COOLING A MOLD ASSEMBLY

BACKGROUND

[0001] Rotary drill bits are often used to drill wellbores. One type of rotary drill bit is a fixed-cutter drill bit that has a bit body comprising matrix and reinforcement materials, i.e., a "matrix drill bit" as referred to herein. Matrix drill bits are typically manufactured by placing powder material into a mold and infiltrating the powder material with a binder material, such as a metallic alloy. The various features of the resulting matrix drill bit, such as blades, cutter pockets, and/or fluid-flow passageways, may be provided by shaping the mold cavity and/or by positioning temporary displacement materials within interior portions of the mold cavity. A preformed bit blank (or steel mandrel) may be placed within the mold cavity to provide reinforcement for the matrix bit body and to allow attachment of the resulting matrix drill bit with a drill string. A quantity of matrix reinforcement material (typically in powder form) may then be placed within the mold cavity with a quantity of the binder material.

[0002] The mold is then placed within a furnace and heated to a desired temperature to allow the binder (e.g., metallic alloy) to liquefy and infiltrate the matrix reinforcement material. The furnace typically maintains a desired temperature until the infiltration process is deemed complete, such as when a specific location in the bit reaches a certain temperature. Once the designated process time or temperature has been reached, the mold is then removed from the furnace and begins to rapidly lose heat to its surrounding environment via heat transfer, such as radiation and/or convection in all directions.

[0003] This heat loss continues to a large extent until the mold is moved and placed on a cooling or quench plate and an insulation enclosure or "hot hat" is lowered around the mold. The insulation enclosure drastically reduces the rate of heat loss from the top and sides of the mold while heat is drawn from the bottom of the mold through the cooling plate. This controlled cooling of the mold and the infiltrated matrix bit contained therein can facilitate axial solidification dominating radial solidification, which is loosely termed directional solidification. As the molten material of the infiltrated matrix bit cools, there is a tendency for shrinkage that could result in voids forming within the bit body unless the molten material is able to continuously backfill such voids. In some cases, for instance, one or more intermediate regions within the bit body may sol idify prior to adjacent regions and thereby stop the flow of molten material to locations where shrinkage porosity is developing . In other cases, shrinkage porosity may result in poor metal l urgical bonding at the interface between the bit blank and the molten materials, which can resu lt in the formation of cracks within the bit body that can be difficu lt or impossible to inspect.

[0004] While the mold is positioned on the quench plate, water is often ejected out of one or more nozzles provided in the quench plate to impinge u pon the bottom of the mold and thereby promote directional sol idification . As it contacts the heated mold, however, the water can generate a sig nificant amou nt of steam or vapor that often enters the insu lation enclosure and increases heat transfer from the u pper section of the mold, possibly by wetting the insulation (thereby increasing its conductivity) or by creating or enhancing convective currents inside the insulation enclosu re. This additional cool ing can produce mu ltiple sol idification fronts, which could resu lt in blank bond-l ine cracking, apex cracking, binder-rich zones, bevel cracking, a nd cracking between nozzles.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The following figu res are included to il lustrate certain aspects of the present disclosu re, and shou ld not be viewed as excl usive embodiments.

The subject matter disclosed is capable of considerable modifications, alterations, combinations, and eq uivalents in form and function, without departing from the scope of this disclosu re.

[0006] FIG. 1 is a perspective view of a n exemplary fixed-cutter drill bit that may be fabricated in accordance with the principles of the present disclosu re.

[0007] FIG. 2 is a cross-sectional view of the dril l bit of FIG. 1.

[0008] FIG. 3 is a cross-sectiona l side view of an exemplary mold assembly for use in forming the drill bit of FIG. 1.

[0009] FIGS. 4A-4C are progressive schematic diagrams of a n exemplary method of fabricating a dril l bit.

[0010] FIGS. 5A-5C are partial cross-sectional side views of exemplary thermal sink systems used to cool the mold assembly of FIG. 3. [0011] FIG. 6 is a partial cross-sectional side view of another exemplary thermal sink system used to cool the mold assembly of FIG. 3.

[0012] FIGS. 7A-7C depict exemplary flow channel designs that may be employed in a quench plate.

[0013] FIGS. 8A and 8B are partial cross-sectional side views of additional exemplary thermal sink systems used to cool the mold assembly of FIG. 3.

[0014] FIG. 9 is an isometric view of an exemplary quench plate. DETAILED DESCRIPTION

[0015] The present disclosure relates to downhole tool manufacturing and, more particularly, to thermal sink systems having impermeable quench plates that prevent the influx of steam or vapor during cooling of infiltrated downhole tools.

[0016] The embodiments described herein provide thermal sink systems that may be used to help cool a mold assembly following an infiltration process for an infiltrated downhole tool. The thermal sink systems described herein include a quench plate configured to prevent the mold assembly from being exposed to a thermal fluid that is used to help cool the mold assembly through the quench plate. The thermal fluid may either impinge upon the bottom of the quench plate or flow through one or more flow channels defined through the quench plate to exchange thermal energy with the mold assembly across or through the quench plate via thermal conduction. The impermeable quench plate may prevent any vapor that may be generated from the thermal fluid from escaping into an insulation enclosure placed about the mold assembly and resting on the quench plate. In some cases, the quench plate may include an insert made of a thermally conductive material that accelerates heat transfer between the mold assembly and the thermal fluid through the quench plate.

