Syntactic foam parts and related methods of manufacture

Abstract

To provide a syntactic foam component and a corresponding method of making such a component.SOLUTION: The syntactic foam component includes low density spheres with at least one internal distribution media layer. The internal distribution media layer is disposed within the low density sphere and is at a predetermined height. They are encapsulated in a resin. The at least one internal distribution media layer promotes resin flow along the entirety of the at least one distribution media layer before flowing out of the at least one distribution media layer, thus resetting the resin level at the infusion interface during the infusion process.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE

[0001] This disclosure relates generally to lightweight foams, and more particularly to syntactic lightweight foams made of low density spheres embedded in a resin. [Background technology]

[0002]

[0002] Lightweight foams are incorporated into components to facilitate their lightweight nature in higher density fluids. Some components that incorporate lightweight foams include, but are not limited to, submarines, ships, oil rigs and their components, offshore platforms, and other marine-based systems. Typical lightweight foams are compression resistant and, in some cases, water resistant, durable, and reliable. Producing lightweight foams with these properties in an efficient, cost-effective, and reliable manufacturing process can be difficult. Summary of the Invention

[0003]

[0003] The subject matter of the present application was developed in response to the current state of the art, and in particular in response to the shortcomings of conventional lightweight foams and conventional methods of making such lightweight foams. These shortcomings have not yet been fully addressed by currently available technology. Accordingly, the subject matter of the present application was developed to provide syntactic foam parts and corresponding methods of making such parts, which overcome at least some of the shortcomings of the prior art.

[0004]

[0004] Below is a non-exhaustive list of several examples of the subject matter disclosed in this specification, which may or may not be claimed.

[0005]

[0005] A method for making a syntactic foam part is disclosed herein. The method includes loading a first set of low-density spheres into a mold to fill a first section of the mold. The method also includes placing an internal distribution media layer over the first set of low-density spheres in the first section of the mold, the internal distribution media layer defining an injection interface within the mold. The method further includes loading a second set of low-density spheres into the mold to fill a second section of the mold. After filling the mold, the method includes applying a vacuum to the mold by opening a primary vacuum port. The method also includes introducing a first portion of resin into the first section of the mold through a primary resin inlet. After the first portion of resin reaches a predetermined level, the method further includes opening a secondary resin inlet to flow the second portion of resin along the entire internal distribution media layer to introduce a second portion of resin into the second section of the mold from the injection interface. After the second portion of the predetermined amount of resin enters the primary vacuum port, the method includes closing the primary vacuum port. The preceding subject matter of this paragraph characterizes Example 1 of the present disclosure.

[0006]

[0006] The step of applying a vacuum to the mold further includes applying a vacuum to the mold by opening a secondary vacuum port. The secondary vacuum port is disposed between the primary vacuum port and the primary resin inlet and adjacent to the internal distribution media layer. Prior to opening the secondary resin inlet, the method includes closing the secondary vacuum port. The preceding subject matter of this paragraph characterizes Example 2 of the present disclosure, which also includes subject matter according to Example 1 above.

[0007]

[0007] After introducing the first portion of resin and the second portion of resin into the mold, the method includes solidifying the first portion of resin and the second portion of resin. The preceding subject matter of this paragraph characterizes Example 3 of the present disclosure, which also includes subject matter according to Examples 1 or 2 above.

[0008]

[0008] Before loading the low-density spheres into the first section of the mold, the method includes disposing a lower distribution media layer at the bottom of the mold. The lower distribution media layer defines a lower pouring interface, and the inner distribution media layer is disposed above the lower distribution media layer. The preceding subject matter of this paragraph characterizes Example 4 of the present disclosure, which also includes subject matter according to any one of Examples 1 to 3 above.

[0009] After loading the second set of low-density spheres into the second section of the mold, the method includes disposing an upper distribution media layer on top of the second set of low-density spheres in the second section of the mold. The upper distribution media layer defines an upper pouring interface, and the inner distribution media layer is disposed below the upper distribution media layer. The preceding subject matter of this paragraph characterizes examples of the present disclosure, and Example 5 also includes subject matter according to any one of Examples 1 to 4 above.

[0010]

[0010] The inner distribution media layer inhibits migration of low density spheres through the inner distribution media layer. The preceding subject matter of this paragraph characterizes Example 6 of the present disclosure, which also includes subject matter according to any one of Examples 1 to 5 above.

[0011]

[0011] A first portion of the resin is introduced into the bottom of the mold and fills the mold generally from bottom to top. The preceding subject matter of this paragraph characterizes Example 7 of the present disclosure, which also includes subject matter according to any one of Examples 1 through 6 above.

[0012]

[0012] Each one of the first set of low-density spheres in the first section of the mold and the second set of low-density spheres in the second section of the mold has a first flow resistance. The inner distribution media layer has a second flow resistance. The first flow resistance is greater than the second flow resistance. The preceding subject matter of this paragraph characterizes Example 8 of the present disclosure, which also includes subject matter according to any one of Examples 1 to 7 above.

[0013]

[0013] The step of applying a vacuum to the mold by opening the secondary vacuum ports further includes applying a vacuum to the mold from a plurality of secondary vacuum ports. Each secondary vacuum port is positioned adjacent to the internal distribution media layer at spaced locations around the mold. Thereby, each one of the plurality of secondary vacuum ports is positioned adjacent to the internal distribution media layer. The preceding subject matter of this paragraph characterizes Example 9 of the present disclosure, which also includes subject matter according to Example 2 above.

[0014] The method includes actively pushing a first portion of the resin from the bottom of the mold to urge the first portion of the resin to flow generally in a bottom-to-top direction through the mold. The preceding subject matter of this paragraph characterizes Example 10 of the present disclosure, which also includes subject matter according to any one of Examples 1 through 9 above.

[0015]

[0015] The internal distribution media layer includes at least one low resistance flow region. A region of the internal distribution media layer other than the at least one low resistance flow region includes a high resistance flow region. The at least one low resistance flow region has a lower resistance to resin flow compared to the high resistance flow region. This allows a second portion of the resin to flow faster through the at least one low resistance flow region. Opening the secondary resin inlet to flow the second portion of the resin along the entire internal distribution media layer includes causing the second portion of the resin in the at least one low resistance flow region to flow from the at least one low resistance flow region into and fill the high resistance flow region. The preceding subject matter of this paragraph characterizes Example 11 of the present disclosure, which also includes subject matter according to any one of Examples 1 to 10 above.

[0016]

[0016] Further disclosed herein is a syntactic foam component comprising low-density spheres and at least one internal distribution media layer disposed within the low-density spheres at a predetermined height and defining an injection interface. Resin encapsulates the low-density spheres and the at least one internal distribution media layer. The at least one internal distribution media layer is configured to promote resin flow along the entirety of the at least one internal distribution media layer to introduce resin from the at least one internal distribution media layer, thereby resetting the resin level at the injection interface during the injection process. The preceding subject matter of this paragraph characterizes Example 12 of the present disclosure.

[0017] The low-density spheres encapsulated in the resin have a first density, and at least one inner distribution media layer encapsulated in the resin has a second density. The second density is greater than the first density. The preceding subject matter of this paragraph characterizes Example 13 of the present disclosure, which also includes subject matter according to Example 12 above.

[0018]

[0018] The at least one internal distribution media layer includes a plurality of sublayers. Each sublayer is configured to perform at least one of the following functions: inhibiting migration of low-density spheres through the at least one internal distribution media layer, allowing resin to flow through the at least one internal distribution media layer, conducting heat, and conducting electrical current. The preceding subject matter of this paragraph characterizes Example 14 of the present disclosure, which also includes subject matter according to Examples 12 or 13 above.

[0019]

[0019] At least one inner distribution media layer is made of a fibrous material. The preceding subject matter of this paragraph characterizes Example 15 of the present disclosure, which also includes the subject matter of any one of Examples 12 to 14 above.

[0020] At least one internal distribution media layer includes at least one low resistance flow region, and a region of the at least one internal distribution media layer other than the low resistance flow region includes a high resistance flow region. The at least one low resistance flow region has a lower resistance to resin flow compared to the high resistance flow region. This allows the resin to flow faster through the at least one low resistance flow region. The preceding subject matter of this paragraph characterizes Example 16 of the present disclosure, which also includes subject matter according to any one of Examples 12 to 15 described above.

