Method and system for 3D printing tilting functional articles on an extrusion basis

Abstract

The present invention discloses a slurry feedstock, a method for preparing the same, and a method and system for extrusion-based 3D printing and / or casting of functionally graded articles under low pressure and room temperature. The slurry feedstock includes a build material including metal, ceramic, or any combination thereof, an organic polymer binder, an additive, and a volatile organic solvent. The build material mixed with the additive and the organic polymer binder dissolved in the volatile organic solvent form a first premix and a second premix, respectively. They are mixed to form a substantially uniform and flowable slurry mixture for producing an article.

Description

Technical Field

[0001] The present invention generally relates to the fields of additive manufacturing and / or mold casting. More specifically, the present invention relates to an extrusion-based 3D printing method for functionally graded articles and the system therefor. Those who Method and for the same system.

Background Art

[0002] Additive manufacturing, also known as 3D printing, is a transformative approach to industrial production that creates three-dimensional articles or parts from digital files. This technology enables the creation of solid objects in 3D and, thus, the realization of complex parts. Typically, thin layers of material are deposited to create complex shapes that could not be manufactured by conventional techniques such as casting, forging, and machining. 3D printing is regarded as one of the important innovative industrial processes in the coming years. It is a very interesting and profitable market in the investment community, bringing infinite options to companies and industries around the world.

[0003] One of the major advancements in additive manufacturing is the ability to manufacture functionally graded materials (FGMs). FGMs are those whose structural properties vary along their quantity and have the properties of two raw materials mixed together. In contrast, conventional composite materials are homogeneous mixtures and, thus, they require a compromise between the desirable properties of the constituent raw materials. Since most FGMs contain the pure forms of their respective components, the need for compromise between the desirable properties of the constituent raw materials is eliminated. The properties of both components can be utilized to the maximum extent. For example, a ceramic can be mixed with a metal to finally form an FGM article without sacrificing the toughness on the metal side or the fire resistance on the ceramic side. Conventionally, laser powder deposition and solid powder forging have been utilized for the manufacture of FGMs. Other conventional manufacturing methods include in-situ treatment techniques such as laser cladding, spray forming, sedimentation, and solidification.

[0004] Among additive manufacturing technologies, vat photopolymerization, which uses ultraviolet light to form chains and crosslink between molecules of liquid, lightly curable resins, thereby solidifying the resin, is used to produce FGM parts or articles. Laser-based processes such as selective laser sintering and selective laser melting, along with melt deposition modeling, can also be used to deposit materials of various geometric shapes, layer upon layer (i.e., add material to create an object). Interestingly, a common feature of these additive manufacturing technologies is that changes in material properties are limited to a one-dimensional space, typically having distinct forms directed in the print direction or along the z-axis. These technologies, unfortunately, do not adequately address FGM and its echoes. Furthermore, a major drawback of vat photopolymerization and FDM is that they are primarily involved in printing thermoplastics or plastic composites (which have the form of solid raw materials), which reduces and further weakens their versatility. Another major drawback of many conventional 3D printing methods is that they allow printing only one material at a time by arranging continuous layers of material, limiting many potential applications that require the integration of different materials with varying constituent components in the same object, such as FGM articles. Another drawback is that conventional 3D printing, which uses solid feedstock, does not allow for in-situ mixing of material components during the printing process. Therefore, there is a need to develop new materials and additive manufacturing techniques that can produce FGM articles with variations or gradients across two or more axes.

[0005] On the other hand, casting is basically done by pouring a liquid material, usually molten metal, into a cavity of a mold that has the shape of the desired part. The liquid material is then cooled, usually by heat being released through the mold, until it solidifies into the desired shape. While this may sound simple, casting is generally a very complex process due to the complex metallurgy involved in using molten metal. Casting processes can be divided into consumable mold processes and permanent mold processes. In consumable mold processes, the mold (typically made from sand, plaster, and ceramic) is broken to remove the casting. In contrast, in permanent mold processes, the mold (typically made from metal that retains its strength at high temperatures) is reused and therefore must be designed so that the casting can be easily removed.

[0006] One of the challenges in conventional casting is that the metal must be pre-melted before being poured into the mold cavity. This melting process is disadvantageous because it requires high energy to reach extremely high temperatures, depending on the melting point of the metal being used. In addition, while gravity can pull the molten metal down, in practice, a considerable amount of pressure must be applied or added to force the molten metal into the entire mold cavity. Unfortunately, other casting methods, such as powder injection molding, also have similar high-pressure requirements, as the mold itself must be subjected to very high pressure, and they also involve high tooling costs and long setup lead times. Therefore, there is a need to develop new, greener raw material and mold casting technologies that can significantly reduce energy demands and tooling costs, enabling the production of metal / ceramic articles.

[0007] As background, U.S. Patent Application Publication 2014 / 0087210 A1 (hereinafter, '210') discloses a method for producing metal or ceramic parts, such as cutting tools or forming tools, from at least two distinct powdery precursors. In '210', the method includes forming a first mixture consisting of composite material particles of tough coated hard powder (TCHP) produced by encapsulating extremely hard core particles, a very tough binder and multiple coating particles such as structural materials and at least one supporting powder such as carbides, typically WC-Co. According to '210', this mixture is formed into a green body and sintered to form a graded-function or multi-component article. International Publication 2018 / 009593 A1 (hereinafter, '593') discloses several methods for producing metallic objects. According to Publication No. 593, these methods generally involve adding a metal powder slurry to a sacrificial mold, for example, a mold made by 3D printing, and heating the slurry / mold mixture. Publication No. 593 states that the heating step may include a step of curing the slurry to produce a green part in the mold, a debonding step of burning off the mold and binder to produce a brown part, a sintering step, and a hot isostatic pressing step. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] U.S. Patent Application Publication No. 2014 / 0087210(A1) [Patent Document 2] International Publication No. 2018 / 009593(A1) [Overview of the project] [Problems that the invention aims to solve]

[0009] The above In conventional technology, The process involves three-dimensional (3D) printing of tilting functional parts using an extrusion base. For practical purposes, Regarding making it usable in a quick and easy way, There is considerable room for improvement. [Means for solving the problem]

[0010] Below is a simplified overview of the present invention to provide a basic understanding of some aspects of the invention. This overview is not intended to be a comprehensive overview of the invention. Its sole purpose is to present some of the concepts of the invention in a simplified form as a prelude to the more detailed explanation that will be presented later.

[0011] Therefore, the present invention provides a slurry feed material for three-dimensional (3D) printing of gradient functional articles on an extrusion base.

[0012] The slurry supply material of the present invention comprises a construction material comprising metal, ceramic, or any combination thereof, being porous, non-porous, or any combination thereof, in an amount of 10% to 90% by volume; an organic polymer binder selected from the group comprising cellulose esters, cellulose ethers, and their derivatives, in a concentration of 150 g / L to 550 g / L; an additive selected from the group comprising plasticizers, defoamers, dispersants, sacrificial materials, dissipative materials, skeletal materials, water-soluble inorganic salts, foaming agents, graphene, graphene oxide, flame retardants, toners, release additives, stabilizers, antistatic agents, impact modifiers, colorants, antioxidants, and any combination thereof; and a volatile organic solvent. The invention may be characterized by mixing the material and the additive to form a first premix, dissolving the organic polymer binder in the volatile organic solvent to form a second premix, mixing them to form a substantially homogeneous, fluid slurry mixture to be printed as a preceding part of the gradient-functional article, wherein the organic polymer binder is debonded from the preceding part by either or both a thermal decomposition treatment and / or a solvent debonding treatment, and a subsequent sintering treatment produces the final part containing the constructing material, in which the composition, including the filling pattern, or any combination thereof, is selectively and gradually changed over the volume of the final part of the gradient-functional article in one or more directions.

[0013] Preferably, this metal is selected from the group including ferrous metals, nonferrous metals, ferrous metal alloys, and nonferrous metal alloys.

[0014] Preferably, this ceramic is a silicate ceramic containing clay, cordierite ceramics, steatite, stoneware, pottery, porcelain, kaolin, quartz, silicates, camot, bentonite, mullite; alumina, zirconia including zirconia stabilized in yttria (Y3O2), beryllium oxide, yttrium oxide, titanium oxide, magnesium oxide, calcium oxide, barium oxide, zinc oxide, uranium oxide (UO2), plutonium dioxide (PuO2), yttrium barium copper oxide, spinel, magnetoplanvite, perovskite, thialite; titanium carbide, boron carbide, Non-oxide ceramics including carbide ceramics containing tungsten carbide and silicon carbide, silicon nitride, boron nitride, aluminum nitride, aluminum oxide nitride, and nitride ceramics containing SiAION; bioceramics including calcium phosphate ceramics containing hydroxyapatite (HAP), tricalcium phosphate (TCP), amorphous calcium phosphate (ACP), octacalcium phosphate (OCP), anhydrous dicalcium phosphate (DCPA), dicalcium phosphate dihydrate (DCPD), tetracalcium monoxide (TetCp), and biphase calcium phosphate (BCP); and any combination thereof.

[0015] Preferably, this construction material includes a particle mesh size of 300 μm or less.

[0016] Preferably, the cellulose ester is selected from the group comprising cellulose acetate, cellulose acetate phthalate, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose butyrate, cellulose triplyrate, cellulose acetate propionate, cellulose propionate, cellulose triplypropionate, cellulose nitrate, cellulose acetate propionate, carboxymethylcellulose acetate, carboxymethylcellulose acetate propionate, carboxymethylcellulose acetate butyrate, cellulose acetate butyrate succinate, cellulose propionate butyrate, and mixtures thereof.

