U.S. patent application number 13/596796 was filed with the patent office on 2014-03-06 for methods of manufacturing a die body.
The applicant listed for this patent is Thomas William Brew, Steven John Kremer, Christopher John Malarkey, Bryan Michael Miller. Invention is credited to Thomas William Brew, Steven John Kremer, Christopher John Malarkey, Bryan Michael Miller.
Application Number | 20140060253 13/596796 |
Document ID | / |
Family ID | 49115579 |
Filed Date | 2014-03-06 |
United States Patent
Application |
20140060253 |
Kind Code |
A1 |
Brew; Thomas William ; et
al. |
March 6, 2014 |
METHODS OF MANUFACTURING A DIE BODY
Abstract
A method of making a die body configured to extrude a honeycomb
body, the method comprising the step (I) of manufacturing a die
body and the step (II) of predetermining an upstream slot width W1
of the die body such that the upstream slot width W1 is optimized
while a root of each die pin includes a section modulus within a
predetermined section modulus range. The method still further
comprises the step (III) of predetermining a slot length L such
that a pin stress is within a predetermined pin stress range.
Inventors: |
Brew; Thomas William;
(Corning, NY) ; Kremer; Steven John; (Big Flats,
NY) ; Malarkey; Christopher John; (Corning, NY)
; Miller; Bryan Michael; (Addison, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Brew; Thomas William
Kremer; Steven John
Malarkey; Christopher John
Miller; Bryan Michael |
Corning
Big Flats
Corning
Addison |
NY
NY
NY
NY |
US
US
US
US |
|
|
Family ID: |
49115579 |
Appl. No.: |
13/596796 |
Filed: |
August 28, 2012 |
Current U.S.
Class: |
76/107.1 |
Current CPC
Class: |
B28B 3/269 20130101;
B29C 48/11 20190201; B29C 2948/92828 20190201; B29L 2031/757
20130101; B30B 11/221 20130101; B29C 2948/9259 20190201; B29C
2948/926 20190201; B29C 2948/92885 20190201; B29C 2948/92952
20190201; B23P 15/243 20130101; B29C 48/404 20190201 |
Class at
Publication: |
76/107.1 |
International
Class: |
B21K 5/20 20060101
B21K005/20 |
Claims
1. A method of making a die body configured to extrude a honeycomb
body, the method comprising the steps of: (I) manufacturing a die
body including a plurality of feed holes and an array of pins that
are spaced apart to define a honeycomb network of discharge slots
in fluid communication with the feed holes, wherein each discharge
slot is manufactured with a slot length L, each discharge slot is
further manufactured with an upstream portion with an upstream slot
width W1 in fluid communication with at least one feed hole and a
downstream portion with a downstream slot width W2 in fluid
communication with an extrusion face of the die body, and the
upstream portion and the downstream portion of each discharge slot
are manufactured such that W1>W2; (II) predetermining the
upstream slot width W1 such that the upstream slot width W1 is
optimized while a root of each die pin includes a section modulus
within a predetermined optimized section modulus range; and (III)
predetermining the slot length L such that a pin stress is within a
predetermined pin stress range.
2. The method of claim 1, wherein step (II) predetermines the
upstream slot width W1 such that the upstream slot width W1 is
maximized while the root of each die pin includes a section modulus
within a predetermined maximized section modulus range.
3. The method of claim 1, wherein the predetermined optimized
section modulus range of step (II) includes a range of from about
9.3.times.10.sup.-6 cm.sup.3 to about 2.8.times.10.sup.-5
cm.sup.3.
4. The method of claim 1, wherein the predetermined pin stress
range of step (III) includes a range of from about 240 MPa to about
750 MPa.
5. The method of claim 1, wherein the predetermined pin stress
range of step (III) is based on a calculated pin stress of a
reference die body including a reference slot having a
substantially constant reference slot width substantially equal to
W2 along an overall length of the reference slot.
6. The method of claim 1, wherein the predetermined stress range of
step (III) is determined based by a calculated pin stress of the
die body undergoing a cleaning procedure.
7. The method of claim 1, wherein step (I) includes manufacturing
the die body as a monolithic single piece die body.
8. The method of claim 1, wherein step (I) includes manufacturing
the die body with L.ltoreq.about 2.5 mm.
9. The method of claim 1, wherein step (I) includes manufacturing
the die body with W2.ltoreq.about 255 .mu.m.
10. The method of claim 1, wherein step (I) manufactures the
upstream portion of the slot with a length L1 and the downstream
portion of the slot with a length L2, wherein L.gtoreq.about
L1+L2.