[0017] FIG. 1 illustrates a perspective view of an example fixed-cutter drill bit 100 that may be fabricated in accordance with the principles of the present disclosure. It should be noted that, while FIG. 1 depicts a fixed-cutter drill bit 100, the principles of the present disclosure are equally applicable to any type of downhole tool that may be formed or otherwise manufactured through an infiltration process. For example, suitable infiltrated downhole tools that may be manufactured in accordance with the present disclosure include, but are not limited to, oilfield drill bits or cutting tools (e.g., fixed-angle drill bits, roller-cone drill bits, coring drill bits, bi-center drill bits, impregnated drill bits, reamers, stabilizers, hole openers, cutters, cutting elements), non-retrievable drilling components, aluminum drill bit bodies associated with casing drilling of wellbores, drill-string stabilizers, cones for roller-cone drill bits, models for forging dies used to fabricate support arms for roller-cone drill bits, arms for fixed reamers, arms for expandable reamers, internal components associated with expandable reamers, sleeves attached to an uphole end of a rotary drill bit, rotary steering tools, logging-while-drilling tools, measurement-while-drilling tools, side-wall coring tools, fishing spears, washover tools, rotors, stators and/or housings for downhole drilling motors, blades and housings for downhole turbines, and other downhole tools having complex configurations and/or asymmetric geometries associated with forming a wellbore.

[0018] As illustrated in FIG. 1, the fixed-cutter drill bit 100 (hereafter "the drill bit 100") may include or otherwise define a plurality of cutter blades 102 arranged along the circumference of a bit head 104. The bit head 104 is connected to a shank 106 to form a bit body 108. The shank 106 may be connected to the bit head 104 by welding, brazing, or other fusion methods, such as using submerged arc or metal inert gas arc welding that results in the formation of a weld 110 around a weld groove 112. The shank 106 may further include or otherwise be connected to a threaded pin 114.

[0019] In the depicted example, the drill bit 100 includes five cutter blades 102, in which multiple recesses or pockets 116 are formed. Cutting elements 118 may be fixedly installed within each pocket 116. This can be done, for example, by brazing each cutting element 118 into a corresponding pocket 116. As the drill bit 100 is rotated in use, the cutting elements 118 engage the rock and underlying earthen materials, to dig, scrape or grind away the material of the formation being penetrated.

[0020] During drilling operations, drilling fluid or "mud" can be pumped downhole through a drill string (not shown) coupled to the drill bit 100 at the threaded pin 114. The drilling fluid circulates through and out of the drill bit 100 at one or more nozzles 120 positioned in nozzle openings 122 defined in the bit head 104. Junk slots 124 are formed between each adjacent pair of cutter blades 102. Cuttings, downhole debris, formation fluids, drilling fluid, etc., may pass through the junk slots 124 and circulate back to the well surface within an annulus formed between exterior portions of the drill string and the inner wall of the wellbore being drilled.

[0021] FIG. 2 is a cross-sectional side view of the drill bit 100 of FIG. 1. Similar numerals from FIG. 1 that are used in FIG. 2 refer to similar components that are not described again. As illustrated, the shank 106 may be securely attached to a metal blank (or mandrel) 202 at the weld 110 and the metal blank 202 extends into the bit body 108. The shank 106 and the metal blank 202 are generally cylindrical structures that define corresponding fluid cavities 204a and 204b, respectively, in fluid communication with each other. The fluid cavity 204b of the metal blank 202 may further extend longitudinally into the bit body 108. At least one flow passageway (shown as two flow passageways 206a and 206b) may extend from the fluid cavity 204b to exterior portions of the bit body 108. The nozzle openings 122 may be defined at the ends of the flow passageways 206a and 206b at the exterior portions of the bit body 108. The pockets 116 are formed in the bit body 108 and are shaped or otherwise configured to receive the cutting elements 118 (FIG. 1).

[0022] FIG. 3 is a cross-sectional side view of a mold assembly 300 that may be used to form the drill bit 100 of FIGS. 1 and 2. While the mold assembly 300 is shown and discussed as being used to help fabricate the drill bit 100, those skilled in the art will readily appreciate that mold assembly 300 and its several variations described herein may be used to help fabricate any of the infiltrated downhole tools mentioned above, without departing from the scope of the disclosure. As illustrated, the mold assembly 300 may include several components such as a mold 302, a gauge ring 304, and a funnel 306. In some embodiments, the funnel 306 may be operatively coupled to the mold 302 via the gauge ring 304, such as by corresponding threaded engagements, as illustrated. In other embodiments, the gauge ring 304 may be omitted from the mold assembly 300 and the funnel 306 may instead be operatively coupled directly to the mold 302, such as via a corresponding threaded engagement, without departing from the scope of the disclosure.

[0023] In some embodiments, as illustrated, the mold assembly 300 may further include a binder bowl 308 and a cap 310 placed above the funnel 306. The mold 302, the gauge ring 304, the funnel 306, the binder bowl 308, and the cap 310 may each be made of or otherwise comprise graphite or alumina (Al ₂ 0 ₃ ), for example, or other suitable materials. An infiltration chamber 312 may be defined or otherwise provided within the mold assembly 300. Materials, such as consolidated sand or graphite, may be positioned within the mold assembly 300 at desired locations to form various features of the drill bit 100 (FIGS. 1 and 2). For example, consolidated sand legs 314a and 314b may be positioned to correspond with desired locations and configurations of the flow passageways 206a, b (FIG. 2) and their respective nozzle openings 122 (FIGS. 1 and 2). Moreover, a cylindrically-shaped consolidated central displacement 316 may be placed on the legs 314a, b. The number of legs 314a, b extending from the central displacement 316 will depend upon the desired number of flow passageways and corresponding nozzle openings 122 in the drill bit 100.

[0024] After the desired materials, including the central displacement 316 and the legs 314a, b, have been installed within the mold assembly 300, matrix reinforcement materials 318 may then be placed within the mold assembly 300. For some applications, two or more different types of matrix reinforcement materials 318 may be deposited in the mold assembly 300. Suitable matrix reinforcement materials 318 include, but are not limited to, tungsten carbide, monotungsten carbide (WC), ditungsten carbide (W ₂ C), macrocrystalline tungsten carbide, other metal carbides, metal borides, metal oxides, metal nitrides, natural and synthetic diamond, and polycrystalline diamond (PCD). Examples of other metal carbides may include, but are not limited to, titanium carbide and tantalum carbide, and various mixtures of such materials may also be used.

