing a sheet of material, such as a glass sheet,
include finishing an edge portion of the sheet of material with
magnetorheological finishing. In one example, the average thickness
of the sheet of material between a first face and a second face is
from 50 .mu.m to about 500 .mu.m. In another example, the method
consists essentially of a single step of finishing the edge portion
of the glass sheet with magnetorheological finishing such that the
entire edge portion is shaped between the first face and the second
face during the a single magnetorheological finishing step.
Inventors: |
Shorey; Aric Bruce; (Painted
Post, NY) ; Strong; Daniel Duane; (Hector,
NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Shorey; Aric Bruce
Strong; Daniel Duane |
Painted Post
Hector |
NY
NY |
US
US |
|
|
Family ID: |
49003358 |
Appl. No.: |
13/721557 |
Filed: |
December 20, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61604863 |
Feb 29, 2012 |
|
|
|
Current U.S.
Class: |
451/36 |
Current CPC
Class: |
B24B 31/112 20130101;
B24B 31/00 20130101; B24B 9/10 20130101 |
Class at
Publication: |
451/36 |
International
Class: |
B24B 31/00 20060101
B24B031/00 |
Claims
1. A method of finishing a sheet of material comprising the steps
of: (I) providing a sheet of material with a first face and a
second face, wherein an average thickness of the sheet of material
between the first face and the second face is from about 50 .mu.m
to about 500 .mu.m; and (II) finishing an edge portion of the sheet
of material with magnetorheological finishing.
2. The method of claim 1, wherein step (I) provides the sheet of
material as a glass sheet.
3. The method of claim 1, wherein step (I) provides the average
thickness of the sheet of material from about 50 .mu.m to about 300
.mu.m.
4. The method of claim 3, wherein step (I) provides the average
thickness of the sheet of material from about 75 .mu.m to about 200
.mu.m.
5. The method of claim 4, wherein step (I) provides the average
thickness of the sheet of material from about 75 .mu.m to about 150
.mu.m.
6. The method of claim 1, wherein step (I) provides the sheet of
material positioned along a plane at a predetermined orientation
within an angular range of from about +45.degree. to about
-45.degree. with respect to a vertical axis.
7. The method of claim 6, wherein the predetermined orientation of
the sheet of material is maintained during step (II).
8. The method of claim 1, wherein step (I) provides the edge
portion extending along a peripheral portion of the sheet of
material between the first face and the second face.
9. The method of claim 1, further comprising a step of
strengthening the edge portion before step (II).
10. The method of claim 1, further comprising a step of separating
the sheet of material to provide the edge portion before step
(II).
11. The method of claim 10, wherein the step of separating occurs
after step (I).
12. The method of claim 10, further comprising a step of
strengthening the edge portion after the step of separating and
before step (II).
13. The method of claim 1, further comprising a step of edging the
sheet of material to provide the edge portion before step (II).
14. The method of claim 13, wherein the step of edging occurs after
step (I).
15. The method of claim 13, further comprising a step of separating
the sheet of material before the step of edging the sheet of
material.
16. The method of claim 13, further comprising a step of
strengthening the edge portion after the step of edging and before
step (II).
17. A method of finishing an edge portion of a glass sheet having a
first face and a second face with the edge portion extending along
a peripheral portion of the glass sheet between the first face and
the second face, the method consisting essentially of a single step
of: finishing the edge portion of the glass sheet with
magnetorheological finishing such that the entire edge portion is
shaped between the first face and the second face during the a
single magnetorheological finishing step.
18. A method of finishing an edge portion of a glass sheet
consisting essentially of the steps of: (I) providing a glass sheet
with a first face and a second face, wherein an average thickness
of the glass sheet between the first face and the second face is
from about 50 .mu.m to about 500 .mu.m; and (II) finishing an edge
portion of the glass sheet with magnetorheological finishing.
19. The method of claim 18, wherein, during step (II), the entire
edge portion is shaped between the first face and the second face
during a single magnetorheological finishing step.
20. The method of claim 18, wherein step (I) provides the average
thickness of the glass sheet from about 75 .mu.m to about 150
.mu.m.
Description
[0001] This application claims the benefit of priority under 35
U.S.C. .sctn.119 of U.S. Provisional Application Ser. No.
61/604,863 filed on Feb. 29, 2012 the content of which is relied
upon and incorporated herein by reference in its entirety.
TECHNICAL FIELD
[0002] The present disclosure relates generally to methods of
finishing a sheet of material and, more particularly, to methods of
finishing an edge portion of a sheet of material with
magnetorheological finishing.
BACKGROUND
[0003] It is known to produce a sheet of material, such as
display-quality glass sheets, by various techniques. Once formed, a
glass sheet is typically separated to trim edge portions from the
glass sheet and/or to resize the glass sheet to accommodate a
particular application. Typical separation procedures can result in
undesirable rough/sharp edge portions that are vulnerable to
cracking.
SUMMARY
[0004] Examples will now be described more fully hereinafter with
reference to the accompanying drawings in which example embodiments
are shown. Whenever possible, the same reference numerals are used
throughout the drawings to refer to the same or like parts.
However, aspects may be embodied in many different forms and should
not be construed as limited to the embodiments set forth
herein.
[0005] In one aspect, a method of finishing a sheet of material
comprises the step (I) of providing a sheet of material with a
first face and a second face, wherein an average thickness of the
sheet of material between the first face and the second face is
from about 50 .mu.m to about 500 .mu.m. The method further
comprises the step (II) of finishing an edge portion of the sheet
of material with magnetorheological finishing.
[0006] In one example of the aspect, step (I) provides the sheet of
material as a glass sheet.
[0007] In another example of the aspect, step (I) provides the
average thickness of the sheet of material from about 50 .mu.m to
about 300 .mu.m.
