Single-build parts for passive cooling

Abstract

Methods and systems for the manufacture of single-build parts for passive cooling. Embodiments include a single-build part comprising at least one internal chamber configured to hold a fluid. Some embodiments include manufacture via laminated object manufacturing methods, which includes patterning a plurality of metal sheets so that the metal sheets comprise a plurality of voids, stacking the patterned metal sheets, and bonding the stacked metal sheets to form a single-build part.

Description

ALY-017PCSINGLE-BUILD PARTS FOR PASSIVE COOLINGCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of and priority to United States Provisional Application No. 63 / 681,058, filed on August 8, 2024, the entire disclosure of which is hereby incorporated by reference as if set forth in its entirety herein.TECHNICAL FIELD

[0002] Embodiments described herein generally relate to methods and apparatus for manufacturing metal parts, and more specifically to the manufacture of single-build parts for passive cooling.BACKGROUND

[0003] Passive cooling parts, such as thermosiphons, heat pipes and vapor chambers, are commonly used in electronic devices, aerospace systems, and other applications where effective heat transfer is essential. Passive cooling parts can transfer heat away from heat sources without the use of powered mechanical devices. Rather, passive cooling parts rely on passive mechanisms such as conduction, convention, radiation, and / or phase change to transfer heat. Such parts often rely on internal structures such as wicks and sealed fluid chambers to facilitate heat transfer mechanisms.

[0004] Conventional manufacturing techniques for manufacturing cooling parts with internal structures often require the assembly of multiple discrete parts. For example, a cooling part can be fabricated by machining separate metal components and then joining them through welding, brazing, and / or other bonding techniques. However, the configuration and placement of internal features are often constrained by various limitations of conventional techniques. For example, internal features may be assembled under casting, extruding, stamping, and / or brazing design constraints, which can restrict the number, configuration, and size of these features within the part.

[0005] Alternative manufacturing techniques present promising alternatives to traditional techniques for manufacturing passive cooling parts. For example, additive manufacturing techniques such as laminated object manufacturing (LOM) can allow for the manufacture of single-build parts without casting constraints or welding of parts.

[0006] Accordingly, a need exists for improved designs and improved methods of manufacturing single-build parts for passive cooling.ALY-017PCSUMMARY

[0007] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description section. This summary is not intended to identify or exclude key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0008] According to one aspect, the techniques described herein relate to a single-build part formed via an additive manufacturing process, the part including at least one internal chamber configured to hold a fluid.

[0009] In some embodiments, the part is formed without welding separate components together.

[0010] In some embodiments, the fluid is loaded into the internal chamber during or after the formation of the part.

[0011] In some embodiments, the part is configured to use the fluid for transferring heat.

[0012] In some embodiments, the part includes a passive valve formed from at least one patterned metal sheet.

[0013] In some embodiments, the part further includes at least one fin within the chamber, the fin configured to increase heat transfer on at least one surface of the part.

[0014] In some embodiments, at least one internal surface of the part is textured with wicking channels configured to transfer the fluid within the part.

[0015] In some embodiments, the length of at least one wicking channel is at least 150 microns.

[0016] In some embodiments, at least one internal surface of the part is textured with nucleation sites configured to promote evaporation within the part.

[0017] In some embodiments, the part further includes a plurality of subsurface capillaries fluidically connected to the internal chamber for forming an internal flow path.

[0018] In some embodiments, the part further includes a breakable vial for releasing the fluid to the internal chamber.

[0019] In some embodiments, the internal chamber includes a foam for promoting capillary action across a surface of the internal chamber.

[0020] In some embodiments, the internal chamber includes a plurality of zones for forming a convection loop using the fluid.ALY-017PC

[0021] In some embodiments, the part further includes: a contoured frame; and a plurality of wicking structures placed within at least one extremity of the frame to promote heat transfer under a contoured surface of the frame.

[0022] According to another aspect, the techniques described herein relate to a method for forming a single-build part via a laminated manufacturing process, the method including: patterning a plurality of metal sheets so that the metal sheets include a plurality of voids; stacking the patterned metal sheets; and bonding the stacked metal sheets to form the part, the part including at least one internal chamber formed from at least some of the voids and configured to hold a fluid.

[0023] In some embodiments, the part is formed without welding separate components together.

[0024] In some embodiments, the method further includes loading the fluid into the internal chamber during or after the formation of the part.

[0025] In some embodiments, at least one internal surface of the part is textured with wicking channels configured to transfer the fluid within the part.

[0026] In some embodiments, the part includes at least one passive valve formed from the patterned metal sheets.