[0025] The metal blank 202 may be supported at least partially by the matrix reinforcement materials 318 within the infiltration chamber 312. More particularly, after a sufficient volume of the matrix reinforcement materials 318 has been added to the mold assembly 300, the metal blank 202 may then be placed within mold assembly 300. The metal blank 202 may include an inside diameter 320 that is greater than an outside diameter 322 of the central displacement 316, and various fixtures (not expressly shown) may be used to position the metal blank 202 within the mold assembly 300 at a desired location. The matrix reinforcement materials 318 may then be filled to a desired level within the infiltration chamber 312.

[0026] Binder material 324 may then be placed on top of the matrix reinforcement materials 318, the metal blank 202, and the central displacement 316. Various types of binder materials 324 may be used and include, but are not limited to, metallic alloys of copper (Cu), nickel (Ni), manganese (Mn), lead (Pb), tin (Sn), cobalt (Co), phosphorous (P), and silver (Ag). Various mixtures of such metallic alloys may also be used as the binder material 324. In some embodiments, the binder material 324 may be covered with a flux layer (not expressly shown). The amount of binder material 324 and optional flux material added to the infiltration chamber 312 should be at least enough to infiltrate the matrix reinforcement materials 318 during the infiltration process. In some instances, some or all of the binder material 324 may be placed in the binder bowl 308, which may be used to distribute the binder material 324 into the infiltration chamber 312 via various conduits 326 that extend therethrough. The cap 310 (if used) may then be placed over the mold assembly 300, thereby readying the mold assembly 300 for heating.

[0027] Referring now to FIGS. 4A-4C, with continued reference to FIG. 3, illustrated are schematic diagrams that sequentially illustrate an example method of heating and cooling the mold assembly 300 of FIG. 3, in accordance with the principles of the present disclosure. In FIG. 4A, the mold assembly 300 is depicted as being positioned within a furnace 402. The temperature of the mold assembly 300 and its contents are elevated within the furnace 402 until the binder material 324 liquefies and is able to infiltrate the matrix reinforcement materials 318. Once a specific location in the mold assembly 300 reaches a certain temperature in the furnace 402, or the mold assembly 300 is otherwise maintained at a particular temperature for a predetermined amount of time, the mold assembly 300 is then removed from the furnace 402 and immediately begins to lose heat by radiating thermal energy to its surroundings while heat is also convected away by cooler air outside the furnace 402.

[0028] As depicted in FIG. 4B, the mold assembly 300 may be transported to and set down upon a thermal sink 404. The radiative and convective heat losses from the mold assembly 300 to the environment continue until an insulation enclosure 406 is lowered around the mold assembly 300. The insulation enclosure 406 may be a rigid shell or structure used to insulate the mold assembly 300 and thereby slow the cooling process. In some cases, the insulation enclosure 406 may include a hook 408 attached to a top surface thereof. The hook 408 may provide an attachment location whereby the insulation enclosure 406 may be grasped and/or otherwise attached to for transport. For instance, a chain or wire 410 may be coupled to the hook 408 to lift and move the insulation enclosure 406, as illustrated.

[0029] The insulation enclosure 406 may include an outer frame 412, an inner frame 414, and insulation material 416 arranged between the outer and inner frames 412, 414. In some embodiments, both the outer frame 412 and the inner frame 414 may be made of rolled steel and shaped {i.e., bent, welded, etc.) into the general shape, design, and/or configuration of the insulation enclosure 406. In other embodiments, the inner frame 414 may be a metal wire mesh that holds the insulation material 416 between the outer frame 412 and the inner frame 414. The insulation material 416 may be selected from a variety of insulative materials. In at least one embodiment, the insulation material 416 may be a ceramic fiber blanket, such as INSWOOL® or the like.

[0030] As depicted in FIG. 4C, the insulation enclosure 406 may enclose the mold assembly 300 such that thermal energy radiating from the mold assembly 300 is dramatically reduced from the top and sides of the mold assembly 300 and is instead directed substantially downward and otherwise toward/into the thermal sink 404 or back towards the mold assembly 300. With the insulation enclosure 406 positioned over the mold assembly 300 and the thermal sink 404 in operation, the majority of the thermal energy is transferred through the bottom 418 of the mold assembly 300 and into the thermal sink 404. This controlled cooling of the mold assembly 300 and its contents allows an operator to regulate or control the thermal profile of the mold assembly 300 to a certain extent and may help facilitate directional solidification of the molten contents within the mold assembly 300, where axial solidification of the molten contents dominates radial solidification. Within the mold assembly 300, the face of the drill bit {i.e., the end of the drill bit that includes the cutters) may be positioned at the bottom 418 of the mold assembly 300 and otherwise adjacent the thermal sink 404 while the shank 106 (FIG. 1) may be positioned adjacent the top of the mold assembly 300. As a result, the drill bit 100 (FIGS. 1 and 2) may be cooled axially upward, from the cutters 118 (FIG. 1) toward the shank 106 (FIG. 1). Such directional solidification (from the bottom up) may prove advantageous in reducing the occurrence of voids due to shrinkage porosity, cracks at the interface between the metal blank 202 (FIGS. 2 and 3) and the molten materials, and nozzle cracks. [0031] The thermal sink 404 may comprise a system that includes a quench plate designed to circulate a fluid (e.g., water) at a reduced temperature relative to the mold assembly 300 (i.e., at or near ambient) to draw thermal energy from the mold assembly 300 and into the circulating fluid, and thereby reduce the temperature of the mold assembly 300. The circulating fluid contacts the bottom 418 of the mold assembly 300 and, as a result, vapor may be generated and escape into the interior of the insulation enclosure 406 and thereby increase the heat transfer from the upper portions of the mold assembly 300. As used herein, the term "vapor" refers to any gasified liquid including, but not limited to, water vapor in the form of steam. This additional cooling can produce unwanted solidification fronts within the mold assembly 300, which could result in defects caused by lack of thermal control. The embodiments of the present disclosure describe several concepts for reducing or eliminating the influx of vapor into the interior of the insulation enclosure 406.