[0017] Preferably, the cellulose ether is selected from the group comprising methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylhydroxyethylcellulose, methylhydroxypropylcellulose, ethylhydroxyethylcellulose, methylethylhydroxyethylcellulose, hydrophobic modified ethylhydroxyethylcellulose, hydrophobic modified hydroxyethylcellulose, alkylcellulose, hydroxyalkylcellulose, carboxyalkylcellulose, carboxyalkylhydroxyalkylcellulose, and mixtures thereof.

[0018] Preferably, the number-average molecular weight of this organic polymer binder is 150,000 or less.

[0019] Preferably, this volatile organic solvent is a ketone including acetone, butanone, methyl ethyl ketone, methyl amyl ketone, methyl isobutyl ketone and cyclohexanone; an aliphatic hydrocarbon; an aromatic hydrocarbon; an alcohol including methanol, ethanol, propanol, isopropyl alcohol and butanol; methyl formate; ethylene carbonate; propylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate, 1,2-dimethoxyethane, γ-butyrolactone, ethyl acetate, isopropyl acetate, ethyl ether, methyl tert-butyl ether, tetrahydrofuran, dioxane, nitromethane, acetonitrile, methylcyclohexane, n-heptane, n-hexane, cyclohexane, dipropylene glycol n-butyl ether, and a mixture thereof selected from the group consisting of.

[0020] Preferably, this substantially homogeneous and fluid slurry mixture includes two or more substantially homogeneous and fluid slurry mixtures each including a respective first premix and a respective second premix.

[0021] Preferably, these two or more substantially homogeneous and fluid slurry mixtures are instantaneously mixed by a static or dynamic mixer in situ to form one substantially homogeneous and fluid slurry mixture.

[0022] Preferably, this second premix is in an amount of 10% to 90% by volume.

[0023] Preferably, this slurry feedstock further comprises a support material that forms a substantially homogeneous and fluid support mixture configured to print a support structure for an overhang or cantilever portion of an inclined functional article.

[0024] Preferably, this support material includes a ceramic, a sacrificial material, a dissipative material, or any combination thereof.

[0025] Preferably, the sacrificial material is debonded from the preceding component by either a thermal decomposition treatment or a solvent debonding treatment, or both.

[0026] Preferably, the dissipative material is debonded from the preceding component by either a thermal decomposition treatment or a solvent debonding treatment, or both.

[0027] A second aspect of the present invention provides a method for preparing a slurry feed material for three-dimensional (3D) printing of a gradient functional article on an extrusion base.

[0028] The present invention provides a preparation method comprising: a step of preparing a construction material comprising a metal, a ceramic, or any combination thereof, comprising the steps of supplying the construction material which is porous, non-porous, or any combination thereof, and supplying the construction material in an amount of 10% to 90% by volume; a step of preparing an organic polymer binder selected from the group comprising cellulose esters, cellulose ethers, and derivatives thereof, comprising the step of supplying the organic polymer binder at a concentration of 150 g / L to 550 g / L; and a step of preparing a plasticizer, defoamer, dispersant, sacrificial material, dissipative material, skeletal material, water-soluble inorganic salt, foaming agent, graphene, graphene oxide, flame retardant, toner, release additive, stabilizer, antistatic agent, impact modifier, colorant, antioxidant, and any combination thereof. The process may be characterized by comprising the steps of: preparing an additive selected from the group including a blend; preparing a volatile organic solvent; mixing the construction material and the additive to form a first premix; mixing an organic polymer binder and the volatile organic solvent to form a second premix; and mixing the first premix and the second premix to form a substantially homogeneous, fluid slurry mixture to be printed as a preceding part of a functionally graded article, wherein the organic polymer binder is debonded from the preceding part by either or both a thermal decomposition treatment and a solvent debonding treatment, and a subsequent sintering treatment produces a final part containing a construction material whose composition, including a filling pattern, or any combination thereof, selectively and gradually changes over the volume of the final part of a functionally graded article in one or more directions.

[0029] Preferably, the method includes the step of forming two or more substantially homogeneous, fluid slurry mixtures, each comprising a first premix and a second premix.

[0030] Preferably, this method includes the step of instantaneously mixing two or more substantially homogeneous and fluid slurry mixtures in situ using a static or dynamic mixer to form one substantially homogeneous and fluid slurry mixture.

[0031] Preferably, the method includes the step of preparing a support material that forms a substantially uniform and fluid support mixture configured to print support structures for overhangs or cantilevers of a tilting functional article.

[0032] A third aspect of the present invention provides a method for three-dimensional (3D) printing of a tilting functional article on an extrusion base.

[0033] The present invention relates to a printing method comprising: a step of preparing a construction material comprising supplying a slurry supply raw material, wherein the construction material comprises metal, ceramic, or any combination thereof, and the construction material is porous, non-porous, or any combination thereof; and a step of supplying the construction material in an amount of 10% to 90% by volume; a step of preparing an organic polymer binder selected from the group comprising cellulose esters, cellulose ethers, and derivatives thereof, and the organic polymer binder is provided at a concentration of 150 g / L to 550 g / L; and a step of preparing an organic polymer binder selected from the group comprising plasticizers, defoamers, dispersants, sacrificial materials, dissipative materials, skeletal materials, water-soluble inorganic salts, foaming agents, graphene, graphene oxide, flame retardants, toners, release additives, stabilizers, antistatic agents, impact modifiers, colorants, antioxidants, and any combination thereof. The process may be characterized by comprising: a step of preparing an additive; a step of preparing a volatile organic solvent; a step of supplying a slurry feedstock including; a step of mixing the construction material and the additive to form a first premix; a step of mixing an organic polymer binder and a volatile organic solvent to form a second premix; a step of mixing the first premix and the second premix to form a substantially homogeneous, fluid slurry mixture to be printed as a leading part of a gradient functional article; a step of debinding the organic polymer binder from the leading part by either or both of a pyrolysis treatment and / or a solvent debinding treatment; and a step of subjecting the debound leading part to a sintering treatment to produce a final part containing a construction material in which the composition, filling pattern, or any combination thereof selectively and gradually changes over the volume of the final part of a gradient functional article in one or more directions.

[0034] Preferably, the method includes the step of forming two or more substantially homogeneous, fluid slurry mixtures, each comprising a first premix and a second premix.

[0035] Preferably, this method includes the step of instantaneously mixing two or more substantially homogeneous and fluid slurry mixtures in situ using a static or dynamic mixer to form one substantially homogeneous and fluid slurry mixture.

[0036] Preferably, the method includes the step of providing a support structure for an overhang or cantilever portion of an inclined functional article. The support structure comprises a substantially homogeneous and fluid support mixture formed of a support material.

[0037] According to a fourth aspect of the present invention, a system is provided for three-dimensional (3D) printing of a tilting functional article on an extrusion base.

[0038] The system of the present invention comprises one or more containers for containing slurry supply material, the slurry supply material comprising metal, ceramic, or any combination thereof, porous, non-porous, or any combination thereof, in an amount of 10% to 90% by volume; an organic polymer binder selected from the group comprising cellulose esters, cellulose ethers, and their derivatives, in a concentration of 150 g / L to 550 g / L; and plasticizers, defoamers, dispersants, sacrificial materials, dissipative materials, skeletal materials, water-soluble inorganic salts, foaming agents, graphene, graphene oxide, etc. The system comprises additives selected from the group including ions, flame retardants, toners, mold release additives, stabilizers, antistatic agents, impact modifiers, colorants, antioxidants, and any combination thereof, and a volatile organic solvent, wherein the building material and additives are mixed to form a first premix, an organic polymer binder is dissolved in the volatile organic solvent to form a second premix, and these are mixed to form a substantially homogeneous and fluid slurry mixture, the system regulating the injection of slurry supply material contained in one or more containers, and includes solenoid valves, mechanical pumps, and combinations thereof. A calculation unit comprising a control unit configured to generate control signals for the injection adjustment means selected from a group, wherein the control unit is connected to a database comprising a predetermined set of materials and rheology profiles used for which the control signals operationally influence the final part of a gradient functional article; a fluid drive selected from a group including pneumatic drive devices, hydraulic drive devices, mechanical drive devices, and any combination thereof, configured to provide fluid pressure to a slurry feed material contained in one or more containers or to the injection adjustment means, and to cause movement of the slurry feed material contained in one or more connected containers to provide pressurized slurry feed material; and a print head operably driven by the calculation unit and configured to spray a substantially uniform and fluid slurry mixture to produce a preceding part of a gradient functional article, wherein the organic polymer binder is debonded from the preceding part by either or both a thermal decomposition treatment and a solvent debonding treatment, and subsequently sintered to form a composition, filling pattern, etc., over the volume of the final part in one or more directions.Alternatively, it may be characterized by the fabrication of a final component containing building materials that selectively and gradually change in any combination thereof.

[0039] Preferably, the system includes a static or dynamic mixer that instantaneously mixes two or more substantially homogeneous and fluid slurry mixtures in situ to form one substantially homogeneous and fluid slurry mixture before being moved to the printhead.

[0041] Preferably, one or more containers contain a support material that forms a substantially uniform and fluid support mixture, which prints a support structure for the overhang or cantilever portion of the tilting functional article through the print head or other print heads.

[0042] According to a fifth aspect of the present invention, a slurry feed material for casting articles at low pressure and room temperature is provided.

