U.S. patent application number 15/699549 was filed with the patent office on 2019-03-14 for systems and methods for additive manufacturing of wick structure for vapor chamber.
This patent application is currently assigned to TOYOTA MOTOR ENGINEERING & MANUFACTURING NORTH AMERICA, INC.. The applicant listed for this patent is TOYOTA MOTOR ENGINEERING & MANUFACTURING NORTH AMERICA, INC.. Invention is credited to Ercan Dede, Shailesh N. Joshi, Feng Zhou.
Application Number | 20190082560 15/699549 |
Document ID | / |
Family ID | 65631922 |
Filed Date | 2019-03-14 |
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United States Patent
Application |
20190082560 |
Kind Code |
A1 |
Dede; Ercan ; et
al. |
March 14, 2019 |
SYSTEMS AND METHODS FOR ADDITIVE MANUFACTURING OF WICK STRUCTURE
FOR VAPOR CHAMBER
Abstract
A vapor chamber includes a wick structure created by an additive
selective laser sintering process. The wick structure includes a
substrate, a first copper powder layer, a second copper powder
layer, and a plurality of additional layers. The first copper
powder layer is deposited across the substrate, wherein the first
copper powder layer is subsequently selectively fused via a fusing
instrument. The second copper powder layer is deposited across the
first copper powder layer, wherein the second copper powder layer
is subsequently selectively fused via the fusing instrument.
Additionally, a plurality of additional copper powder layers are
deposited wherein each additional layer is deposited on the
previous layer, wherein each of the additional copper powder layers
is selectively fused with a predetermined structure.
Inventors: |
Dede; Ercan; (Ann Arbor,
MI) ; Zhou; Feng; (South Lyon, MI) ; Joshi;
Shailesh N.; (Ann Arbor, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOYOTA MOTOR ENGINEERING & MANUFACTURING NORTH AMERICA,
INC. |
Erlanger |
KY |
US |
|
|
Assignee: |
TOYOTA MOTOR ENGINEERING &
MANUFACTURING NORTH AMERICA, INC.
Erlanger
KY
|
Family ID: |
65631922 |
Appl. No.: |
15/699549 |
Filed: |
September 8, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22F 7/002 20130101;
G06F 2200/201 20130101; F28F 2255/18 20130101; H05K 7/20381
20130101; B22F 3/1121 20130101; Y02P 10/25 20151101; B22F 7/08
20130101; B22F 3/008 20130101; B33Y 10/00 20141201; B22F 2999/00
20130101; G06F 1/20 20130101; B22F 5/10 20130101; B22F 7/004
20130101; B22F 2003/1056 20130101; B33Y 80/00 20141201; B22F 3/1055
20130101; A61L 2209/135 20130101; G06F 1/203 20130101; B01B 1/005
20130101; H05K 7/20336 20130101; B22F 2999/00 20130101; B22F
2201/02 20130101 |
International
Class: |
H05K 7/20 20060101
H05K007/20; B22F 3/105 20060101 B22F003/105; B01B 1/00 20060101
B01B001/00; B33Y 80/00 20060101 B33Y080/00 |
Claims
1. A vapor chamber, comprising: a wick structure, wherein the wick
structure includes a substrate, a first copper powder layer
deposited across the substrate, wherein the first copper powder
layer is subsequently selectively fused via a fusing instrument, a
second copper powder layer deposited across the first copper powder
layer, wherein the second copper powder layer is subsequently
selectively fused via the fusing instrument, and a plurality of
additional copper powder layers, wherein each additional layer is
deposited on the previous layer, wherein each of the additional
copper powder layers is selectively fused with a predetermined
structure.
2. The vapor chamber of claim 1, wherein the predetermined
structure includes liquid supply posts and each liquid supply post
includes an arch structure.
3. The vapor chamber of claim 1, wherein the fusing instrument is a
laser.
4. The vapor chamber of claim 1, wherein the predetermined
structure includes surface enhancement features, wherein the
surface enhancement features include enhancements to a base wick or
enhancements to the base wick and the substrate.