11. The method of claim 1, wherein step (I) manufactures each
discharge slot with a transition region between the upstream
portion and the downstream portion of the discharge slot, the
transition region including a transition surface extending at an
angle .alpha. from a surface of the upstream portion to a surface
of the downstream portion of the discharge slot, wherein
45.degree..ltoreq..alpha..ltoreq.60.degree..
12. The method of claim 1, wherein step (I) manufactures at least
one pin of the array of pins with a divot located within the
downstream portion of the discharge slot.
13. A method of making a die body configured to extrude a honeycomb
body, the method comprising the steps of: (I) manufacturing a die
body including a plurality of feed holes and an array of pins that
are spaced apart to define a honeycomb network of discharge slots
in fluid communication with the feed holes, wherein each discharge
slot is manufactured with a slot length L, each discharge slot is
further manufactured with an upstream portion with an upstream slot
width W1 in fluid communication with at least one feed hole and a
downstream portion with a downstream slot width W2 in fluid
communication with an extrusion face of the die body, and the
upstream portion and the downstream portion of each discharge slot
are manufactured such that W1>W2; (II) predetermining the
upstream slot width W1 to provide a root of each die pin includes a
section modulus within a predetermined section modulus range of
from about 9.3.times.10.sup.-6 cm.sup.3 to about
2.8.times.10.sup.-5 cm.sup.3; and (III) predetermining the slot
length L such that a pin stress is within a predetermined pin
stress range based on a calculated pin stress of a reference die
body including a reference slot having a substantially constant
reference slot width substantially equal to W2 along an overall
length of the reference slot.
14. The method of claim 13, wherein the predetermined pin stress
range of step (III) includes a range of from about 240 MPa to about
750 MPa.
15. The method of claim 13, wherein step (II) predetermines the
upstream slot width W1 such that the upstream slot width W1 is
maximized while the root of each die pin includes a section modulus
within the predetermined section modulus range.
16. The method of claim 13, wherein step (I) includes manufacturing
the die body as a monolithic single piece die body.
17. A method of making a die body configured to extrude a honeycomb
body, the method comprising the steps of: (I) manufacturing a die
body including a plurality of feed holes and an array of pins that
are spaced apart to define a honeycomb network of discharge slots
in fluid communication with the feed holes, wherein each discharge
slot is manufactured with a slot length L, each discharge slot is
further manufactured with an upstream portion with an upstream slot
width W1 in fluid communication with at least one feed hole and a
downstream portion with a downstream slot width W2 in fluid
communication with an extrusion face of the die body, and the
upstream portion and the downstream portion of each discharge slot
are manufactured such that W1>W2; (II) predetermining the
upstream slot width W1 to provide a root of each die pin includes a
section modulus within a predetermined section modulus range of
from about 9.3.times.10.sup.-6 cm.sup.3 to about
2.8.times.10.sup.-5 cm.sup.3; and (III) predetermining the slot
length L such that a pin stress is within a predetermined pin
stress range determined based by a calculated pin stress of the die
body undergoing a cleaning procedure.
18. The method of claim 17, wherein the predetermined pin stress
range of step (III) includes a range of from about 240 MPa to about
750 MPa.
19. The method of claim 17, wherein step (II) predetermines the
upstream slot width W1 such that the upstream slot width W1 is
maximized while the root of each die pin includes a section modulus
within the predetermined section modulus range.
20. The method of claim 17, wherein step (I) includes manufacturing
the die body as a monolithic single piece die body.
Description
FIELD
[0001] The present disclosure relates generally to methods of
manufacturing a die body and, more particularly, to methods of
manufacturing a die body including predetermining an upstream slot
width and a slot length.
BACKGROUND
[0002] It is known to manufacture die bodies with a plurality of
feed holes and an array of pins that are spaced apart to define a
honeycomb network of discharge slots. The die body may be mounted
to portions of an extrusion die apparatus to extrude a green body
from a batch of ceramic and/or ceramic-forming material. The green
body is typically subsequently processed into a ceramic honeycomb
substrate that may be used as a particulate filter and/or a
catalytic carrier to process exhaust, for example, from a diesel
engine.