[0008] In still another example of the aspect, step (I) provides
the average thickness of the sheet of material from about 75 .mu.m
to about 200 .mu.m.
[0009] In yet another example of the aspect, step (I) provides the
average thickness of the sheet of material from about 75 .mu.m to
about 150 .mu.m.
[0010] In still another example of the aspect, step (I) provides
the sheet of material positioned along a plane at a predetermined
orientation within an angular range of from about +45.degree. to
about -45.degree. with respect to a vertical axis.
[0011] In another example of the aspect, the predetermined
orientation of the sheet of material is maintained during step
(II).
[0012] In yet another example of the aspect, step (I) provides the
edge portion extending along a peripheral portion of the sheet of
material between the first face and the second face.
[0013] In another example of the aspect, the method includes a step
of strengthening the edge portion before step (II).
[0014] In a further example of the aspect, the method includes a
step of separating the sheet of material to provide the edge
portion before step (II).
[0015] In still a further example of the aspect, the step of
separating occurs after step (I).
[0016] In another further example of the aspect, the method further
includes a step of strengthening the edge portion after the step of
separating and before step (II).
[0017] In yet another example of the aspect, the method further
includes a step of edging the sheet of material to provide the edge
portion before step (II).
[0018] In a further example of the aspect, the step of edging
occurs after step (I).
[0019] In yet another example of the aspect, the method includes a
step of separating the sheet of material before the step of edging
the sheet of material.
[0020] In still another example of the aspect, the method includes
a step of strengthening the edge portion after the step of edging
and before step (II).
[0021] In another aspect, a method is provided for finishing an
edge portion of a glass sheet having a first face and a second face
with the edge portion extending along a peripheral portion of the
glass sheet between the first face and the second face. The method
consists essentially of a single step of finishing the edge portion
of the glass sheet with magnetorheological finishing such that the
entire edge portion is shaped between the first face and the second
face during the a single magnetorheological finishing step.
[0022] In yet another aspect, a method for finishing an edge
portion of a glass sheet consists essentially of the steps of: (I)
providing a glass sheet with a first face and a second face,
wherein an average thickness of the glass sheet between the first
face and the second face is from about 50 .mu.m to about 500 .mu.m;
and (II) finishing an edge portion of the glass sheet with
magnetorheological finishing.
[0023] In one example of the aspect, during step (II), the entire
edge portion is shaped between the first face and the second face
during a single magnetorheological finishing step.
[0024] In another example of the aspect, step (I) provides the
average thickness of the glass sheet from about 75 .mu.m to about
150 .mu.m.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] These and other aspects are better understood when the
following detailed description is read with reference to the
accompanying drawings, in which:
[0026] FIG. 1 illustrates a glass manufacturing apparatus
configured to produce a glass sheet that may be used with methods
in accordance with the disclosure;
[0027] FIG. 2 illustrates methods of separating edge members from a
separated glass sheet with a first separation device and a second
separation device while supporting the separated glass sheet in
accordance with methods of the disclosure;
[0028] FIG. 3 illustrates edge members after separating from the
remaining portion of the glass sheet with the methods of separating
illustrated in FIG. 2;
[0029] FIG. 4 illustrates a side view of the first separation
device of FIG. 2;
[0030] FIG. 5 illustrates a side view of the second separation
device of FIG. 2;
[0031] FIG. 6 illustrates a method step of breaking away the edge
member after scoring with the second separation device of FIG.
5;
[0032] FIG. 7 illustrates a side view of the separated glass sheet
and a magnetorheological finishing apparatus and further
illustrates a method step of finishing an edge portion of the
separated glass sheet with magnetorheological finishing;
[0033] FIG. 8 is a front view of the separated glass sheet and
magnetorheological finishing apparatus of FIG. 7;
[0034] FIG. 9 is a first example flow chart illustrating example
methods of the disclosure;
[0035] FIG. 10 is a second example flow chart illustrated further
example methods of the disclosure;
[0036] FIG. 11 is an enlarged view of an edge portion of a glass
sheet after separating and before finishing, wherein the glass
sheet has a thickness of about 100 .mu.m between a first face and a
second face of the glass sheet; and
[0037] FIG. 12 is an enlarged view of the edge portion of FIG. 11
after magnetorheological finishing.
DETAILED DESCRIPTION
[0038] Examples will now be described more fully hereinafter with
reference to the accompanying drawings in which example embodiments
are shown. Whenever possible, the same reference numerals are used
throughout the drawings to refer to the same or like parts.
However, aspects may be embodied in many different forms and should
not be construed as limited to the embodiments set forth
herein.
[0039] Methods are provided for finishing a sheet of material. The
sheets of material of the present invention may comprise various
materials such as glasses, glass-ceramics, ceramics, silicon,
semiconductor materials, and combinations of the preceding
materials. In one particular example, the sheet of material can
comprise a glass sheet, such as a display-quality glass sheet. Such
display-quality glass sheets can be transparent and incorporated in
liquid crystal display devices and/or other electronic devices.
Example methods of the present invention will be described with
reference to the sheet of material comprising display-quality glass
sheet material although it will be appreciated that the sheet of
material may comprise other glass sheets and/or other materials
such as the alternative materials mentioned above.
[0040] The glass sheet may be formed by a wide range of techniques.
As shown in FIG. 1, there is shown a schematic view of an exemplary
glass manufacturing apparatus 101 that may be used in accordance
with aspects of the disclosure. The exemplary glass manufacturing
apparatus 101 is illustrated as a down draw fusion apparatus
although other forming apparatus may be used in further
examples.
[0041] The glass manufacturing apparatus 101 can include a melting
vessel 103, a fining vessel 105, a mixing vessel 107, a delivery
vessel 109, a forming device 111, a pull roll device 113 and a
separating device 115.