[0043] The slurry supply material of the present invention comprises a building material comprising metal, ceramic, or any combination thereof, being porous, non-porous, or any combination thereof, in an amount of 10% to 90% by volume; an organic polymer binder selected from the group comprising cellulose esters, cellulose ethers, and their derivatives, in a concentration of 50 g / L to 550 g / L; and a plasticizer, defoamer, dispersant, sacrificial material, dissipative material, skeletal material, water-soluble inorganic salt, foaming agent, graphene, graphene oxide, flame retardant, toner, release additive, stabilizer, antistatic agent, impact modifier, colorant, antioxidant, and any combination thereof. The invention may be characterized by comprising an additive selected from a group and a volatile organic solvent, wherein the constructing material and the additive are mixed to form a first premix, and an organic polymer binder is dissolved in the volatile organic solvent to form a second premix, and these are mixed to form a substantially homogeneous, fluid slurry mixture that is subjected to casting in a mold cavity substantially immersed in a solidification tank for producing a preceding part of an article by phase inversion, the organic polymer binder being debonded from the preceding part by either or both a thermal decomposition treatment and a solvent debonding treatment, and the final part of the article being produced by a subsequent sintering treatment.

[0044] A sixth aspect of the present invention provides a method for preparing slurry feedstock for casting articles at low pressure and room temperature.

[0045] The method of the present invention comprises the steps of: preparing a construction material comprising a metal, a ceramic, or any combination thereof, comprising the steps of supplying a construction material which is porous, non-porous, or any combination thereof, and supplying the construction material in an amount of 10% to 90% by volume; preparing an organic polymer binder selected from the group comprising cellulose esters, cellulose ethers, and derivatives thereof, comprising the steps of supplying the organic polymer binder at a concentration of 50 g / L to 550 g / L; and a plasticizer, defoamer, dispersant, sacrificial material, dissipative material, skeletal material, water-soluble inorganic salt, foaming agent, graphene, graphene oxide, flame retardant, toner, release additive, stabilizer, antistatic agent, impact modifier, colorant, The process may be characterized by the steps of: preparing additives selected from the group including antioxidants and any combination thereof; preparing a volatile organic solvent; mixing the building materials and additives to form a first premix; mixing an organic polymer binder and a volatile organic solvent to form a second premix; and mixing the first premix and the second premix to form a substantially homogeneous, fluid slurry mixture to be cast in a mold cavity substantially immersed in a solidification tank for producing a preceding part of an article by phase inversion, wherein the organic polymer binder is debonded from the preceding part by either or both a pyrolysis treatment and a solvent debonding treatment, and the final part of the article is produced by a subsequent sintering treatment.

[0046] According to a seventh aspect of the present invention, a method for casting an article under low pressure and at room temperature is provided.

[0047] The method of the present invention comprises a step of preparing a constructing material, comprising the steps of supplying a slurry supply raw material, preparing a constructing material, wherein the constructing material is porous, non-porous, or any combination thereof, and supplying the constructing material in an amount of 10% to 90% by volume; a step of preparing an organic polymer binder, comprising the steps of preparing an organic polymer binder selected from the group comprising cellulose esters, cellulose ethers, and derivatives thereof, wherein the organic polymer binder is provided at a concentration of 50 g / L to 550 g / L; a step of preparing an additive selected from the group comprising plasticizers, defoamers, dispersants, sacrificial materials, dissipative materials, skeletal materials, water-soluble inorganic salts, foaming agents, graphene, graphene oxide, flame retardants, toners, release additives, stabilizers, antistatic agents, impact modifiers, colorants, antioxidants, and any combination thereof; and a step of preparing a volatile organic solvent. The process may be characterized by comprising: a step of supplying slurry supply material containing; a step of mixing the mixed building materials and additives to form a first premix; a step of mixing the dissolved organic polymer binder and a volatile organic solvent to form a second premix; a step of mixing the first premix and the second premix to form a substantially homogeneous and fluid slurry mixture; a step of subjecting the substantially homogeneous and fluid slurry mixture to casting in a mold; a step of substantially immersing the mold having a cavity filled with the substantially homogeneous and fluid slurry mixture in a solidification tank to produce a preliminary part of an article by phase inversion; a step of debonding the organic polymer binder from the preliminary part by either or both of a thermal decomposition treatment and a solvent debonding treatment; and a step of subjecting the preliminary part from which the organic polymer binder has been debonded to a sintering treatment to produce a final part of an article.

[0048] According to an eighth aspect of the present invention, a system for casting articles under low pressure and at room temperature is provided.

[0049] The system of the present invention comprises one or more containers for containing slurry supply material, the slurry supply material comprising a building material comprising metal, ceramic, or any combination thereof, being porous, non-porous, or any combination thereof, in an amount of 10% to 90% by volume; an organic polymer binder selected from the group comprising cellulose esters, cellulose ethers, and their derivatives, in a concentration of 50 g / L to 550 g / L; an additive selected from the group comprising plasticizers, defoamers, dispersants, sacrificial materials, dissipative materials, skeletal materials, water-soluble inorganic salts, foaming agents, graphene, graphene oxide, flame retardants, toners, release additives, stabilizers, antistatic agents, impact modifiers, colorants, antioxidants, and any combination thereof; and a volatile organic solvent, wherein the building material and additives The system may be characterized by comprising: a mold configured to cast a substantially homogeneous and fluid slurry mixture contained in one or more containers; a solidification tank configured to substantially immerse a mold having a cavity filled with a substantially homogeneous and fluid slurry mixture for the purpose of producing a preceding part of an article by phase inversion; and a debonding means for debonding the organic polymer binder from the preceding part, wherein the debonding means comprises either or both a thermal decomposition treatment and a solvent debonding treatment, followed by a sintering treatment for producing a final part of an article.

[0050] The above and other objects, features, embodiments, and advantages of the present invention will be better understood by carefully reading the detailed description provided below with due reference to the accompanying drawings.

[0051] By referring to the attached drawings and examining the following detailed description, the present invention will be more fully understood, and its many associated effects will be easily grasped. [Brief explanation of the drawing]