SUMMARY
[0003] In a first aspect, a method of making a die body configured
to extrude a honeycomb body. The method comprises the step (I) of
manufacturing a die body including a plurality of feed holes and an
array of pins that are spaced apart to define a honeycomb network
of discharge slots in fluid communication with the feed holes. Each
discharge slot is manufactured with a slot length L. Each discharge
slot is further manufactured with an upstream portion with an
upstream slot width W1 in fluid communication with at least one
feed hole and a downstream portion with a downstream slot width W2
in fluid communication with an extrusion face of the die body. The
upstream portion and the downstream portion of each discharge slot
are manufactured such that W1>W2. The method further includes
the step (II) of predetermining the upstream slot width W1 such
that the upstream slot width W1 is optimized while a root of each
die pin includes a section modulus within a predetermined optimized
section modulus range. The method also includes the step (III) of
predetermining the slot length L such that a pin stress is within a
predetermined pin stress range.
[0004] In accordance with one example of the first aspect, step
(II) predetermines the upstream slot width W1 such that the
upstream slot width W1 is maximized while the root of each die pin
includes a section modulus within a predetermined maximized section
modulus range.
[0005] In accordance with another example of the first aspect, the
predetermined optimized section modulus range of step (II) includes
a range of from about 9.3.times.10.sup.-6 cm.sup.3 to about
2.8.times.10.sup.-5 cm.sup.3.
[0006] In accordance with still another example of the first
aspect, the predetermined pin stress range of step (III) includes a
range of from about 240 MPa to about 750 MPa.
[0007] In accordance with yet another example of the first aspect,
the predetermined pin stress range of step (III) is based on a
calculated pin stress of a reference die body including a reference
slot having a substantially constant reference slot width
substantially equal to W2 along an overall length of the reference
slot.
[0008] In accordance with another example of the first aspect, the
predetermined stress range of step (III) is determined based by a
calculated pin stress of the die body undergoing a cleaning
procedure.
[0009] In accordance with yet another example of the first aspect,
wherein step (I) includes manufacturing the die body as a
monolithic single piece die body.
[0010] In accordance with still another example of the first
aspect, wherein step (I) includes manufacturing the die body with
L.ltoreq.about 2.5 mm.
[0011] In accordance with a further example of the first aspect,
wherein step (I) includes manufacturing the die body with
W2.ltoreq.about 255 .mu.m.
[0012] In accordance with another further example of the first
aspect, step (I) manufactures the upstream portion of the slot with
a length L1 and the downstream portion of the slot with a length
L2, wherein L.gtoreq.about L1+L2.
[0013] In accordance with another example of the first aspect, step
(I) manufactures each discharge slot with a transition region
between the upstream portion and the downstream portion of the
discharge slot, the transition region including a transition
surface extending at an angle .alpha. from a surface of the
upstream portion to a surface of the downstream portion of the
discharge slot, wherein
45.degree..ltoreq..alpha..ltoreq.60.degree..
[0014] In accordance with still another example of the first
aspect, step (I) manufactures at least one pin of the array of pins
with a divot located within the downstream portion of the discharge
slot.
[0015] Any of the examples of the first aspect listed above may be
carried out alone or in any combination of the remaining examples
of the first aspect listed above.
[0016] In accordance with a second aspect, a method of making a die
body configured to extrude a honeycomb body is provided. The method
includes the step (I) of manufacturing a die body including a
plurality of feed holes and an array of pins that are spaced apart
to define a honeycomb network of discharge slots in fluid
communication with the feed holes. Each discharge slot is
manufactured with a slot length L. Each discharge slot is further
manufactured with an upstream portion with an upstream slot width
W1 in fluid communication with at least one feed hole and a
downstream portion with a downstream slot width W2 in fluid
communication with an extrusion face of the die body. The upstream
portion and the downstream portion of each discharge slot are
manufactured such that W1>W2. The method further includes step
(II) of predetermining the upstream slot width W1 to provide a root
of each die pin includes a section modulus within a predetermined
section modulus range of from about 9.3.times.10.sup.-6 cm.sup.3 to
about 2.8.times.10.sup.-5 cm.sup.3. The method still further
includes the step (III) of predetermining the slot length L such
that a pin stress is within a predetermined pin stress range based
on a calculated pin stress of a reference die body including a
reference slot having a substantially constant reference slot width
substantially equal to W2 along an overall length of the reference
slot.
[0017] In accordance with an example of the second aspect, the
predetermined pin stress range of step (III) includes a range of
from about 240 MPa to about 750 MPa.
[0018] In accordance with another example of the second aspect,
step (II) predetermines the upstream slot width W1 such that the
upstream slot width W1 is maximized while the root of each die pin
includes a section modulus within the predetermined section modulus
range.