[0027] According to yet another aspect, the techniques described herein relate to a system for manufacturing a single-build part via a laminated manufacturing process, the system including: a laminated object manufacturing device configured to: pattern a plurality of metal sheets so that the metal sheets include a plurality of voids; and stack the patterned metal sheets; and a pressor configured to bond the stacked metal sheets by applying a mechanical force for forming the part, the part including at least one internal chamber formed from at least some of the voids and configured to hold a fluid.BRIEF DESCRIPTION OF DRAWINGS

[0028] Non-limiting and non-exhaustive embodiments of this disclosure are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified:

[0029] Figure 1 depicts a cross-section of a part configured with a capillary;

[0030] Figure 2A depicts a cross-section of a heat pipe configured with an internal chamber and subsurface capillaries;

[0031] Figure 2B depicts a top-down cross-section of the heat pipe depicted in Figure 2A;ALY-017PC

[0032] Figure 3 depicts a cross-section of a heat pipe charged with a fluid encapsulated in a ceramic vial;

[0033] Figure 4 depicts a cross-section of a heat pipe with an encapsulated foam to promote wicking;

[0034] Figure 5 depicts a cross-section of a thermosiphon in accord with the present invention;

[0035] Figure 6 depicts a cross-section of a vapor chamber in accord with the present invention;

[0036] Figure 7 depicts a cross-section of another vapor chamber in accord with the present invention;

[0037] Figure 8 depicts a cross-section of a heat pipe in accord with the present invention;

[0038] Figure 9A depicts a cross-section of a cooling device configured for pumpless flow boiling;

[0039] Figure 9B depicts a cross-section of the lower chamber of the cooling device depicted in Figure 9 A;

[0040] Figure 10 depicts a cross-section of a quadcopter frame comprising a passive cooling device with integrated structural wicks; and

[0041] Figure 11 depicts a flowchart of a method for forming a single-build part in accord with the present invention.DETAILED DESCRIPTION

[0042] Various embodiments are described more fully below with reference to the accompanying drawings, which form a part hereof, and which show specific exemplary embodiments. However, the concepts of the present disclosure may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided as part of a thorough and complete disclosure, to fully convey the scope of the concepts, techniques and implementations of the present disclosure to those skilled in the art. Embodiments may be practiced as methods, systems or devices. The following detailed description is, therefore, not to be taken in a limiting sense.

[0043] Reference in the specification to “one embodiment” or to “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least one example implementation or technique in accordance with the presentALY-017PC disclosure. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.

[0044] In addition, the language used in the specification has been principally selected for readability and instructional purposes and may not have been selected to delineate or circumscribe the disclosed subject matter. Accordingly, the present disclosure is intended to be illustrative, and not limiting, of the scope of the concepts discussed herein.Definitions

[0045] Unless otherwise specified, the following terms as used herein shall have the meanings as provided below:

[0046] The term “laminated object manufacturing” (LOM) refers to a method of manufacturing a part, containing additive and subtractive steps, beginning with contiguous sheets of material, and processing sheets sequentially to form a part.

[0047] The term “bonding” refers to the process through which the contiguous sheets of material are formed into a part. The workpiece is subjected to a combination of heat and applied force which form covalent and / or metallic bonds between the sheets of material, forming an object.

[0048] The term “part” refers to a manufactured object.

[0049] The term “single-build part” refers to a part that is manufactured as a unified part in a single manufacturing process.

[0050] The term “workpiece” refers to a stack of metal sheets to be bonded into at least one part and at least one corresponding support structure.

[0051] The term “metal sheet” refers to a metal sheet or foil that is stacked in a workpiece. In some embodiments, the metal sheet may comprise a core layer and / or a clad layer. In some embodiments, the metal sheet may comprise at least one of titanium, aluminum, copper, magnesium, aluminum alloy, magnesium alloy, and / or titanium alloy.

[0052] The term “sheet” refers generally to a metallic layer between 25 pm to 10 cm in thickness.

[0053] The term “void” refers to a volume cut out of a metal sheet which is fully enclosed.

[0054] The term “internal chamber” refers to a fluidically connected void space within a part. An internal chamber may serve as the envelope of a heat pipe or otherwise be charged with a fluid and sealed to serve as a cooling part such as a vapor chamber, heat pipe, or thermosiphon.ALY-017PC

[0055] The term “fluid” refers to any suitable refrigerant that exhibits phase change behavior (e.g. evaporation and condensation) over the desired temperature range of operation of a part. Suitable refrigerants may include water, ammonia, acetone, methanol, ethanol, and / or other specialized refrigerants.Embodiments

[0056] In embodiments of this invention, a single-build part may be formed via a suitable manufacturing process such as an additive manufacturing process. The part may comprise at least one internal chamber configured to carry a fluid. In some embodiments, the part may comprise at least one of a heat pipe, a thermosiphon or a vapor chamber.