[0052] [Figure 1]A comparative example shows the configuration for binary material printing. [Figure 2] This diagram shows a configuration for a binary material print, where Material A represents a first substantially homogeneous and fluid slurry mixture (e.g., metal as a building material) according to one embodiment of the present invention, and Material B represents a second substantially homogeneous and fluid slurry mixture (e.g., ceramic as a building material) according to one embodiment of the present invention. [Figure 3A] Side and top views of a gradient functional article manufactured using a slurry feed material through an extrusion-based three-dimensional (3D) printing according to one embodiment of the present invention, where material A represents a first substantially homogeneous and fluid slurry mixture (e.g., metal as a building material) according to one embodiment of the present invention, and material B represents a second substantially homogeneous and fluid slurry mixture (e.g., ceramic as a building material) according to one embodiment of the present invention. [Figure 3B] Side and top views of a gradient functional article manufactured using a slurry feed material through an extrusion-based three-dimensional (3D) printing according to one embodiment of the present invention, where material A represents a first substantially homogeneous and fluid slurry mixture (e.g., metal as a building material) according to one embodiment of the present invention, and material B represents a second substantially homogeneous and fluid slurry mixture (e.g., ceramic as a building material) according to one embodiment of the present invention. [Figure 4] This figure shows the porosity gradient of a porous functional article manufactured using a slurry-supplied material by extrusion-based 3D printing according to one embodiment of the present invention. [Figure 5A] This is a perspective view of a gradient functional article manufactured using a slurry feed material through extrusion-based 3D printing, where Material A represents a first substantially homogeneous and fluid slurry mixture (e.g., metal as a building material) according to one embodiment of the present invention, and Material B represents a second substantially homogeneous and fluid slurry mixture (e.g., ceramic as a building material) according to one embodiment of the present invention. [Figure 5B]Figure 5A is a cross-sectional view of a gradient functional article along line AA, where material A represents a first substantially homogeneous and fluid slurry mixture (e.g., metal as a building material) according to one embodiment of the present invention, and material B represents a second substantially homogeneous and fluid slurry mixture (e.g., ceramic as a building material) according to one embodiment of the present invention. [Figure 6A] This figure shows a photograph of a cross-section of a concentric green component, which is a tilting functional article manufactured by extrusion-based 3D printing using slurry supply material according to one embodiment of the present invention. [Figure 6B] This figure shows a photograph of a cross-section of a concentric green component, which is a tilting functional article manufactured by extrusion-based 3D printing using slurry supply material according to one embodiment of the present invention. [Figure 6C] This figure shows the gradient transition in the xy-plane of the first layer of the green component in Figures 6A and 6B of one embodiment of the present invention. [Figure 6D] This figure shows the gradient transition in the xy-plane of the second layer of the green component in Figures 6A and 6B of one embodiment of the present invention. [Figure 7] This is a flowchart showing a method for preparing slurry feed material for 3D printing a tilting functional article of one embodiment of the present invention on an extrusion base. [Figure 8] This is a flowchart showing a method for 3D printing a tilting functional article on an extrusion basis according to one embodiment of the present invention. [Figure 9A] This figure shows a system configuration for 3D printing an extruded-based article with tilting functionality according to one embodiment of the present invention. [Figure 9B] This figure shows a mechanism for 3D printing an inclined functional article of one embodiment of the present invention on an extrusion base. [Figure 10] This figure shows a first system, a second system, and a third system employed to 3D print a gradient functional article on an extrusion base using a slurry feed material according to one embodiment of the present invention. [Figure 11]This figure shows a first system, a second system, and a third system employed to 3D print a gradient functional article on an extrusion base using a slurry feed material according to one embodiment of the present invention. [Figure 12] This figure shows a first system, a second system, and a third system employed to 3D print a gradient functional article on an extrusion base using a slurry feed material according to one embodiment of the present invention. [Figure 13] This figure shows a first system, a second system, and a third system employed to 3D print a gradient functional article on an extrusion base using a slurry feed material according to one embodiment of the present invention. [Figure 14] This figure shows a filling pattern and its density for use in a tilting functional article according to one embodiment of the present invention. [Figure 15] This figure shows a support configuration printed on a platform for an overhang or cantilever portion of an inclined functional article according to one embodiment of the present invention. [Figure 16] This figure shows a first configuration for printing a support structure for an overhang or cantilever portion of the tilting functional article using a single print head or nozzle, wherein material A represents a first substantially homogeneous and fluid slurry mixture (e.g., metal as a building material) according to one embodiment of the present invention, material B represents a second substantially homogeneous and fluid slurry mixture (e.g., ceramic as a building material) according to one embodiment of the present invention, and material C refers to a substantially homogeneous and fluid support mixture, wherein materials A, B, and C are mixed in a single static or dynamic mixer according to one embodiment of the present invention. [Figure 17]The figure shows a second configuration for printing a support structure for an overhang or cantilever portion of the tilting functional article using two printheads or nozzles, wherein material A represents a first substantially homogeneous and fluid slurry mixture (e.g., metal as a building material) according to one embodiment of the present invention, material B represents a second substantially homogeneous and fluid slurry mixture (e.g., ceramic as a building material) according to one embodiment of the present invention, and material C refers to a substantially homogeneous and fluid support mixture, wherein materials A and B are mixed in a single static or dynamic mixer according to one embodiment of the present invention, and material C is led to the other printhead. [Figure 18] This figure shows a system according to one embodiment of the present invention, which requires a support structure for its overhang or cantilever portion, and is used for 3D printing a tilting functional article on an extrusion base using a slurry feed material. [Figure 19] This figure shows a reusable mold according to one embodiment of the present invention, comprising a first part having a recessed or formed cavity inside, and a second part that removably encloses the first part, the cavity containing a single substantially homogeneous and fluid mixture according to one embodiment of the present invention. [Figure 20] This figure shows the cavity of the mold in Figure 1, adapted to accommodate two substantially homogeneous, fluid mixtures according to one embodiment of the present invention. [Figure 21] This figure shows the cavity of the mold in Figure 1, adapted to receive two substantially homogeneous and fluid mixtures using a static or dynamic mixer, according to one embodiment of the present invention. [Figure 22] This is a flowchart showing a method for preparing slurry feed material for casting articles at room temperature under low pressure, according to one embodiment of the present invention. [Figure 23] This is a flowchart showing a method for casting an article at room temperature under low pressure according to one embodiment of the present invention. [Figure 24] This block diagram shows a current embodiment of a method for casting articles at room temperature under low pressure (as described in Figure 5). [Figure 25] This figure shows a direct printing system according to one embodiment of the present invention. [Figure 26] This diagram shows the configuration of a multi-material printer according to one embodiment of the present invention. [Figure 27] This figure shows the configuration of an in-situ mixing printer according to one embodiment of the present invention. [Figure 28] This is a flowchart showing a process involving a 3D printed item according to one embodiment of the present invention. [Figure 29] This figure shows the thermal decoupling and sintering profiles according to one embodiment of the present invention. [Figure 30] This is a side view of a stainless steel-based feedstock print according to one embodiment of the present invention. [Figure 31] This is a perspective view of a stainless steel-based hardened article according to one embodiment of the present invention. [Figure 32] This is a perspective view of a stainless steel-based sintered article according to one embodiment of the present invention. [Figure 33] This is a side view of a ceramic-based material print according to one embodiment of the present invention. [Figure 34] This is a perspective view of a ceramic-based cured product according to one embodiment of the present invention. [Figure 35] This is a perspective view of a ceramic-based sintered product according to one embodiment of the present invention. [Modes for carrying out the invention]

[0053] Please note that the drawings may not be to scale. The drawings are intended to show only typical embodiments of the invention and should therefore not be considered to limit the scope of the invention.

[0054] This invention discloses a slurry feed material for use in three-dimensional (3D) printing of a functionally graded material (FGM) on an extrusion base, a method for preparing it, a method for 3D printing an article on an extrusion base, and a system therefor. The advantage is that, by providing a slurry feed material for 3D printing on an extrusion base, the invention produces an FGM article containing a material in which the composition, including the filling pattern, or any combination thereof, selectively changes over the volume of the final part in one or more directions, including a (triaxial) three-dimensional style. Remarkably, such an FGM article produced by the invention exhibits linear or continuous properties between two layers in one or more directions, including distinct, clearly defined, and interchangeable properties, e.g., changes in composition, including the filling pattern, or any combination thereof, and / or discrete, incremental changes. Furthermore, the invention can be used and maintained in a very specific, compact, cost-effective, quick, and simple manner without the use of complex and sophisticated processes, components, or parts (e.g., feed material heaters).

[0055] Essentially, the present invention relates to heterogeneous articles characterized by a gradual change in their multiphase properties (i.e., microstructure and mechanical properties such as tensile strength, thermal conductivity, and Young's modulus). Conventionally, FGM manufacturing techniques can be classified according to thin-film and bulk FGM. In the former case, thin-film FGM is typically formed by surface coating or vapor deposition techniques. In the latter case, bulk FGM manufacturing techniques include powder metallurgy, centrifugal processes, and additive manufacturing. In additive manufacturing, bulk FGM can be formed by vat photopolymerization processes, laser-based processes such as selective laser sintering (SLS) and selective laser melting (SLM), or fused deposition modeling (FDM). These conventional methods can only change material properties within a single dimensional space, usually on the print direction or z-axis. In contrast, FDM and vat photopolymerization are used almost exclusively for thermoplastic or plastic composite prints, though not all. These conventional methods cannot print FGM articles that have variations in composition, structure, filling pattern, and / or properties, or variations in at least one type of building material, e.g., metal or ceramic, across a plane in three-dimensional (3D) space (where the Cartesian coordinate system is based on three mutually perpendicular coordinate axes, i.e., the x, y, and z axes).

[0056] As used herein, the term “slurry” refers to a solid-fluid mixture, including both solid-liquid and solid-gas mixtures. For convenience, with respect to solid-liquid slurries, the present invention discusses them as feed material compositions in which the solid and liquid exist in separate phases. Solid-liquid slurries also include solids and liquids that are introduced into the system of the present invention and are completely or partially separated.

[0057] Where used herein, the term “supply material” is defined as a raw material or mixture of raw materials having properties suitable for being supplied to the System, which can produce gradient functional articles or FGM articles, and is construed to mean components that have not yet been mixed or have been further mixed to produce a mixture suitable for injection into the System.

[0058] As used herein, the term “premix” refers to a component that, when mixed together, forms one part of a mixture that constitutes a slurry mixture.

[0059] As used herein, the terms “filling pattern” or “structural filler” refer to a pattern that leaves void spaces inside and / or outside a graded functional article. The pattern is preferably invisible. The pattern includes, but is not limited to, lines, zigzag structures, grid structures, triangular structures, basket weave structures, honeycomb structures, 3D honeycomb structures, cubic structures, cubic subdivision structures, octet structures, gyroid structures, star structures, octagram spiral structures, Archimedes chord structures, Hilbert curve structures, linear structures, concentric structures, or any combination thereof. The filling pattern is preferably formed using an adaptive filling print process.

[0060] As used herein, the terms “three-dimensional printing” or “3D printing” refer to printing by extrusion through a print nozzle (i.e., extrusion-based 3D printing), or the process of providing a three-dimensional portion or object extending in three directions (e.g., length, width, and height) on a flat surface, plate, or substrate.

[0061] As used herein, the terms “preceding part” or “green part” refer to an article or preform of a gradient functional article that is in a pre-sintered state and manufactured by the present invention for further processing by other manufacturing techniques.

[0062] As used herein, the term “brown component” refers to a graded functional article manufactured from a preceding or green component that has been subjected to a thermal decomposition treatment and / or solvent debonding treatment to remove binders, sacrificial materials and / or dissipative materials that previously held the supply raw materials together. The brown component may be further heated to completely sinter or subjected to sintering in order to manufacture the final or finished component of the graded functional article.

[0063] As used herein, the terms “varied” or “variable” are broad terms and are used in their ordinary sense, including, but not limited to, divergence or magnitude of variation from a point, line, or set of data. In one embodiment, the composition and / or structure of the construction material in the final component of a gradient functional material may have variation that includes a range outside a criterion or dataset representing, for example, a range of possibilities based on known or standard 3D printed materials. This term may encompass positive variation, negative variation, and neutral variation. Positive variation may represent a positive deviation exceeding the criterion or dataset. Negative variation may represent a negative deviation that cannot achieve the criterion or dataset. Neutral variation may represent zero variation of the composition and / or structure of the construction material with respect to the criterion or dataset, e.g., the absence of a transition gradient.

[0064] According to a preferred embodiment of the present invention, the slurry feedstock comprises a construction material, an organic polymer binder, an additive (optional), and a volatile organic solvent. In this regard, the organic polymer binder dissolves in the volatile organic solvent, thus producing an organic polymer binder solution. The additive is added to the construction material to obtain predetermined rheological behavior and print properties. The slurry feedstock can essentially be formed by blending the organic polymer binder solution with the construction material mixed with the additive. The resulting slurry feedstock can be printed and dried at room temperature without external heat supply means.