[0019] In accordance with still another example of the second
aspect, step (I) includes manufacturing the die body as a
monolithic single piece die body.
[0020] Any of the examples of the second aspect listed above may be
carried out alone or in any combination of the remaining examples
of the second aspect listed above.
[0021] In accordance with a third aspect, a method of making a die
body configured to extrude a honeycomb body is provided. The method
includes the step (I) of manufacturing a die body including a
plurality of feed holes and an array of pins that are spaced apart
to define a honeycomb network of discharge slots in fluid
communication with the feed holes. Each discharge slot is
manufactured with a slot length L. Each discharge slot is further
manufactured with an upstream portion with an upstream slot width
W1 in fluid communication with at least one feed hole and a
downstream portion with a downstream slot width W2 in fluid
communication with an extrusion face of the die body. The upstream
portion and the downstream portion of each discharge slot are
manufactured such that W1>W2. The method also includes the step
(II) of predetermining the upstream slot width W1 to provide a root
of each die pin includes a section modulus within a predetermined
section modulus range of from about 9.3.times.10.sup.-6 cm.sup.3 to
about 2.8.times.10.sup.-5 cm.sup.3. The method also includes the
step (III) of predetermining the slot length L such that a pin
stress is within a predetermined pin stress range determined based
by a calculated pin stress of the die body undergoing a cleaning
procedure.
[0022] In accordance with an example of the third aspect, the
predetermined pin stress range of step (III) includes a range of
from about 240 MPa to about 750 MPa.
[0023] In accordance with another example of the third aspect, step
(II) predetermines the upstream slot width W1 such that the
upstream slot width W1 is maximized while the root of each die pin
includes a section modulus within the predetermined section modulus
range.
[0024] In accordance with yet another example of the third aspect,
step (I) includes manufacturing the die body as a monolithic single
piece die body.
[0025] Any of the examples of the third aspect listed above may be
carried out alone or in any combination of the remaining examples
of the third aspect listed above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] These and other features, aspects and advantages of the
claimed invention are better understood when the following detailed
description is read with reference to the accompanying drawings, in
which:
[0027] FIG. 1 is a schematic representation of an extrusion
apparatus in accordance with aspects of the present disclosure;
[0028] FIG. 2 is an enlarged partial sectional perspective view of
portions of a schematically illustrated die body of the extrusion
apparatus of FIG. 1 in accordance with aspects of one example of
the disclosure;
[0029] FIG. 3 is an enlarged partial sectional perspective view of
the die body of FIG. 2;
[0030] FIG. 4 is an enlarged partial sectional view of a die body
in accordance with another example of the disclosure; and
[0031] FIG. 5 is a flow chart illustrating example steps of methods
of making a die body configured to extrude a honeycomb body.
DETAILED DESCRIPTION
[0032] Aspects of the claimed invention will now be described more
fully hereinafter with reference to the accompanying drawings in
which example embodiments of the claimed invention are shown.
Whenever possible, the same reference numerals are used throughout
the drawings to refer to the same or like parts. However, the
claimed invention may be embodied in many different forms and
should not be construed as limited to the embodiments set forth
herein. These example embodiments are provided so that this
disclosure will be both thorough and complete, and will fully
convey the scope of the claimed invention to those skilled in the
art.
[0033] FIG. 1 provides a schematic representation of an extrusion
apparatus 101 for processing a batch of materials. Various batch
materials may be provided that comprise ceramic or ceramic forming
material. The extrusion apparatus 101 can extrude green bodies of
various shapes and sizes. In one example, the extrusion apparatus
101 can be used to extrude a honeycomb body that may be later fired
into a honeycomb ceramic body. The honeycomb ceramic body can then
be further processed as part of a filter to treat the exhaust
stream of an engine. For instance, the honeycomb ceramic body can
provide a particulate filter for a diesel or other engine type.
[0034] The extrusion apparatus 101 may include a barrel 103 with
one or more screws 105 provided therein. In one example embodiment,
the barrel 103 can be shaped to provide one or more chambers 107
that each house a screw 105 rotatably mounted within the chambers
107 at a central portion of the barrel 103. The screws 105 may be
powered by one or more driving mechanisms 109 (e.g., motors). On a
second, downstream end 111 of the extrusion apparatus 101, a
schematically represented die body 113 is mounted to the barrel
103. The die body 113 is configured to extrude the batch material
in the desired shape, e.g., a honeycomb body. Near an upstream end
115, a supply port 117 may be provided to allow the batch of
materials from a feeder 119 to enter the chamber 107. As further
illustrated, the extrusion apparatus 101 may include a control
system 121. The control system 121 can be configured to adjust
rotation of the screws 105 by way of the driving mechanisms 109
and/or adjust the feed rate of the batch material introduced by the
feeder 119.