[0057] The embodiments described herein may have various benefits over conventional techniques for forming metal parts. For example, as described above, manufacturing cooling devices as single-build parts may remove the limitations of casting design constraints for conventional techniques. Additionally, the described embodiments may reduce manufacturing complexity and eliminate potential misalignment between assembled components.

[0058] Non-limiting examples of these configurations are further discussed below.Part Manufacture

[0059] As described above, metal parts may be formed using a variety of manufacturing processes, such as additive manufacturing processes (e.g., binding jetting, laminated object manufacturing, powder bed fusion, etc.) and / or traditional manufacturing techniques (e.g., machining, casting, stamping, forming, etc.). In some embodiments, a metal part may be formed as a single-build part using a single manufacturing process. The single-build part may be formed without the need for welding and / or soldering components to form any internal and / or surface features.

[0060] In some embodiments, a metal part may be formed using LOM. For example, a workpiece consisting of a plurality of metal sheets may be assembled and bonded to form a metal part. The workpiece may be assembled in a laminated fashion with the metal sheets. The metal sheets may be patterned such that the pattern of the metal sheets partitions the workpiece into at least one support region and at least one part region.

[0061] The metal sheets may be bonded using any suitable bonding method, such as solid-state diffusion bonding, semi-solid state diffusion bonding, and / or transient liquid-phase bonding. The metal sheets may be bonded in a heated press, a more complicated bonding machine comprising a heated press and a vacuum chamber, and / or a bonding machine of any configuration appropriateALY-017PC for laminated object manufacturing of metal parts. The metal sheets may be bonded by applying a mechanical force along at least one axial direction of the metal sheets.

[0062] In some embodiments, each metal sheet may have a unique pattern which comprises a cross-sectional slice of the part. The pattern on each metal sheet (e.g., a pattern of void spaces) may be configured to transmit force through the metal sheets.

[0063] In some embodiments, the metal sheets may be patterned so that material is removed from at least one part region of each metal sheet. This may create a pattern of voids within the workpiece. The voids may be formed via any appropriate cutting technique, such as drag knife cutting, laser cutting, and / or etching. The voids may be formed from regular, geometric patterns and / or random distributions within the part. In some embodiments, the pattern of voids may form larger holes or cavities within the part.Internal Features

[0064] In embodiments of this invention, a metal part may be formed to include at least one internal feature. For example, the metal part may include an internal chamber configured to carry a fluid. The chamber may be formed from at least one void cut within the metal sheets forming the part without the need for any post-forming processes (e.g., bonding and / or shaping). The fluid may be introduced into the chamber prior to, during, and / or after the formation of the part.

[0065] The chamber may include any suitable geometry and / or shape for carrying fluid. For example, the chamber may be cylindrical, rectangular, spherical, and / or elliptical in shape. In some examples, the chamber may include at least one channel that defines a flow path for the fluid, such as a closed-loop flow path, a tortuous or serpentine path, a linear path, a helical path, and / or a radial path from a central cavity.

[0066] In some embodiments, the chamber may include manifolds, ribs, columns, and / or other internal features to partition the chamber into multiple zones. Each zone may be loaded with a different fluid, which may be selected based on its compatibility with its respective zone. At least a portion of the zones may be thermally coupled but fluidically isolated. At least a portion of the zones may include restricted flow paths that control fluid exchange between the zones.

[0067] In some embodiments, the chamber may be fluidically connected to at least one valve for controlling the flow of fluid. The valve may be located at a port or channel connected to the chamber and / or within internal sections of the chamber. In some embodiments, the valve may be a passive valve, such as a check valve (e.g., a Tesla valve), a pressure relief valve (e.g., a burst disc, a spring-loaded relief valve), a flap valve, a weighted ball valve, and / or a reed valve.ALY-017PC

[0068] In some embodiments, capillaries may be formed by cutting narrow channels into the part. The channels may be fluidically connected to the internal chamber, which may promote wicking and capillary flow. In some embodiments, the channels may have the width of a single kerf of the cutting tool. The cuts may be offset on adjacent layers to create capillaries with flow restrictions less than the kerf width of the cutting tool to increase the capillary effect.

[0069] Figure 1 depicts a schematic of a part 100 configured with a capillary 102. The capillary 102 may have a single kerf width-based contact angle for wicking. The capillary 102 may be formed by a series of cuts placed at an offset from a center line that is less than the kerf width of the cutting tool. Figure 1 depicts the curved meniscus of a fluid 104 within the part 100. The meniscus may span a distance less than the kerf width of the cut in a single layer.