[0021]

[0021] A method for making a syntactic foam part is also disclosed herein. The method includes loading low-density spheres and multiple internal distribution media layers into a mold. Each of the multiple internal distribution media layers is positioned at a predetermined height and defines an injection interface within the mold. The method also includes applying a vacuum to the mold by opening a primary vacuum port and multiple secondary vacuum ports. Each of the multiple secondary vacuum ports is between the primary vacuum port and the primary resin inlet and is positioned adjacent to one of the multiple internal distribution media layers. The method further includes introducing resin into the mold through the primary resin inlet. The method includes sequentially closing each of the multiple secondary vacuum ports when a predetermined amount of resin has entered a corresponding one of the multiple secondary vacuum ports. After a corresponding one of the multiple secondary vacuum ports is closed, the method includes sequentially opening each of the multiple secondary resin inlets to flow the second portion of the resin along the entire corresponding one of the multiple internal distribution media layers to introduce a second portion of the resin into the mold from the corresponding injection interface. The preceding subject matter of this paragraph characterizes Example 17 of the present disclosure.

[0022] The predetermined height of each of the plurality of internal distribution media layers is uniformly arranged in the mold. Thereby, the spacing between adjacent ones of the plurality of internal distribution media layers, the spacing between the bottom of the mold and the first internal distribution media layer, and the spacing between the top of the mold and the highest internal distribution media layer are the same. The preceding subject matter of this paragraph characterizes Example 18 of the present disclosure, and Example 18 also includes the subject matter according to Example 17 above.

[0023] The predetermined height of each of the plurality of internal distribution media layers is non-uniformly arranged in the mold. Thereby, at least one of the spacing between adjacent ones of the plurality of internal distribution media layers, the spacing between the bottom of the mold and the first internal distribution media layer, and the spacing between the top of the mold and the highest internal distribution media layer is different. The preceding subject matter of this paragraph characterizes Example 19 of the present disclosure, and Example 19 also includes the subject matter according to Example 17 above.

[0024] The method includes observing the resin level through at least one transparent window in the mold. The step of sequentially closing each one of the plurality of secondary vacuum ports further includes sequentially closing each one of the plurality of secondary vacuum ports when a predetermined level of resin is observed to be reached. The preceding subject matter of this paragraph characterizes Example 20 of the present disclosure, which also includes subject matter according to any one of Examples 17 to 19 above.

[0025]

[0025] The quantity of the multiple internal distribution media layers can be adjusted based on the desired infusion time of the resin through the mold. The preceding subject matter of this paragraph characterizes Example 21 of the present disclosure, which also includes subject matter according to any one of Examples 17 to 20 above.

[0026] The described features, structures, advantages, and / or characteristics of the presently disclosed subject matter may be combined in any suitable manner in one or more examples and / or embodiments. In the following description, numerous specific details are presented to facilitate a comprehensive understanding of multiple examples of the presently disclosed subject matter. Those skilled in the art will recognize that the presently disclosed subject matter can be practiced without one or more of the specific features, details, components, materials, and / or methods of a particular example or implementation. In other cases, additional features and advantages may be recognized in particular examples and / or implementations, but may not be present in all examples or implementations. Furthermore, in some instances, well-known structures, materials, or steps have not been described or shown in detail so as not to obscure aspects of the presently disclosed subject matter. The features and advantages of the presently disclosed subject matter will become more apparent from the following description and appended claims, or may be learned by practicing the subject matter as described below.

[0027]

[0027] So that the advantages of the present subject matter may be more readily understood, a more detailed description of the subject matter outlined above will be given by reference to specific embodiments illustrated in the accompanying drawings. It will be understood that these drawings, which are not necessarily drawn to scale, depict only certain examples of the subject matter and therefore should not be considered limiting of its scope, and that the subject matter will be described with added specificity and detail using the drawings. [Brief explanation of the drawings]

[0028] [Figure 1A]

[0028] FIG. 1 is a schematic perspective view of a syntactic foam component according to one or more embodiments of the present disclosure. [Figure 1B]

[0029] FIG. 1 is a top view of one embodiment of an internal distribution media layer according to one or more embodiments of the present disclosure. [Figure 1C]

[0030] FIG. 1 is a schematic side elevation view of one embodiment of an inner distribution media layer, according to one or more embodiments of the present disclosure. [Figure 2]

[0031] FIG. 1 is a schematic front elevation view of low density spheres being loaded into a mold in accordance with one or more embodiments of the present disclosure. [Figure 3A]

[0032] FIG. 1 is a schematic front elevation view of a mold before resin is introduced into the mold, in accordance with one or more embodiments of the present disclosure. [Figure 3B]

[0033] FIG. 1 is a schematic graph illustrating a representative penetration height versus time for a syntactic foam part forming process, according to one or more embodiments of the present disclosure. [Figure 4A]

[0034] FIG. 3B is a schematic front elevation view of resin being introduced into the mold of FIG. 3A and beginning to fill, the resin layers below the first internal distribution media layer, and one secondary vacuum port for each internal distribution media layer, in accordance with one or more embodiments of the present disclosure. [Figure 4B]

[0035] FIG. 4B is a schematic front elevation view of the mold of FIG. 4A having two secondary vacuum ports for each inner distribution media layer, according to one or more embodiments of the present disclosure. [Figure 4C]

[0036] FIG. 4B is a schematic front elevation view of the mold of FIG. 4A with a secondary vacuum port for each inner distribution media layer above a corresponding inner distribution media layer, according to one or more embodiments of the present disclosure. [Figure 5]

[0037] FIG. 3B is a schematic front elevation view of resin filling the mold of FIG. 3A, where the resin layer is in a first internal distribution media layer, in accordance with one or more embodiments of the present disclosure. [Figure 6]

[0038] FIG. 3B is a schematic front elevation view of resin filling the mold of FIG. 3A, where the resin layer is in a second, internal distribution media layer, in accordance with one or more embodiments of the present disclosure. [Figure 7]

[0039] FIG. 3B is a schematic front elevation view of resin filling the mold of FIG. 3A, with the resin layer on top of the mold, in accordance with one or more embodiments of the present disclosure. [Figure 8]

[0040] FIG. 1 is a schematic perspective view of a mold for forming a syntactic foam part according to one or more embodiments of the present disclosure. [Figure 9]

[0041] 1 is a schematic flowchart of a method of making a syntactic foam part according to one or more embodiments of the present disclosure. [Figure 10]

[0042] 1 is a schematic flowchart of a method of making a syntactic foam part according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0029]

[0043] When reference is made herein to "one embodiment," "an embodiment," or similar phrases, it means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. The phrases "one embodiment," "an embodiment," and similar phrases appearing throughout this specification may, but do not necessarily, all refer to the same embodiment. Similarly, the term "embodiment" means an embodiment having a particular feature, structure, or characteristic described in connection with one or more embodiments of the present disclosure, but the embodiment may be associated with one or more embodiments unless there is a clear correlation suggesting otherwise.

[0030]

[0044] Some conventional methods for making syntactic foam parts involve adding low-density spheres in a densely packed state into a mold to form a bed of spheres, and then injecting liquid resin into the mold (thereby embedding the spheres). As the resin is injected into the bed of spheres, the injection rate decreases as the path length through the bed of spheres increases. In other words, the injection rate decreases as the distance the resin needs to travel through the bed of spheres increases, or as the height of the part increases. Furthermore, as the density of the bed of spheres increases, it becomes more difficult to infiltrate the bed of spheres with resin, resulting in decreased permeability. Generally, the height of a syntactic foam part is limited due to the long injection time required to embed the bed of spheres. For certain types of low-density spheres, the height of a syntactic foam part is limited to 6 inches. Ultimately, the resin injection rate limits the final height of a syntactic foam part that can be effectively injected for a given resin viscosity and assortment density.

[0031]

[0045] Described herein are several examples of methods for making syntactic foam parts made with low-density spheres embedded in resin that reduce the injection time required to produce the foam. The methods result in syntactic foam parts being formed at a faster injection rate per unit height compared to conventional syntactic foam parts, thereby enabling parts to be produced with greater heights than are feasible with conventional methods. The methods include disposing at least one distribution media layer within the low-density spheres to increase the injection rate within the mold. The distribution media layer, along with a corresponding resin inlet and, in some embodiments, a corresponding vacuum port, reduces the time required to embed the syntactic foam part and allows for the use of a variety of resins, including those with higher viscosity or performance than conventionally used resins.

[0032]

[0046] Referring to FIG. 1A, a syntactic foam component 100 is shown formed using a method such as method 200 described below with reference to FIG. 9. The syntactic foam component 100 includes low-density spheres 126 and at least one internal distribution media layer 110 disposed within the low-density spheres 126. A solidified resin 118 encapsulates the low-density spheres 126 and the at least one internal distribution media layer 110. While depicted as a solid block, the syntactic foam component 100 is comprised of low-density spheres 126 closely packed together, with gaps 134 between adjacent spheres. The gaps 134 are filled with resin 118, as shown by a representative block. The internal distribution media layer 110 is disposed within the low-density spheres 126 at a predetermined height H1, as shown by another representative block. In particular, the syntactic foam component 100 has a final height H2 and includes a first section of low density spheres 126 and a second section of low density spheres 126 separated by an inner distribution media layer 110.