[0035] In operation, batch material may be introduced to the supply
port 117 by the feeder 119 as indicated by arrow 123. As shown by
arrow 125a, the batch material then enters into the barrel 103 and
is propagated forward by the rotating screws 105 as shown at 125b,
125c such that the batch can contact and then enter the die body
113 at 125d. The rate at which the batch is fed into the supply
port 117 (i.e., a feed rate) and/or the rate at which the screws
105 rotate (i.e., a rotational rate or screw speed) can be
adjustable at any time during the flow of the batch through the
extrusion apparatus 101.
[0036] FIG. 2 illustrates optional aspects of one example die body
113 of the example extrusion apparatus 101 of FIG. 1. The die body
113 can include a monolithic single piece die body 113 including a
plurality of feed holes 201a, 201b and an array of die pins 205
integrally formed together and spaced apart to define a honeycomb
network 207 of discharge slots 209. As shown, all of the discharge
slots 209 can be in direct fluid communication with at least one of
the feed holes. For example, as shown in FIG. 2, rows of feed holes
201a can be offset from one another with each feed hole 201a having
an axis extending along slot intersections 202. Further rows can
also include feed holes 201b that are likewise offset from one
another with each feed hole 201b having an axis extending along
slot intersections 204.
[0037] FIG. 3 illustrates example features of the example die body
113. The overall slot length L (also referred to as "slot length L"
throughout the disclosure) can be defined between a downstream end
302 in fluid communication with an extrusion face 301 of the die
body 113 and an upstream end 303 in fluid communication with at
least one feed hole 201a. As shown, each discharge slot 209 can
include an upstream portion 305 including the upstream end 303 and
a downstream portion 307 including the downstream end 302. The
upstream portion 305 is in fluid communication with the downstream
portion 307 with the upstream portion 305 positioned substantially
entirely upstream from the downstream portion 307.
[0038] The overall slot length L can at least include an upstream
length L1 of the upstream portion 305 of the discharge slot 209
added to a downstream length L2 of the downstream portion 307 of
the discharge slot 209. As such, the overall length L can be
greater than or equal to about L1+L2.
[0039] Each discharge slot 209 can also include an optional
transition region 309 between the upstream portion 305 and the
downstream portion 307 of the discharge slot 209. The transition
region 309, if provided can include a transition surface 311
extending at an angle .alpha. from a surface 314 of the upstream
portion 305 to a surface 315 of the downstream portion 307 of the
discharge slot 209. In some examples,
45.degree..ltoreq..alpha..ltoreq.60.degree. although other
transition angles may be used in further examples. The transition
length L3 can be significantly less than L1 or L2. In such
examples, the overall length L can still be greater than or equal
to about L1+L2. In the illustrated example, the transition length
L3 is considered part of the upstream length L1 wherein the overall
length L is about equal to L1+L2. With more significant transition
lengths, the transition length L3 may be considered separate from
the upstream length L1 wherein the overall length L can be greater
than or equal to about L1+L2+L3.
[0040] The upstream portion 305 can include an upstream width W1
that is greater than a downstream width W2 of the downstream
portion 307 of the discharge slot 209. As such, a further shown in
FIG. 3, W1 can be greater than W2 (i.e., W1>W2).
[0041] As discussed below, the upstream width W1 can be optimized,
and in one example, even maximized while a root 313 of each die pin
205 includes a section modulus within a predetermined section
modulus range. The upstream width W1 may be within a range of from
about 0.2 mm to about 0.5 mm, such as from about 0.3 mm to about
0.4 mm although other upstream widths may be used in further
examples.
[0042] The downstream width W2 can be selected to define the final
thickness of the intersecting cell walls of honeycomb substrate
being extruded from the die body 113 in use. For example, the
downstream width W2 can be within a range of from about 0.04 mm to
about 0.20 mm, such as from about 0.05 mm to about 0.15 mm, such as
from about 0.06 mm to about 0.14 mm, although other downstream
widths may be provided in further examples.
[0043] In further examples, the upstream length L1 can be related
to the upstream width W1. For instance, in some examples, the
upstream length L1 can be greater than or equal to about 5W1.