[0042] The melting vessel 103 is where the glass batch materials
are introduced as shown by arrow 117 and melted to form molten
glass 119. The fining vessel 105 has a high temperature processing
area that receives the molten glass 119 (not shown at this point)
from the melting vessel 103 and in which bubbles are removed from
the molten glass 119. The fining vessel 105 is connected to the
mixing vessel 107 by a finer to stir chamber connecting tube 121.
The mixing vessel 107 is connected to the delivery vessel 109 by a
stir chamber to bowl connecting tube 123. The delivery vessel 109
delivers the molten glass 119 through a downcomer 125 to an inlet
127 and into the forming device 111.
[0043] Various forming devices may be used in accordance with
aspects of the disclosure. For example, as shown in FIG. 1, the
forming device 111 includes an opening 129 that receives the molten
glass 119 which flows into a trough 131. The molten glass 119 from
the trough 131 then overflows and runs down two sides 132 (one side
shown in FIG. 1) before fusing together at a root 133 of the
forming device 111. The root 133 is where the two sides 132 come
together and where the two overflow walls of molten glass 119
flowing over each of the two sides 132 fuse together as the glass
ribbon 106 is drawn downward off the root 133.
[0044] A portion of the glass ribbon 106 is drawn off the root 133
into a viscous zone 135 wherein the glass ribbon 106 begins
thinning to a final thickness. The portion of the glass ribbon 106
is then drawn from the viscous zone 135 into a setting zone 137. In
the setting zone 137, the portion of the glass ribbon 106 is set
from a viscous state to an elastic state with the desired profile.
The portion of the glass ribbon 106 is then drawn from the setting
zone 137 to an elastic zone 139. Once in the elastic zone 139, the
glass ribbon 106 may be deformed, within limits, without
permanently changing the profile of the glass ribbon 106.
[0045] After the portion of the glass ribbon 106 enters the elastic
zone 139, the separating device 115 may be provided to sequentially
separate a plurality of separated glass sheets 141 from the glass
ribbon 106 over a period of time. The separating device 115 may
include the illustrated traveling anvil machine although further
separating devices may be provided in further examples.
[0046] As further illustrated in FIG. 1, the glass manufacturing
apparatus 101 may be provided with support devices 143, such as a
suction cup apparatus, air bearing, or other support device, to
help support the glass sheet, such as the glass ribbon 106 and/or
the separated glass sheets 141. For purposes of this application,
"glass sheet" can be considered to include the glass ribbon and/or
the separated glass sheets that are separated from the glass
ribbon. As such, when discussing applicability and methods of the
present disclosure with the glass sheet, it is understood that the
methods can be interpreted as being carried out with various forms
of the glass sheet (e.g., the glass ribbon 106, separated glass
sheets 141 that are separated from the glass ribbon, or glass
sheets formed by other techniques).
[0047] As such, while various methods of the disclosure are
described with respect to the separated glass sheets 141, it is
understood that the methods of the disclosure may be carried out
with other forms of the glass sheets (e.g., the glass ribbon 106 or
glass sheets formed with other techniques).
[0048] As discussed above, the glass sheet can be initially formed
as a glass ribbon 106 by way of the example glass manufacturing
apparatus, although glass sheets may be formed by other techniques.
A separating device 115, such as the illustrated traveling anvil
machine can be used to separate the glass ribbon 106 into the
separated glass sheets 141. As such, the traveling anvil machine
may create a first edge portion 141a and a second edge portion
141b, wherein the length of the separated glass ribbon 141 is
defined between the first and second edge portions 141a, 141b. It
will be appreciated that in further examples, the width of the
separated glass ribbon 141 can be defined between the first and
second edge portions 141a, 141b. As further shown in FIG. 1, the
glass manufacturing apparatus 101 may include a magnetorheological
finishing apparatus 145 that may be part of the glass manufacturing
apparatus 101 although the magnetorheological finishing apparatus
145 may be provided at a downstream processing location from the
glass manufacturing apparatus 101 in further examples. In such
examples, the support devices 143 may be operated to transport the
separated glass sheet 141 such that the first and/or second edge
portions 141a, 141b are finished with the magnetorheological
finishing apparatus 145. In some examples, the support devices 143
can support the glass ribbon 106 and then continue to support the
separated glass sheet 141 throughout the entire separating and
finishing process techniques illustrated in FIGS. 2-8 described
more fully below.
[0049] As shown in FIGS. 2 and 3, the first and second edge members
201, 203 may further be removed by various techniques. Removal of
the second edge members may be desired to remove thickness
inconsistencies in the edge members that may result from the
formation of the glass ribbon with the glass manufacturing
apparatus 101. Alternatively, similar separation techniques may be
employed to subdivide the separated glass sheets into a plurality
of smaller glass sheets depending on the particular application.
Although not shown in FIGS. 2 and 3, the magnetorheological
finishing apparatus 145 may be provided at the station where the
edge members are removed. For example the magnetorheological
finishing apparatus 145 may be used to finish one or both of the
first and second edge portion 141a, 141b while the edge members are
being removed as illustrated in FIG. 2. In addition or
alternatively, the magnetorheological finishing apparatus 145 may
be used to finish one or both of the second and third edge portions
301a, 301b shown in FIG. 3.
[0050] Various glass separation devices may be used in accordance
with aspects of the present disclosure in order to separate the
first and second edge members from the remaining portion of the
separated glass sheet 141. FIGS. 2 and 4 illustrate just one glass
separation technique that may include use of a first separation
device 205 that can include a laser 401 configured to heat a
surface of the separated glass sheet 141 and a liquid cooling
device 403 configured to propagate a crack to separate the first
edge member 201 from the remaining portion of the separated glass
sheet 141.