[0033]

[0047] The low-density spheres 126 encapsulated within the resin 118 have a first density. In contrast, the at least one internal distribution media layer 110, also encapsulated within the resin 118, has a second density greater than the first density. In other words, the at least one internal distribution media layer 110 has a higher density than the low-density spheres 126 because it must have free volume to allow resin flow. However, the at least one internal distribution media layer 110 can be designed to strike a balance between density and resin flow, optimizing the material to a density sufficient to promote efficient resin distribution while minimizing the overall weight of the syntactic foam part 100.

[0034]

[0048] At least one internal distribution media layer 110 is positioned at a strategic height (i.e., a predetermined height) within the low-density spheres 126 to increase the infusion rate at the level of the internal distribution media layer 110. That is, the internal distribution media layer 110 is utilized to reset the path length (i.e., resin level) of the resin 118 to the level of the internal distribution media layer 110. This causes the infusion rate to increase with each internal distribution media layer and then gradually decrease as the resin 118 continues to infuse through the low-density spheres 126. Therefore, the number of internal distribution media layers 110 within the syntactic foam component 100 may depend on the final height H2 of the syntactic foam component 100. In some embodiments, the syntactic foam component 100 includes one internal distribution media layer 110, as shown in FIG. 1A. In other embodiments, the syntactic foam component 100 includes at least two internal distribution media layers 110. In still other embodiments, the syntactic foam part 100 can include any number of internal distribution media layers 110 necessary to efficiently infuse the resin through the mold during the infusion process. Furthermore, the at least one internal distribution media layer is configured to promote flow of the resin 118 along the entirety of the at least one internal distribution media layer, thus resetting the resin level at the infusion interface during the infusion process. In some embodiments, the resin 118 flows substantially along the entirety of the at least one internal distribution media layer 110 before flowing out of the at least one internal distribution media layer 110. In other words, the resin 118 flows more rapidly along the at least one internal distribution media layer 110 than through the surrounding spheres. This allows the resin 118 to preferentially flow along the internal distribution media layer 110.

[0035]

[0049] The internal distribution media layer 110 is composed of a material characterized by a high free volume with open spaces within its structure, allowing the internal distribution media layer 110 to be porous to the resin 118. The internal distribution media layer 110 facilitates resin flow through the material because the high free volume provides a path for the resin 118 to travel. Consequently, the resin 118 can flow at a faster rate through the internal distribution media layer 110 compared to flow through the densely packed low-density spheres 126. In other words, the low-density spheres 126 have a first flow resistance, and the internal distribution media layer 110 has a second flow resistance. The first flow resistance is greater than the second flow resistance. This causes the resin to move through the low-density spheres 126 at a slower rate than through the internal distribution media layer 110. To ensure compatibility with the resin 118 used in the syntactic foam component 100, the material of the internal distribution media layer 110 can also be low-density and able to withstand the resin infusion process without compromising functionality, thus allowing the resin 118 to flow through the material. This includes resistance to rapid dissolution and clogging. However, in certain embodiments, the material can be configured to dissolve gradually due to the high temperatures during the infusion process. In some embodiments, dissolution can partially consolidate the internal distribution media layer 110, thereby improving the density of the low-density sphere 126 assortment and increasing the final sphere content and foam density of the syntactic foam component 100. Furthermore, the material of the internal distribution media layer 110 prevents penetration of the low-density spheres 126 during the infusion process because the pores in the internal distribution media layer 110 are sized to prevent the low-density spheres 126 from penetrating through. Thus, the internal distribution media layer 110 inhibits (i.e., prevents) the migration of the low-density spheres 126. This leaves the first set of low density spheres 126 in the first section 106 of the mold 104 (see, eg, FIG. 2).

[0036]

[0050] In certain embodiments, the internal distribution media layer 110 may be made of a fibrous material including a plurality of fibers 111. The internal distribution media layer 110 may be made from any of a variety of fibrous materials, such as carbon fiber, aramid fiber, or thermoplastic fiber (including PES, PEI, PEEK, and other high-performance thermoplastics). The plurality of fibers 111 of the fibrous material may be woven or nonwoven, such as unidirectional or randomly oriented fibers, to form a layer that provides high free volume. Thus, the internal distribution media layer 110 may take various forms, such as nonwoven fabric, woven fabric, felt, continuous fiber, yarn, tow, or chopped fiber. The fibrous nature of the material ensures that the internal distribution media layer 110 maintains structural integrity while providing the necessary pathways for the resin 118 to travel through. Alternatively, the internal distribution media layer 110 may be composed of a non-fibrous material, such as expanded metal foil with a mesh-like pattern that provides high free volume. The material of the inner distribution media layer 110, in some examples, may be a thermally conductive material, such as a metal foil or thermally conductive fabric, to help overcome challenges associated with heating the mold 104 to cure the resin 118 and mitigate heat generation in the resin 118 as it cures. Additionally or alternatively, the material may be an electrically conductive material, such as a conductive fabric or coating, to allow electrical current to flow therethrough.

[0037]

[0051] The internal distribution media layer 110 can have a variety of shapes, including flat, wavy, or corrugated. Furthermore, the internal distribution media layer 110 can be a continuous sheet sized to extend across the entire length and width of the mold 104 at a predetermined height H1. Furthermore, the internal distribution media layer 110 can be a discontinuous sheet, such as an assembly of connecting strips near the resin inlet. Furthermore, in certain embodiments, the internal distribution media layer 110 can be perforated, such as having a series of holes or perforations throughout the layer, allowing the resin 118 to pass through the perforations while maintaining the structural integrity of the layer. For example, the internal distribution media layer 110 can be a perforated metal sheet or foil, which, in some embodiments, can be formed via a stamping process. The internal distribution media layer 110 can be designed to adequately direct resin flow while minimizing layer material to reduce layer density.

[0038]

[0052] As shown in FIG. 1B , in some embodiments, the internal distribution media layer 110 includes at least one low-resistance flow region 151. The at least one low-resistance flow region 151 has a lower resistance to resin flow compared to other regions of the internal distribution media layer 110, referred to as high-resistance flow regions 153. The at least one low-resistance flow region 151 allows for engineered distribution of resin flow to generate a desired supply of resin 118 throughout the internal distribution media layer 110. The resin 118 thereby flows faster through the at least one low-resistance flow region 151 than through the high-resistance flow region 153. For example, the at least one low-resistance flow region 151 may include channels, perforations, or areas having a different material composition that provides lower resistance to resin flow. The at least one low-resistance flow region 151 may be located around or throughout the internal distribution media layer 110 to optimize resin flow and ensure resin distribution throughout the internal distribution media layer 110. In one embodiment, the inner distribution media layer 110 includes a channel portion 150 and a central portion 154. The channel portion 150 is a low resistance flow region 151 that surrounds the outer periphery 152 of the inner distribution media layer 110. The central portion 154 is a high resistance flow region 153, inside the channel portion 150. Because the channel portion 150 has a lower resistance to resin flow than the central portion 154, the resin flows at a faster rate through the channel portion 150, filling the outer periphery 152 of the inner distribution media layer 110 before spreading to the central portion 154.

[0039]

[0053] In some embodiments, the internal distribution media layer 110 is comprised of a single layer. Referring to FIG. 1C , in other embodiments, the internal distribution media layer 110 may have multiple sublayers 113. In this case, each of the multiple sublayers 113 may be configured to perform at least one function of the internal distribution media layer 110. For example, the multiple sublayers 113 may inhibit migration of the low-density spheres 126 through the internal distribution media layer 110, allow resin flow, conduct heat, conduct electrical current, provide structural support, or provide other functions of the internal distribution media layer 110. As shown, the internal distribution media layer 110 includes three sublayers: a first sublayer 113a, a second sublayer 113b, and a third sublayer 113c. However, the internal distribution media layer 110 may include more or fewer than three sublayers 113. Each of the multiple sublayers 113 may be configured to perform the same function, such as all of the sublayers having the same material composition. Alternatively, at least one of the sub-layers may be configured to perform a different function than the other sub-layers. In certain embodiments, some portions of the internal distribution media layer 110 may have more sub-layers 113 than other portions of the internal distribution media layer 110. The number of sub-layers 113 may be used to control the rate of resin flow within a particular portion of the internal distribution media layer 110. For example, referring to FIG. 1B , the flow channel portion 150 may have one or more additional layers than the central portion 154, making the flow channel portion 150 thicker and therefore allowing resin to flow more quickly throughout the flow channel portion 150.