Likewise, the downstream length L2 can be related to the downstream
width W2. For example, the downstream length L2 can be greater than
or equal to about 5W2, such as greater than or equal to about
7W2.
[0044] In some examples, the overall length L can be less than or
equal to about 3 mm such as from about 1 mm to about 2.6 mm, such
as from about 2 mm to about 2.6 mm, although other lengths can be
used in further examples. In some examples the upstream length L1
can be from about 1 mm to about 2 mm, such as from about 1.4 mm to
about 1.7 mm, although various lengths can be used in further
examples. In further examples, the downstream length L2 can be less
than about 1.5 mm such as from about 0.4 mm to about 1 mm, although
other lengths can be used in further examples.
[0045] In some examples, the upstream width W1 can be less than
about 0.5 mm such as from about 0.2 mm to about 0.5 mm, such as
from about 0.3 mm to about 0.45 mm, such as from about 0.3 mm to
about 0.4 mm although other upstream widths may be used in further
examples. In further examples, the downstream width W2 can be less
than 0.3 mm, such less than about 0.2 mm, such as from about 0.06
mm to about 0.14 mm, although further lengths can be used in
additional examples.
[0046] FIG. 4 illustrates another example die body 401 including at
least one divot 403 that may be provided to surround at least one
of the pins 405. As shown, the divot 403, if provided, can be
located within a downstream portion 407 of a discharge slot 409.
The discharge slot 409 can also include an upstream portion 411
including a width W1 greater than a width W2 of the downstream
portion 407. As further shown, the discharge slot 409 with
differing widths may be provided only with a selected number of the
discharge slots with one or more remaining discharge slots 413
having substantially the same width along the length of the
discharge slot outside the divot 403, if provided. In such designs,
reduced manufacturing costs associated with the single width
portion can be achieved while still providing a sufficient number
slots with an enlarged upstream width W2 to reduce slot pressure
and improve batch spreading.
[0047] Methods of making die bodies will now be described with
reference to the die body illustrated in FIG. 3 with the
understanding that similar, such as identical methods may be
carried out to make the die body illustrated in FIG. 4 or other die
bodies in accordance with aspects of the disclosure. Methods of the
present disclosure can manufacture the die body 113 with a
plurality of feed holes 201a, 201b and an array of die pins 205
that are spaced apart to define the honeycomb network 207 of
discharge slots 209 in fluid communication with the feed holes
201a, 201b. Each discharge slot 209 is manufactured with a slot
length L. Each discharge slot 209 is further manufactured with the
upstream portion 305 including the upstream slot width W1 in fluid
communication with at least one feed hole 201a, 201b. Each
discharge slot 209 is still further manufactured with the
downstream portion 307 including the downstream slot width W2 in
fluid communication with the extrusion face 301 of the die body
113. As mentioned previously, the upstream portion 305 and the
downstream portion 307 of each discharge slot are manufactured such
that W1>W2.
[0048] The method of making the die bodies further includes the
step of predetermining the upstream slot width W1 such that the
upstream slot width W1 is optimized while a root 313 of each die
pin includes a section modulus within a predetermined section
modulus range. Optimizing the upstream slot width W1 can provide a
sufficiently large section modulus to provide reduced back pressure
and enhanced flow characteristics while providing enhanced strength
due to an increased section modulus. In one example, although not
required in all examples, optimizing the upstream slot width W1 can
maximize the slot width W1. Maximizing the upstream slot width W1
can be beneficial to maximize lateral expansion and maximize
reduced pressure of the batch material as it spreads into the
discharge slots 209 within the expansion region E. Sufficient
spreading of batch material within the network of discharge slots
can reduce pressure of the batch material while permitting
desirable knitting of the walls of the honeycomb substrate being
extruded from the extrusion face 301 of the die body 113. However,
while increasing the slot width W1 can be beneficial to facilitate
spreading and reduce pressure of the batch material, the structural
integrity of the die pin can be compromised by manufacturing the
die body with an excessively wide upstream slot width W1. Indeed,
increasing the upstream slot width W1 generally decreases the
section modulus at the root 313 of the die pin 205. As such, it may
be beneficial to manufacture the upstream slot width W1 to a
maximum size while maintaining the section modulus of the root 313
of the die pin 205 within a predetermined section modulus range. In
further examples, it may be desirable to optimize the slot width
W1, without necessarily maximizing the slot width, to provide
further strength to the die pins while still providing the benefits
of an increased size of the upstream slot width W1. In one example,
the upstream slot width W1 can be optimized, such as maximized,
while the root 313 of the die pin 205 includes a section modulus
within a section modulus range of from about 9.3.times.10.sup.-6
cm.sup.3 to about 2.8.times.10.sup.-5 cm.sup.3. Maintaining the
root of the die pin within the section modulus range discussed
above can help maintain structural integrity of the die body under
various operating conditions. Moreover, cleaning procedures are
frequently performed to periodically clean the die body from batch
material. Typically, such cleaning procedures can expose the die
pins to significant forces applied by pressurized cleaning fluid
during the cleaning procedure. Providing the root 313 of the die
pin 205 a section modulus within the range of section modulus
discussed above can provide the die pins with sufficient rigidity
to resist the bending forces that may otherwise cause failure of
the die pins at the root 313.