[0051] FIGS. 2, 5 and 6 illustrated another example of a second
separation device 207 comprising a scoring device 501 that can
create a score line 209 along a separation path. Once formation of
the score line is complete, a pivot member 601 can be applied on
the opposite side of the score line 209 and a force 603 can be
applied to break away the second edge member 203 from the remaining
portion of the separated glass sheet 141.
[0052] As shown in FIG. 3, once the first and second edge members
201, 203 are removed, the separated glass sheet 141 includes a
third edge portion 301a and a fourth edge portion 301b, wherein the
width of the separated glass ribbon 141 is defined between the
third and fourth edge portions 301a, 301b. It will be appreciated
that in further examples, the length of the separated glass ribbon
141 can be defined between the third and fourth edge portions 301a,
301b.
[0053] The traveling anvil machine (e.g., see the separation device
115 shown in FIG. 1), the first separation device 205 and the
second separation device 207 are mere examples of various possible
separation devices that may be used to separate the glass sheets.
Regardless of the techniques used, each edge portion 141a, 141b,
301a, 301b may include undesirable rough/sharp edge portions that
are vulnerable to cracking of the glass sheet.
[0054] Methods of the present disclosure can be used with a sheet
of material (e.g., glass sheet comprising a glass ribbon, separated
glass sheet, etc.) with a wide range of average thicknesses such as
average thicknesses above 500 .mu.m. For example, the average
thicknesses can be from greater than 500 .mu.m to about 2 mm, such
as from about 700 .mu.m to about 1.5 mm, such as from about 900
.mu.m to about 1.2 mm, such as about 1.1 mm.
[0055] Removal of undesirable rough/sharp edge portions may be
complicated for relatively thin glass sheets that can be brittle
and/or relatively fragile. There is an increasing demand for
relatively thin glass sheets with particular performance
characteristics. For example, as shown in FIG. 4, the relatively
thin separated glass sheets 141 can have average thicknesses "T"
between a first face 405 and a second face 407, wherein an average
thickness of the glass sheet between the first face 405 and the
second face 407 is less than or equal to about 500 .mu.m, such as
less than or equal to about 400 .mu.m, such as less than or equal
to about 300 .mu.m, such as less than or equal to about 200 .mu.m,
such as less than or equal to about 100 .mu.m, such as less than or
equal to about 75 .mu.m. In one example, the average thickness "T"
between the first face 405 and the second face 407 is from about 50
.mu.m to about 500 .mu.m, such as from about 50 .mu.m to about 400
.mu.m, such as from about 50 .mu.m to about 300 .mu.m, such as from
about 50 .mu.m to about 200 .mu.m, such as from about 50 .mu.m to
about 100 .mu.m, such as from about 50 .mu.m to about 75 .mu.m,
such as from about 75 .mu.m to about 500 .mu.m, such as from about
75 .mu.m to about 400 .mu.m, such as from about 75 .mu.m to about
300 .mu.m, such as from about 75 .mu.m to about 200 .mu.m, such as
from about 75 .mu.m to about 150 .mu.m, such as from about 75 .mu.m
to about 100 .mu.m, such as from about 100 .mu.m to about 500
.mu.m, such as from about 100 .mu.m to about 400 .mu.m, such as
from about 100 .mu.m to about 300 .mu.m, such as from about 100
.mu.m to about 200 .mu.m. Providing glass sheets having a thin
average thickness "T" can be desirable to enhance performance
characteristics.
[0056] Finishing the edge portions 141a, 141b, 301a, 301b can
include the step of finishing the edge portion with a
magnetorheological finishing (MRF) technique. For example, MRF
apparatus and/or methods set forth in U.S. patent application Ser.
No. 13/112,498 filed May 20, 2011 and/or U.S. patent application
Ser. No. 13/169,499 filed Jun. 27, 2011 may be incorporated in
accordance with aspects of the disclosure. U.S. patent application
Ser. No. 13/112,498 filed May 20, 2011 and U.S. patent application
Ser. No. 13/169,499 filed Jun. 27, 2011 are each herein
incorporated by reference in its entirety.
[0057] MRF may remove damage and/or imperfections such undesirable
rough/sharp edge portions generated when separating the glass
sheet. MRF can also reduce processing time and/or overcome process
complications that may otherwise result when attempting to finish
the edge portions of relatively thin glass sheets. For example, MRF
can remove relatively little material to achieve the desired
finished edge profile. Furthermore, MRF can be used for machining
the relatively fragile edge portions of relatively thin glass
sheets. Still further, MRF can be used to reduce processing time
regardless of the average thickness of the separated glass sheet
141.
[0058] MRF uses a fluid-based conformable tool, called a
magnetorheological fluid (Hereinafter "MR fluid"), for finishing.
MR fluid can include micron-sized magnetizable particles and
micron-sized to nano-sized abrasive particles suspended in a liquid
vehicle. For example, the sizes of the magnetizable particles may
be in a range from 1 .mu.m to 100 .mu.m or greater, for example, 1
.mu.m to 150 .mu.m, for example, 5 .mu.m to 150 .mu.m, for example,
5 .mu.m to 100 .mu.m, for example, 5 .mu.m to 50 .mu.m, for
example, 5 .mu.m to 25 .mu.m, for example, 10 .mu.m to 25 .mu.m and
the sizes of the abrasive particles may be in a range from 15 nm to
10 .mu.m. The magnetizable particles may have a uniform or a
non-uniform particle size distribution, the same or different
shapes, and regular or irregular shapes. Also, the magnetizable
particles may be made of a single magnetizable material or a
combination of different magnetizable materials. Examples of
magnetizable materials include iron, iron oxide, iron nitride, iron
carbide, carbonyl iron, chromium dioxide, low-carbon steel, silicon
steel, nickel, cobalt, and a combination of the preceding
materials. The magnetizable particles may also be coated or
encapsulated, for example, with or in a protective material. In one
embodiment, the protective material is a material that is
chemically and physically stable in the liquid vehicle and that
does not react chemically with the magnetizable material. Examples
of suitable protective materials include zirconia, alumina, and
silica. Similarly, the abrasive particles may have a uniform or a
non-uniform particle size distribution, the same or different
shapes, and regular or irregular shapes. Also, the abrasive
particles may be made of a single non-magnetizable material or a
combination of different non-magnetizable materials. Examples of
abrasive materials include cerium oxide, diamond, silicon carbide,
alumina, zirconia, and a combination of the preceding materials.