5. The vapor chamber of claim 4, wherein the surface enhancement
features include dimples and bumps, and each can have a pyramid,
elliptical, rectangular, or diamond shape.
6. The vapor chamber of claim 1, wherein the predetermined
structure includes an optimized wick structure, wherein the
optimized wick structure includes a structured based wick with a
non-uniform height and a tapered outlet vent.
7. The vapor chamber of claim 1, wherein the predetermined
structure includes angled vapor vents configured to direct vapor
toward a periphery of the vapor chamber.
8. The vapor chamber of claim 1, wherein the predetermined
structure includes tilted liquid supply posts.
9. The vapor chamber of claim 1, wherein the predetermined
structure includes combining the angled vapor vents and the titled
liquid supply posts.
10. The vapor chamber of claim 1, wherein the predetermined
structure includes a manifold microchannel wick structure.
11. A method for additive selective laser sintering, comprising:
depositing a first copper powder layer across a substrate;
subsequently selectively fusing the first copper powder layer via a
fusing instrument; depositing a second copper powder layer across
the first copper powder layer; selectively fusing the second copper
powder layer via the fusing instrument; and depositing a plurality
of additional copper powder layers wherein each additional layer is
deposited on the previous layer; selectively fusing each of the
additional copper powder layers; and creating a predetermined wick
structure based on the selective fusing of each additional copper
powder layer.
12. The method of claim 11, wherein each copper powder layer is
deposited via a print nozzle.
13. The method of claim 12, wherein the print nozzle is
pre-programmed with the porous multi-layer wick structure.
14. The method of claim 11, further comprising: removing loose
copper powder remaining after selectively fusing each copper powder
layer.
15. The method of claim 14, further comprising: replacing the
removed loose copper powder with sacrificial carbonate particles,
wherein the sacrificial carbonate particles include a binding agent
that is curable between each layer, the sacrificial carbonate
particles being removed with the wick structure is complete.
16. The method of claim 11, wherein the copper powder is suspended
in a slurry with a binding agent.
17. The method of claim 11, wherein the predetermined wick
structure includes surface enhancement features, wherein the
surface enhancement features include enhancements to a base wick or
enhancements to the base wick and the substrate.
18. The method of claim 11, wherein the predetermined wick
structure includes an optimized wick structure, wherein the
optimized wick structure includes a structured based wick with a
non-uniform height and a tapered outlet vent.
19. The method of claim 11, wherein the predetermined structure
includes tilted liquid supply posts.
20. The method of claim 11, wherein the predetermined structure
includes a manifold microchannel wick structure.
Description
BACKGROUND
[0001] The "background" description provided herein is for the
purpose of generally presenting the context of the disclosure. Work
of the presently named inventors, to the extent it is described in
this background section, as well as aspects of the description
which may not otherwise qualify as prior art at the time of filing,
are neither expressly or impliedly admitted as prior art against
the present invention.
[0002] The intensifying electrification of transportation systems
and clean-energy-production technologies has dramatically increased
the waste heat load that must be dissipated from high-density power
electronic devices. This trend has pushed conventional air-cooling
thermal management architectures to the limit. A reliance on
conduction heat spreading from devices to the heat rejection
surfaces incurs an overly large thermal resistance at power levels
well below the inherent electrical power density limits of
devices.
[0003] Vapor chamber heat spreaders offer a viable solution if
implemented as a heat sink base, unlike alternative solid heat
conduction spreaders that are fundamentally limited to a linearly
decreasing performance (increasing thermal resistance) with
effective heat transfer distance. A sealed vapor chamber can be
filled with a working fluid that evaporates when locally heated.
The vapor flows away from the hotspot and condenses over a diffuse
heat rejection surface. A porous wick structure lining the chamber
pumps liquid back to the heat sources via capillary action. This
two-phase cycle allows passive heat spreading at a temperature
gradient that can be orders of magnitude lower than conduction
through solid materials. Vapor chambers have high reliability,
passive operation, and effective heat transport.
SUMMARY
[0004] The foregoing paragraphs have been provided by way of
general introduction, and are not intended to limit the scope of
the following claims. The described embodiments, together with
further advantages, will be best understood by reference to the
following detailed description taken in conjunction with the
accompanying drawings.