[0040]

[0054] According to some embodiments, a method 200 for making a syntactic foam part, such as the syntactic foam part of FIG. 1A, is shown in FIG. 9. Referring generally to FIG. 9 and particularly to FIG. 2, the method 200 includes loading a first set of low-density spheres 126 into the mold 104 to fill the first section 106 of the mold 104 (block 202). In some embodiments, the mold 104 includes a selectively openable lid that selectively covers an opening in the mold 104 through which the low-density spheres 126 and the inner distribution media layer 110 can be loaded into the mold 104. The low-density spheres 126 are loaded such that the low-density spheres 126 are generally closely packed. That is, the low-density spheres 126 are spaced closely together to minimize spacing between the spheres. Thus, the low-density spheres 126 contact one another to form a stable structure with minimal gaps between adjacent low-density spheres. The gap 134 is defined between one of the low-density spheres 126 and at least one of the following: (1) a second low-density sphere 126, and (2) the inner periphery of the mold 102. However, in some embodiments, the gap 134 between adjacent spheres need not be uniform. While the figures show the low-density spheres 126 in two-dimensional space, it can be understood that when considered in three-dimensional space, the low-density spheres 126 may be arranged to extend into and / or out of the page. Thus, in three-dimensional space, the gap 134 between adjacent ones of the low-density spheres 126 may be defined by a large number of low-density spheres 126, rather than just the two shown. According to some embodiments using spheres distributed in a single size, the low-density spheres 126 are packed into the mold 104 at a maximum of 74%, for example, at a maximum of 69% in one embodiment, and at a maximum of 50% in another embodiment.

[0041]

[0055] The method 200 also includes placing the internal distribution media layer 110 over the first set of low-density spheres 126 in the first section 106 of the mold 104 (block 204). While only two low-density spheres 126 are shown in the mold 104, the first section 106 of the mold 104 may be entirely filled before the internal distribution media layer 110 is placed in the mold 104. The internal distribution media layer 110 is thereby supported by the low-density spheres 126. The internal distribution media layer 110 defines an injection interface 124 within the mold 104. The injection interface 124 designates a level within the mold 104 at which additional resin, such as a second portion of resin, is introduced into the mold 104. Furthermore, the internal distribution media layer 110 separates the first section 106 of the mold 104 from the second section 108 of the mold. In other words, the inner distribution media layer 110 separates a first set of low density spheres 126 in the first section 106 from a second set of low density spheres 126 in the second section 108 .

[0042]

[0056] The method 200 further includes loading a second set of low-density spheres 126 into the mold 104 to fill the second section 108 of the mold 104 (block 206). The second set of low-density spheres 126 are loaded above the internal distribution media layer 110, not shown, so that the internal distribution media layer 110 supports the second set of low-density spheres 126. The second set of low-density spheres 126 are loaded in a closely packed state. In some embodiments, the low-density spheres 126 in the first section 106 and the second section 108 of the mold 104 have the same assortment density. In other embodiments, the low-density spheres 126 in the first section 106 and the second section 108 of the mold 104 can have different assortment densities.

[0043]

[0057] The size and shape of the internal cavity 109 of the mold 104, including the first section 106 and the second section 108 of the mold 104, determine the size and shape of the syntactic foam part 100 (i.e., see FIG. 1 ). Furthermore, in certain embodiments, the size and shape of the internal cavity 109 can be configured to ensure a particular arrangement and / or quantity of low-density spheres 126 are loaded into the mold 104. Thus, the size and shape of the internal cavity 109 can depend on the size of the low-density spheres 126, or vice versa. Note that the low-density spheres 126 and the mold 104 are not necessarily drawn to scale. For example, in the depicted representation, the size of the low-density spheres 126 is abnormally large relative to the size of the mold 104 to more clearly illustrate and explain the present invention. In practice, the size of the low-density spheres 126 will be significantly smaller relative to the size of the mold 104 than depicted. In some embodiments, the maximum diameter D of the low-density spheres 126 is between 5 microns and 153 millimeters (mm), inclusive; for example, in one embodiment, between 20 microns and 10,000 microns, inclusive; in another embodiment, between 25 microns and 5,000 microns, inclusive; for example, in another embodiment, between 250 microns and 35,000 microns, inclusive; and in yet another embodiment, between 500 microns and 1,000 microns, inclusive. In some embodiments, all of the low-density spheres 126 loaded into the mold 104 have the same size. However, in other embodiments, the low-density spheres 126 loaded into the mold 104 may have different sizes and may be loaded into the mold 104 at different times corresponding to their sizes.

[0044]

[0058] According to some embodiments, each or at least one of the low-density spheres 126 is a hollow sphere 128. The hollow sphere 128 has a hollow interior space 129 defined by an inner sidewall 130 that also defines an outer surface 132 of the low-density sphere 126. The hollow sphere 128 has a thin-walled structure. In other words, the thickness T of the sidewall is less than the radius of the low-density sphere 126. In some embodiments, the ratio of the thickness T to the diameter D is between 0.001 and 0.1, inclusive, such as between 0.01 and 0.1, inclusive, in one embodiment, and between 0.02 and 0.08, inclusive, in another embodiment. The hollow sphere 128 may be made of any of a variety of materials, including, but not limited to, glass, ceramic, polymer, or metal.

[0045]

[0059] In alternative embodiments not shown, each or at least one of the low-density spheres 126 is a solid foam sphere. In such embodiments, the solid foam sphere does not have a single hollow space, such as hollow sphere 128. Rather, the solid foam sphere is made of a solid piece of foam having a plurality of hollow spaces in the form of open or closed cells. In some embodiments, the foam of the solid foam sphere is one or more of polystyrene foam, expanded polystyrene (EPS) foam, expanded polypropylene (EPP) foam, polyethylene foam, polyurethane foam, and / or any of various other types of foam. As used herein, in certain embodiments, low-density sphere 126 refers to a sphere having a density of 0.005 g / cm, inclusive. 3 and 0.6 g / cm 3 For example, in one embodiment, 0.05 g / cm 3 and 0.4 g / cm 3 and in another embodiment, 0.1 g / cm 3 and 0.3 g / cm 3 and in yet another embodiment, 0.02 g / cm 3 and 0.15 g / cm 3 and in a further embodiment, 0.015 g / cm 3 and 0.03 g / cm 3 A hollow or solid sphere having a density between .

[0046]

[0060] Although not shown, in some embodiments, the low-density spheres 126 may be pre-coated with a uniform coating before being loaded into a smaller mold. The uniform coating has a consistent (i.e., non-varying) thickness throughout the sphere. The uniform coating may be made of any of a variety of materials, including, but not limited to, preceramic materials, polymers, ceramics, etc. In some cases, such as when the low-density spheres 126 are solid foam spheres, the uniform coating may provide strength and / or enhanced thermal stability to the underlying spheres.

[0047]

[0061] In some embodiments, the low-density spheres 126, when introduced into the internal cavity 109 of the mold 104, occupy at least 50% of the total volume of the internal cavity 109. In some embodiments, the low-density spheres 126 occupy more than 50% and less than 99% of the total volume of the internal cavity 109.

[0048]

[0062] The mold 104 forms a portion of the molding tool 102, which further includes a primary resin inlet 116 and a primary vacuum port 112. The primary resin inlet 116 is operable to introduce resin into the interior cavity 109 of the mold 104. In particular, the primary resin inlet 116 is operable to introduce resin from a resin source (not shown) into the first section 106 of the mold 104. The primary resin inlet 116 may include a valve selectively operable to regulate the flow of resin into the interior cavity 109. In the illustrated embodiments, the primary resin inlet 116 is located at the bottom of the mold 104. In other embodiments, the primary resin inlet 116 may be located at other locations on the mold 104 adjacent the first section 106 of the mold 104.

[0049]

[0063] The primary vacuum port 112 is operable to apply a vacuum to the interior cavity 109 of the mold 104. In particular, the primary vacuum port 112 is connected to a vacuum source (not shown) and is operable to evacuate air and gas from the interior cavity 109 and create a vacuum environment. The vacuum environment helps infuse resin through the low-density spheres 126, remove air pockets, and reduce the risk of voids in the final syntactic foam part. The primary vacuum port 112 may include a valve selectively operable to adjust the vacuum pressure applied to the interior cavity 109. In the illustrated embodiments, the primary vacuum port 112 is located at the top of the mold 104. However, in other embodiments, the primary vacuum port 112 may be located in different locations on the mold 104 to optimize the infusion process based on the particular design and requirements of the molding tool 102. In certain embodiments, the primary resin inlet 116 and the primary vacuum port 112 are located at opposite ends of the mold 104 to aid in efficient flow and uniform distribution of resin throughout the mold 104. This arrangement helps to create a consistent vacuum and draw resin evenly throughout the low density spheres 126 .