Other abrasive materials not specifically included in this list and
known to be useful in polishing a surface may also be used. The
liquid vehicle included in a MR fluid may be aqueous or
non-aqueous. Examples of vehicles include mineral oil, synthetic
oil, water, and ethylene glycol. The vehicles may further include
stabilizers, e.g., stabilizers to inhibit corrosion of the
magnetizable particles, and surfactants.
[0059] In another embodiment, a MR fluid that can etch while
finishing is provided. The etching MR fluid includes magnetizable
particles and abrasive particles suspended in a liquid vehicle
including an etching agent. The etching agent is one that is
capable of etching the material of the sheet of material and would
be selected based on the material of the sheet of material. The
liquid vehicle may further include a solvent for the etching agent.
The liquid vehicle may further include stabilizers and surfactants.
The liquid vehicle may be aqueous or non-aqueous, as described
above. The magnetizable particles and abrasive particles are as
described above for the non-etching MR fluid. The magnetizable
particles may be coated or encapsulated, for example, with or in a
protective material, as described above. The protective material,
when used, is a material that is chemically and physically stable
in the presence of the etching agent and other materials in the
liquid vehicle. The protective material is also a material that
does not react with the magnetizable particles. Suitable examples
of protective materials are zirconia and silica.
[0060] In one embodiment, the etching agent included in the etching
MR fluid has a pH less than or equal to 5. In one embodiment, the
etching agent that has a pH less than or equal to 5 comprises an
acid. In one embodiment, the etching agent is an acid. The acid may
exist in liquid form or may be dissolved in a suitable solvent.
Examples of suitable acids include, but are not limited to,
hydrofluoric acid and sulfuric acid. The liquid vehicle may further
include one or more stabilizers, e.g., a stabilizer to inhibit
corrosion of the magnetizable particles. Stabilizers used in the
liquid vehicle should be stable in the presence of the acid or,
more generally, in the presence of the etching agent.
[0061] In another embodiment, the etching agent included in the
etching MR fluid has a pH greater than or equal to 10. In one
embodiment, the etching agent that has a pH greater than or equal
to 10 comprised an alkali salt. In one embodiment, the etching
agent is an alkali salt. Examples of such alkali salts include, but
are not limited to, alkali hydroxides, e.g., potassium hydroxide,
sodium hydroxide, and compounds containing alkali hydroxides. A
detergent containing an alkali hydroxide may be used as the alkali
salt in the liquid vehicle, for example. The liquid vehicle may
include other materials besides alkali salts, such as surfactants
and other materials that may be found in detergents.
[0062] FIG. 7 illustrates a side schematic view of a
magnetorheological finishing apparatus 145 configured to carry out
MRF in accordance with aspects of the disclosure. As shown, MR
fluid is deposited on a support surface in the form of an MRF
ribbon 701. Typically, the support surface is a moving surface, but
the support surface may also be a fixed surface. The support
surface may have a variety of shapes, e.g., spherical, cylindrical,
or flat. For illustration purposes, FIG. 7 shows a side view of the
MRF ribbon 701 on a rotating wheel 703. In this case, the
circumferential surface 705 of the rotating wheel 703 provides a
moving cylindrical support surface for the MRF ribbon 701. A nozzle
707 is used to deliver the MRF ribbon 701 to one end of a segment
the surface 705, and a nozzle 709 is used to collect the MRF ribbon
701 from another end of the segment of the surface 705. During the
MRF, a magnet 711 applies a magnetic field to the MRF ribbon
701.
[0063] The applied magnetic field induces polarization on the
magnetizable particles, causing the magnetizable particles to form
chains or columnar structures that restrict flow. This increases
the apparent viscosity of the MRF ribbon 701, changing the MRF
ribbon 701 from a liquid state to a solid-like state. The edge
portion 141a, 141b, 301a, 301b of the separated glass sheet 141 can
be finished by contact with the stiffened MRF ribbon 701 and
translating the edge portion of the separated glass sheet 141 along
direction 713 relative to the stiffened MRF ribbon 701. The
relative motion between the edge portion 141a, 141b, 301a, 301b and
the MRF ribbon 701 is such that all the portions of the edge
portion to be finished make contact with the stiffened MRF ribbon
701. In the case of glass sheets having a relatively thin average
thickness in the ranges discussed above (e.g., from about 50 .mu.m
to about 500 .mu.m) all portions of a segment of the edge portion
141a, 141b, 301a, 301b extending between the first face 405 and the
second face 407 of the glass sheet 141 can simultaneously be
finished and make contact with the stiffened MRF ribbon 701. As
such, the entire edge portion 141a, 141b, 301a, 301b can shaped
between the first face 405 and the second face 407 during a single
magnetorheological finishing step. In one particular example, the
single magnetorheological finishing step can comprise a single pass
of each of the edge portions to be finished over the stiffened MRF
ribbon 701. For instance, as shown in FIG. 7, finishing of the
second edge portion 141b may be carried out with one pass of the
separated glass sheet 141 relative to the magnetorheological
finishing apparatus 145. As reciprocation is not necessary,
finishing of each edge portion 141a, 141b, 301a, 301b of the glass
sheet 141 can be carried out with reduced processing time.