[0005] According to embodiments of the disclosed subject matter, a
vapor chamber includes a wick structure created by an additive
selective laser sintering process. The wick structure includes a
substrate, a first copper powder layer, a second copper powder
layer, and a plurality of additional layers. The first copper
powder layer is deposited across the substrate, wherein the first
copper powder layer is subsequently selectively fused via a fusing
instrument. The second copper powder layer is deposited across the
first copper powder layer, wherein the second copper powder layer
is subsequently selectively fused via the fusing instrument.
Additionally, a plurality of additional copper powder layers are
deposited Wherein each additional layer is deposited on the
previous layer, Wherein each of the additional copper powder layers
is selectively fused with a predetermined structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] A more complete appreciation of the disclosure and many of
the attendant advantages thereof will be readily obtained as the
same becomes better understood by reference to the following
detailed description when considered in connection with the
accompanying drawings, wherein:
[0007] FIG. 1A depicts an exemplary overview of a vapor chamber
according to one or more aspects of the disclosed subject
matter;
[0008] FIG. 1B depicts a detailed view of a portion of a vapor
chamber according to one or more aspects of the disclosed subject
matter.
[0009] FIG. 2A depicts exemplary steps in an additive layer
fabrication process for a multi-layer wick structure according to
one or more aspects of the disclosed subject matter;
[0010] FIG. 2B depicts exemplary steps in an additive layer
fabrication process for a multi-layer wick structure according to
one or more aspects of the disclosed subject matter;
[0011] FIG. 2C depicts exemplary steps in an additive layer
fabrication process for a multi-layer wick structure according to
one or more aspects of the disclosed subject matter;
[0012] FIG. 3A depicts a wick unit cell from an optimized wick
structure according to one or more aspects of the disclosed subject
matter;
[0013] FIG. 3B depicts a side view of an optimized wick structure
according to one or more aspects of the disclosed subject
matter;
[0014] FIG. 3C depicts a top view of an optimized wick structure
according to one or more aspects of the disclosed subject
matter;
[0015] FIG. 4 depicts vapor vents angled towards the periphery of a
vapor chamber according to one or more aspects of the disclosed
subject matter;
[0016] FIG. 5 depicts tilted liquid supply posts according to one
or more aspects of the disclosed subject matter;
[0017] FIG. 6A depicts exemplary surface enhancements with a flat
substrate according to one or more aspects of the disclosed subject
matter;
[0018] FIG. 6B depicts exemplary surface enhancements with a
featured substrate according to one or more aspects of the
disclosed subject matter;
[0019] FIG. 7A depicts a manifold microchannel wick structure
according to one or more aspects of the disclosed subject matter;
and
[0020] FIG. 7B depicts a close up view of a portion of a manifold
microchannel wick structure according to one or more aspects of the
disclosed subject matter.
DETAILED DESCRIPTION
[0021] The description set forth below in connection with the
appended drawings is intended as a description of various
embodiments of the disclosed subject matter and is not necessarily
intended to represent the only embodiment(s). In certain instances,
the description includes specific details for the purpose of
providing an understanding of the disclosed subject matter.
However, it will be apparent to those skilled in the art that
embodiments may be practiced without these specific details. In
some instances, well-known structures and components may be shown
in block diagram form in order to avoid obscuring the concepts of
the disclosed subject matter.
[0022] Reference throughout the specification to "one embodiment"
or "an embodiment" means that a particular feature, structure,
characteristic, operation, or function described in connection with
an embodiment is included in at least one embodiment of the
disclosed subject matter. Thus, any appearance of the phrases "in
one embodiment" or "in an embodiment" in the specification is not
necessarily referring to the same embodiment. Further, the
particular features, structures, characteristics, operations, or
functions may be combined in any suitable manner in one or more
embodiments. Further, it is intended that embodiments of the
disclosed subject matter can and do cover modifications and
variations of the described embodiments.
[0023] It must be noted that, as used in the specification and the
appended claims, the singular forms "a," "an," and "the" include
plural referents unless the context clearly dictates otherwise.