[0065] The constructing material of the present invention refers to a powder preferably used to form a slurry feed material, on which gradient functional articles are constructed within the extrusion-based 3D printing system of the present invention. The powder, or particulate material or particles, has a variety of mesh sizes. In one embodiment, the constructing material has a particle size of about 300 μm or less, preferably less than about 200 μm. The constructing material is preferably a layering material for use in the extrusion-based 3D printing system of the present invention. The constructing material may also be in various forms, such as granular powder, fibrous powder, and flaky powder. In a preferred embodiment, the constructing material is used in an amount of about 10% to about 90% by volume, more preferably about 30% to about 90% by volume.

[0066] The construction material preferably includes metals, ceramics, or any combination thereof. In one embodiment of the present invention, the construction material may be porous, non-porous, or any combination thereof. For example, porous metal means metal particles having significant porosity, e.g., porosity greater than about 0.5 cc / g. The construction material may have pores less than 100 μm (microporous) and / or greater than 100 μm (mesoporous). Non-porous metal, on the other hand, means metal particles with little or no porosity, e.g., porosity less than about 0.05 cc / g. Porous ceramics preferably have porosity with controllable porosity and good mechanical properties. The term "porosity," as used herein, refers to the volume fraction of void space in a porous article, e.g., its porous construction material.

[0067] The porous metals and / or porous ceramics used in the present invention are preferably microporous and can be produced, for example, by direct foaming using a suitable foaming agent, sacrificial material, dissipative material, skeletal material, etc. The porosity can also be controlled by the size of the salt crystals.

[0068] In one preferred embodiment of the present invention, the construction material may consist solely of metal (porous and / or non-porous) or ceramic (porous and / or non-porous). Alternatively, the construction material may include a combination of metal and ceramic in predetermined mixing ratios or volume ratios to adequately satisfy the desired properties of the construction material for its functionally graded article. Examples of such combinations include metal and ceramic; porous metal and ceramic; metal and porous ceramic; porous metal, non-porous metal and ceramic; metal, porous ceramic and non-porous ceramic; porous metal, non-porous metal, porous ceramic and non-porous ceramic, and so on. Various other combinations are possible (e.g., first metal, second metal, first ceramic, second ceramic, etc.).

[0069] The metal used in the present invention is preferably selected from the group including ferrous metals, nonferrous metals, ferrous metal alloys, and nonferrous metal alloys.

[0070] The ferrous metal is selected from steel, stainless steel, mild steel, cast iron, malleable iron, ductile cast iron, and the like. Preferably, the ferrous metal includes iron, iron-chromium alloys, iron-chromium-nickel alloys, iron-chromium-zinc alloys, iron-chromium-aluminum alloys, iron-chromium-magnesium alloys, iron-chromium-lead alloys, iron-aluminum alloys, iron-zinc alloys, stainless steel, iron-nickel alloys, and combinations thereof. Preferred examples of steel and / or stainless steel include AISI 304, AISI 304L, AISI 316, AISI 316L, AISI 430, AISI 630 (17-4PH), and AISI 631 (17-7PH). Other steels such as A2-A5, D2, H13, M2, and 4140 can also be used in this invention.

[0071] Nonferrous metals are selected from aluminum, aluminum alloys, magnesium, magnesium alloys, zinc, zinc alloys, cadmium, chromium(III), copper, copper(II)-cadmium, lead, cobalt, cobalt-chromium, cobalt-chromium-molybdenum, nickel, nickel alloys, molybdenum, titanium, tantalum, niobium, silver, and gold. Preferred examples of aluminum and / or aluminum alloys include AlSi10Mg, AlSi7Mg, ADC12, and AlMg5Mn. Preferred examples of nickel alloys include alloy 706, alloy 718, alloy 625, and Invar types such as FeNi36 or 64FeNi, or Hastelloy X, Hastelloy C, and Kovar.

[0072] The ceramics used in the present invention are preferably selected from the group including silicate ceramics, oxide ceramics, non-oxide ceramics, bioceramics, and any combination thereof.

[0073] Silicate ceramics preferably include, but are not limited to, clay, cordierite ceramics, steatite, stoneware, pottery, porcelain, kaolin, quartz, silicates, camott, bentonite, mullite, and any combination thereof.

[0074] Oxide ceramics preferably include, but are not limited to, alumina, zirconia including zirconia stabilized in yttria oxide (Y3O2), beryllium oxide, yttrium oxide, titanium oxide, magnesium oxide, calcium oxide, barium oxide, zinc oxide, uranium oxide (UO2), plutonium dioxide (PuO2), yttrium barium copper oxide, spinel, magnetoplanvite, perovskite, cheerite, and any combination thereof.

[0075] Non-oxide ceramics preferably include, but are not limited to, carbide ceramics such as titanium carbide, boron carbide, tungsten carbide, and silicon carbide; nitride ceramics such as silicon nitride, boron nitride, and aluminum nitride; nitride ceramics including aluminum oxide nitride, SiAION (ceramics based on the elements silicon (Si), aluminum (Al), oxygen (O), and nitrogen (N)); and any combination thereof.

[0076] The bioceramics are preferably calcium phosphate ceramics and include, but are not limited to, hydroxyapatite (HAP), tricalcium phosphate (TCP), amorphous calcium phosphate (ACP), octacalcium phosphate (OCP), anhydrous dicalcium phosphate (DCPA), dicalcium phosphate dihydrate (DCPD), tetracalcium monoxide phosphate (TetCp), biphase calcium phosphate (BCP), and any combination thereof.

[0077] The construction material of the present invention may include other sinterable materials that do not crack, sag, or delaminate, such as glass powder, acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), and polyether ether ketone (PEEK).

[0078] The organic polymer binder used in the present invention preferably has at least two thermal decomposition temperatures. In thermal decomposition, decomposition products (i.e., functionally graded articles) that can act as reducing agents are formed when the organic polymer binder is heated at these temperatures. The organic polymer binder is preferably selected so as not to inhibit the reaction between powder, i.e., metal and / or ceramic particles. The organic polymer binder is preferably decomposed or evaporated at a temperature below its corresponding thermal decomposition temperature.

[0079] The organic polymer binder is preferably selected from the group comprising cellulose esters, cellulose ethers, and their derivatives. The organic polymer binder is preferably used at a concentration of about 150 g / L to about 550 g / L, more preferably about 200 g / L to about 500 g / L. In various embodiments of the present invention, the number-average molecular weight of the organic polymer binder is about 150,000 or less, more preferably about 100,000 or less.

[0080] The cellulose ester is preferably selected from the group comprising cellulose acetate, cellulose acetate phthalate, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose butyrate, cellulose triplyrate, cellulose acetate propionate, cellulose propionate, cellulose triplyrate, cellulose nitrate, cellulose acetate propionate, carboxymethylcellulose acetate, carboxymethylcellulose acetate propionate, carboxymethylcellulose acetate butyrate, cellulose acetate butyrate succinate, cellulose propionate butyrate, and mixtures thereof.

[0081] Cellulose ester derivatives can be prepared by esterification of cellulose. Preferred cellulose ester derivatives include cellulose acetate, butyrate, benzoate, phthalate, and anthranilate esters, preferably cellulose acetate phthalate (CAP), cellulose acetate butyrate (CAB), cellulose acetate trimellitate (CAT), hydroxypropyl methylcellulose phthalate (HPMCP), succinoylcellulose, cellulose fluoroate, cellulose carbanillate, and mixtures thereof.

[0082] The cellulose ether is preferably selected from the group comprising methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylhydroxyethylcellulose, methylhydroxypropylcellulose, ethylhydroxyethylcellulose, methylethylhydroxyethylcellulose, hydrophobic modified ethylhydroxyethylcellulose, hydrophobic modified hydroxyethylcellulose, alkylcellulose, hydroxyalkylcellulose, carboxyalkylcellulose, carboxyalkylhydroxyalkylcellulose, and mixtures thereof.

[0083] Cellulose ether derivatives can be prepared by carboxymethylation, carboxyethylation, and carboxypropylation. Preferred examples of cellulose ether derivatives include, but are not limited to, nanocellulose, carboxymethylcellulose (CMC), sodium carboxymethylcellulose (NaCMC), hydroxypropylcellulose (HPC), hydroxyethylcellulose (HEC), hydroxypropylmethylcellulose (HPMC), methylcellulose (MC), ethylcellulose (EC), and tritylcellulose.

[0084] Some organic polymer binders may use cationic cellulose derivatives. Some of these organic polymer binders may include alginates, starches, polysaccharides such as chitin and chitosan, agarose, hyaluronic acid, and their derivatives or copolymers (e.g., graft copolymers, block copolymers, random copolymers), or mixtures thereof.

[0085] The additives used in the present invention may be added to the building material and its organic polymer binder to achieve any desired properties, such as desired physical, mechanical, and thermal properties in the slurry raw material. In preferred embodiments of the present invention, the additives are selected from the group including plasticizers, defoamers, dispersants, sacrificial materials, dissipative materials, skeletal materials, water-soluble inorganic salts, foaming agents, graphene, graphene oxide, flame retardants, toners, release agents, stabilizers, antistatic agents, impact modifiers, colorants, antioxidants, and any combination thereof. The additives are preferably used in amounts of about 1 vol% to about 15 vol%. It is understood that the amount of additives may vary outside the above range depending on the specific type of additive selected in the present invention.

