Multi-component compound products

Abstract

Compositions and methods are provided for fabricating multi-component composite articles using three-dimensionally printed sacrificial tooling. In one embodiment, a multi-component composite article is described that includes: 1) three-dimensionally printing a sacrificial tool from a soluble material; 2) three-dimensionally printing one or more additional materials to create a secondary structure; 3) adding a fluid material to the sacrificial tool and contacting the secondary structure; 4) hardening the fluid material to a solid state; and 5) dissolving the sacrificial tool with a solvent. In another embodiment, the secondary structure is orthogonally soluble, and once orthogonally removed, a voided composite article results. The articles of the present invention have utility in a wide range of industries, including automotive parts, jigs and fixtures, tooling, and aerospace parts.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Application No. 63 / 396,648, filed August 10, 2022, which is hereby incorporated by reference. FIELD OF THE INVENTION

[0002] The present invention relates generally to methods and tools for fabricating complex composite materials. [Background technology]

[0003] The greatest advantage of the additive manufacturing (AM) process, commonly referred to as three-dimensional (3D) printing, is its ability to create complex shapes that would be extremely difficult or cost-prohibitive to produce through other molding methods, such as injection molding, thermoforming, or milling. While this makes AM attractive for producing complex shapes, not all materials can be easily 3D printed. For example, two-component liquid polyurethanes do not layer and rapidly solidify as easily as thermoplastic polylactic acid (PLA) at the same time scale and resolution. For this reason, it is often advantageous to use easily 3D-printable materials as tooling or molds that are subsequently used to shape less easily printable materials. This method can deliver the benefits of both complex part geometries and superior functional material properties in the final product, while also being a time- and cost-efficient process. For example, when considering casting two-component polyurethane materials, molds printed from a fused filament fabrication (FFF) printer can produce parts nearly identical to those from machined aluminum molds, while also being significantly cheaper and faster to produce.

[0004] Another advantage of AM processes is the geometric freedom afforded by layer-by-layer manufacturing. One way "complex designs" are typically implemented is through the use of space-filling infill patterns used in FFF printing. While often hidden behind solid exterior walls, these infill patterns provide structure to FFF parts and can significantly affect extrinsic part properties such as density and stiffness. Some of these infill patterns could be manufactured or machined through non-AM processes, but this would require significant additional design or manufacturing time and result in additional waste material. Conversely, with FFF printing, these infill patterns are often quickly and automatically generated by software, saving both printing time and material usage.

[0005] An additional benefit arises when using soluble 3D printed tools. Because soluble tools sacrifice, complex, multi-part mold designs can be reduced to a single-part mold. Additionally, when using a single-part mold, pickouts and parting lines are eliminated, creating a cleaner molded part.

[0006] FFF-printed water-soluble molds have the potential to mold complex geometries that cannot be produced with simple two-part molds. However, there are two limitations to this concept: 1) molds with significant overhangs cannot be produced, and 2) cast parts tend to be isotropic. The lack of overhangs significantly reduces the potential number of shapes that can be molded using this method.

[0007] In addition to serving as internal structures, infill patterns often also function as external support structures in AM. While support structures are not necessary for all printed features, they are essential for any printed feature that contains overhanging features. In FFF printing without support structures, any overhanging features can be difficult to print because there is no substrate to support the material being deposited as each new layer of material is deposited into the space. When implemented, the support structures act as that substrate, allowing the overhanging features to print cleanly.

[0008] Multi-material AM can be used to create reinforced cylindrical composites with beneficial anisotropic properties. These composites can be fabricated by 3D printing three-layer structures with two materials, with the middle layer designed as a reinforcement. This method requires that both materials in the final composite be 3D printable and that they be printed onto a mandrel substrate, inherently limiting the 3D shapes that can be obtained. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention provides such a method for fabricating a composite using sacrificial tooling. These and other advantages of the present invention, as well as additional inventive features, will become apparent from the description of the invention provided herein. [Means for solving the problem]

[0010] In one aspect, the present disclosure provides a method for fabricating multi-component composite materials using both sacrificial tooling and embedded secondary structures, the design and composition of which can impart unique material properties to the composite.