That is, unless clearly specified otherwise, as used herein the
words "a" and "an" and the like carry the meaning of "one or more."
Additionally, it is to be understood that terms such as "left,"
"right," "top," "bottom," "front," "rear," "side," "height,"
"length," "width," "upper," "lower," "interior," "exterior,"
"inner," "outer," and the like that may be used herein, merely
describe points of reference and do not necessarily limit
embodiments of the disclosed subject matter to any particular
orientation or configuration. Furthermore, terms such as "first,"
"second," "third," etc., merely identify one of a number of
portions, components, points of reference, operations and/or
functions as described herein, and likewise do not necessarily
limit embodiments of the disclosed subject matter to any particular
configuration or orientation.
[0024] Referring now to the drawings, wherein like reference
numerals designate identical or corresponding parts throughout the
several views.
[0025] FIGS. 1A-1B depicts an exemplary overview of a vapor chamber
105 according to one or more aspects of the disclosed subject
matter. FIGS. 1A-1B depicts a detailed view of a portion of a vapor
chamber according to one or more aspects of the disclosed subject
matter. The vapor chamber 105 may be used to cool a device 110,
wherein the device 110 may be a CPU, a graphics card, and the like,
for example. The vapor chamber 105 may include a capillary-fed
boiling wick base layer 115, one or more liquid-feeding posts 120,
a wick cap layer 125, liquid inflow 130, vapor outflow 135, vapor
core 140, a condenser-side wick 145, a condenser-side copper wall
150, and one or more vapor vents 155. The vapor chamber 105 can be
an example of a typical vapor chamber and one or more components of
the vapor chamber 105 may be modified and/or removed. Additionally,
new components may be added and new processes for creating one or
more components may be used as further described herein. Further,
one or more components of the vapor chamber 105 may simply be used
for reference when describing aspects of the disclosed subject
matter.
[0026] FIG. 2A-FIG. 2C depicts an additive layer fabrication
process for the multi-layer wick structure, The additive layer
fabrication process is advantageous in that it can solve a wick
degradation issue from laser etching. Additionally, the process can
enable the integration of surface features or micro-structures not
easily attainable from molding or subtractive fabrication methods.
For example, arch structures and other unique structures may now be
included during manufacturing which would not be possible through a
subtractive process. The arch structures may reduce a pressure drop
of cooling fluid returning to the base wick layer from a condensing
layer, for example.
[0027] An advantage of fabricating the porous multi-wick structure
of a vapor chamber using an additive manufacturing process is that
numerous designs may be manufactured without the need for new
tooling or implementation of damaging subtractive manufacturing
processes such as laser etching or machining.
[0028] In general, one embodiment of an additive manufacturing
process may include starting with a first copper powder layer
(S205) which is selectively fused/sintered by a laser (S210). In an
embodiment, any copper power layer can be a copper alloy powder
layer, for example. A second copper powder layer may be added on
top of the selectively fused first copper powder layer (S215) and a
laser may again selectively fuse portions of the second copper
powder layer (S220). The cycle of adding layers of copper powder
and selectively fusing portions of the copper powder may be
repeated until the porous multi-layer wick structure is formed. The
loose copper powder that remains may be removed in a
post-processing step, for example.
[0029] In an embodiment, once the copper powder in the previously
applied layer is fused the loose/unfused copper powder may be
removed (e.g., by compressed air) and replaced with sacrificial
carbonate particles to provide support for the subsequent layers of
copper powder. The sacrificial carbonate particles may include a
binding agent that is curable between applications to prevent the
binding agent from being removed during subsequent applications of
copper powder layers. Once the multi-layer wick structure is
constructed, the sacrificial carbonate particles may be sintered
out through a loose sintering process which may additionally sinter
the copper particle preform into a final porous multi-layer wick
structure.