[0064] In one embodiment, one or all of the edge portions 141a,
141b, 301a, 301b of the glass sheet 141 can be finished by
immersing the respective edge portion into the stiffened MRF ribbon
701. Although the finishing process has been described in terms of
finishing a single glass sheet using MRF, it should be noted that
multiple glass sheets may be polished simultaneously in a single
finishing process.
[0065] As shown in FIG. 8, the glass sheet can be positioned along
a plane at a predetermined orientation within an angular range of
from about +45.degree. to about -45.degree. with respect to a
vertical axis. Indeed, as shown, the glass sheet 141 is positioned
along a plane that is parallel with a vertical axis 801. In further
examples, the glass sheet can be oriented at any orientation
between an angle .alpha. and an angle .beta. of about
45.degree..
[0066] MRF removes material from the surface being finished by
shearing. This is in contrast to the fracturing mechanism
associated with mechanical processes such as mechanical grinding.
With this mechanism, MRF has an opportunity to remove material from
the edge portion without inducing new fracture sites in the edge
portion that could lower the strength of the edge portion.
Simultaneously, MRF removes defects from the edge portion that
results in an increase in the strength of the edge portion, i.e.,
from the first edge strength to the second edge strength. Moreover,
the MRF ribbon 701, which is fluid-based, has the ability to
conform to the shape of the edge portion, no matter the complexity,
e.g., in terms of curvature or profile, of the edge portion, which
leads to complete, high-quality finishing of the edge portion. MRF
is governed by several parameters, e.g., the viscosity of the MR
fluid, the rate at which the MR fluid is delivered to the moving
surface, the speed of the moving surface, the intensity of the
magnetic field, the height of the MRF ribbon, the depth to which
the edge portion is immersed into the MRF ribbon, and the rate at
which material is removed from the edge.
[0067] FIG. 9 is a first example flow chart illustrating example
methods of the disclosure. All of the various methods of FIG. 9
begin at the start position 901 with the step 903 of providing a
sheet of material with a first face and a second face. As discussed
above, in one example, the sheet of material can comprise a glass
sheet, such as the glass ribbon 106 or the separated glass sheet
141 with the first face 405 and the second face 407. Methods of the
present disclosure can be used with a sheet of material (e.g.,
glass sheet comprising a glass ribbon, separated glass sheet, etc.)
with a wide range of average thicknesses such as average
thicknesses above 500 .mu.m. For example, the average thicknesses
can be from greater than 500 .mu.m to about 2 mm, such as from
about 700 .mu.m to about 1.5 mm, such as from about 900 .mu.m to
about 1.2 mm, such as about 1.1 mm. In further examples, methods of
the present disclosure can be used with a sheet of material
including an average thickness "T" between the first face 405 and
the second face 407 from about 50 .mu.m to about 500 .mu.m, such as
material from about 50 .mu.m to about 300 .mu.m, such as from about
75 .mu.m to about 200 .mu.m, such as from about 75 .mu.m to about
150 .mu.m.
[0068] The step 903 of providing can occur at various relative
times in the production process. For example, as shown in FIG. 1,
the step 903 of providing can occur immediately after formation of
the separated glass sheet 141. In further examples, the step 903 of
providing can occur at a later time. For example, the separated
glass sheet 141 may be transported to a different location wherein
the sheet is subsequently provided during step 903 for processing.
In further examples, the glass ribbon 106 may be coiled onto a
storage roll. In such circumstances, the step of providing may
occur prior to coiling the glass ribbon 106 onto the storage roll.
In such examples, the edges of the ribbon may be finished with MRF
prior to coiling onto the storage roll. In addition or
alternatively, the coil of glass ribbon may be transferred to a
different location for subsequent separation into desired separated
glass sheets 141. In such examples, the step 903 of providing may
occur as the glass ribbon is subsequently uncoiled for processing
the separated glass sheets 141.
[0069] As indicated by arrow 905, the method can then optionally
proceed from the step 903 of providing to a step 907 of separating
the sheet of material to provide the edge portion 141a, 141b, 301a,
301b before a step 919 of finishing the edge portion of the sheet
of material with MRF. As such, although not required, as shown in
FIG. 9, the step 907 of separating can occur after the step 903 of
providing.
[0070] The step 907 of separating may be carried out in a wide
variety of ways. For example, separating may be carried out by
mechanical separation, laser separation, ultrasonic separation or
other separation techniques. The first separation device 205
illustrated in FIGS. 2 and 4 depict just one example laser
separation device that may involve creating a mechanical flaw near
an edge, then thermally run across the article using a laser 401
then separated using a stress gradient induced by the liquid
cooling device 403, such as a water spray. The second separation
device 207 illustrated in FIGS. 2 and 5 depict an example
mechanical separation device. The second separation device 207 can
include the scoring device 501 that may comprise a scoring wheel,
water jets, or abrasive water jets. Then, as shown in FIG. 6, the
sheet of material can be separated along the score lines, for
example, by applying a force 603 to break away the edge member
along the score line. Once separated, there may be a single sheet
of material or a plurality of sheets of material. If a plurality of
sheets of material are generated, one or all of the sheets of
material may be processed.
[0071] As indicated by arrow 909, the method can then optionally
proceed from the step 907 of separating to a step 911 of edging the
sheet of material. If provided, the step 911 of edging the sheet of
material can modify the shape and/or texture of the edge of the
sheet of material by removing material from the edge. Any of a
number of processes may be employed in the step 911 of edging.
Examples include, but are not limited to, abrasive machining,
abrasive jet machining, chemical etching, ultrasonic polishing,
ultrasonic grinding, chemical-mechanical polishing. The step 911 of
edging may include a single material removal process or a series or
combination of material removal processes. For example, one example
step 911 of edging may include a series of grinding steps, where
the grinding parameters, such as the grit size of the grinding
material, are altered for each step in the series to achieve a
different edging result at the end of each step.