[0070] In some embodiments, subsurface capillaries may run parallel along an internal chamber of the part and be fluidically connected at the extreme ends to the internal chamber. Networks of subsurface capillaries may be used to complete an internal flow path within the part. The flow path may comprise the internal chamber, an arbitrary number of subsurface capillaries, and / or manifolds or other fluidic connections between the internal chamber and subsurface capillaries.

[0071] Figure 2A depicts a cross-section of a heat pipe 200 configured with an internal chamber 202 and subsurface capillaries in a collar region 204. Figure 2A depicts the cross-section along the axial line 206. The internal chamber 202 may be cylindrical with two wider end regions 208 that fluidically link to the capillaries within the collar region 204. The capillaries may be configured to fluidically connect across the otherwise solid collar region 204. The internal chamber 202 may be charged with a fluid 210 that submerges at least one terminus of the capillaries. .

[0072] Figure 2B depicts a top-down cross-section of the heat pipe 200. The capillary channels 212 may be cut into the collar region 204. The dashed line depicted in Figure 2B may represent at least one cut on adjacent layers that allows the fluid to flow into the sub-surface capillaries, or capillaries that are disconnected from the main part of the chamber on at least one layer. The subsurface capillaries may have various benefits, such as increasing the cross-sectional area to convey fluid, preventing the vapor phase from pumping the fluid out, and / or increasing the stability of the sheets used to fabricate the heat pipe.

[0073] The part may be configured to use the fluid to function as a passive cooling component, such as a heat pipe, heat sink, thermosiphon, and / or vapor chamber. For example, the fluid may be used in a phase-change heat transfer process. The fluid may absorb thermal energy from a heat source, evaporate to a vapor, move through the internal chamber toward cooler regions of the part,ALY-017PC and condense back into a liquid to release the absorbed heat. The released heat may be dissipated to the surrounding environment. The part may cool any suitable heat source, such as electronic components (e.g., CPUs, GPUs, circuit boards, etc.), battery systems, mechanical equipment (e.g., motors, actuators, etc.), and / or industrial tools.

[0074] In some embodiments, the chamber may allow sequential or staged phase-change mechanisms. For example, a first fluid within a first zone may vaporize at a lower temperature to initiate heat transfer while a second fluid within a second zone may begin vaporizing only once a higher temperature threshold is reached, thereby extending the heat transfer process across a broader temperature range.

[0075] In some embodiments, the interior surfaces of the chamber may be coated with various materials, such as hydrophilic and / or hydrophobic coatings. The coating materials may include silane-based compounds, metal oxides, and / or fluorinated polymer. The materials may be applied using vapor deposition, dip coating, spraying through accessible openings, and / or any other suitable chemical deposition technique. The coating material may be applied during the assembly process, prior to bonding the part.

[0076] In some embodiments, the chamber may be fluidically connected to at least one port and / or any other surface feature for receiving and / or releasing fluid and / or gas. The port may serve as an entry and / or exit point for fluid used for passive cooling. The port may include a valve, septum, and / or other resealable feature that permits fluid to be received or released.

[0077] In some embodiments, the chamber may be sealed during the formation of the port (e.g., during bonding of the part) and / or after the fluid is received. The port may be sealed using any suitable technique such as laser welding, soldering, mechanical crimping, and / or application of a sealant. The port may include a break-off stem, pinch tube, and / or burstable membrane that is severed or collapsed after the port is sealed.

[0078] In some embodiments, the chamber may be fluidically connected to multiple ports that are configured for different purposes. For example, the chamber may be fluidically connected to an inlet port and an outlet port. The inlet port may be configured to receive fluid and the outlet port may be configured to release fluid and / or vapor gas. The inlet port may be located at low points of the part for receiving fluid. The outlet port may be located at high points for gas release.

[0079] In some embodiments, a multi-zoned chamber may use a single port for receiving fluid. In other embodiments, each zone may receive fluid from a separate port.

[0080] In some embodiments, the fluid may be charged to at least one chamber by encapsulating the fluid in a vial. The vial may be comprised of a ceramic material, glass, and / orALY-017PC any other suitable material that does not melt, decompose, or react during the bonding process. The material may be selected to be brittle and may be broken by the impact against the part material after bonding is complete. The vial may be placed within the part during the assembly process (e.g., prior to bonding the part). After bonding, the vial may be sealed within the part.

[0081] In some embodiments, the vial may be shattered against at least one internal wall of the chamber to release the fluid. At least one internal wall of the chamber may be configured with a spike and / or other raised feature to shatter the vial. In some embodiments, the vial may be torn, punctured, split, and / or otherwise opened.

[0082] Figure 3 depicts a cross-section of a heat pipe 300 charged with a fluid in an encapsulated ceramic vial 302. The configuration of the heat pipe 300 may be similar to that of the heat pipe 200. An encapsulated ceramic vial 302 may be inserted into the heat pipe 300 (e.g., during the build process) and filled with a fluid. The encapsulated ceramic vial 302 may be mechanically broken to release the fluid and charge the internal chamber 304. The internal chamber 304 may be sealed to the exterior after the bonding process is complete.