[0050]

[0064] The molding tool 102 further includes at least one secondary resin inlet 120 corresponding to each internal distribution media layer 110. The at least one secondary resin inlet 120 is disposed at a position on the molding tool 102 between the primary resin inlet 116 and the primary vacuum port 112 and is operable to introduce a second portion of resin into the mold 104. The at least one secondary resin inlet 120 is disposed adjacent to the internal distribution media layer 110. As used herein, adjacent refers to a position that is either aligned with the internal distribution media layer 110 or disposed slightly above or below the internal distribution media layer 110. In other words, the at least one secondary resin inlet 120 is disposed along a side of the molding tool 102 at a height corresponding to the internal distribution media layer 110. In particular, the secondary resin inlet 120 is operable to introduce resin from a resin source (not shown) at an infusion interface 124. The infusion interface 124 defines the location where resin is introduced into the inner distribution media layer 110 and may be planar or non-planar depending on the configuration of the inner distribution media layer 110. The secondary resin inlet 120 may include a valve to regulate further resin flow during the infusion process.

[0051]

[0065] In some embodiments, the molding tool 102 further includes at least one secondary vacuum port 114 corresponding to each internal distribution media layer 110. The at least one secondary vacuum port 114 is disposed on the molding tool 102 at a position between the primary resin inlet 116 and the primary vacuum port 112 and is operable to apply a secondary vacuum to the molding tool 102. That is, the secondary vacuum port 114 is operable to apply a vacuum to the mold 104 from a position adjacent to a corresponding one of the internal distribution media layers 110. In other words, the secondary vacuum port 114 is disposed along the side of the molding tool 102 at a height corresponding to the internal distribution media layer 110. The secondary vacuum port 114 assists in injecting resin through the mold 104. The secondary vacuum port 114 may also include a valve for selectively adjusting the vacuum pressure.

[0052]

[0066] The method 200 further includes applying a vacuum to the mold 104 by opening the primary vacuum port 112 (block 208). After applying the vacuum to the mold 104, the method 200 includes introducing a first portion of resin into the first section 106 of the mold 104 via the primary resin inlet 116 (block 210). In some embodiments, in which the mold includes only the primary vacuum port 112, the vacuum is applied to the mold 104 exclusively using the primary vacuum port 112. In other embodiments, the vacuum is applied to the mold 104 by the primary vacuum port 112 and at least one secondary vacuum port 114. In these embodiments, the primary vacuum port 112 and the secondary vacuum port 114 cooperate to facilitate injecting the first portion of resin through the mold 104, filling the first section 106 and encapsulating the first set of low-density spheres 126. Because the secondary vacuum port 114 is closest to the primary resin inlet 116 , the first portion of the resin reaches the secondary vacuum port 114 after a certain time interval and begins to be drawn into the secondary vacuum port 114 .

[0053]

[0067] Once the first portion of resin reaches a predetermined level, the method 200 includes opening the secondary resin inlet 120 (block 212) to flow the second portion of resin along the entire interior distribution media layer 110 to introduce the second portion of resin from the infusion interface 124 into the second section 108 of the mold 104. Thus, the second portion of resin resets the path length of the resin at the infusion interface 124, thereby increasing the infusion rate at the infusion interface 124. In some embodiments, the first portion of resin and the second portion of resin are introduced into the mold 104 from the same resin source. In other embodiments, the first portion of resin and the second portion of resin are introduced from different resin sources. For example, the source of the second portion of resin may include a resin that was mixed more recently than the first portion of resin, resulting in a lower viscosity of the second portion of resin due to the resin's increased viscosity as it dwells. In still other embodiments, the first portion of resin and the second portion of resin may be different resins having different properties, such as different cure times or viscosities.

[0054]

[0068] The secondary resin inlet 120 is opened when a first portion of the resin reaches a predetermined level. The predetermined level is set to a level that ensures that the resin has properly filled the corresponding section of the mold 104. In certain embodiments in which the molding tool 102 includes secondary vacuum ports 114 corresponding to each one of the internal distribution media layers 110, the predetermined level is reached when a predetermined amount of resin enters the secondary vacuum port 114 (representing that the first section 106 of the mold 104 has been completely infused with resin). The secondary vacuum port 114 is then closed before the secondary resin inlet 120 is opened in block 212. In other embodiments, the predetermined level is reached when the resin level is visually observed to be at the predetermined level, such as through a transparent window (see, for example, FIG. 8 ). In still other embodiments, the predetermined level is reached when a predetermined time has elapsed. That is, the predetermined level of resin is time-based. The secondary resin inlet 120 can be opened automatically or manually when the predetermined level is reached.

[0055]

[0069] The primary vacuum port 112 facilitates the infusion of the second portion of resin through the remainder of the mold 104, filling the second section 108 and encapsulating the second set of low-density spheres 126. After the predetermined amount of the second portion of resin has entered the primary vacuum port 112, the method 200 further includes closing the primary vacuum port 112 (block 214). Entering the predetermined amount of resin into the primary vacuum port 112 ensures that the second section 108 of the mold 104 is completely infused with resin before the primary vacuum port 112 is closed. The first portion of resin and the second portion of resin are then solidified to form the syntactic foam part 100. Solidifying the resin 118 includes changing the state of the resin 118 from one state to a harder state (e.g., from a flowable or semi-flowable state to a non-flowable state), where such a change changes the resin 118 from a fluid to a solid. According to one embodiment, solidifying the resin 118 includes partially or fully curing or drying the resin 118. Fully curing the resin 118 may include raising the temperature of the resin 118 to a curing temperature of the resin 118. In alternative embodiments, the resin 118 is partially or fully cured through alternative methods, such as radiation treatment of the resin 118 (e.g., ultraviolet treatment, electron beam treatment, x-ray treatment, etc.). In some embodiments, the resin 118 is cured at an injection temperature. As the resin solidifies, its viscosity increases. There is thereby a finite amount of time available for injection of the resin 118 through the mold 104.

[0056]

[0070] In some embodiments, without limitation, the solidification temperature of resin 118 is between 21° C. (i.e., room temperature) and 232° C., inclusive, such as between 21° C. and 180° C., inclusive, in one particular embodiment, between 21° C. and 125° C., inclusive, in another particular embodiment, and between 21° C. and 65° C., inclusive, in yet another particular embodiment. Resin 118 is held at the solidification temperature for a predetermined period of time (and / or resin 118 may undergo multiple identical or different cure cycles associated with particular temperatures and ramp rates) to effect solidification of resin 118.

[0057]

[0071] According to some embodiments, after the resin 118 has solidified, the low density spheres 126, the at least one internal distribution media layer 110, and the resin 118 form the syntactic foam part 100. The method 200 may further include removing the syntactic foam part 100 from the mold 104. After being removed from the mold 104, the syntactic foam part 100 may form a stand-alone part or may be combined with one or more other parts or components to form a larger or more complex part.

[0058]

[0072] 10 generally and 3-7 specifically, another embodiment of a method 300 for making a syntactic foam part 100 is shown. In particular, the method 300 includes loading (block 302) low-density spheres 126 and a plurality of inner distribution media layers 110 into a mold 104. Referring to FIG. 3A, the mold is filled with low-density spheres 126 (not shown) and is then raised to a first predetermined height H1. a a first inner distribution media layer 110a at a second predetermined height H1 b 1 and 2, each layer having a secondary resin inlet 120 and a corresponding one of the secondary vacuum ports 114 adjacent the layer.

[0059]

[0073] In some embodiments, prior to loading the low-density spheres 126 into the mold 104, a lower distribution media layer 142 may be placed on the bottom 136 of the mold 104. This makes the lower distribution media layer 142 the lowest distribution media layer within the mold 104. The lower distribution media layer 142 defines a lower infusion interface 144. Similar to the inner distribution media layer 110, the lower distribution media layer 142 is composed of a high-free-volume material, which allows resin to flow throughout the lower distribution media layer 142 when the resin is introduced through the primary resin inlet 116. In other words, the lower distribution media layer 142 functions to promote uniform initial infusion of resin from the lower infusion interface 144 into the mold 104. In some embodiments, the lower distribution media layer 142 and the inner distribution media layer 110 are composed of the same material composition. In other embodiments, the lower distribution media layer 142 may have a different material composition than the inner distribution media layer 110. For example, the lower distribution media layer 142 may have a material or coating whereby the lower distribution media layer 142 does not permanently adhere to the resin, allowing the lower distribution media layer 142 to be removed from the syntactic foam component 100 prior to use.