[0072] The step 911 of edging may include abrasive machining that
may involve one or more and any combination of mechanical grinding,
lapping, and polishing. These processes are mechanical in the sense
that they involve contact between a solid tool and the surface
being processed. Each of the grinding, lapping, and polishing may
be accomplished in one or more steps. Grinding is a fixed-abrasive
process, while lapping and polishing are loose-abrasive processes.
Grinding may be accomplished using abrasive particles embedded in a
metal or polymer bonded to a metal wheel. Alternatively, grinding
may be accomplished using an expendable wheel made of an abrasive
compound. In lapping, abrasive particles, typically suspended in a
liquid medium, are disposed between a lap and an edge of a sheet of
material. Relative motion between the lap and the edge of the sheet
of material abrades material from the edge. In polishing, abrasive
particles, typically suspended in a liquid medium, are applied to
an edge of the sheet of material using a conformable soft pad or
wheel. The conformable soft pad or wheel may be made of a polymeric
material, e.g., butyl rubber, silicone, polyurethane, and natural
rubber. Abrasives used in abrasive machining may be selected from,
for example, alumina, silicon carbide, diamond, cubic boron
nitride, and pumice.
[0073] As indicated by arrow 913, the method can then optionally
proceed from the step 911 of edging to a step 915 chemical
strengthening of the edge portion of the sheet of material (e.g.,
glass sheet). In one embodiment, the chemical-strengthening process
is an ion-exchange process. In order to implement the ion-exchange
process, the article provided in the step 903 of providing must be
made of an ion-exchangeable material. Typically, ion-exchangeable
materials are alkali-containing glasses with smaller alkali ions,
such as Li.sup.+ and/or Na.sup.+, that can be exchanged for larger
alkali ions, e.g., K.sup.+, during an ion-exchange process.
Examples of suitable ion-exchangeable glasses are described in U.S.
patent application Ser. Nos. 11/888,213, 12/277,573, 12/392,577,
12/393,241, and 12/537,393, U.S. Provisional Application Nos.
61/235,767 and 61/235,762 (all assigned to Corning Incorporated),
the contents of which are incorporated herein by reference. These
glasses can be ion-exchanged at relatively low temperatures and to
a depth of at least 30 .mu.m.
[0074] An ion-exchange process is described in, for example, U.S.
Pat. No. 5,674,790 (Araujo, Roger J.). The process typically occurs
at an elevated temperature range that does not exceed the
transition temperature of the glass. The process is carried out by
immersing the glass in a molten bath comprising an alkali salt
(typically a nitrate) with ions that are larger than that of the
host alkali ions in the glass. The host alkali ions are exchanged
for the larger alkali ions. For example, a glass containing
Na.sup.+ may be immersed in a bath of molten potassium nitrate
(KNO.sub.3). The larger K.sup.+ present in the molten bath will
replace the smaller Na.sup.+ in the glass. The presence of the
larger alkali ions at sites formerly occupied by small alkali ions
creates a compressive stress at or near the surface of the glass
and tension in the interior of the glass. The glass is removed from
the molten bath and cooled down after the ion-exchange process. The
ion-exchange depth, i.e., the penetration depth of the invading
larger alkali ions into the glass, is typically on the order of 20
.mu.m to 300 .mu.m, for example, 40 .mu.m to 300 .mu.m and is
controlled by the glass composition and immersion time.
[0075] As indicated by arrow 917, the method can then optionally
proceed from the step 915 of chemical strengthening of the edge
portion of the sheet of material (e.g., glass sheet) to the step
919 of finishing the edge portion of the sheet of material with
magnetorheological finishing (MRF). For example, as shown in FIG. 8
the separated glass sheet 141 may be moved along direction 713
during a single pass of the separated glass sheet 141 across the
magnetorheological finishing apparatus 145 for each edge portion
141a, 141b, 301a, 301b.
[0076] As shown in FIG. 8, the step 903 of providing can position
the sheet of material along a plane at a predetermined orientation
wherein angles .alpha. and .beta. are each 45.degree. such that the
predetermined orientation may be positioned within an angular range
of from about +45.degree. to about -45.degree. with respect to the
vertical axis 801 that can extend along the direction of gravity.
In the example illustrated in FIG. 8, the separated glass sheet 141
is positioned vertically along a plane that includes the vertical
axis 801 such that there is a 0.degree. angle between the vertical
axis 801 and the plane of the separated glass sheet 141. In a
further example, the predetermined orientation of the sheet of
material can be maintained during the step 919 of finishing the
edge portion of the sheet of material with MRF.
[0077] As shown in some examples of FIG. 9, various the steps 907,
911, 915 of separating, edging and/or chemical strengthening can
occur in any order and one or all of the steps may be omitted. For
example, as indicated by arrow 921, the method may proceed from the
step 903 of providing to the step 911 of edging; thereby omitting
the step 907 of separating. Alternatively, as shown by arrow 923,
the method may proceed from the step 903 of providing to the step
915 of chemical strengthening of the edge portion of the sheet of
material (e.g., glass sheet); thereby omitting the steps 907, 911
of separating and edging. Still further, as shown by arrow 925, the
method may proceed from the step 903 of providing directly to the
step 919 of finishing the edge portion of the sheet of material
with MRF; thereby omitting the steps 907, 911, 915 of separating,
edging and chemical strengthening. As such, the method can consist
essentially of the step 903 of providing and the step 919 of
finishing the edge portion of the sheet of material with MRF.
[0078] As further shown in FIG. 9, after performing the step 907 of
separating, if provided, the method may alternatively omit one or
both of the subsequent steps 911, 915 of edging and/or chemical
strengthening. For example, as shown by arrow 927, the method may
proceed from the step 907 of separating to the step 915 of
chemical-strengthening; thereby omitting the step 911 of edging. In
another example, as shown by arrow 929, the method may proceed from
the step 907 of separating to the step 919 of finishing the edge
portion of the sheet material with MRF; thereby omitting both steps
911, 915 of edging and chemical-strengthening may be omitted.