[0083] In some embodiments, the fluid may be selected so that it exhibits phase-change behavior (e.g., evaporation and / or condensation) within the operating temperature range of the part. The selection and quantity of fluid may be selected to achieve a desirable vapor pressure across the operating range of the part, thereby supporting efficient two-phase heat transfer. Appropriate fluids may include, but are not limited to, water, ammonia, acetone, methanol, ethanol, and / or specialized refrigerants.

[0084] In some embodiments, the amount of fluid carried in the chamber may be selected to achieve a desired vapor-to-liquid ratio within the chamber. For example, in heat pipe or vapor chamber configurations, the chamber may be filled to 30 to 70% of its internal volume. This may enable effective phase-change operations while leaving sufficient vapor space to allow for expansion and pressure-driven fluid motion.

[0085] In some embodiments, the part may include at least one internal fin. The fin may be positioned within the chamber and / or at any suitable surface of the part. The fin may be configured to increase heat transfer from at least the heated surface of the part. For example, the fin may increase the effective surface area available for heat transfer, direct and / or regulate fluid flow within the part, and / or enhance thermal coupling between interior surfaces and the fluid.

[0086] In some embodiments, the fin may be formed from at least one metal sheet or layer. For example, the fin may be formed from a single metal sheet. The fin may be formed from fin regions within at least one metal sheet.ALY-017PC

[0087] In some embodiments, the fin may include openings, slots, perforations, and / or other features that enable fluid to pass through or around them. In some embodiments, the fin may include at least one channel. At least one flow path within the fin may be formed from the channel to introduce fluid and / or gas through the fin. The flow path may improve internal convective heat transfer and / or enable secondary thermal regulation.

[0088] In some embodiments, the fin may be structurally attached to only one wall of the chamber, such that the fin extends into the interior volume without cross-support. Any number of such fins may be positioned along at least one surface of the chamber.

[0089] In some embodiments, the fin may serve as a wick to promote heat transfer within the part. The fin may include a porous or micro-textured surface to promote capillary action across its surface. In some embodiments, the fin may include grooves or ridges that function as wicking channels.

[0090] In some embodiments, a foam or other high specific surface area mesh may be encapsulated within at least one internal chamber. The foam may serve as a wick to promote heat transfer within the part. The foam may have a textured surface to promote capillary action across the same surface. The foam may be concentrated in at least one zone or region of the internal chamber (e.g., behind a solid barrier) to promote fluid flow in a desired configuration within the internal chamber.

[0091] Figure 4 depicts a cross-section of a heat pipe 400 with an internal chamber 402 comprising an encapsulated foam 404 to promote wicking. The foam 404 may be concentrated in a region similar to the collar region 204 depicted in Figures 2A and 2B.

[0092] In some embodiments, multiple fins may be arranged in any suitable spatial arrangement. For example, the fins may be interdigitated and / or interleaved. In some examples, the fins may be arranged in parallel arrays, staggered arrays, and / or radial patterns. Adjacent fins may be separated by air gaps, which may be of any suitable thickness, such as the thickness of the fin and / or a single metal sheet (and / or a multiple thereof). In some embodiments, the air gaps may be uniform across an entire array.

[0093] In some embodiments, the chamber may be configured to form a closed loop path, annular path, and / or other tortuous flow path that connects to itself. The flow path may allow fluid circulation between at least one hot surface and at least one cold surface of the part to allow a two- phase heat transfer flow. The flow path may allow the part to function as a heat pipe, with vaporization occurring near the hot surface and condensation near the cold surface.ALY-017PC

[0094] In some embodiments, at least one internal surface of the chamber may be textured with wicking channels. The channels may use capillary action aided by channel geometry and surface tension to pump liquid from cold regions of the part to hot regions. The channels may be formed by patterning slots and / or ridges into at least one metal sheet or layer. The cross-section of the channels may be of any suitable geometry, such as tapered, rounded, trapezoidal, and / or rectangular. At least one dimension of the channels (e.g., a length) may range from 50 to 700 microns.

[0095] In some embodiments, at least one internal surface of the chamber may be textured with nucleation sites to promote boiling in hot regions. The nucleation sites may include microscale cavities, surface textures, and / or surface irregularities that trap small pockets of vapor or gas. The nucleation sites may be formed by patterning slots, ridges, dimples, and / or etching into at least one metal sheet or layer. At least one dimension of the nucleation sites may range from 1 to 100 microns.Part Configurations

[0096] In embodiments of this invention, the part may be configured as a passive cooling part, such as a thermosiphon, vapor chamber, heat sink, and / or heat pipe. The part may use any of the features described herein to passively cool a heat source.