[0049] The method of making the die bodies can further include the
step of predetermining the overall length L of the discharge slot
such that a pin stress is within a predetermined pin stress range.
There can be a benefit in maintaining a sufficiently large overall
slot length L to permit sufficient knitting of the walls of the
honeycomb substrate prior to being extruded from the extrusion face
301 of the die body 113. However, increasing the overall slot
length L can undesirably increase the operating pressure of the
honeycomb extrusion apparatus and can also increase a predetermined
pin stress; thereby resulting in potential structural failure of
the die pins and increase operating costs. As such, example methods
can predetermine the overall length L of the discharge slot to
minimize the length L to reduce pin stress to within a
predetermined pin stress range while still providing a sufficiently
long overall length L to permit appropriate knitting of the walls
of the honeycomb structure.
[0050] In one example, the predetermined pin stress range can be
from about 240 MPa to about 750 MPa. In further examples, the
predetermined pin stress range can be based on a calculated pin
stress of a reference die body including a reference slot having a
substantially constant reference slot width substantially equal to
W2 along an overall length of the reference slot. For example, an
existing die body may include a substantially constant width along
substantially the entire slot length. In such examples, the
existing die body may be analyzed under a slot width substantially
equal to the downstream slot width W2 of the downstream slot
portion 307 to determine a pin stress under certain operating or
cleaning procedures. Such pin stress may then be used as the
predetermined pin stress range to maximize the overall length L of
the discharge slot 209 in the die body 113. As such, the overall
length L of the discharge slot 209 may be minimized while still
maintaining similar pin stress used with an existing die body that
may have a substantially constant slot width.
[0051] In still further examples, the predetermined stress range
can be determined based on a calculated pin stress of the die body
undergoing a cleaning procedure. For example, an existing design
with an acceptable pin design may be modeled to calculate the pin
stress of the die body undergoing a cleaning procedure. This
predetermined stress can then be used to help determine the maximum
length L of the discharge slot that may be achieved while
maintaining the pin stress within a predetermined pin stress
range.
[0052] FIG. 5 represents example steps of manufacturing a die body.
The method can include the step 501 of predetermining the upstream
slot width W1 as discussed above. More particularly, the upstream
slot width W1 is predetermined such that the upstream slot width W1
is optimized, such as maximized, while a root of each die pin
includes a section modulus within a predetermined section modulus
range, such as from about 9.3.times.10.sup.-6 cm.sup.3 to about
2.8.times.10.sup.-5 cm.sup.3 although other ranges may be possible
in further examples.
[0053] The method can then optionally proceed to step 503 of
obtaining the predetermined stress range based on a calculated pin
stress. In a first example, the predetermined pin stress range of
step is based on a calculated pin stress of a reference die body
including a reference slot having a substantially constant
reference slot width substantially equal to W2 along an overall
length of the reference slot. In a second example, in addition or
alternative to the first example, the predetermined stress range is
determined based by a calculated pin stress of the die body
undergoing a cleaning procedure.
[0054] Next, the method can proceed to step 505 of predetermining
the slot length L such that a pin stress is within a predetermine
pin stress range. In some examples, the predetermined stress range
is from about 240 MPa to about 750 MPa. In further examples, the
method can proceed directly from step 501 of predetermining the
upstream slot width W1 to the step 505 of predetermining the slot
length L. In further examples, also not illustrated in FIG. 5, the
method can begin with step 505 and then proceed to optional step
503 or directly to step 501. In either case, once the upstream slot
width W1 and the slot length L are predetermined, the upstream slot
width W1 and the slot length L, together with the remaining die
body parameters can be used to manufacture the die body during step
507.