[0060]

[0074] Additionally or alternatively, in some embodiments, after filling the mold 104 with the low density spheres 126, the upper distribution media layer 146 may extend beyond the top 138 of the mold 104 or the third predetermined height H1. c The upper distribution media layer 146 may be positioned at a height above the upper injection interface 148, thereby making it the highest distribution media layer within the mold 104. The upper distribution media layer 146 defines the upper injection interface 148. Like the other distribution media layers within the mold 104, the upper distribution media layer 146 is composed of a high free volume material that allows resin to flow efficiently. Additionally, the upper distribution media layer 146 aids in maintaining a uniform vacuum, ensuring that the vacuum is evenly distributed throughout the upper injection interface 148. This even vacuum distribution aids in infusing resin throughout the mold 104. Like the lower distribution media layer 142, the upper distribution media layer 146 may have a material or coating that allows it to be removed from the syntactic foam part 100 prior to use, and may be made from the same or a different material composition.

[0061]

[0075] As shown generally in Figure 10 and particularly in Figure 3A, the method 300 further includes applying a vacuum (block 304) by opening the primary vacuum port 112 and, in some embodiments, the plurality of secondary vacuum ports 114. Each one of the plurality of secondary vacuum ports 114 is located below the primary vacuum port 112 and adjacent to one of the plurality of inner distribution media layers 110. Thus, in a mold having multiple secondary vacuum ports 114, all of the vacuum ports in the mold 104 are opened and a vacuum is applied before resin is introduced into the mold 104.

[0062]

[0076] As shown in FIG. 3B, a graph illustrates a typical penetration height versus infusion time for a syntactic foam part 100 using the mold 104 of FIG. 3A. The graph shows two different infusion rates: the solid line represents the use of two internal distribution media layers 110 and corresponding secondary resin inlets and secondary vacuum ports, as in FIG. 3A, and the dotted line represents the absence of an internal distribution media layer 110, as in existing methods. The starting point of the infusion process in FIG. 3A corresponds to the origin (0,0) on the chart. As shown, the infusion rate represented by the solid line significantly improves penetration height over time. In particular, the internal distribution media layers 110 create low-resistance flow regions that allow the resin to flow more quickly, resulting in cyclical increases in infusion rate corresponding to each internal distribution media layer. In contrast, the existing approach exhibits a slower infusion rate that steadily slows down over time and fails to reach the height indicated within the time frame of the chart. Therefore, the internal distribution media layers of FIG. 3A accelerate the infusion process, achieving a higher penetration height in a shorter time than existing methods.

[0063]

[0077] As shown generally in FIG. 10 and particularly in FIG. 4A , the method 300 includes introducing resin 118 into the mold 104 (block 306). Thus, a first portion of the resin 118 is being introduced into the mold 104. The resin 118 thereby begins to fill a first section of the mold 104 (i.e., the area below the first inner distribution media layer 110a) and the gaps 134 between the low-density spheres 126. Because the mold 104 includes a lower distribution media layer 142, the resin 118 is forced to flow throughout the layer such that the resin 118 is infused from a lower infusion interface 144. When the resin 118 is initially introduced into the mold 104, all vacuum ports are open, actively pulling the resin 118 through the mold 104 via negative pressure. In one embodiment, resin 118 is introduced into mold 104 through primary resin inlet 116 at the bottom 136 of mold 104, and resin 118 flows through mold 104 from bottom 136 of mold 104 to top 138 of mold 104 in a generally bottom-to-top direction (i.e., a direction generally parallel to the directional arrow). In other embodiments, resin 118 may be introduced into mold 104 through a primary resin inlet located at the top of mold 104 and passively gravity-fed through mold 104 in a generally top-to-bottom direction, thereby filling the top section of the mold before any lower sections of the mold. In some embodiments, resin 118 is pumped (i.e., actively pushed) into mold 104 through primary resin inlet 116 via a pump (not shown) in addition to being actively pulled through a vacuum port.

[0064]

[0078] The resin 118 can be any of a variety of resins that help encapsulate and immobilize the low-density spheres 126. According to some embodiments, the resin 118 is one or more of a pure resin material (e.g., epoxy resin), a preceramic resin (e.g., silane preceramic resin), a resin matrix composite (i.e., a reinforcing material embedded within a matrix material), a high modulus polymer (e.g., a highly crosslinked rigid-chain polymer, a nanoparticle-loaded polymer, a colloidal silica nanoparticle-loaded resin), etc. The reinforcing material of a resin matrix composite can be any of a variety of materials, such as fumed silica, nanoparticles, crushed carbon fiber, etc. According to some embodiments, the resin 118 includes a density-reducing component, such as smaller low-density spheres (e.g., glass spheres), which helps reduce the density of the resin 118 without compromising its strength.

[0065]

[0079] 4B , in some embodiments, a plurality of secondary resin inlets 120 correspond to each interior distribution media layer 110. Additionally, in some embodiments, a plurality of secondary vacuum ports 114 also correspond to each one of the plurality of secondary resin inlets 120 of the corresponding interior distribution media layer 110. For example, the first interior distribution media layer 110a has two resin inlets, including a first secondary resin inlet 120a and a third secondary resin inlet 120c, and two corresponding vacuum ports, including a first secondary vacuum port 114a and a third secondary vacuum port 114c, and the second interior distribution media layer 110b has two resin inlets, including a second secondary resin inlet 120b and a fourth secondary resin inlet 120d, and two corresponding vacuum ports, including a second secondary vacuum port 114b and a fourth secondary vacuum port 114d. The placement of multiple secondary resin inlets 120 and multiple secondary vacuum ports 114 at spaced locations around the mold 104 adjacent each internal distribution media layer 110 supports more efficient resin flow and uniform resin distribution through the corresponding internal distribution media layer 110. The addition of multiple secondary resin inlets 120 and secondary vacuum ports 114 per internal distribution media layer can enhance the infusion process for larger syntactic foam parts 100 and allows for greater control over resin flow and vacuum application at various locations on the mold 104.

[0066]

[0080] In some embodiments, as shown in FIG. 4C , a secondary vacuum port 114 may be positioned above a corresponding internal distribution media layer 110, rather than being aligned adjacent to the corresponding internal distribution media layer 110. This positioning allows resin to completely fill the area below the corresponding internal distribution media layer 110 (i.e., see FIG. 5 ) before the corresponding secondary resin inlet opens, thus preventing air from being trapped below the corresponding internal distribution media layer 110. In practice, the secondary resin inlet 120 is opened only after a sufficient amount of resin has exited the corresponding one of the secondary vacuum ports 114, ensuring that the lower section of the mold 104 is fully infused before proceeding with the infusion process.

[0067]

[0081] As generally shown in FIG. 10 , the method 300 includes sequentially closing each one of the plurality of secondary vacuum ports 114 (block 308) when a predetermined amount of resin 118 has entered the corresponding one of the plurality of secondary vacuum ports 114. After the corresponding one of the plurality of secondary vacuum ports 114 is closed, the method 300 further includes sequentially opening each one of the plurality of secondary resin inlets 120 (block 310) to flow the second portion of the resin 118 along the entire corresponding one of the plurality of internal distribution media layers 110 to introduce the second portion of the resin 118 into the mold 104 from the corresponding injection interface 124, as particularly shown in FIGS. 5-7 . While illustrated as having two internal distribution media layers 110, the mold 104 may include three or more internal distribution media layers 110. This may be determined based on the height of the final part. For molds 104 having three or more internal distribution media layers 110, the sequential closing of corresponding secondary vacuum ports 114 and sequential opening of secondary resin inlets 120 may continue until the highest internal distribution media layer 110 is reached. The quantity of multiple internal distribution media layers 110 may be adjusted based on the desired infusion time and / or infusion rate of resin 118 through the mold 104. Additionally, the quantity may be adjusted for the stability of the resin at the infusion temperature to ensure the infusion process is optimized for different resin properties and processing conditions.