[0032] Referring now to FIGS. 5A-5C, illustrated are partial cross- sectional side views of exemplary thermal sink systems 500 that may be used to cool the mold assembly 300, according to one or more embodiments. More particularly, FIG. 5A depicts a first thermal sink system 500a, FIG. 5B depicts a second thermal sink system 500b, and FIG. 5C depicts a third thermal sink system 500c. Each thermal sink system 500a-c may be similar in some respects to the thermal sink 404 described above with reference to FIGS. 4B and 4C. As illustrated, each thermal sink system 500a-c may include a quench plate 502, a table 504 that supports the quench plate 502, and a fluid reservoir 506 disposed below the quench plate 502. The table 504 may provide or otherwise define one or more shoulders 508 configured to receive and support the quench plate 502 above the fluid reservoir 506.

[0033] The mold assembly 300 may be positioned on the quench plate 502 such that the bottom 418 is in direct contact with the upper surface of the quench plate 502, and the insulation enclosure 406 may be disposed about the mold assembly 300 and rest on the quench plate 502. A gap 510 may be defined between the table 504 and the quench plate 502. In some embodiments, the quench plate 502 may exhibit a generally square shape, and the gap 510 may also be square to accommodate the shape of the quench plate 502. In other embodiments, however, the quench plate 502 may exhibit other shapes, such as circular, ovoid, or other polygonal shapes (e.g., rectangular, etc.).

[0034] The quench plate 502 may be configured to prevent exposure of the mold assembly 300 to a thermal fluid 512 used to help cool the mold assembly 300. The thermal fluid 512 may be any suitable fluid or gas including, but not limited to, water, steam, an oil, a coolant (e.g. , glycols), a gas (e.g. , air, carbon dioxide, argon, helium, oxygen, nitrogen), a molten metal, a molten metal alloy, a fluidized bed, or a molten salt. Suitable molten metals or metal alloys used for the thermal fluid 512 may include Pb, Bi, Pb-Bi, K, Na, Na-K, Ga, In, Sn, Li, Zn, or any alloys thereof. Suitable molten salts used for the thermal fluid 512 include alkali fluoride salts (e.g. , LiF-KF, LiF-NaF-KF, LiF-RbF, LiF-NaF- RbF), BeF ₂ salts (e.g. , LiF-BeF ₂ , NaF-BeF ₂ , LiF-NaF-BeF ₂ ), ZrF ₄ salts (e.g. , KF- ZrF ₄ , NaF-ZrF ₄ , NaF-KF-ZrF ₄ , LiF-ZrF ₄ , LiF-NaF-ZrF ₄ , RbF-ZrF ₄ ), chloride-based salts (e.g., LiCI-KCI, LiCI-RbCI, KCI-MgCI ₂ , NaCI-MgCI ₂ , LiCI-KCI-MgCI ₂ , KCI-NaCI- MgCI ₂ ), fluoroborate-based salts (e.g., NaF-NaBF ₄ , KF-KBF ₄ , RbF-RbBF ₄ ), or nitrate-based salts (e.g., NaN0 ₃ -KN0 ₃ , Ca(N0 ₃ ) ₂ -NaN0 ₃ -KN0 ₃ , LiN0 ₃ -NaN0 ₃ - KN0 ₃ ), and any alloys thereof.

[0035] One or more nozzles 514 may be positioned within the fluid reservoir 506 and otherwise configured to eject the thermal fluid 512 such that it impinges on a bottom surface 516 of the quench plate 502. The quench plate 502 may be impermeable to the thermal fluid 512 and otherwise prevent the thermal fluid 512 from coming into direct contact with the mold assembly 300. Instead, the thermal fluid 512 may thermally communicate with the mold assembly 300 across or through the quench plate 502 via thermal conduction and subsequently flow into the fluid reservoir 506 for recycling or disposal. As used herein, the term "thermally communicate," or any variation thereof, refers to the ability to exchange thermal energy between the thermal fluid 512 and the mold assembly 300 and/or its contents, even across the quench plate 502.

[0036] Any vapor that may be generated from contacting the thermal fluid 512 on the bottom surface 516 of the quench plate may either condense into the fluid reservoir 506 or migrate along the bottom surface 516 of the quench plate 502 until eventually locating the gap 510 and escaping into the surrounding environment outside of the insulation enclosure 406. In some embodiments, however, the quench plate 502 may sealingly engage and otherwise form a seal against the shoulder 508 and thereby prevent the efflux of vapor into the surrounding environment. In such embodiments, a pressure- release line (not shown) may be included to relieve any built-up pressure in the fluid reservoir 506 caused by the vapor.

[0037] The insulation enclosure 406 may prevent any escaping vapor from entering the interior 518 of the insulation enclosure 406 and, upon contacting the cooler air of the surrounding environment, some of the vapor may condense and flow back into the fluid reservoir 506 via the gap 510. Furthermore, the interior 518 may be sealed off using an appropriate member between the quench plate 502 and insulation enclosure 406. In such embodiments, the interior 518 may be evacuated to provide a vacuum (and thermal insulation) between the insulation enclosure 406 and the mold assembly 300. Alternatively, the interior 518 may be filled with a controlled atmosphere by flowing in a gas, such as argon or helium, at an elevated temperature to promote directional solidification of the contents of the mold assembly 300 by insulating the upper portions of mold assembly 300 while its bottom portion is cooled via the quench plate 502.

[0038] The quench plate 502 may be made of a variety of materials that help facilitate thermal energy transfer from the mold assembly 300 to the thermal fluid 512. Suitable materials for the quench plate 502 include, but are not limited to, a ceramic (e.g., oxides, carbides, borides, nitrides, silicides), a metal (e.g., steel, stainless steel, nickel, tungsten, titanium or alloys thereof), alumina, graphite, diamond, graphene, and any combination thereof. FIGS. 5A- 5C depict various exemplary designs and configurations of the quench plate 502 that may be employed to help cool the mold assembly 300 while simultaneously isolating the mold assembly 300 from the thermal fluid 512 and any vapor generated therefrom.