[0011] In another aspect, the present disclosure provides a method of making a multi-component composite article, comprising: 1) three-dimensionally printing a sacrificial tool from a soluble material; 2) three-dimensionally printing one or more additional materials to create a secondary structure; 3) adding a fluid material to the sacrificial tool and contacting the secondary structure; 4) hardening the liquid material to a solid state; and 5) dissolving the sacrificial tool with a solvent.

[0012] In yet another aspect, the present disclosure provides a method of making an article, comprising: 1) three-dimensionally printing a sacrificial tool from a soluble material; 2) three-dimensionally printing one or more additional materials to create a secondary structure that acts as a support structure for the sacrificial tool; 3) dissolving the secondary structure with a solvent; 4) adding a fluid material to the sacrificial tool and contacting the secondary structure; 4) hardening the liquid material to a solid state; and 5) dissolving the sacrificial tool with a solvent.

[0013] Other aspects, objects and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.

[0014] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects of the invention and, together with the description, serve to explain the principles of the invention. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a three-dimensional model illustrating various secondary structures. [Figure 2] Figure 2 shows three-dimensionally printed AQ120 and PLA molds for fabricating PDMS / PLA composites that exhibit different stiffness in different x, y, and z directions. [Figure 3] Figure 3 shows a three-dimensionally printed mold of AQ120 and black PLA to create a reinforced composite, illustrating the different stiffness in the reinforced and unreinforced sections. [Figure 4]Figure 4 is a three-dimensional printed AQ120 mold for making porous articles. [Figure 5] FIG. 5 is a three-dimensional printed AQ120 mold for making a partially porous article containing hollow gyroid-shaped voided spaces. DETAILED DESCRIPTION OF THE INVENTION

[0016] While the present invention will be described in connection with particular embodiments, it is not intended to limit the invention to those embodiments, but rather to cover all alternatives, modifications, and equivalents included within the spirit and scope of the invention as defined by the appended claims. (Detailed Description of the Invention)

[0017] Unless the context otherwise requires, the following terms shall have the following meanings, applicable to both the singular and the plural:

[0018] The use of the terms "a," "an," and "the" and similar referents in the context of describing the present invention (particularly in the context of the claims that follow) should be construed to encompass both the singular and the plural unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" should be construed as open-ended terms (i.e., meaning "including, but not limited to") unless otherwise noted. The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each and every value falling within the range, unless otherwise indicated herein, and each and every value is incorporated herein as if it were individually set forth herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or clearly contradicted by context. The use of any and all examples or exemplary language (e.g., "such as") provided herein is intended merely to further clarify the invention and does not limit the scope of the invention unless specifically claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0019] The terms "additive manufacturing," "three-dimensional printing," "3D printing," or "3D printed" refer to any process used to create three-dimensional objects in which successive layers of material are formed under computer control (e.g., electron beam melting (EBM), fused filament fabrication (FFF), material jetting, thin film deposition modeling (LOM), selective laser sintering (SLS), and stereolithography (SL)).

[0020] The term "backfilling" refers to the process of pouring or injecting a second fluid material into the voids of a hardened first fluid material.

[0021] The term "curing" refers to the process of converting a fluid material into a solid material by chemical reaction or by the addition or removal of an external source of energy (e.g., heat, moisture, electricity, sound, actinic radiation).

[0022] The term "dissolving" refers to the process of dissolving a material (eg, a sacrificial tool) with a solvent.

[0023] The term "flowable material" refers to a material in a flowable state that can be utilized to fill a sacrificial tool and encapsulate a secondary structure. The flowable material solidifies once cured and does not dissolve upon removal / dissolution of the sacrificial tool, resulting in a multi-component composite article.