[0055] Various manufacturing techniques may be used to manufacture
the die body including wired EDM, plunge EDM or an abrasive
slitting operation. The die body can be manufactured with the
plurality of feed holes 201a, 201b and the array of die pins 205
that are spaced apart to define the honeycomb network 207 of
discharge slots 209 in fluid communication with the feed holes
201a, 201b. Each discharge slot is manufactured with the
predetermined slot length L. Each discharge slot is further
manufactured with the upstream portion 305 with the upstream slot
width W1 in fluid communication with at least one feed hole 201a,
201b and the downstream portion 307 with the downstream slot width
W2 in fluid communication with the extrusion face 301 of the die
body 113. The upstream portion 305 and the downstream portion 307
are manufactured such that W1>W2.
[0056] Example methods of making a die body will now be described
with respect to the table below
TABLE-US-00001 TABLE 1 Section Handling- Web Modulus Cleaning
Sample Thickness L1 L2 W1 W2 L of Pin Root Pin Stress # (mm) (mm)
(mm) (mm) (mm) (mm) (cm.sup.3) % Yield 1 0.114 1.52 0.800 0.305
0.114 2.44 1.52E-05 49 2 0.140 1.42 0.978 0.406 0.140 2.54 2.80E-05
28 3 0.140 1.42 0.978 0.406 0.140 2.54 2.10E-05 38 4 0.114 1.65
0.800 0.330 0.114 2.57 9.70E-06 81 5 0.089 1.65 0.622 0.330 0.089
2.36 9.30E-06 80 6 0.064 1.65 0.445 0.330 0.064 2.16 1.40E-05 47 7
0.089 1.65 0.622 0.330 0.089 2.36 1.30E-05 55
[0057] For each sample, the die body parameters can be modeled to
determine the section modulus of the root 313 of the die pin 205 as
well as the handling-cleaning pin stress % yield. Initially, as
shown in the table, the upstream slot width W1 can be optimized
(e.g., from about 0.3 mm to about 0.4 mm) while the root of the die
pin includes a section modulus illustrated in the table that is
within a predetermined section modulus range (e.g., from about
9.3.times.10.sup.-6 cm.sup.3 to about 2.8.times.10.sup.-5
cm.sup.3). Next, the slot length L can be minimized (e.g., from
about 2.2 mm to about 2.6 mm) to provide sufficient knitting of the
walls while reducing a pin stress within a predetermined pin stress
range (e.g., with a predetermined pin stress range associated with
a Handling-Cleaning Pin Stress % Yield of from about 28 to about
81).
[0058] Aspects of the disclosure can provide enhanced knit strength
of the cell walls of a substrate that may prevent cracking from
occurring subsequent drying and firing processes. Moreover,
relatively thin cell walls can be achieved by downstream slot
portions with a relatively small downstream width without raising
the operating pressure in the slot region of the die body to
prohibitively high levels. Indeed, reduced pressures from about 10%
to over 30% from standard pressures may be achieved to result in
higher throughput capacity; thereby reducing production costs.
[0059] By increasing the upstream slot width W1 relative to the
downstream slot width W2, spreading of the batch and the spread
angle can be more precisely controlled ensuring the unfed
intersection areas (i.e., see intersections not labeled 202 or 204
in FIG. 2) have comparable strength to the fed intersection zones
(see 202, 204). In addition, this increased upstream slot width
(W1) allows the overall length L of the discharge slot 209 to be
reduced, thereby improving manufacturing variability and speeding
up the manufacture of the die body 113. The reduced length L of the
discharge slot 209 coupled with its increased width decreases the
pressure drop in this hole/slot intersection of the expansion zone
E (see FIG. 3) and also in the overall slot zone significantly. In
addition, fluid flow modeling confirmed by actual test runs has
shown that this wider slot zone can dampen out flow variability
that may be introduced to the slot. In some cases, the modeling
confirmed by actual test runs showed a 50% flow velocity difference
being damped down to under 5%. This type of design is not limited
to one expansion and constriction zone. Rather, any number of
expansion/constriction zones can be placed in the die design to
optimize the aforementioned die design parameters (knit strength,
pressure drop and/or flow uniformity). Aspects of the disclosure
can improve uniformity of batch flow through the die by as much as
10.times. which greatly reduces the impact of process/material
variability and die tolerance variability.
[0060] It will be apparent to those skilled in the art that various
modifications and variations can be made to the described
embodiments without departing from the spirit and scope of the
claimed invention. Thus, it is intended that the present claimed
invention cover the modifications and variations of the embodiments
described herein provided they come within the scope of the
appended claims and their equivalents.
* * * * *