[0039] In FIG. 5A, for example, the quench plate 502 may comprise a monolithic slab or block of material having a generally uniform thickness. As illustrated, a single nozzle 514 may be positioned within the fluid reservoir 506 and otherwise configured to eject the thermal fluid 512 such that it impinges on the bottom surface 516 at or near the center of the quench plate 502. As will be appreciated, more than one nozzle 514 may be employed, without departing from the scope of the disclosure.

[0040] In FIG. 5B, the quench plate 502 is depicted as an arched member and otherwise narrowing toward its center. More particularly, the thickness of the quench plate 502 may be g reater at its outer periphery as compared to the center. As will be appreciated, this configuration provides less mass at or near the center of the quench plate 502, thereby al lowing for qu icker heat conduction through the reduced-mass sections. FIG. 5B also il lustrates a pl ural ity of nozzles 514 (three shown) configu red to eject the thermal fl uid 512 such that it impinges on the bottom su rface 516 across a larger area as compared to the single nozzle 514 of FIG. 5A. In another embodiment, the bottom su rface 516 may be designed in conju nction with the nozzles 514 to facilitate attachment of a cooling fil m to the bottom su rface 516, el iminate a vapor bou ndary layer at the bottom surface 516, and/or promote tu rbu lent flow at the interface between the quench plate 502 and the thermal fl uid 512.

[0041 ] In FIG . 5C, the quench plate 502 may provide one or more grooves 520 (three shown) defined into the bottom surface 516 thereof. The grooves 520 may prove advantageous in providing local zones in the quench plate 502 that provide less mass and thereby al low for quicker heat conduction through the quench plate 502 at those areas. Alternatively, or in addition thereto, the grooves 520 may facil itate attached fl u id flow along the bottom surface 516, thereby enhancing the heat-transfer rate. As il lustrated, the thermal sink system 500c may incl ude a nozzle 514 (three shown) a ligned with each groove 520 to eject the thermal fl uid 512 into the grooves 520 and thereby provide for local ly increased heat transfer. Each nozzle 514 may be oriented at a specific angle with respect to the bottom surface 516, such as perpendicular (90°, as shown), 60°, 45°, 30°, 0°, or any orientation within the 0-90° range to optimize fl uid flow and heat transfer via the q uench plate 502 a long bottom surface 516.

[0042] The quench plate 502 design of FIG. 5C may function as a type of heat excha nger, with the thicker portions of the quench plate 502 between the g rooves 520 simu lating or otherwise serving as at type of heat-exchanging fins. As wil l be a ppreciated, various designs and configu rations of the grooves 520 may be integrated into the quench plate 520 as heat-exchang ing features that include, but are not l imited to, protruding knobs, fins, cyl inders, coils, tu bes, bundled tubes, concentric tu bes, plates, corrugated plates, strips, shells, baffles, channels, micro-channels, finned coils, finned plates, finned strips, louvered fins, wavy fins, pin fins, and the l ike, or any combination thereof to ma ke the bottom surface 516 of the quench plate 502 operate as a heat exchanger. Alternatively, such heat-exchanging features may be integrated in other locations on the bottom surface 516 of a quench plate 502 to enhance heat transfer between the quench plate 502 and the fluid reservoir 506.

[0043] Referring now to FIG. 6, with continued reference to FIGS. 5A- 5C, illustrated is a partial cross-sectional side view of another exemplary thermal sink system 600 that may be used to cool the mold assembly 300, according to one or more embodiments. The thermal sink system 600 may be similar in some respects to the thermal sink systems 500a-c of FIGS. 5A-5C, respectively, and therefore may be best understood with reference thereto, where like numerals represent like components not described again in detail. As illustrated, the thermal sink system 600 may include the quench plate 502, the table 504 that supports the quench plate 502, and the fluid reservoir 506 disposed below the quench plate 502. Moreover, the mold assembly 300 may be positioned on the quench plate 502 and the insulation enclosure 406 may be disposed about the mold assembly 300 and rest on the quench plate 502.

[0044] Unlike the thermal sink systems 500a-c of FIGS. 5A-5C, however, the thermal sink system 600 may include one or more flow channels 602 defined within and otherwise through the quench plate 502. As illustrated, the flow channel 602 may extend between an inlet 604a and an outlet 604b, and a nozzle 514 or other type of piping or conduit may be configured to provide the thermal fluid 512 into the flow channel 602 via the inlet 604a. In operation, the thermal fluid 512 may be provided to the inlet 604a and flowed into the flow channel 602 and subsequently exit the flow channel 602 at the outlet 604b where it flows into the fluid reservoir 506 for recycling or disposal. While circulating through the flow channel 602, the thermal fluid 512 may thermally communicate {i.e., exchange thermal energy) with the mold assembly 300 across or through the quench plate 502 via thermal conduction.

[0045] The flow channel 602 may prove advantageous in allowing the thermal fluid 512 to thermally communicate with the mold assembly 300 through the quench plate 502 while simultaneously preventing the thermal fluid 512 from coming into direct contact with the mold assembly 300. Any vapor that may be generated as the thermal fluid 512 circulates through the flow channel 602 may either condense into the fluid reservoir 506 or migrate along the bottom surface 516 of the quench plate 502 until eventually locating the gap 510 and escaping into the surrounding environment outside of the insulation enclosure 406.