[0024] The term "infill" refers to a software-generated, space-filling structure that fills the interior volume of the shape you want to print. Infill often contains void space and can take the form of many different types of structures.

[0025] The term "multi-component composite article" refers to a material having at least one additional material therein that has been three-dimensionally printed.

[0026] The term "orthogonally soluble" refers to a combination of two materials in which each material is soluble in one solvent system and insoluble in the solvent system of the other material in the combination.

[0027] The term "sacrificial tool" refers to a three-dimensional printed structure having a hollow cavity that can be filled with a liquid material and dissolved after the liquid material has hardened to a solid state.

[0028] The term "secondary structure" refers to a three-dimensional printed structure that is printed simultaneously with and / or placed in contact with a sacrificial tool, and that is in contact with and / or encapsulated in a liquid material to create a three-dimensional structure that does not dissolve upon removal / dissolution of the sacrificial tool.

[0029] The term "slicing software" refers to software used to digitally convert 3D digital files (often in .stl file format) into instructions (often in .gcode file format) that can be read by a 3D printer.

[0030] The term "support material" or "support structure" refers to material that is printed in three dimensions using an additive manufacturing process to physically support or support a printed part during 3D printing, and that can be removed after the additive manufacturing process.

[0031] The term "voided composite article" means a composite resulting from the removal of secondary structure from a multi-component composite article (whether by physical removal or removal by dissolution, chemical decomposition, or exposure to energy / actinic radiation).

[0032] The recitation of numerical ranges using endpoints includes all numbers subsumed within that range (eg, 1 to 5 includes 1, 1.5, 3, 3.95, 4.2, 5, etc.).

[0033] This disclosure defines a method for fabricating unique composites with embedded reinforcements that combine both printed sacrificial tooling and designed infill patterns. The process for fabricating multi-component composite articles includes: 1) three-dimensionally printing a sacrificial tool from a soluble material; 2) three-dimensionally printing one or more additional materials to create a secondary structure; 3) adding a fluid material to the sacrificial tool and contacting the secondary structure; 4) curing the fluid material to a solid state; and 5) dissolving the sacrificial tool with a solvent.

[0034] The tool may take the form of a mold and may include typical mold features such as a basin, sprue, runners, and gates. To print the sacrificial roots, any 3D printing method useful for printing thermoplastic materials can be utilized. Non-limiting examples of 3D printing methods include Fused Filament Fabrication (FFF), Selective Laser Sintering (SLS), Selective Toner Electrophotographic Lamination (STEP), and Powder Bed Fusion Bonding.

[0035] The sacrificial tool may be made from any 3D-printable, soluble material. Water-soluble materials can be used due to their ease of use and the non-toxic nature of water. Non-limiting examples of water-soluble materials useful in the present invention include polymers and copolymers of polyalkylene glycols, polyalkylene oxides, sulfopolyester salts, polyoxazolines, polyvinylpyrrolidones, and polyvinyl alcohols. In addition to water-soluble materials, materials that dissolve or decompose in acidic or basic solutions or solvents may also form the sacrificial tool. Non-limiting examples of materials that can dissolve or decompose in acidic or basic solutions useful in the present invention include polymers and copolymers of polyacrylic acid, polymethacrylic acid, polyalkyl acrylates and methacrylates, polyesters, polyethers, and polycarbonates. Non-limiting examples of materials that can be dissolved or decomposed in polyalkylacrylic solvents useful in the present invention include polymers and copolymers of polyacrylates, polymethacrylates, polystryenics, polycarbonates, polyesters, polyethers, polysiloxanes, polyacrylonitrile-styrene-butadiene copolymers, polyolefins, and polyamides. As long as the material is sufficiently dissolved, decomposed, swelled, or weakened to be removed from the multi-component composite article, it may be used to form the sacrificial tool.