[0068]

[0082] As shown in FIG. 5 , resin 118 fills the section of the mold 104 below the first internal distribution media layer 110a (i.e., the first section of the mold), and a predetermined amount of resin 118 enters the first secondary vacuum port 114a. Accordingly, the first secondary vacuum port 114a is closed, and the first secondary resin inlet 120a is opened to introduce a second portion of resin 118 into the mold 104. The resin 118, which may be from the same resin source as the first portion of resin or a different resin source, flows along the entirety of the first internal distribution media layer 110a to introduce the resin 118 from the injection interface 124 into the area above the first internal distribution media layer 110a (i.e., the second section of the mold). In some embodiments, in addition to being actively pulled through the vacuum port, the resin 118 is pumped (i.e., actively pushed) into the mold 104 through the first secondary resin inlet 120a via a pump (not shown). Referring to the graph of FIG. 3B, after the second portion of resin 118 is introduced through injection interface 124, the first predetermined height H1 a The injection rate is increased in

[0069]

[0083] 6, the resin 118 continues to fill the second section of the mold 104 until the resin 118 fills the section of the mold 104 below the second internal distribution media layer 110b and a predetermined amount of the resin 118 enters the second secondary vacuum port 114b. Accordingly, the second secondary vacuum port 114b is closed, and the second secondary resin inlet 120b is opened to introduce a third portion of the resin 118 into the mold 104. The resin 118, which may be from the same or a different resin source as the resin sources of the first and second portions, is flowed along the entire second internal distribution media layer 110b to introduce the resin 118 from the inlet interface 124 into the area above the second internal distribution media layer 110b (i.e., the third section of the mold). Referring to the graph of FIG. 3B, after the third portion of the resin 118 has been introduced from the inlet interface 124, the resin 118 reaches a second predetermined height H1. b The injection rate is increased in

[0070]

[0084] 7 , the resin 118 continues to fill the third section of the mold 104 until the resin 118 fills the entire mold 104 and a predetermined amount of the resin 118 enters the primary vacuum port 112. Therefore, the primary vacuum port 112 is closed. Furthermore, the primary resin inlet 116 and the secondary resin inlets 120 are also closed to stop the flow of resin into the mold 104. The primary resin inlet 116 and all secondary resin inlets 120 can be closed simultaneously at the end of the infusion process. In other words, when opened, all resin inlets actively introduce resin into the mold 104 during the infusion process. In other embodiments, only one resin course actively introduces resin into the mold 104. Thus, the primary resin inlet 116 is closed after the first secondary resin inlet 120a is opened, and the first secondary resin inlet 120a is closed after the second secondary resin inlet 120b is opened.

[0071]

[0085] In some embodiments, the multiple internal distribution media layers 110 of the method 300 can be arranged within the mold 104 in either a uniform or non-uniform manner. When arranged uniformly, the internal distribution media layers 110 are evenly spaced within the mold 104. This means that the spacing between adjacent internal distribution media layers 110, the spacing between the bottom 136 of the mold 104 and the first internal distribution media layer 110a, and the spacing between the top 138 of the mold 104 and the tallest internal distribution media layer 110 are the same. This uniform spacing results in a consistent pour rate between each internal distribution media layer 110. In other embodiments, the internal distribution media layers 110 can be arranged non-uniformly, whereby at least one of the spacing between adjacent internal distribution media layers 110, the spacing between the bottom 136 of the mold 104 and the first internal distribution media layer 110a, and the spacing between the top 138 of the mold 104 and the tallest internal distribution media layer 110 is different. The non-uniform distribution allows for tailoring of the injection rate between the inner distribution media layers 110 to accommodate specific part requirements or to accommodate variations in mold geometry.

[0072]

[0086] As shown in FIG. 8 , according to some embodiments, a molding tool 102 utilized to create a syntactic foam part 100 is depicted. The molding tool 102 includes a mold 104, a primary resin inlet 116, a primary vacuum port 112, at least one secondary resin inlet 120, and at least one secondary vacuum port 114. While the vacuum port and resin inlet are shown extending from the same side of the molding tool 102, the vacuum port and resin inlet may be located in other locations on the molding tool 102, such as on opposite sides of the molding tool 102. In some embodiments, the molding tool 102 includes at least one transparent window 140. The transparent window 140 can be used to observe the level of resin within the mold 104. In some embodiments, closing a secondary vacuum port and / or opening a secondary resin inlet may be based on observing when the level of resin 118 is at a predetermined level. For example, the predetermined level may be past the corresponding secondary vacuum port to avoid trapping air below the corresponding internal distribution media layer 110.

[0073]

[0087] In the above description, certain terms may be used, such as "up," "down," "upper," "lower," "horizontal," "vertical," "left," "right," "over," "under," etc. These terms are used where appropriate to provide some clarity to the description when referring to interrelationships. However, these terms are not intended to imply absolute relationships, positions, and / or orientations. For example, with respect to an object, the "upper" surface may become the "lower" surface simply by turning the object upside down; it is still the same object. Furthermore, the words "including," "comprising," "having," and variations thereof mean "including, but not limited to" (unless expressly stated otherwise). Listed items do not imply that any or all of the items are mutually exclusive and / or inclusive, unless expressly stated otherwise. Terms such as "a," "an," and "the" also refer to "one or more," unless expressly stated otherwise. Additionally, the term "plurality" may be defined as "at least two." Furthermore, unless expressly stated otherwise, as made clear herein, a plurality of a particular feature does not necessarily refer to every particular feature of a particular set or class.

[0074]

[0088] While in some embodiments, the terms "about" or "substantially" are defined to mean within + / - 5% of a given value, in further embodiments, any disclosure of "about" can be further narrowed and claimed to mean within + / - 4% of a given value, within + / - 3% of a given value, within + / - 2% of a given value, within + / - 1% of a given value, or the exact given value. Furthermore, when at least two values ​​of a variable are disclosed, such disclosure is specifically intended to include a range between the two values, whether or not disclosed in terms of separate embodiments or examples thereof, and is specifically intended to include a range up to and including at least the lower of the two values ​​and / or a range up to and including the higher of the two values. Furthermore, when at least three values ​​of a variable are disclosed, such disclosure is specifically intended to include ranges between any two of the values, whether or not they are disclosed with respect to separate embodiments or examples, and is specifically intended to include ranges up to and including at least value A and / or value B, where A can be any of the disclosed values ​​other than the maximum disclosed value, and B can be any of the disclosed values ​​other than the minimum disclosed value.

[0075]

[0089] Furthermore, in this specification, an instance where one element is "coupled" to another element may include direct and indirect coupling. A direct coupling may be defined as one element being connected to another element and being in some contact with the other element. An indirect coupling may be defined as coupling between two elements that are not in direct contact with each other but have one or more additional elements between the coupled elements. Furthermore, in this specification, fixing one element to another element may include direct fixing and indirect fixing. Additionally, in this specification, "adjacent" does not necessarily mean contact. For example, one element may be adjacent to another element without contacting it.

[0076]

[0090] As used herein, the phrase "at least one of" used in conjunction with enumerated items means that various combinations of one or more of the enumerated items may be used, and that only one of each enumerated item may be required. An item may be a specific object, article, or category. In other words, "at least one of" means that any combination or number of items from the list may be used, but not all of the enumerated items may be required. For example, "at least one of item A, item B, and item C" may mean, for example, "item A," "item A and item B," "item B," "item A, item B, and item C," or "item B and item C." In some cases, "at least one of item A, item B, and item C" may mean, by way of example and not limitation, "two item A, one item B, and ten item C," "four item B, and seven item C," or other suitable combinations.

[0077]

[0091] Unless otherwise indicated, the terms "first," "second," etc. are used herein merely as designators and are not intended to impose any sequential, positional, or hierarchical requirements on the items they refer to. Furthermore, a reference to, e.g., a "second" item does not require or exclude the presence of, e.g., a "first" or lower numbered item and / or, e.g., a "third" or higher numbered item.

[0078]

[0092] As used herein, a system, device, structure, article, element, component, or hardware that is "configured to" perform a specified function does not mean that it is, in fact, capable of performing the specified function without any modification and is merely likely to perform the specified function after further modification. In other words, a system, device, structure, article, element, component, or hardware that is "configured to" perform a specified function is specifically selected, created, implemented, utilized, programmed, and / or designed for the purpose of performing the specified function. As used herein, the phrase "configured to" means that there are characteristics of the system, device, structure, article, element, component, or hardware that enable the system, device, structure, article, element, component, or hardware to perform a particular function without further modification. In this disclosure, a system, apparatus, structure, article, element, component, or hardware described as being "configured to" perform a particular function may additionally or alternatively be described as being "adapted to" and / or "operative to" perform that function.

[0079]

[0093] The schematic flow diagrams included herein are generally defined as logical flow diagrams. As such, the depicted order and labeled steps represent one embodiment of the presented method. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more steps, or portions thereof, of the depicted method. Furthermore, it is understood that the format and symbols employed are provided to illustrate the logical steps of the method and do not limit the scope of the method. While various types of arrows and lines may be used in the flow diagrams, it is understood that these do not limit the scope of the corresponding method. In fact, some arrows or other connectors may be used only to indicate the logical flow of the method. For example, arrows may indicate an indefinite amount of waiting or monitoring time between listed steps of the depicted method. Furthermore, the order in which a particular method is performed may or may not strictly follow the order of the corresponding steps depicted.