[0097] In some embodiments, the part may be configured as a thermosiphon. The thermosiphon may allow passive heat transfer through gravity-assisted convective circulation of a fluid. The thermosiphon may include an internal chamber containing a fluid having a vapor pressure suitable for phase-change operation within a designed temperature range. When a region of the thermosiphon is exposed to a heat source, the fluid within that heated region may evaporate, forming a vapor that rises toward a cooler region of the chamber. Upon reaching the cooler region, the vapor may condense, releasing latent heat and converting back to a liquid phase. The condensed liquid may return to the heated region under the influence of gravity, thereby completing a thermally driven convective loop.

[0098] Figure 5 depicts a cross-section of a thermosiphon 500. The thermosiphon 500 may include an internal chamber 502 and a port 504. The thermosiphon 500 may be formed as a singlebuild part, such that the chamber 502 and port 504 are formed during the manufacture of the part.

[0099] The thermosiphon 500 may be configured to transfer heat through gravity-assisted convective circulation of a fluid 506 contained in the chamber 502. A region of the chamber 502 may be exposed to a heat source and the fluid 506 may evaporate. As shown by the curved arrows, the fluid 506 may rise to a cooler region of the chamber 502, where it may condense and releaseALY-017PC latent heat. The condensed fluid 506 may return to the heated region (e.g., using a return flow path within the chamber 502).

[0100] In some embodiments, the part may be configured as a vapor chamber. The vapor chamber may include a sealed or sealable enclosure for a fluid. The vapor chamber may be configured to enable rapid two-dimensional heat spreading by allowing the fluid to vaporize at a localized heat source region and condense at other regions within the vapor chamber, thereby redistributing thermal energy laterally across the vapor chamber. The vapor chamber may include at least one fin disposed along at least one interior surface. The fins may serve as wicks to increase heat transfer at the vapor chamber.

[0101] Figure 6 depicts a cross-section of a vapor chamber 600 with as-built wicks 602. The vapor chamber 600 may be formed as a single-build part with an internal cavity, such that the cavity and the wicks 602 are formed during the manufacture of the part.

[0102] As shown, the wicks 602 may be placed along one interior surface of the vapor chamber 600. The wicks 602 may be configured as internal fins that serve to facilitate capillary transport of a fluid within the vapor chamber 600.

[0103] Figure 7 depicts a cross-section of another vapor chamber 700 with as-built wicks 702 and wicks 704. As shown, the wicks 702 and 704 may be placed along two interior surfaces of the chamber 700. The interior surfaces may be opposing and / or adjacent surfaces. As shown, the wicks 702 may be offset from the wicks 704 along a dimension of the vapor chamber 700. The wicks 702 and 704 may be interdigitated or interleaved. In some embodiments, the wicks 702 and 704 may be aligned with each other along a dimension of the vapor chamber 700.

[0104] In some embodiments, the part may be configured to function as a heat pipe, such as a traditional straight heat pipe, loop heat pipe, oscillating heat pipe, and / or pulsating heat pipe. In such configurations, a fluid within the heat pipe may undergo evaporation in a heated region and condensation in a cooler region, with the fluid returning to the heat source via capillary or pressure- driven means.

[0105] Figure 8 depicts a cross-section of an oscillating heat pipe 800. The heat pipe 800 may include a flow path 802 (represented by the bold line) and a port 804. The heat pipe 800 may be formed as a single-build part, such that the flow path 802 and port 804 are formed during the manufacture of the part.

[0106] The flow path 802 may be a closed-loop flow path for passive circulation of a fluid through internal phase change mechanisms. The flow path 802 may be formed from at least one internal chamber and / or channel formed during the manufacture of the heat pipe 800. The portALY-017PC804 may connect to the flow path 802 to receive the fluid for the flow path 802. The port 804 may be sealed after the fluid is loaded into the heat pipe 800.

[0107] In some embodiments, the flow path 802 may traverse multiple regions of the heat pipe 800, such that different portions of the flow path 802 come into contact with hot and cold regions of the heat pipe 800. The heat pipe 800 may passively circulate fluid near the hot and cold regions for transferring heat away from a heat source.

[0108] The oscillating configuration of the heat pipe 800 may require that each z-layer of the part build is fully continuous around the cut space which comprises the flow path and that the structure distributes force during the bonding process without appreciable deformation.