[0036] Secondary structures can take a variety of shapes and be composed of a variety of materials. A simple way to generate secondary structure configurations is by adjusting the "infill" settings in the Cura software. Secondary structures can take the form of Grid, Lines, Triangle, Tri-Hexagon, Cubic, Cubic Subdivision, Octet, Quarter Cubic, Concentric, Zig Zag, Cross, Cross 3D, Gyroid, or Lightning infill patterns, all of which are available through Cura, or can take the form of custom, hand-designed structures. Figure 1 illustrates various secondary structures. 102 illustrates a secondary structure in the form of Triangles. Reference numeral 104 illustrates a secondary structure in the form of a grid. Reference numeral 106 illustrates a secondary structure in the form of lines. Reference numeral 108 illustrates a secondary structure in the form of a cross. Reference numeral 110 illustrates a secondary structure in the form of a gyroid. Reference numeral 112 illustrates a secondary structure in the form of a tri-hexagon. Each structure will have distinct advantages and disadvantages as a reinforcement material, and one structure may be preferable over another depending on the intended function of the final composite. Secondary structures can also be produced with various volumetric filling levels. For example, a 20% infill density will create a looser structure than an 80% infill density, and therefore the material properties of the secondary structure will dominate the composite properties to a greater extent at 80% infill compared to 20%.

[0037] The secondary structure can be any type of insoluble polymeric material, including, but not limited to, polymers, copolymers, and blends of polyesters, polyolefins, polyamides, polycarbonates, polyarylethers, polyethers, polyacrylates, and polymethacrylates. The secondary structure can be a material that does not swell, weaken, or otherwise change when exposed to water, although certain hydrophilic materials (such as polyesters and polyamides) can be used as the secondary structure.

[0038] In some embodiments, the secondary structure is an orthogonally soluble material, meaning that it dissolves or disintegrates in a solvent, acidic solution, or basic solution that does not dissolve the primary soluble tool. In such embodiments, the first soluble material can be a water-soluble polymer, and the orthogonally soluble material dissolves in the solvent. For example, Aquasys General Purpose is a suitable water-soluble polymer, and high-impact polystyrene (HIPS) is a suitable orthogonally soluble polymer. Aquasys General Purpose is soluble in water but not in limonene. Conversely, HIPS is soluble in limonene but not in water. As another example, Aquasys General Purpose and acrylonitrile-butadiene-styrene (ABS) can be used as orthogonally soluble polymers. ABS is readily soluble in acetone but not in water. Aquasys General Purpose is insoluble in acetone. The combination of two orthogonally soluble materials allows for selective dissolution, allowing one material to dissolve before the other.

[0039] The flowable material can be a variety of materials, including, but not limited to, thermoplastic polymers, thermosetting polymer precursor mixtures, thermoplastic powders, metals, etc. In embodiments using meltable thermoplastics, metals, or powders, a requirement for these materials is that they have a sufficiently low melting point so as not to deform or degrade the sacrificial tool and secondary structure. Non-limiting examples of thermosetting polymers include epoxies, polysiloxanes, polyurethanes, and polyesters. Non-limiting examples of thermoplastic polymers and thermoplastic powders include polyolefins, polyamides, polyesters, thermoplastic elastomers, polycarbonates, fluoropolymers, polyarylethers, and polyethers. Non-limiting examples of metal powders include titanium, aluminum, stainless steel, copper, silver, and gold. In some embodiments, low-viscosity, liquid flowable materials can be used to achieve rapid and complete filling of the sacrificial tool. In other embodiments, the flowable material can be selected for its ability to be unaffected by solvents and dissolution processes.