[0046] The flow channel 602 defined in the quench plate 502 may exhibit various configurations and designs while isolating the mold assembly 300 from contact with the thermal fluid 512 or vapor generated therefrom. FIGS. 7A-7C, for example, show at least three exemplary designs for the flow channel 602 that may be employed in the quench plate 502 to provide enhanced or more controlled thermal profiles for the mold assembly 300. In FIG. 7A, the flow channel 602 may provide a plurality of branches 702 that extend from a common and/or centralized inlet 604a. Each of the branches 702 may be fed thermal fluid 512 from the central inlet 604a and may terminate in a corresponding outlet 604b.

[0047] In FIG. 7B, the flow channel 602 is depicted as comprising a plurality of flow channels shown as flow channels 602a, 602b, and 602c. Each flow channel 602a-c may be configured to circulate the thermal fluid 512 between an inlet 604a and an outlet 604b. In the illustrated embodiment, the flow channels 602a-c each form a generally angled or triangular flow pathway. It will be appreciated, however, that other designs or configurations of the flow channels 602a-c may alternatively be employed, without departing from the scope of the disclosure. Moreover, while only three flow channels 602a-c are depicted in FIG. 7B (six if the full quench plate 502 were shown past the centerline), it will be appreciated that more or less than three flow channels 502a-c may be employed.

[0048] In FIG. 7C, the flow channel 602 is depicted as a single flow channel 602 that is spiraled or coiled within the quench plate 502. As illustrated, the flow channel 602 may include the inlet 604a located at or near the center of the quench plate 502, and the outlet 604b located adjacent the outer periphery of the quench plate 502. It will be appreciated that several other designs for the flow channel 602 may be possible and are contemplated as being within the scope of the present disclosure.

[0049] Referring now to FIGS. 8A and 8B, illustrated are partial cross- sectional side views of other exemplary thermal sink systems 800 that may be used to cool the mold assembly 300, according to one or more embodiments. More particularly, FIG. 8A depicts a first thermal sink system 800a, and FIG. 8B depicts a second thermal sink system 800b. The thermal sink systems 800a, b may be similar in some respects to the thermal sink systems 500a-c and 600 of FIGS. 5A-5C and 6, respectively, and therefore may be best understood with reference thereto, where like numerals represent like components not described again in detail. As illustrated, each thermal sink system 800a, b may include the quench plate 502, the table 504 that supports the quench plate 502, and the fluid reservoir 506 disposed below the quench plate 502. Moreover, the mold assembly 300 may be positioned on the quench plate 502 and the insulation enclosure 406 may be disposed about the mold assembly 300 and rest on the quench plate 502.

[0050] Unlike the thermal sink systems 500a-c and 600 of FIGS. 5A-5C and 6, however, the quench plate 502 of the thermal sink systems 800a, b may comprise a multi-component structure. More particularly, the quench plate 502 may define an aperture 802 configured to receive and seat an insert 804 that forms part of the quench plate 502. In some embodiments, as illustrated, the aperture 802 may provide a radial shoulder 806 configured to support the insert 804 within the aperture 802 as the quench plate 502 is supported by the table 504 at the shoulder 508. In other embodiments, the aperture 802 may receive the insert 804 via a threaded engagement or the insert 804 may be secured within the aperture 802 using one or more mechanical fasteners (e.g., screws, bolts, snap rings, pins, etc.). The use of a compression fitting may be necessary in some cases to provide a complete seal along the interface between the insert 804 and the quench plate 502. Additionally, an appropriate sealing material or device (e.g., O-ring, etc.) may be positioned between the insert 804 and quench plate 502 to further prevent the thermal fluid 512 or vapor from entering the interior 518. In at least one embodiment, the insert 804 may be permanently bonded to the quench plate 502 using an appropriate method, such as brazing or welding. Moreover, in some embodiments, as illustrated, the aperture 802 may be defined at or near the center of the quench plate 502. In other embodiments, however, the aperture 802 may alternatively be defined off- center, without departing from the scope of the disclosure.

[0051] The insert 804 may be made of a variety of materials configured to provide different thermal properties (e.g., thermal conductivity) intended to produce different thermal profiles in the mold assembly 300 during the cooling process. Suitable materials for the insert 804 include, but are not limited to, a ceramic (e.g., oxides, carbides, borides, nitrides, silicides), a metal (e.g., steel, stainless steel, nickel, copper, tungsten, titanium or alloys thereof), alumina, graphite, and any combination thereof. In some embodiments, the insert 804 and the quench plate 502 may be made of the same material. In other embodiments, however, the insert 804 and the quench plate 502 may be made of dissimilar materials. The material of the insert 804 may prove advantageous in quickly drawing heat out of the mold assembly 300 during operation whereas the material of the quench plate 502 may prove advantageous in retaining heat in the insulation enclosure 406 and/or the interior 518, thereby promoting directional solidification of the mold assembly 300 and its contents.

[0052] As illustrated, the insert 804 in FIG. 8A is smaller than the insert

804 of FIG. 8B. In FIG. 8A, one nozzle 514 is depicted as ejecting the thermal fluid 512 such that it impinges on the bottom surface 516 of the quench plate 502 and, more particularly, on a bottom or underside 808 of the insert 804. In FIG. 8B, a plurality of nozzles 514 (four shown) are depicted as ejecting the thermal fluid 512 such that it impinges on the underside 808 of the insert 804. As the thermal fluid 512 contacts the insert 804, thermal energy may be transferred from the mold assembly 300, through the insert 804, and to the thermal fluid 512.

[0053] Referring now to FIG. 9, with continued reference to the prior figures, illustrated is an isometric view of an exemplary quench plate 900, according to one or more embodiments. The quench plate 900 may be similar in some respects to the quench plate 502 described above, and therefore able to prevent exposure of the mold assembly 300 (FIGS. 5A-5C, 6, 8A-8B) to the thermal fluid 512 (FIGS. 5A-5C, 6, 8A-8B) that is used to cool the mold assembly 300 and any resulting vapor generated by the thermal fluid 512. In the illustrated embodiment, the quench plate 900 may include one or more backstops 902 (shown as backstops 902a, 902b, and 902c) to assist in accurate and repeatable locating of the mold assembly 300 during the transfer process from the furnace 402 (FIG. 4A) to the quench plate 900.