[0030] In an embodiment, a copper powder suspended in a slurry with
a binding agent (e.g., polymeric) may be prepared. The slurry may
be applied to a substrate in layers via an applicator nozzle (e.g.,
print nozzle 295 in FIG. 2C) preprogrammed with the porous
multi-layer wick structure. The print nozzle 295 and/or a machine
controlling the print nozzle 295 can include a memory to store
instructions and predetermined wick structures, for example, and a
processor to perform the steps for creating the predetermined wick
structure. The binding agent may be partially cured as each layer
is applied to form a 3-dimensional construct of the porous
multi-layer wick structure. The construct may then be sintered such
that the copper powder forms a porous structure and the binding
agent is removed.
[0031] In an embodiment, an ultrasonic bonding process may be
utilized to initially bond portions of copper powder or copper
power slurry constructs during an additive layering process. The
ultrasonically bonded copper powder may finally be formed through a
subsequent ultrasonic process or a sintering process, for
example.
[0032] More specifically, FIG. 2A-2C includes an example
step-by-step process flow of an additive selective laser sintering
process. Each step includes a cross-sectional view and top view for
reference. As noted above, variations to the general additive layer
manufacturing process may be utilized in achieving the desired
porous multi-layer wick structure.
[0033] In S205, copper powder 202 can be deposited across a support
surface 204. The support surface 204 may be a copper plate, a mold,
or any other surface for supporting the additive manufacturing of
the multi-layer wick structure.
[0034] In S210, laser (e.g., or a similar fusing instrument) can be
used to selectively fuse the copper powder (e.g., fused copper
powder 206).
[0035] Once the copper powder is fused, another layer of copper
powder may be added to the fused layer in S215 and subsequently
selectively fused with a laser or similar fusing instrument (e.g.,
the entire build platform may be positioned in an oven) in
S220.
[0036] Similarly, S225, S230, S235, S240, S245, and S250 show the
addition of additional copper powder layers and the subsequent
selective fusing (e.g., laser, oven, etc.). The selectively fused
copper powder is shown by way of dark grey and free or loose copper
powder is shown as light grey. Additionally, the formation of
liquid supply posts 208 is depicted wherein the liquid supply posts
include an arch structure. The arch structure may provide
additional structural support to the multi-wick layer as well as
improved cooling of vapor.
[0037] Further, S255, S260, S265, S270, S275, S280, S285, and S290
continue the build-up of the multi-layer wick structure through the
continued addition of copper powder and selective fusing of the
copper powder (e.g., via a laser or oven). S290 also depicts an
exemplary print nozzle 295 that may be part of an additive
manufacturing machine, for example. The print nozzle 295 may be
used in the additive manufacturing process to apply a slurry to a
substrate in layers wherein the print nozzle may be preprogrammed
with the porous multi-layer wick structure.
[0038] It should be appreciated that the process described in FIGS.
2A-2C is an example of a design and one example additive layer
manufacturing process. The multi-layer wick structure may further
be assembled with a vapor chamber housing and cooling fluid. The
completed vapor chamber may be coupled to a heat source such as an
electronics package for purposes of removing heat generated by the
electronics package.
[0039] The additive method of fabrication can avoid the issues
created by laser etching sintered wick structures to remove
material. Further, surface enhancement features, arch structures,
and other unique features may be formed without the need for
specialized molds or subtractive processes.
[0040] In an embodiment, each layer in S205 through S290 can be
printed (e.g., via a 3D printer) at room temperature, where the
polymeric binder produces a geometrically (i.e., gravity) stable
part including the metal particles. The fusing or sintering of the
metal particles may be done in a single post-printing step where
the polymeric binder can be burned off, for example.
[0041] Further considerations may include adjusting laser sintering
temperatures for forming porous wick structures versus forming a
solid metal structure. Additionally, unique binding agents (e.g.
chemical binders or physical (e.g. polymeric) binders) may be used.
Further, intermediate heating or cooling steps to control porosity
of the multi-layer wick may be used.
[0042] FIG. 3A depicts a wick unit cell 305 from an optimized wick
structure according to one or more aspects of the disclosed subject
matter. The wick unit cell 305 can include an arched liquid feeding
post 315 (e.g., seen more clearly in FIG. 3B), a structured based
wick 320 with non-uniform height (e.g., thicker further from liquid
feeding post), and a tapered outlet vent 325, for example.