[0040] Various fillers can be added to the sacrificial tool along with the flowable material. In light of the present disclosure, one or more fillers can be selected to improve mechanical and thermal properties for a desired application, including, for example, lowering the coefficient of thermal expansion of the letdown product. Non-limiting examples of fillers include inorganic and organic fillers, including carbonates, silicates, talc, mica, wollastonite, clay, silica, alumina, carbon fiber, carbon black, carbon nanotubes, graphite, graphene, volcanic ash, expanded volcanic ash, perlite, glass fiber, solid glass microspheres, hollow glass microspheres, cenospheres, ceramics, and conventional cellulosic materials, including wood flour, wood fiber, sawdust, shavings, newsprint, paper, flax, hemp, wheat straw, rice husks, kenaf, jute, sisal, peanut shells, soybean hulls, or any cellulose-containing material.

[0041] In some embodiments, the filler used in combination with the flowable material may include one or more lightweight fillers, non-limiting examples of which include hollow glass microspheres, cenospheres, perlite, and expanded volcanic ash.

[0042] The flowable material may be added to the sacrificial tool by pouring or injection. In some embodiments, the flowable material has a low enough viscosity so that it quickly fills the cavities of the sacrificial tool. In other embodiments, a pressurized injection is required to fill the tool with the flowable material within the time frame before curing begins.

[0043] In some embodiments, the secondary structure will be present when the fluent material is added. In other embodiments, the secondary structure is dissolved or otherwise removed before the fluent material is added. In embodiments where a secondary structure is present, the fluent material must contact a portion of the secondary structure before hardening. The secondary structure may be a lattice structure that is embedded in the final multi-component composite article. In another embodiment, the secondary structure may be an impermeable shape that does not allow the fluent material to fill the volume of the sacrificial tool. In some embodiments, the fluent material only needs to contact a portion of the secondary structure, for example, when multiple fluent materials are used to fill the sacrificial tool.

[0044] The curing process involves converting the fluid material into a solid material. Examples of curing can include, but are not limited to, solidification of a material from a molten state and solidification of a liquid induced by an external stimulus, including heat, moisture, electricity, sound, or actinic radiation. Another example of curing involves mixing a two-part resin system and allowing sufficient time for solidification to occur. In some embodiments, the curing process may be paused or permanently stopped before the dissolving process. In these cases, sufficient curing is achieved once the fluid material retains its shape when the sacrificial tool is removed.

[0045] The dissolution process involves immersing the filled sacrificial tool in a solvent, waiting a sufficient duration for the solvent to dissolve the tool, removing the cast form from the solvent, and allowing a sufficient duration for the solvent to evaporate. Optionally, agitation, solvent renewal, and heat can be applied during dissolution to accelerate the process, and vacuum, heat, or a dry environment can be used to accelerate solvent evaporation.

[0046] The printed soluble material may dissolve or dissolve in water, acidic solutions, basic solutions, or solvents. For example, polyvinyl alcohol (PVOH), AquaSys 120, and AquaSys General Purpose are non-limiting examples of water-soluble materials. Polyester is a non-limiting example of a material that is decomposable and soluble in acidic and / or basic solutions. Stratasys SR30 / SR35 support material is a non-limiting example of a basic-soluble material, and high-impact polystyrene (HIPS) is a non-limiting example of a solvent-soluble material. In some embodiments, water-soluble materials are used because they avoid the use of harmful solvents. One such water-soluble material that can be used is Aquasys General Purpose due to its high print quality and rapid dissolution in water.

[0047] In some embodiments, the dissolution solvent is water, but can include additional solvents such as limonene, acetone, dichloromethane, methanol, ethanol, and acidic and basic aqueous solutions. Dissolving the sacrificial tool in water is relatively harmless compared to other solvents that may be used.

[0048] In some embodiments, the secondary structure can be dissolved or removed to obtain a voided composite article. A voided composite article may contain hollow pores, channels, planes, or volumes where the secondary structure has been removed. The voids may be interconnected or separate. Because the voids are formed by removing the secondary structure, there must be a path for the solvent to reach the secondary structure. As an example, a separate channel void may be formed if it has a portion that reaches the outside of the multi-component composite article.