[0109] In some embodiments, the internal chamber may be configured to promote pumpless flow boil wherein the internal volume and associated zones are configured to promote natural convection. The natural convection may be promoted with the vapor pressure of a heated refrigerant acting on at least one pool of condensate. At least four zones may be present in the chamber, with one zone near a heated surface to evaporate the fluid, one zone with a fluid reservoir to condense the fluid, and at least two additional zones fluidically connecting the first two zones. The part may be configured such that the chamber closest to the heated surface is beneath the fluid reservoir with respect to gravity. The process of boiling and evaporating the fluid may generate natural convection, forming a flow loop where vapor is continuously removed from the heat transfer surface through one of the connecting zones and fresh liquid-phase fluid is replenished to the heat transfer surface through a second connecting zone without the use of a pump.

[0110] Pumpless flow boiling structures are often difficult to fabricate in useful geometries with traditional manufacturing methods. Figures 9A and 9B depict exemplary geometries that may be efficiently manufactured using LOM. The geometries may include solid regions and open regions that are radially alternated to create appropriate flow patterns and increase surface area while preserving the stenciling and force transfer necessary for successful LOM fabrication. The solid and open regions may be achieved with a triply-periodic minimal surface (TPMS) such as a gyroid to increase surface area and open area for vapor transfer.

[0111] Figure 9A depicts a cross-section of a passive cooling device 900 configured for pumpless flow boiling. The device 900 may include an internal chamber 902 that is subdivided into several sections by solid part regions 904. A heated surface 906 (e.g., the surface closest to the heat source) may evaporate a fluid 908 within the chamber 902. As shown by the curved arrows, the evaporated fluid 908 may rise through wide channels and condense in the upper zone of the chamber 902. The condensed fluid 908 may become concentrated in a catchment 910, asALY-017PC shown by the downward arrows in the upper zone. The concentrated fluid 908 may return to the heated surface via smaller channels 912, as shown by the downward arrow in the lower zone.

[0112] Figure 9B depicts a cross-section of the lower chamber of the device 900 near the heated surface 906. As described above, the geometry of the device 900 may include the solid part regions 904 radially alternated with open regions 914. To manufacture the device 900 via laminated object manufacturing, the solid part regions 904 may be required to contact the heated surface to distribute force during the bonding process. This may be accomplished by configuring the solid part regions 904 with archways, cusps, channels, and / or other tunnel features that enable the solid part regions 904 and outer housing to be one continuous structure while allowing the flow pattern as described in Figure 9A. Catchments such as the catchment 910 may be configured to collect condensate from wide evaporation channels 916 and return through a smaller channel 918.

[0113] In some embodiments, the chamber may be placed within a structural frame and / or other component of a vehicle, satellite, machine, and / or other structural component manufacturable via laminated object manufacturing. For example, an aeroframe may be manufactured with a hollow chamber that comprises a passive cooling device. Capillary-action wicks may be placed within extremities of the part to promote heat transfer under contoured surfaces.

[0114] Figure 10 depicts a cross-section of a quadcopter frame 1000 comprising a passive cooling device with integrated structural wicks. The solid white region 1002 corresponds to the solid region of the frame 1000. The lined region 1004 corresponds to a network of capillaries contoured to the outer shell of the frame 1000, which may be charged with a fluid to serve as a passive cooling device.

[0115] Figure 11 depicts a flowchart of a method 1100 for forming a single-build part. While Figure 11 shows illustrative operations according to one embodiment, other embodiments may omit, add to, reorder, and / or modify any of the operations shown in Figure 11. As described, the method 1100 may be implemented by any suitable laminated manufacturing system, such as a system including a laminated object manufacturing device and a pressor.

[0116] Operation 1102 may include patterning a plurality of metal sheets so that the metal sheets include a plurality of voids. The voids may be formed by removing material from the metal sheets using any appropriate cutting technique, such as drag knife cutting, laser cutting, and / or etching.

[0117] Operation 1104 may include stacking the patterned metal sheets. The metal sheets may be stacked so that multiple voids and / or other features are aligned with each other.ALY-017PC

[0118] Operation 1106 may include bonding the stacked metal sheets to form the part. A pressor may bond the stacked metal sheets by applying mechanical force and / or heat. The part may be similar to any of the parts described herein. The part may be a passive cooling part configured to transfer heat away from heat sources without the use of powered mechanical devices. The part may include at least one internal chamber formed from at least some of the voids and configured to hold a fluid. The internal chamber may be configured to carry a fluid for passive cooling.Equivalents

[0119] The methods, systems, and devices discussed above are examples. Various configurations may omit, substitute, or add various procedures or components as appropriate. For instance, in alternative configurations, the methods may be performed in an order different from that described, and that various steps may be added, omitted, or combined. Also, features described with respect to certain configurations may be combined in various other configurations. Different aspects and elements of the configurations may be combined in a similar manner. Also, technology evolves and, thus, many of the elements are examples and do not limit the scope of the disclosure or claims.