[0086] Preferably, a plasticizer refers to a substance added to the slurry feedstock to improve workability, flexibility, and plasticity. Preferably, the plasticizer includes phthalate esters such as dibutyl phthalate, diaryl phthalate, diethyl phthalate, dimethyl phthalate, dihexyl phthalate, di-2-methoxyethyl phthalate, triphenyl phthalate, (dipropylene glycol) butyl ether, dibutyl tartrate, and diethylene glycol monoricinoleate; natural or synthetic waxes selected from the group consisting of cetyl alcohol, stearyl alcohol, cetostearyl alcohol, beeswax, candelilla wax, shellac wax, carnauba wax, petroleum wax, or mixtures thereof; glycerol, triethyl citrate, acetyl triethyl citrate, ethyl o-benzoyl benzoate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, N-ethyltoluenesulfonamide, o-cresyl p-toluenesulfonate, triethyl phosphate, triphenyl phosphate, and any combination thereof.

[0087] An antifoaming agent is a substance that eliminates foam by reducing the surface tension of the slurry feed material. The antifoaming agent alters the surface properties of metals and ceramics, reducing the interfacial tension of volatile organic solvents and thus removing foam. The antifoaming agent is preferably selected from the group comprising polyethylene glycol, polypropylene glycol copolymer, alkyl polyacrylate, polydimethylsiloxane (silicone oil), ethylene bis-stearamide (EBS), paraffin wax, ester wax, fatty alcohol wax, white oil or vegetable oil, wax having long-chain fatty alcohol, fatty acid soap, ester, polyether-modified polysilicane and trialkane / alkene phosphate, and mixtures thereof.

[0088] The dispersant is preferably a component that acts to maintain the interdispersion of metals and ceramics during slurry reduction. The dispersant is preferably a compound selected from the group consisting of silicate compounds, sodium polycarbonate, and alcohols.

[0089] The sacrificial material is preferably a substance that, if present in the green or brown component before sintering, is not present in any significant amount, at least in the same form, within the fully sintered body (i.e., the final component) formed by sintering the brown component until the final graded functional article or final component is formed. In one embodiment, the sacrificial material forms a layer on the green or brown component and is later removed, leaving a void. The sacrificial material may include aluminum orthophosphate, which, when heated during the sintering process, first forms a liquid phase within the green or brown component, and then vaporizes or decomposes as one or more gaseous byproducts, leaving the green or brown component. The sacrificial material preferably includes paraffin wax.

[0090] The dissipative material is preferably a material that can function as a mold for casting ceramic and / or metal parts into a three-dimensional form of a tilting functional article, and can then be removed from the ceramic and / or metal parts by melting, dissolving and / or evaporating without damaging the ceramic and / or metal castings. The dissipative material used in the present invention may be a rubber or plastic material selected to achieve desired properties such as having thermal expansion and / or dissipative properties (relative to the ceramic or metal core material).

[0091] In one embodiment, the sacrificial material, dissipative material, or a combination thereof is removed from the preceding part or from the preceding part from which the polymer binder has been detached (i.e., the browned part) by thermal decomposition, solvent debonding, or any combination thereof. Thermal decomposition can preferably be selected from the group including heating, thermal debonding, densification / sintering, partial or complete melting of the dissipative material other than the sacrificial material and / or building material, i.e., metal particles and / or ceramic particles. The solvent debonding may include immersing the preceding part, the browned part, and / or the final part in a solvent that dissolves the sacrificial material and / or dissipative material. It is possible to better control strain and significantly reduce the debonding time. The solvent is, but is not limited to, alternative solvents such as n-hexane, heptane, thinner, acetone, methyl ethyl ketone, carbon tetrachloride, trichloroethylene, methylene chloride, and supercritical carbon dioxide, as well as water.

[0092] The skeletal material is preferably a buttress material for imparting mechanical integrity to the slurry raw material. The skeletal material may be selected from the group including gel-like materials such as chitosan, fibrin, and modified alginates; robust materials such as polycaprolactone and other plastics; and slurries containing ceramics and other powders, hydroxyapatite, or tricalcium phosphate. The skeletal material may also include polycaprolactone, polylactic acid, polyglycolic acid, and poly(lactide-co-glycolide).

[0093] The water-soluble inorganic salts used in the present invention are preferably selected from the group including nitrates, borates, chlorates, perchlorates, sulfates, halide salts, sodium carbonate, potassium carbonate, silicates, phosphates, salts of Group I elements, ammonium salts, and combinations thereof. In one embodiment, the water-soluble inorganic salt includes a rare earth metal chloride.

[0094] A foaming agent (or blowing agent) refers to a component, or combination of components, that can form a foam, preferably generally a bubbly foam, in a slurry raw material, particularly in the metal and / or ceramic building material. The foaming agent may be a solid, liquid, or supercritical material.

[0095] In preferred embodiments of the present invention, the blowing agent is a pyrolytic agent that is liquid or solid at room temperature, has a decomposition temperature lower than the melting temperature of the building material, and decomposes when heated to a temperature higher than the decomposition temperature, generating gases such as nitrogen, carbon dioxide, or ammonia. The blowing agent may be selected from the group including azodicarbonamide and / or its metal salts, hydrazodicarbonamide, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, calcium azide, trihydrazino-sym-triazine, pp'-oxybisbenzenesulfonyl hydrazide, dinitrosopentamethylenetetramine, azobisisobutylodinitrile, toluenesulfonyl hydrazide, p-toluenesulfonyl hydrazide, benzenesulfonyl hydrazide, bisbenzenesulfonyl hydrazide, p,p'-oxybis(benzenesulfonyl hydrazide), azobisisobutyronitrile, barium azodicarboxylate, and combinations thereof. The polysaccharide foaming agent preferably includes arrowroot powder, tapioca starch, potato starch, wheat, rice, and corn powder. The amount of foaming agent can be determined according to the desired expansion coefficient.

[0096] The graphene used as an additive in the present invention is preferably a polycyclic aromatic compound in which multiple carbon atoms are covalently bonded. The covalently bonded carbon atoms form a 6-membered carbon ring as a repeating unit, and may further include 5-membered carbon rings and / or 7-membered carbon rings. In the present invention, graphene is not limited to monolayer graphene, but also includes, for example, multigraphene having up to 10 monolayer graphene layers. Graphene preferably includes pure or natural graphene in addition to modified graphene such as graphene oxide or amide-modified graphene.

[0097] Graphene oxide, also known as "graphite acid" and "graphite oxide," may include structures in which oxygen-containing functional groups, such as carboxyl groups, hydroxyl groups, or epoxy groups, are bonded to graphene in varying proportions, but may be obtained by treating graphite with a strong oxidizing agent. In one embodiment of the present invention, graphene oxide includes a nanocomposite containing graphene oxide. Graphene oxide also includes reduced graphene oxide, i.e., graphene oxide in a reduced form, such as graphene oxide that has been subjected to a reduction treatment and is partially or substantially reduced. Reduced graphene oxide also refers to graphene oxide in which the percentage of oxygen has been reduced by a reduction treatment.

[0098] Other additives, such as flame retardants, toners, release agents, stabilizers, antistatic agents, impact modifiers, colorants, antioxidants, and release agents, can be used in this invention.

[0099] The volatile organic solvent is chemically inert to the construction material, but is preferably evaporated or released during or after printing by the system of the present invention. The volatile organic solvent is necessary to completely dissolve components of the slurry feedstock other than the construction material (e.g., organic polymer binders) and also functions as a wetting agent to prevent clogging of the print nozzles of the print head of the system. Furthermore, it is desirable to use a volatile organic solvent that promotes variability (variation) of the construction material (i.e., metals and ceramics) in the composition of the gradient functional article, the structure including the filling pattern, or any combination thereof, and has a relatively high flash point and relatively low odor. The volatile organic solvent is preferably a solvent with a low vapor pressure greater than about 0.133 mbar or 13.3 Pa (0.1 mmHg) at about 20°C.

[0100] The volatile organic solvent is preferably used in an amount of about 1% to about 50% by volume. In one embodiment of the present invention, an appropriate amount of the volatile organic solvent should be used in the organic polymer binder, taking into consideration the preferred or desired concentration of the solution obtained as a second premix, which is an organic polymer binder solution.

[0101] The volatile organic solvent is preferably selected from the group comprising acetone, butanone, ketones including methyl ethyl ketone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone, aliphatic hydrocarbons, aromatic hydrocarbons, methanol, ethanol, propanol, alcohols including isopropyl alcohol, and butanol, methyl formate, ethylene carbonate, propylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate, 1,2-dimethoxyethane, γ-butyrolactone, ethyl acetate, isopropyl acetate, ethyl ether, methyl tert-butyl ether, tetrahydrofuran, diozan, nitromethane, acetonitrile, methylcyclohexane, n-heptane, n-hexane, cyclohexane, dipropylene glycol n-butyl ether, and mixtures thereof.

[0102] In various embodiments of the present invention, it is preferable that the building material mixed with the additive forms a first premix, and the organic polymer binder, together with or dissolved in a volatile organic solvent (i.e., the organic polymer binder solution), forms a second premix. The first and second premixes are preferably mixed to form a substantially homogeneous and fluid slurry mixture, which is then preferably printed as a leading part of the gradient-function article. The amount of the second premix is ​​preferably about 10% to about 90% by volume, more preferably about 10% to about 70% by volume.

[0103] The mixing preferably forms or produces a substantially homogeneous and fluid slurry mixture that is printed in this system as a preceding component of the gradient functional article. Accordingly, Figures 3A and 3B, 4, 5A and 5B illustrate a gradient functional article manufactured according to the present invention. The substantially homogeneous and fluid slurry mixture of the present invention can refer to a composition that is homogeneously mixed to have substantially one morphological phase in the same state, such that at least two random samples of the composition have roughly or substantially the same amount, concentration and distribution of its components (e.g., building materials, organic polymer binders, additives, and / or volatile organic solvents). The substantially homogeneous and fluid slurry mixture of the present invention also means that it includes compositions that are fluid under gravity and / or can be pumped in (pumped). Furthermore, the substantially homogeneous and fluid slurry mixture indicates the performance of a composition when transported from a storage container such as a container by gravity or by conventional mechanical, hydraulic, or pneumatic pumping means.