[0049] Once an article with voids is formed, a backfilling process may be used. A second fluid material may be used to completely or partially fill the voids. After the second fluid material hardens, this process forms a multi-component composite material, where neither of the two materials forming the composite need be 3D printable. In some embodiments, the second fluid material is a different material than the first fluid material.

[0050] The articles of the present invention have utility in a wide range of industries, including automotive parts, jigs and fixtures, tooling, and aerospace parts. (Example)

[0051] All examples were 3D printed on an Ultimaker S3 fused filament fabrication 3D printer using Cura 4.10.0 as the slicing software. Examples 1 and 2 used Aquasys 120 (Infinite Materials Solutions, Prescott, Wisconsin, USA) as the water-soluble filament and Tough PLA Black (Ultimaker BV, Utrecht, The Netherlands) as the secondary structure material. Examples 5 and 6 used only Aquasys 120 filament. All filaments were 2.85 mm diameter, the standard diameter for Ultimaker printers. As recommended by the material manufacturer, Tough PLA Black was printed using an AA print core, and Aquasys 120 was printed using a BB print core.

[0052] Each example was printed with the default recommended print profile settings for each material, including some representative settings listed below. TIFF2025526600000002.tif68143

[0053] Examples 1, 2, 5, and 6 consisted of cube-shaped molds with sides 20 mm long. These were set up in Cura as two separate identical cubes placed completely on top of each other. One cube was used to create the mold walls, and the other cube was used to create the secondary structure (infill). All molds were made with the following settings: TIFF2025526600000003.tif63133

[0054] The mold was designed with a solid bottom and side walls but no top to allow for easy casting of the flowable material.

[0055] The fluid material was the two-component silicone EcoFlex 00-30 (Smooth-On, Macungie, PA, USA). Prior to casting, parts A and B of EcoFlex 00-30 were combined in the indicated 1:1 weight ratio and thoroughly mixed by hand for approximately 1 minute. The mixture was then placed in a vacuum oven under full vacuum for approximately 5 minutes to remove any trapped air bubbles. After degassing, the silicone was slowly poured into a cubic mold to avoid introducing any new air bubbles. The mold was then left at room temperature for 24 hours to allow the silicone to cure. After this, the part and mold were placed in a glass jar filled with tap water and then placed in an oven at 80 °C for 24 hours to dissolve the Aquasys 120. When the Aquasys 120 was completely dissolved, the parts were removed from the jar, rinsed with tap water for 1 minute to remove any residual surface material, and placed in an 80°C oven to dry for approximately 16 hours. [Example]

[0056] Example 1: Reinforced composite with engineered anisotropy This demonstrates the anisotropic mechanical properties imparted by the embedded secondary structure. This infill structure was generated in Cura using a zigzag infill pattern, 15% infill density, and infill line direction [1]. The Tough PLA Black printed structure has solid walls in the Y and Z directions, contributing to the structure's stiffness in these directions. However, in the X direction, the mechanical properties are dominated by the soft, flexible silicone (and the ability of the PLA struts to bend), resulting in a more compliant behavior. Figure 2 illustrates an AQ120 and black PLA mold 202 that can be used to fabricate PDMS / PLA composites 204 that exhibit different stiffness in different x, y, and z directions 206. [Example]

[0057] Example 2: Partially Reinforced Composite This example demonstrates localized control of mechanical properties through the spatial arrangement of secondary structures. Tough PLA Black was printed as a gyroid structure (15% infill density), which provides both an open structure for silicone infiltration and relatively uniform mechanical stiffness in the x, y, and z directions. The rigid gyroid structure was localized to only half of the volume of the solid, resulting in stiff reinforced regions and highly compliant unreinforced silicone regions. Figure 3 illustrates an AQ120 and black PLA mold 302 that can be used to fabricate a partially reinforced PDMS / PLA composite 304 with differential stiffness between reinforced and unreinforced regions 306 and 308. [Example]