[0054] Three imaginary mold base diameters 904 are depicted on the quench plate 900 as 904a, 904b, and 904c. Each mold base diameter 904a-c corresponds generally to a size of the bottom 418 (FIGS. 5A-5C, 6, 8A-8B) of the mold assembly 300 (FIGS. 5A-5C, 6, 8A-8B), and each mold base diameter 904a-c provides a different design or type of backstop 902 configured to receive and center the mold assembly 300 on the quench plate 900. More particularly, the first and smallest mold base diameter 904a illustrates a first backstop 902a design, the second mold base diameter 904b illustrates a second backstop 902b design, and the third and largest mold base diameter 904c illustrates a third backstop 902c design.

[0055] The first backstop 902a may include or otherwise provide two or more pegs 906 (three shown) positioned at predetermined locations about the circumference of the first mold base diameter 904a and otherwise protruding from the upper surface of the quench plate 900. The pegs 906 may be configured to receive the bottom 418 (FIGS. 5A-5C, 6, 8A-8B) of the mold assembly 300 (FIGS. 5A-5C, 6, 8A-8B) as the mold assembly 300 is moved in the direction A toward the pegs 906. The pegs 906 may be spaced from each other about the circumference of the first mold base diameter 904a such that the mold assembly 300 is received by the pegs 906 and simultaneously concentrically located on the quench plate 900 around the center 908.

[0056] While three pegs 906 are shown, it will be appreciated that more or less {i.e., two) than three pegs 906 can be employed, without departing from the scope of the disclosure. In some embodiments, one or more of the pegs 906 may be inserted into corresponding apertures defined on the upper surface of the quench plate 900. In other embodiments, one or more of the pegs 906 may be threaded into such apertures. In yet other embodiments, one or more of the pegs 906 may penetrate the quench plate 900 and may be secured to the quench plate 900 on its underside, such as through the use of a nut and watertight washer combination.

[0057] The second backstop 902b may include or otherwise provide two or more blocks 910 (three shown) positioned about the circumference of the second mold base diameter 904b and otherwise protruding from the upper surface of the quench plate 900. Similar to the pegs 906, the blocks 910 may be configured to receive the bottom 418 (FIGS. 5A-5C, 6, 8A-8B) of the mold assembly 300 (FIGS. 5A-5C, 6, 8A-8B) as the mold assembly 300 is moved in the direction A toward the blocks 910. The blocks 910 may be spaced from each other about the circumference of the second mold base diameter 904b such that the mold 300 is received by the blocks 910 and simultaneously located on the quench plate 900 at the center 908. While three blocks 910 are shown, it will be appreciated that more or less {i.e., two) than three blocks 910 can be employed, without departing from the scope of the disclosure. In other embodiments, the blocks 910 may be combined into a single arcuate member configured to receive and locate the mold assembly 300 at the center 908. In some embodiments, one or more of the blocks 910 may be inserted into corresponding polygonal apertures defined on the upper surface of the quench plate 900. In other embodiments, one or more of the blocks 910 may be secured to the upper surface of the quench plate 900 using one or more mechanical fasteners, such as screws or bolts that thread into the upper surface of the quench plate 900.

[0058] The third backstop 902c may include an elongate member 912 positioned on the third mold base diameter 904c. While shown in FIG. 9 as generally straight, in at least one embodiment, the elongate member 912 may be curved or otherwise arcuate in shape. In some embodiments, the elongate member 912 may be anchored to the quench plate 900 using one or more mechanical fasteners 914 (one shown in exploded view), such as bolts, screws, pegs, snap rings, etc. In other embodiments, the elongate member 912 may be anchored to the table 504 (FIGS. 5A-5C, 6, 8A-8B) using the same type of mechanical fasteners 916 (one shown in exploded view). The elongate member 912 may be configured to receive the bottom 418 (FIGS. 5A-5C, 6, 8A-8B) of the mold assembly 300 (FIGS. 5A-5C, 6, 8A-8B) as the mold assembly 300 is moved in the direction A toward the elongate member 912. Once the mold assembly 300 is located on the quench plate 900 around the center 908, the elongate member 912 may be removed or otherwise movable, such as via an actuation member, to accommodate the insulation enclosure 406 (FIGS. 5A-5C, 6, 8A-8B) being lowered onto the upper surface of the quench plate 900. In other embodiments, however, the elongate member 912 may be a recessable member, either via an actuation member or with a curved top surface so that the vertical force from the insulation enclosure 406 may force the elongate member 912 to lower.

[0059] As will be appreciated, any of the backstops 902a-c described above may be employed at any of the mold base diameters 904a-c and in any combination, if desired. Moreover, it will be appreciated that the various embodiments described and illustrated herein may be combined in any combination, in keeping within the scope of this disclosure. Indeed, variations in the size and configuration of any of the thermal sink systems described herein may be implemented in any of the embodiments, as generally described herein, without departing from the scope of the disclosure. [0060] Embodiments disclosed herein include:

[0061] A. A thermal sink system that includes a quench plate having an upper surface for receiving a mold assembly to be cooled, and a thermal fluid in thermal communication with the mold assembly via conduction through the quench plate, wherein the quench plate interposes the thermal fluid and the mold assembly and thereby prevents the thermal fluid from contacting the mold assembly.

[0062] B. A method of cooling a mold assembly that includes positioning the mold assembly on an upper surface of a quench plate, placing a thermal fluid in thermal communication with the mold assembly via conduction through the quench plate, and preventing the thermal fluid from contacting the mold assembly with the quench plate.