[0043] FIG. 3B depicts a side view of the optimized wick structure
310 according to one or more aspects of the disclosed subject
matter. The optimized wick structure 310 may include a plurality of
wick unit cells 305, for example. The wick cell units 305 can be
connected via sintering together the wick cell units 305, for
example.
[0044] FIG. 3C depicts a top view of the optimized wick structure
310 according to one or more aspects of the disclosed subject
matter. An advantage of the optimized wick structure 310 can
optimize the vapor flow path. In other words, the vapor can flow to
the condenser side and the liquid can flow to the evaporator side
as efficiently as possible. In an embodiment, the liquid feeding
posts 120 in FIG. 1 can include the optimized wick structure 310,
for example.
[0045] FIG. 4 depicts vapor vents 405 angled towards the periphery
of the vapor chamber (e.g., vapor chamber 105) according to one or
more aspects of the disclosed subject matter. In a typical vapor
chamber, only a center region has two layer wick structure and
vapor can only flow out through vapor vents. The center region of
the condenser side may have vapor flow impinged on it, leading to
non-uniform condensation heat transfer on condenser side and also
potential erosion. However, constructing angled vapor vents 405
(e.g., via 3D printing) angled towards the periphery of the vapor
chamber can better distribute the vapor flow towards the condenser
side, cause less impact to the condenser wick, and provide more
uniform condensation heat transfer.
[0046] FIG. 5 depicts tilted liquid supply posts 505 according to
one or more aspects of the disclosed subject matter. Each titled
liquid supply post 505 can be titled at a more severe angle closer
to the periphery of the vapor chamber. Typically, the area that has
vapor vents can be the same as the area of heat source. Because the
volume of vapor is about 1000 times that of liquid, a larger area
for vapor flow can be advantageous. Accordingly, the titled liquid
supply posts 505 can provide a larger area for vapor flow compared
to heat source area. Tilted liquid supply posts 505 can connect
larger vapor vent area and smaller heated area. The titled liquid
supply posts can be advantageous for a vapor chamber with multiple
heat sources with different heat flux levels, for example. In an
embodiment, the tilted liquid supply posts 505 can be combined with
the angled vapor vents 405 shown in FIG. 4.
[0047] FIG. 6A depicts exemplary surface enhancements with a flat
substrate according to one or more aspects of the disclosed subject
matter, and FIG. 6B depicts exemplary surface enhancements with a
featured substrate according to one or more aspects of the
disclosed subject matter. Each surface enhancement example can
include a base wick 605 and a substrate 610, as shown in surface
enhancement example 615, for example. The surface enhancement
features can be added to the base wick 605 only or added to both
base wick 605 and the substrate 610, for example. Additionally, the
surface enhancement features can be constructed via additive
manufacturing, for example. The surface enhancement feature can be
dimples (e.g., 630, 635, 640, 660, 665, and 670) or bumps (e.g.,
615, 620, 625, 645, 650, and 655). The shapes of dimple and bump
can also be pyramid (e.g., 620 and 650), elliptical dimple (e.g.,
615, 645, 630, and 660), rectangular (e.g., 625, 655, 635, and
665), diamond (e.g., 640 and 670), and the like. Any shape of
dimples or bumps can be applicable. When the substrate has the
similar shape of dimples or bumps as the base wick, more uniform
heat flux can be provided to the surface enhancement features. The
geometries of the surface enhancing features are further describe
in provisional application 62/469,784 filed on Mar. 10, 2017, which
is herein incorporated by reference in its entirety.