[0058] Example 3: "Two-Shot" Material from Gradual Dissolution The sacrificial tool can be made from a first soluble material, and the secondary structure can be made from a second, orthogonal soluble material. Potential material combinations include Aquasys 120 (AQ120, water-soluble, limonene-insoluble) and high-impact polystyrene (HIPS, limonene-soluble, water-insoluble). The tool was printed with AQ120, and the secondary structure was printed with HIPS. The tool was filled with a fluid material, which was allowed to solidify. The HIPS portion was then dissolved with limonene, creating a hollow portion in the casting material that could be backfilled with a second fluid material. Once the second material solidified, the tool was dissolved in water, leaving the completed "two-shot" part. [Example]

[0059] (Example 4: Reinforcement acting as a printing support) In this example, the mold and stiffener were made using two orthogonally / separately soluble materials. The mold was printed with AQ120, and the stiffener was printed with HIPS. Many printed shapes have overhanging features that require supports to print. In this example, the HIPS acts as structural support for the AQ120 during printing. After the mold is printed, the supports are no longer needed. The HIPS was dissolved in limonene, leaving a hollow AQ120 mold ready to be filled with castable material. [Example]

[0060] Example 5: Materials with Discrete Hollow Channels This example demonstrates that hollow channels can be formed from secondary structures. This example was created in Cura slicing software using a Lines infill pattern with a 15% density and an infill layer thickness of 0.4 mm. These settings created a sparse network of single printed lines, as shown below. Each line of infill was separate from all other lines. After casting and melting, these printed lines created hollow channels through the silicone cube. Figure 4 illustrates AQ120 402, which can be used to create a porous silicone block 404 containing hollow, non-intersecting channels. [Example]

[0061] Example 6: Material with partially gyroid pores Figure 5 illustrates the localized control of properties by creating localized void spaces. Figure 5 shows an AQ120 mold 502 that can be used to create a partially porous PDMS block containing hollow gyroid-shaped void spaces. [Example]

[0062] Example 7: Materials with graded porosity In this example, both the mold and the reinforcement were printed from AQ120. The reinforcement dimensions would vary within the mold cavity, with higher density in certain areas and lower density in others. The mold was filled with a castable material, which was allowed to solidify. The mold and reinforcement were then dissolved away, leaving behind a part containing graded or variable porosity where the reinforcement had been.

[0063] While particular embodiments have been described above, those skilled in the art will readily appreciate that the teachings herein may be applied to still other embodiments within the scope of the claims appended hereto.

Claims

1. three-dimensionally printing a sacrificial tool from a soluble material; three-dimensionally printing one or more additional materials to create a secondary structure; adding a flowable material to the sacrificial tool and contacting the secondary structure; hardening the liquid material to a solid state; dissolving the sacrificial tool with a solvent; A method of making a multi-component composite article, comprising:

2. The method of claim 1 further comprising dissolving or removing the secondary structure to obtain a voided composite article.

3. The method of claim 2 further comprising backfilling said voids in said multi-component composite article with a second flowable material.

4. The method of claim 1 , wherein the sacrificial tool is three dimensional printed using Fused Filament Fabrication.

5. The method of claim 1 , wherein the flowable material comprises one or more fillers.

6. at least one soluble material; a secondary structure comprising a second material; Three-dimensional printed sacrificial tools, including:

7. The three dimensional printed sacrificial tool of claim 6 , wherein the second material is orthogonally soluble.

8. The three dimensional printed sacrificial tool of claim 6 , wherein the soluble material is water soluble.

9. three-dimensionally printing a sacrificial tool from a soluble material; three-dimensionally printing one or more additional materials to create a secondary structure that acts as a support structure for the sacrificial tool; dissolving the secondary structure with a solvent; adding a flowable material to the sacrificial tool and contacting the secondary structure; hardening the liquid material to a solid state; dissolving the sacrificial tool with a solvent; A method of making an article, comprising:

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