[0104] In one preferred embodiment, a substantially homogeneous and fluid slurry mixture comprises two or more substantially homogeneous and fluid slurry mixtures. As schematically shown in Figure 2, the two or more substantially homogeneous and fluid slurry mixtures are instantaneously mixed in-situ in a static or dynamic mixer to form one substantially homogeneous and fluid slurry mixture. Preferably, the two or more substantially homogeneous and fluid slurry mixtures comprise two substantially homogeneous and fluid slurry mixtures, each comprising a first premix and a second premix. For example, there may be two substantially homogeneous and fluid slurry mixtures, namely a first substantially homogeneous and fluid slurry mixture and a second substantially homogeneous and fluid slurry mixture. The first substantially homogeneous and fluid slurry mixture comprises a first premix comprising a metal, which is a building material, mixed with a dispersant, which is preferably an additive, and a second premix comprising a cellulose ester, which is the organic polymer binder, dissolved in acetone, which is a volatile organic solvent. A second substantially homogeneous and fluid slurry mixture comprises a first premix containing a ceramic, which is a building material mixed with a blowing agent, which is preferably an additive, and a second premix containing cellulose ether, which is the organic polymer binder, dissolved in butanone, which is a volatile organic solvent. The resulting first and second substantially homogeneous and fluid slurry mixtures are mixed in the single static or dynamic mixer to form a single substantially homogeneous and fluid slurry mixture prior to extrusion.

[0105] The term "in-situ" is understood to mean the location where mixing takes place or provides the mixing, or on-site mixing. Therefore, to form slurry feedstock at the mixing site, constructor materials, organic polymer binders, additives, and / or volatile organic solvents are generally co-injected (co-delivered) or supplied together to a single static or dynamic mixer (target site) and mixed or assembled at the co-injection site within the single static or dynamic mixer.

[0106] The terms “instantaneous” or “momentary” may also be understood to mean the time required to prepare the slurry feedstock in a single static or dynamic mixer by mixing the building materials, organic polymer binders, additives, volatile organic solvents, building materials mixed with additives, and / or volatile organic solvents (i.e., organic polymer binder solution) together with or dissolved in the organic polymer binder. In this invention, such instantaneous mixing may occur in a time of one to several seconds. Compared to the total processing time (up to several minutes), mixing in terms of seconds can be considered very rapid or instantaneous.

[0107] It should be further understood that the term “single static or dynamic mixer” as used herein refers to a single unit of static or dynamic mixer, rather than multiple non-operationally coupled random mixers as in the prior art.

[0108] In various embodiments of the present invention, the organic polymer binder is debonded from the preceding component, preferably by a thermal decomposition treatment based on the thermal decomposition temperature, a solvent debonding treatment, or a combination thereof. The thermal decomposition treatment may be selected from the group including heating, thermal debonding, densification / sintering, partial or complete melting, and / or potentially post-densification annealing, of components other than the constructing material, i.e., metal particles and / or ceramic particles, to relieve or further increase residual stress in the preceding component. In some embodiments, the thermal decomposition treatment by heating may be performed at room temperature, or at a lower temperature and shorter time than normal heat treatment times and temperatures, for example, at about 60°C to about 200°C for about 10 minutes to about 1 hour to achieve the effect.

[0109] The solvent debonding treatment of the preceding component may include contacting the preceding component with a solvent to extract a soluble binder (along with any additives) from the main body. Suitable solvents for solvent debonding according to the present invention include preferably acetone, methyl ethyl ketone, heptane, carbon tetrachloride, trichloroethylene, methylene chloride, and alternative solvents such as supercritical carbon dioxide and water.

[0110] The pyrolysis treatment and / or the solvent debonding treatment of the preceding part are followed by a sintering treatment to produce the final part of the gradient functional article. The final part preferably comprises a building material in which the composition, filling pattern, or any combination thereof is selectively and gradually changed over the volume of the final part in one or more directions that form a three-dimensional structure. The change in composition, filling pattern, or any combination thereof is preferably incremental, referring to a change or deviation that occurs continuously or in small steps over a non-zero distance within its volume. The one or more directions preferably include any spatial directions (x, y, and / or z) in space with respect to the reference point system of the gradient functional article.

[0111] The slurry feed material of the present invention preferably further comprises a support material. The support material preferably forms a substantially uniform and fluid support mixture configured to print support structures for overhangs or cantilevers of inclined functional articles. The support structures are an essential element for enabling the manufacture of complex geometric shapes using additive manufacturing.

[0112] The support structure or support layer is typically constructed beneath an overhang or within a cavity of the preceding part of the inclined functional article being formed, where it is not supported by the part material itself. The support structure may be constructed using the same deposition technique to which a substantially uniform and fluid slurry mixture is deposited. A host computer may generate additional geometric shapes that act as support structures for the overhang or free-space portion of the preceding part of the inclined functional article being formed. The support material is then deposited during the printing process from the same print head (similar to the substantially uniform and fluid slurry mixture) or a different print head or nozzle, according to the generated geometric shapes. The support material can be printed using a single nozzle or a multi-nozzle configuration. The support material adheres to the part material during manufacturing and is removable from the finished preceding part of the inclined functional article when the printing process is complete.

[0113] The support material preferably comprises a ceramic, a sacrificial material, a dissipative material, or any combination thereof. In one embodiment of the present invention, the support material preferably has a particle size greater than about 75 μm. According to one representative embodiment, the ceramic, sacrificial material, and / or dissipative material preferably form a first premix, and the organic polymer binder is dissolved in a volatile organic solvent to form a second premix. The first premix and the second premix are added together to form a substantially homogeneous and fluid support mixture.

[0114] Pyrolysis and / or solvent debonding and / or sintering treatments are preferable because they can suppress bonding between the support structure and the preceding components of the functionally graded article. Therefore, the sintered functionally graded article can be easily removed from its support structure.

[0115] In one embodiment of the present invention, for a functionally graded article mainly composed of metal, it is preferable to use a substantially uniform and fluid ceramic as the support material. Relatively coarse ceramic powder forming the support material results in a loosely packed structure after sintering, which is brittle and does not fuse well with the functionally graded article. Therefore, minimal effort is required to remove the support structure from the functionally graded article. In one embodiment of the present invention, for a functionally graded article mainly composed of ceramic, it is preferable to use a substantially uniform and fluid sacrificial material, such as an inorganic salt, as the support material. The support material can be easily removed during a solvent debonding treatment using water. Then, the preceding components of the functionally graded article are embedded in relatively coarse alumina powder for thermal decomposition and sintering to form the final functionally graded article.

[0116] Figures 6A, 6B, 6C, and 6D exemplify unfired samples or parts of gradient functional articles manufactured according to the present invention. In these figures, the green parts exhibit a unique FGM transition gradient that changes in a continuous transition of helical concentricity in the xy plane and z direction. Preferably, it starts with a base having a 10% alumina slurry mixture and a 90% clay slurry mixture, transitions smoothly to an intermediate portion having a 90% alumina slurry mixture and a 10% clay slurry mixture, and then reaches an upper portion having a 10% alumina slurry mixture and a 90% clay slurry mixture. The darker and lighter shades of the green parts in Figures 6A and 6B represent a clay-based mixture and an alumina-based mixture, respectively. The following configurations may be practical to achieve the green parts.

[0117] Table 1: Composition of the first mixture [Table 1]

[0118] Table 2: Composition of the second mixture [Table 2]

[0119] Referring to Figure 7, a method for preparing slurry feed material for use in extrusion-based 3D printing to manufacture tilting functional articles preferably includes the following steps: (a) A preparation step of preparing a building material comprising a metal, a ceramic, or any combination thereof, (a-1) A step of supplying a building material which is porous, non-porous, or any combination thereof, (a-2) The preparation step includes a step of supplying construction materials in an amount of 10% to 90% by volume, (b) A preparation step of preparing an organic polymer binder selected from the group comprising cellulose esters, cellulose ethers, and derivatives thereof, (b-1) The preparation step includes a step of providing an organic polymer binder at a concentration of 150 g / L to 550 g / L, (c) A preparation step of preparing additives selected from the group including plasticizers, defoamers, dispersants, sacrificial materials, dissipative materials, skeletal materials, water-soluble inorganic salts, foaming agents, graphene, graphene oxide, flame retardants, toners, release agents, stabilizers, antistatic agents, impact modifiers, colorants, antioxidants, and any combination thereof, (d) Preparation steps for preparing volatile organic solvents, (e) A forming step of mixing the mixed building materials and additives to form a first premix, (f) A forming step of mixing the dissolved organic polymer binder with a volatile organic solvent to form a second premix, (g) A forming step of mixing a first premix and a second premix to form a substantially uniform, fluid slurry mixture to be printed as a leading part of a gradient functional article.

[0120] Preferably, this method further comprises a forming step of forming two or more substantially homogeneous and fluid slurry mixtures, each containing a first premix and a second premix, respectively, and a forming step of instantaneously mixing the two or more substantially homogeneous and fluid slurry mixtures in situ using a static or dynamic mixer to form one substantially homogeneous and fluid slurry mixture.

[0121] As described in a previous paragraph, the organic polymer binder is debonded from the preceding part by either or both a thermal decomposition treatment and / or a solvent debonding treatment, and a subsequent sintering treatment produces a final part containing the constructing material in which the composition, including the configuration including the filling pattern, or any combination thereof, is selectively and gradually changed over the volume of the final part of a functional article with a gradient in one or more directions.