[0080]

[0094] The subject matter herein may be embodied in other specific forms without departing from its spirit and essential characteristics. The above-described embodiments are to be construed in all respects as merely illustrative and not restrictive. All changes that come within the meaning and range of equivalency of the claims are to be embraced therein.

Claims

1. A method (200) of making a syntactic foam component (100), comprising: loading (202) a first set of low-density spheres (126) into a mold (104) to fill a first section (106) of the mold; disposing (204) an internal distribution media layer (110) on the first set of low-density spheres (126) in the first section (106) of the mold (104), the internal distribution media layer (110) defining a pouring interface (124) within the mold (104); loading (206) a second set of low-density spheres (126) into the mold (104) to fill a second section (108) of the mold (104); applying (208) a vacuum to the mold (104) by opening a primary vacuum port (112); introducing (210) a first portion of resin (118) into the first section (106) of the mold (104) through a primary resin inlet (116); After the first portion of the resin (118) reaches a predetermined level, opening (212) a secondary resin inlet (120) to flow the second portion of the resin (118) along the entire inner distribution media layer (110) to introduce the second portion of the resin (118) from the injection interface (124) into the second section (108) of the mold (104); and The method (200) includes closing (214) the primary vacuum port (112) after a second portion of the predetermined amount of resin (118) enters the primary vacuum port (112).

2. applying a vacuum to the mold (104) by opening a secondary vacuum port (114), the secondary vacuum port (114) being disposed between the primary vacuum port (112) and the primary resin inlet (116) and adjacent the inner distribution media layer (110); and The method (200) of claim 1, further comprising closing the secondary vacuum port (114) before opening the secondary resin inlet (120).

3. 10. The method of claim 1, further comprising solidifying the first portion of the resin and the second portion of the resin after introducing the first portion of the resin and the second portion of the resin into the mold.

4. 2. The method of claim 1, further comprising placing a lower distribution media layer on the bottom of the mold before loading the low-density spheres into the first section of the mold, the lower distribution media layer defining a lower injection interface, and the inner distribution media layer above the lower distribution media layer.

5. 2. The method of claim 1, further comprising, after loading the second set of low-density spheres into the second section of the mold, placing an upper distribution media layer on top of the second set of low-density spheres in the second section of the mold, wherein the upper distribution media layer defines an upper injection interface, and the inner distribution media layer is below the upper distribution media layer.

6. 10. The method (200) of claim 1, wherein the inner distribution media layer (110) inhibits migration of low density spheres (126) through the inner distribution media layer (110).

7. 10. The method of claim 1, wherein a first portion of the resin is introduced into a bottom of the mold and fills the mold in a generally bottom-to-top direction.

8. each one of the first set of low-density spheres (126) in the first section (106) of the mold (104) and the second set of low-density spheres (126) in the second section (108) of the mold (104) has a first flow resistance; The inner distribution media layer (110) has a second flow resistance; The method (200) of claim 1, wherein the first flow resistance is greater than the second flow resistance.

9. 3. The method of claim 2, wherein applying a vacuum to the mold by opening the secondary vacuum ports further comprises applying a vacuum to the mold from a plurality of secondary vacuum ports, each secondary vacuum port positioned adjacent to the internal distribution media layer at spaced apart locations around the mold such that each one of the plurality of secondary vacuum ports is positioned adjacent to the internal distribution media layer.

10. 10. The method of claim 1, further comprising actively pushing a first portion of the resin from a bottom of the mold to urge the first portion of the resin through the mold in a generally bottom-to-top direction.

11. the inner distribution media layer (110) comprises at least one low resistance flow region (151); a region of the inner distribution media layer (110) other than the at least one low resistance flow region (151) comprising a high resistance flow region (153); the at least one low resistance flow region (151) has a lower resistance to the flow of the resin compared to the high resistance flow region (153), such that a second portion of the resin flows faster through the at least one low resistance flow region (151); 2. The method (200) of claim 1, wherein opening the secondary resin inlet (120) to flow a second portion of the resin (118) along the entirety of the internal distribution media layer (110) comprises flowing and filling the second portion of the resin (118) in the at least one low resistance flow region (151) from the at least one low resistance flow region (151) into the high resistance flow region (153).

12. Low density sphere (126), at least one inner distribution media layer (110) disposed within the low density spheres (126) at a predetermined height (H1) and defining an injection interface (124); and a resin (118) encapsulating the low density spheres (126) and the at least one inner distribution media layer (110); The at least one internal distribution media layer (110) is configured to promote flow of the resin (118) along the entirety of the at least one internal distribution media layer (110) to introduce the resin (118) from the at least one internal distribution media layer (110), thus resetting the resin level at the injection interface (124) during the injection process.

13. the low density spheres (126) encapsulated within the resin (118) have a first density; the at least one inner distribution media layer (110) encapsulated within the resin (118) has a second density; 13. The syntactic foam component (100) of claim 12, wherein the second density is greater than the first density.

14. 13. The syntactic foam part (100) of claim 12, wherein the at least one internal distribution media layer (110) includes a plurality of sub-layers (113), each of the plurality of sub-layers (113) configured to perform at least one of the following: inhibit migration of low-density spheres through the at least one internal distribution media layer; allow resin to flow through the internal distribution media layer; conduct heat; and conduct electrical current.

15. The syntactic foam component (100) of claim 12, wherein the at least one inner distribution media layer (110) is made of a fibrous material.

16. the at least one inner distribution media layer (110) comprises at least one low resistance flow region (151); a region of the at least one inner distribution media layer (110) other than the at least one low resistance flow region (151) comprising a high resistance flow region (153); 13. The syntactic foam part (100) of claim 12, wherein the at least one low resistance flow region (151) has a lower resistance to the flow of the resin (118) compared to the high resistance flow region (153), such that the resin (118) flows faster through the at least one low resistance flow region (151).

17. A method (300) of making a syntactic foam component (100), comprising: loading (302) low density spheres (126) and a plurality of internal distribution media layers (110) into a mold (104), each one of the plurality of internal distribution media layers (110) being positioned at a predetermined height (H1) and defining a pouring interface (124) within the mold (104); applying (304) a vacuum to the mold (104) by opening a primary vacuum port (112) and a plurality of secondary vacuum ports (114), each one of the plurality of secondary vacuum ports (114) being between the primary vacuum port (112) and a primary resin inlet (116) and positioned adjacent one of the plurality of internal distribution media layers (110); introducing (306) resin (118) into the mold (104) through the primary resin inlet (116); sequentially closing (308) each one of the plurality of secondary vacuum ports (114) when the predetermined amount of resin (118) reaches a predetermined level; and After a corresponding one of the plurality of secondary vacuum ports (114) is closed, a method (300) includes sequentially opening (310) each one of a plurality of secondary resin inlets (120) to flow a second portion of the resin (118) along the entirety of a corresponding one of the plurality of internal distribution media layers (110) to introduce a second portion of the resin (118) into the mold (104) from the corresponding injection interface (124).

18. 20. The method (300) of claim 17, wherein the predetermined height (H1) of each one of the plurality of internal distribution media layers (110) is uniformly arranged within the mold (104) so ​​that the spacing between adjacent ones of the plurality of internal distribution media layers (110), the spacing between the bottom (136) of the mold (104) and the first internal distribution media layer (110a), and the spacing between the top (138) of the mold (104) and the highest internal distribution media layer (110b) are the same.

19. 20. The method (300) of claim 17, wherein the predetermined height (H1) of each one of the plurality of internal distribution media layers (110) is non-uniformly arranged within the mold (104) such that at least one of the spacing between adjacent ones of the plurality of internal distribution media layers (110), the spacing between the bottom (136) of the mold (104) and the first internal distribution media layer (110a), and the spacing between the top (138) of the mold (104) and the highest internal distribution media layer (110b) is different.

20. 20. The method (300) of claim 17, further comprising observing the level of the resin (118) through at least one transparent window (140) in the mold (104), and wherein sequentially closing each one of the plurality of secondary vacuum ports (114) further comprises sequentially closing each one of the plurality of secondary vacuum ports (114) when the predetermined level of the resin (118) is observed to have been reached.

21. 20. The method (300) of claim 17, wherein the quantity of the plurality of inner distribution media layers (110) is adjustable based on a desired infusion time of the resin (118) through the mold (104).

Images