[0120] Embodiments of the present disclosure, for example, are described above with reference to block diagrams and / or operational illustrations of methods, systems, and computer program products according to embodiments of the present disclosure. The functions / acts noted in the blocks may occur out of the order as shown in any flowchart. For example, two blocks shown in succession may in fact be executed substantially concurrent or the blocks may sometimes be executed in the reverse order, depending upon the functionality / acts involved. Additionally, or alternatively, not all of the blocks shown in any flowchart need to be performed and / or executed. For example, if a given flowchart has five blocks containing functions / acts, it may be the case that only three of the five blocks are performed and / or executed. In this example, any of the three of the five blocks may be performed and / or executed.

[0121] A statement that a value exceeds (or is more than) a first threshold value is equivalent to a statement that the value meets or exceeds a second threshold value that is slightly greater than the first threshold value, e.g., the second threshold value being one value higher than the first threshold value in the resolution of a relevant system. A statement that a value is less than (or is within) a first threshold value is equivalent to a statement that the value is less than or equal to a second threshold value that is slightly lower than the first threshold value, e.g., the second threshold value being one value lower than the first threshold value in the resolution of the relevant system.ALY-017PC

[0122] Specific details are given in the description to provide a thorough understanding of example configurations (including implementations). However, configurations may be practiced without these specific details. This description provides example configurations only, and does not limit the scope, applicability, or configurations of the claims. Rather, the preceding description of the configurations will provide those skilled in the art with an enabling description for implementing described techniques. Various changes may be made in the function and arrangement of elements without departing from the spirit or scope of the disclosure.

[0123] Having described several example configurations, various modifications, alternative constructions, and equivalents may be used without departing from the spirit of the disclosure. For example, the above elements may be components of a larger system, wherein other rules may take precedence over or otherwise modify the application of various implementations or techniques of the present disclosure. Also, a number of steps may be undertaken before, during, or after the above elements are considered.

Claims

ALY-017PCCLAIMSWhat is claimed is:

1. A single-build part formed via an additive manufacturing process, the part comprising at least one internal chamber configured to hold a fluid.

2. The part of claim 1 wherein the part is formed without welding separate components together.

3. The part of claim 1 wherein the fluid is loaded into the internal chamber during or after the formation of the part.

4. The part of claim 1 wherein the part is configured to use the fluid for transferring heat.

5. The part of claim 1 wherein the part comprises a passive valve formed from at least one patterned metal sheet and configured to control the flow of the fluid.

6. The part of claim 1 wherein the part further comprises at least one fin within the chamber, the fin configured to increase heat transfer on at least one surface of the part.

7. The part of claim 1 wherein at least one internal surface of the part is textured with wicking channels configured to transfer the fluid within the part.

8. The part of claim 7 wherein the length of at least one wicking channel is at least 150 microns.

9. The part of claim 1 wherein at least one internal surface of the part is textured with nucleation sites configured to promote evaporation within the part.

10. The part of claim 1 further comprising a plurality of subsurface capillaries fluidically connected to the internal chamber for forming an internal flow path.

11. The part of claim 1 further comprising a breakable vial for releasing the fluid to the internal chamber.ALY-017PC12. The part of claim 1 wherein the internal chamber comprises a foam for promoting capillary action across a surface of the internal chamber.

13. The part of claim 1 wherein the internal chamber comprises a plurality of zones for forming a convection loop using the fluid.

14. The part of claim 1 wherein the part further comprises: a contoured frame; and a plurality of wicking structures placed within at least one extremity of the frame to promote heat transfer under a contoured surface of the frame.

15. A method for forming a single-build part via a laminated manufacturing process, the method comprising: patterning a plurality of metal sheets so that the metal sheets comprise a plurality of voids; stacking the patterned metal sheets; and bonding the stacked metal sheets to form the part, the part comprising at least one internal chamber formed from at least some of the voids and configured to hold a fluid.

16. The method of claim 15 wherein the part is formed without welding separate components together.

17. The method of claim 15 further comprising loading the fluid into the internal chamber during or after the formation of the part.

18. The method of claim 15 wherein at least one internal surface of the part is textured with wicking channels configured to transfer the fluid within the part.

19. The method of claim 15 wherein the part comprises at least one passive valve formed from the patterned metal sheets and configured to control the flow of the fluid.

20. A system for manufacturing a single-build part via a laminated manufacturing process, the system comprising: a laminated object manufacturing device configured to:ALY-017PC pattern a plurality of metal sheets so that the metal sheets comprise a plurality of voids; and stack the patterned metal sheets; and a pressor configured to bond the stacked metal sheets by applying a mechanical force for forming the part, the part comprising at least one internal chamber formed from at least some of the voids and configured to hold a fluid.

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