[0048] FIG. 7A depicts a manifold microchannel wick structure 700
as a schematic of a manifold microchannel heat sink according to
one or more aspects of the disclosed subject matter. The manifold
microchannel wick structure 700 can be applied to a vapor chamber,
for example, and can be constructed via additive manufacturing. The
manifold microchannel wick structure 700 can include a manifold 705
and microchannels 710, wherein the manifold 705 and the
microchannels 710 can be made of a porous wick structure. The
microchannels 710 can be on an evaporator side corresponding to
evaporator 720. FIG. 7B depicts a close up view of a portion of the
manifold microchannel wick structure 700 according to one or more
aspects of the disclosed subject matter. FIG. 7B depicts a vapor
flow cycle (e.g., vapor to liquid cycle) wherein the vapor may rise
from the microchannels 710 through gaps between fingers of the
manifold 705 as depicted by the arrows pointing up and away from
the microchannels 710. Additionally, FIG. 7B more specifically
shows the portions 725 of the manifold, which can be a porous wick
structure. The portions 725 assist in returning liquid, e.g., after
the vapor rising between the gaps between the fingers of the
manifold 705 reaches the condenser (not shown) to the evaporator
720 as indicated by the arrows point down toward the manifold 705,
for example. Although the shape of portions 725 are square, the
shape of portions 725 can include various geometries based on the
construction of the manifold 705, for example, via additive
manufacture. Additionally, portion 735 can correspond to a gap
between the fingers of the manifold 705, for example. More
specifically, the vapor can flow through the open area
corresponding to portion 735 on its way toward the condenser, for
example. An advantage of using additive manufacturing is to create
geometries that are not easily machined, or possibly cannot be
machined. Additionally, the manifold microchannel wick structure
700 can include wider channels on a condenser side (e.g., a side of
the manifold opposite the evaporator side) and narrow channels on
an evaporator side 720. For example, based on a heat capacity and
desired vapor flow configuration, the channels can be wider,
narrower, increase a number of channels, decrease a number of
channels, and the like. All channel walls (e.g., manifold 705,
portions 725, microchannels 710, etc.) can be made of porous wick,
for example. The channel walls can function as a liquid supply
route, and the space between the channel walls can be for vapor
flow.
[0049] The channel walls on the manifold 705 can enhance the liquid
return from condenser side to evaporator side. This can be
advantageous because in a traditional vapor chamber, liquid only
returns through the wick on the side wall of the chamber.
Additionally, denser channel walls on the evaporator side can help
with getting the local liquid supply to a hot spot. The density can
vary based on the heat flux level, for example. Further, the
profile of the channels looking from the side can be sinusoidal,
square, triangle, sawtooth, and the like. An advantage of having
alternative channel profiles can minimize the vapor flow resistance
and/or obstruction to vapor flow and allow better liquid flow. The
channel profile can be selected based on an application of the heat
sink, the heat flux requirement for the application, and the
like.
[0050] Aspects of the disclosed subject matter include several
advantages. For example, manufacturing a porous multi-layer wick
structure for a vapor chamber using an additive manufacturing
method does not require specialized molding tools or subtractive
material processes that can be damaging to the wick and/or wick
structure. Additionally, fabricating the porous multi-wick
structure of a vapor chamber using an additive manufacturing
process can include numerous designs that can be manufactured
without the need for new tooling.
[0051] Additionally, several structural advantages can be provided
via the optimized wick structure, the angled vapor vents, the
titled liquid supply posts, the surface enhancements, the manifold
microchannel wick structure, and the like to improve various
aspects of cooling in a vapor chamber including dealing with
multiple heat sources with different heat flux levels, for example.
It should be appreciated that one or more of the embodiments
described herein can be combined in a vapor chamber.
[0052] Having now described embodiments of the disclosed subject
matter, it should be apparent to those skilled in the art that the
foregoing is merely illustrative and not limiting, having been
presented by way of example only. Thus, although particular
configurations have been discussed herein, other configurations can
also be employed. Numerous modifications and other embodiments
(e.g., combinations, rearrangements, etc.) are enabled by the
present disclosure and are within the scope of one of ordinary
skill in the art and are contemplated as falling within the scope
of the disclosed subject matter and any equivalents thereto.
Features of the disclosed embodiments can be combined, rearranged,
omitted, etc., within the scope of the invention to produce
additional embodiments. Furthermore, certain features may sometimes
be used to advantage without a corresponding use of other features.
Accordingly, Applicant(s) intend(s) to embrace all such
alternatives, modifications, equivalents, and variations that are
within the spirit and scope of the disclosed subject matter.
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