[0079] FIG. 10 illustrates a second example flow chart illustrating
further example methods of the disclosure. As shown, the method may
begin at the start position 1001 and proceed in a wide variety of
paths. As shown in some examples of FIG. 10 and discussed below,
various steps 1005, 1009, 1013 of separating, edging and/or
chemical strengthening can occur in any order and one or all of the
steps may be omitted.
[0080] For example, as indicated by arrow 1003, the method may
continue from the start position 1001 to the step 1005 of
separating. Alternatively, as indicated by arrow 1007, the method
may continue from the start position 1001 to the step 1009 of
edging; thereby omitting the step 1005 of separating. Still
further, as indicated by arrow 1011, the method may continue from
the start position 1001 to the step 1013 of chemically
strengthening; thereby omitting the steps 1005, 1009 of separating
and edging. In another example, as indicated by arrow 1015 the
method may continue from the start position 1001 to the step 1017
of providing; thereby omitting all three steps 1005, 1009, 1013 of
separating, edging and chemically strengthening. In further
examples, as indicated by arrows 1008, 1012, 1016, the method may
sequentially proceed from the step 1005 of separating, to the step
1009 of edging, to the step 1013 of chemically strengthening, and
then to the step 1017 of providing. As such, any of the steps of
separating, edging, and/or chemical strengthening may occur before
the step of providing. As indicated by arrow 1025, the method can
then proceed directly from the step 1017 of providing to the step
1027 of finishing the edge portion of the sheet material with
MRF.
[0081] Moreover, the step 1005 of separating may be present without
the steps 1009, 1013 of edging and/or chemical strengthening.
Indeed, as indicated by arrow 1019, the method may proceed from the
step 1005 of separating to the step 1013 of chemical strengthening;
thereby omitting the step 1009 of edging. As further indicated by
arrow 1021, the method may proceed from the step 1005 of separating
to the step 1017 of providing; thereby omitting the steps 1009,
1013 of edging and chemical strengthening.
[0082] Still further, the step 1009 of edging may be present
without the step 1013 of chemical strengthening. For example, as
indicated by arrow 1023, the method may proceed from the step 1009
of edging directly to the step 1017 of providing; thereby omitting
the step 1013 of chemical strengthening.
[0083] As shown in FIG. 9 some or all of the steps 907, 911, 915 of
separating, edging and/or chemical strengthening may occur after
the step 903 of providing. In further examples, some or all of the
steps 907, 911, 915 may occur before the step of providing. For
example, FIG. 10 demonstrates that all of the steps 1005, 1009,
1013 of separating, edging and chemical strengthening may occur
before the step 1017 of providing. Although not shown, in further
examples any combination of steps 1005, 1009, 1013 may occur before
and/or after the step of providing. For example, one or two of the
steps of separating, edging and chemical strengthening may occur
before the step of providing while the remaining step(s) occur
after the step of providing.
[0084] In one example, of methods of finishing an edge portion
141a, 141b, 301a, 301b of a glass sheet (e.g., glass ribbon,
separated glass sheet, etc.) is provided. The glass sheet 141 can
include the first face 405 and the second face 407. The edge
portion can extend along a peripheral portion of the glass sheet
between the first face and the second face. The method can consist
essentially of a single step 919, 1027 of finishing the edge
portion 141a, 141b, 301a, 301b of the glass sheet with MRF. In such
examples, the entire edge portion may be shaped between the first
face 405 and the second face 407 during the single MRF step.
[0085] In another example, methods of finishing an edge portion
141a, 141b, 301a, 301b of a glass sheet (e.g., glass ribbon,
separated glass sheet, etc.) consists essentially of the step 903,
1017 of providing and the step 919, 1027 of finishing the edge
portion of the glass sheet with MRF. For instance, the step 903,
1017 of providing can provide the glass sheet with the first face
405 and the second face 407, wherein an average thickness of the
glass sheet between the first face and the second face is from
about 50 .mu.m to about 500 .mu.m. In one example, during step 919,
1027, the entire edge portion is shaped between the first face and
the second face during a single magnetorheological finishing
step.
[0086] FIG. 11 illustrates an enlarged view of an edge portion 1101
of a separated glass sheet 141 having a thickness "T" of about 100
.mu.m between the first face 405 and the second face 407 observed
after separating the glass sheet but prior to MRF of the edge
portion. As shown, the edge portion 1101 includes undesirable sharp
edge portions 1103 that are vulnerable to cracking of the glass
sheet. FIG. 12 shows the same observed enlarged view of the edge
portion 1101 after a 6 minute MRF step as set forth by the
disclosure. As shown, the undesired sharp edge portions 1103 are
removed and is left with a smooth surface 1201 that has a smooth
shape along the entire edge portion from the first face 405 to the
second face 407. Indeed, as shown, the smooth surface 1201 has a
rounded and convex shape extending from the first face 405 to the
second face 407 with relatively little material removed.
[0087] The rounded edge profile illustrated in FIG. 12 of thin
glass (e.g., 100 .mu.m) can facilitate manufacture of a variety of
products including thin glass for light weight and portability.
Using a finishing step including MRF can provide a single step
shaped edge for laser and mechanical separated thin glass. Using
MRF as the finishing step can be uniquely beneficial for thin glass
since the low volume removal from the edges, demonstrated by
comparing the slightly different lengths from FIGS. 11 and 12, can
be accomplished with reasonable cycle times.
[0088] It will be apparent to those skilled in the art that various
modifications and variations can be made without departing from the
spirit and scope of the claimed invention.
* * * * *