[0063] Each of embodiments A and B may have one or more of the following additional elements in any combination : Element 1 : wherein the thermal fluid is a fluid selected from the group consisting of water, steam, an oil, a coolant, a gas, a molten metal, a molten metal alloy, a fluidized bed, and a molten salt. Element 2: further comprising a table having a shoulder that receives and supports the quench plate, and a fluid reservoir arranged below the quench plate. Element 3 : wherein the quench plate sealingly engages the table. Element 4: further comprising one or more nozzles arranged to eject the thermal fluid such that the thermal fluid impinges on a bottom surface of the quench plate. Element 5 : wherein the quench plate is arched such that a thickness of the quench plate is greater at an outer periphery as compared to a thickness of the quench plate at a center location. Element 6: further comprising one or more grooves defined in a bottom surface of the quench plate. Element 7: further comprising one or more nozzles arranged to eject the thermal fluid into the one or more grooves. Element 8: further comprising one or more heat- exchanging features defined in a bottom surface of the quench plate. Element 9: further comprising one or more flow channels defined in the quench plate for circulating the thermal fluid. Element 10: wherein the one or more flow channels comprise a plurality of branches extending from a common inlet. Element 11 : wherein the one or more flow channels comprise a single, spiraling flow channel. Element 12: wherein the quench plate defines an aperture and includes an insert receivable into the aperture. Element 13: wherein the insert comprises a thermally conductive material selected from the group consisting of a ceramic, a metal, alumina, graphite, and any combination thereof. Element 14: wherein the insert and the quench plate are made of dissimilar materials. Element 15: further comprising a backstop to locate the mold assembly at a desired location on the upper surface of the quench plate. Element 16: wherein the backstop is at least one of two or more pegs protruding from the upper surface of the quench plate, one or more blocks protruding from the upper surface of the quench plate, an arcuate block member protruding from the upper surface of the quench plate, an elongate member, and an arcuate member. Element 17: further comprising an insulation enclosure that rests on the upper surface of the quench plate and provides an interior for receiving the mold assembly, the quench plate further preventing vapor generated by the thermal fluid from migrating into the interior of the insulation enclosure.

[0064] Element 18: further comprising positioning an insulation enclosure over the mold assembly such that the mold assembly is received into an interior of the insulation enclosure and the insulation enclosure rests on the upper surface of the quench plate, and preventing vapor generated by the thermal fluid from migrating into the interior of the insulation enclosure with the quench plate. Element 19: wherein placing the thermal fluid in thermal communication with the mold assembly comprises ejecting the thermal fluid from one or more nozzles such that the thermal fluid impinges on a bottom surface of the quench plate. Element 20: wherein the bottom surface of the quench plate defines one or more grooves, the method further comprising ejecting the thermal fluid from the one or more nozzles into the one or more grooves. Element 21: wherein the bottom surface of the quench plate defines one or more heat-exchanging features, the method further comprising placing at least one of the thermal fluid and a fluid reservoir in thermal communication with the mold assembly via conduction through the quench plate. Element 22: wherein ejecting the thermal fluid from the one or more nozzles comprises at least one of reducing a vapor boundary layer at the bottom surface of the quench plate, and promoting turbulent flow at the bottom surface of the quench plate. Element 23: wherein placing the thermal fluid in thermal communication with the mold assembly comprises circulating the thermal fluid through one or more flow channels defined in the quench plate. Element 24: wherein the quench plate defines an aperture and includes an insert receivable into the aperture, the method further comprising placing the thermal fluid in thermal commu nication with the mold assembly via conduction through the insert as received in the aperture of the quench plate. Element 25 : wherein positioning the mold assembly on the u pper surface of the quench plate comprises locating the mold assembly at a desired location on the upper su rface of the quench plate with a backstop, wherein the backstop is at least one of two or more pegs protruding from the u pper su rface of the quench plate, one or more blocks protruding from the upper surface of the quench plate, an arcuate block member protruding from the u pper surface of the quench plate, an elongate member, and an arcuate mem ber.

[0065] By way of non-limiting exa mple, exemplary combinations appl icable to A, B, and C incl ude : Element 2 with Element 3 ; Element 6 with Element 7; Element 9 with Element 10; Element 9 with Element 11 ; Element 12 with Element 13 ; Element 12 with Element 14; Element 15 with Element 16; Element 19 with Element 20; Element 19 with Element 21 ; and Element 19 with Element 22.

[0066] Therefore, the disclosed systems and methods are wel l adapted to attain the ends and advantages mentioned as wel l as those that are inherent therein . The particu lar embodiments disclosed above are ill ustrative only, as the teachings of the present disclosu re may be mod ified and practiced in different but equiva lent manners apparent to those skilled in the art having the benefit of the teachings herein. Fu rthermore, no l imitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particu lar il lustrative embodiments disclosed above may be altered, combined, or modified and al l such variations are considered within the scope of the present disclosu re. The systems and methods ill ustratively disclosed herein may su itably be practiced in the absence of any element that is not specifical ly disclosed herein and/or any optional element disclosed herein . While compositions and methods are described in terms of "comprising," "containing," or "incl uding" various components or steps, the compositions and methods can also "consist essential ly of" or "consist of" the various components and steps. Al l nu mbers and ranges disclosed above may vary by some amount. Whenever a numerical range with a lower l imit and an upper limit is disclosed, any number and any incl uded range fal ling within the range is specifically disclosed . In particu lar, every range of values (of the form, "from about a to a bout b," or, equivalently, "from approximately a to b," or, equivalently, "from approximately a-b") disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles "a" or "an," as used in the claims, are defined herein to mean one or more than one of the element that it introduces. If there is any conflict in the usages of a word or term in this specification and one or more patent or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.

[0067] As used herein, the phrase "at least one of" preceding a series of items, with the terms "and" or "or" to separate any of the items, modifies the list as a whole, rather than each member of the list {i.e., each item). The phrase "at least one of" allows a meaning that includes at least one of any one of the items, and/or at least one of any combination of the items, and/or at least one of each of the items. By way of example, the phrases "at least one of A, B, and C" or "at least one of A, B, or C" each refer to only A, only B, or only C; any combination of A, B, and C; and/or at least one of each of A, B, and C.