[0122] This method is presented as a numbered sequence for clarity, but the numbering does not necessarily describe the order of the steps. It should be understood that some of these steps may be omitted, performed in parallel, or carried out without requiring strict adherence to a particular order.

[0123] Referring to Figure 8, a method for printing a tilted functional article (i.e., extrusion-based 3D printing) preferably includes the following steps:

[0124] (a) A supply process for supplying slurry feed material, (a-1) A preparation step of preparing a building material comprising a metal, a ceramic, or any combination thereof, (a-1-1) A step of supplying the construction material which is porous, non-porous, or any combination thereof, (a-1-2) The preparation step includes a step of supplying construction materials in an amount of 10% to 90% by volume, (a-2) A preparation step for preparing an organic polymer binder selected from the group comprising cellulose esters, cellulose ethers, and their derivatives, (a-2-1) The preparation step includes a step of providing an organic polymer binder at a concentration of 150 g / L to 550 g / L, (a-3) A supply step comprising a preparation step of preparing additives selected from the group including plasticizers, defoamers, dispersants, sacrificial materials, dissipative materials, skeletal materials, water-soluble inorganic salts, foaming agents, graphene, graphene oxide, flame retardants, toners, release agents, stabilizers, antistatic agents, impact modifiers, colorants, antioxidants, and any combination thereof, (b) A forming step of mixing the mixed building materials and additives to form a first premix, (c) A forming step of mixing the dissolved organic polymer binder with a volatile organic solvent to form a second premix, (d) A forming step of mixing the first premix and the second premix to form a substantially uniform, fluid slurry mixture to be printed as a leading part of the gradient functional article, (e) A debonding step of debonding the organic polymer binder from the preceding component by either or both of a thermal decomposition treatment and / or a solvent debonding treatment, (f) A sintering step in which a preceding part from which an organic polymer binder has been detached is subjected to a sintering process to produce a final part containing a building material in which the composition, filling pattern, or any combination thereof, which varies selectively and gradually over the volume of the final part of a functional article with a gradient in one or more directions.

[0125] Preferably, this method further comprises a forming step of forming two or more substantially homogeneous and fluid slurry mixtures, each containing a first premix and a second premix, respectively, and a forming step of instantaneously mixing the two or more substantially homogeneous and fluid slurry mixtures in situ using a static or dynamic mixer to form one substantially homogeneous and fluid slurry mixture.

[0126] This method is presented as a numbered sequence for clarity, but the numbering does not necessarily describe the order of the steps. It should be understood that some of these steps may be omitted, performed in parallel, or carried out without requiring strict adherence to a particular order.

[0127] In a preferred embodiment of the present invention, the system used for 3D printing of an extrusion base of a tilting functional article preferably includes one or more vessels, injection regulating means, a calculation unit, a fluid drive, optionally a single static or dynamic mixer, and a print head. Figures 9A and 9B, 10, 11, 12, and 13 illustrate the system of the present invention as an example.

[0128] In Figure 9A, a system having a predetermined print nozzle configuration is preferably positioned on a flat surface or substrate (e.g., a heating plate) within the cavity of a heating chamber. The preceding part extruded from the print nozzle is deposited on the flat surface. In one embodiment of the present invention, the flat surface is a leveling platform (self-leveling or mechanical) that operably cooperates with the print nozzle to produce the part. The leveling platform can be computer-numerically controlled by the same or a different calculation unit for the print nozzle of the print head. The heating chamber and / or heating plate are preferably optional.

[0129] Figure 9B shows a mechanism for extrusion-based 3D printing to manufacture a tilting functional article. In the figure, the slurry feed material is contained in a container connected to a fluid drive, which delivers the slurry feed material to an injection regulating means under control by a control unit in the calculation unit. As soon as the slurry feed material, which is a substantially uniform and fluid slurry mixture, is introduced to the print head, the feed material is extruded onto a flat surface through a print nozzle attached to the print head, producing the green parts of the tilting functional article. The print head preferably does not have a heater or the like. A heating plate is preferably optional. Hot air or room temperature ventilation may be provided on any base.

[0130] One or more containers, or containers, tanks, or vessels, are preferably configured to separately contain slurry supply materials and / or their components, as described in a previous paragraph. The above containers are preferably airtight. The containers may be made from metal, plastic, or a combination thereof, in various shapes and sizes.

[0131] In one embodiment, each container holds the building material, organic polymer binder, additives, and volatile organic solvent in an individual, separate manner. For example, four separate containers are provided, each adapted to store the building material, organic polymer binder, additives, and volatile organic solvent. These four containers are specifically configured for in-situ mixing of the components of the slurry feedstock.

[0132] In another embodiment, the metal and ceramic building materials are housed in different separate containers. For example, metal particles are stored in a first container and ceramic particles in a second container. The metal and ceramic building materials can be stored in many more separate containers depending on, for example, the properties of the particular metal or ceramic (e.g., physical properties, chemical properties, rheological properties, etc.), the type of metal and / or ceramic (e.g., metal A, metal B, ceramic A, ceramic B, porous metal A, porous metal B, porous ceramic A, porous ceramic B, etc.), and the final properties required by their functionally graded articles. In another embodiment of the present invention, the building materials can be mixed with additives that form a first premix and stored in one container, and the organic polymer binder can be dissolved together with or in a volatile organic solvent that forms a second premix and stored in another container. These two containers are configured to supply such mixtures (i.e., premixed building materials and additives, as well as pre-dissolved organic polymer binders in volatile organic solvents) to the static or dynamic mixer.

[0133] In yet another embodiment, the first container is configured to store a slurry feedstock, which is a substantially homogeneous and fluid slurry mixture containing one additive and a building material mixed with the organic polymer binder solution, and the second container is configured to store another additive mixed with the organic polymer binder solution. The first and second containers are preferably arranged to vary the microporosity of the gradient functional article in order to obtain any desired or targeted filling pattern. In this regard, the other additive is a sacrificial material and / or dissipative material. The above container arrangement may not be applicable to variations in microporosity.

[0134] The injection adjustment means is preferably mechanically connected to the container. The injection adjustment means is preferably configured to adjust the injection speed and amount of slurry supply material and / or its components stored in the container by controlling the position of a control piston provided therein. The injection adjustment means is preferably connected to and communicates with the control unit of its calculation unit.

[0135] The injection adjustment means is preferably selected from the group including solenoid valves, mechanical pumps, and combinations thereof.

[0136] The solenoid valve used in this invention, also known as a servo valve, refers to any device that can connect, more specifically, to a slurry feed material and / or its components, stored in a container located upstream of a static or dynamic mixer, in a controlled manner so as to be pressure-controlled by a user circuit located downstream. Such a solenoid valve generally comprises two chambers and a slide valve. Depending on its position, the slide valve is controlled to connect one chamber to a high-pressure supply circuit and the other chamber to a low-speed pressure fluid return circuit. One of the chambers is further connected to the user circuit. It should be noted that this type of solenoid valve device includes a pulsator, which is not directly connected to the user circuit but is operationally connected to it via a vibrating piston controlled by the solenoid valve.

[0137] The term "mechanical pump" or "simple pump" as used herein is a broad term and, according to its usual meaning, any device capable of promoting fluid flow, and at least in this invention, capable of promoting the flow of slurry feed material. As an example, pumps can include syringe pumps, peristaltic pumps, vacuum pumps, electric pumps, mechanical pumps, slurry pumps, centrifugal pumps, hydraulic pumps, and any combination thereof. Pumps and / or pump components suitable for use in some embodiments can be appropriately obtained to ensure effective and consistent pumping of the slurry.

[0138] The calculation unit connected to the control unit preferably refers to any system including a processor and memory. In some embodiments, the calculation unit may include a display. The calculation unit is preferably configured to generate control signals for spray adjustment means, static or dynamic mixers, and / or their print heads. The control signals are a single signal or a set of multiple signals used to control the components connected thereto. The control signals are preferably able to control one or more properties (related to the system) such as spray speed, spray volume, spray time, deposition speed, positioning of the print nozzle or print head, and shape of the tilting functional article. The control unit is preferably connected to a database having a predetermined set of materials and rheology profiles used in the present invention. This database is used so that the control signals operationally influence the final part of the tilting functional article. For example, the control signals are adjusted according to the rheology profile of the construction material so that the spray adjustment means can apply the precise spray speed and / or spray volume corresponding to the profile and the desired tilting functional article. The control unit may include a hardware device including memory and a processor integrated with a server. The memory is configured to store modules / units that execute instructions, and the processor is configured to execute the instructions, specifically to perform one or more operations described herein.

[0139] In some embodiments, the computing unit is an integrated system. In some embodiments, the computing unit is not integrated. The computing unit is a dedicated computer or dedicated computing device equipped with computing power and / or storage memory (e.g., CPU, microprocessor, etc.), which typically preferably runs operating software (e.g., jet adjustment means, static or dynamic mixers and print heads) for operating the system of the present invention and performs a predetermined printing procedure. The computing unit is integrated into the system of the present invention or connected to the system in a dedicated manner to operate the system.

[0140] In a typical embodiment, the computing unit includes a peer-to-peer module for receiving request messages to a peer-to-peer application. The request message contains data and information and customization parameters for the desired product to be manufactured by the system of the present invention, i.e., a tilting functional article.

[0141] The fluid drive device is positioned adjacent to the container or the injection regulating means. The fluid drive device is preferably a pressure drive device, or a pressure drive device for the injection regulating means, configured to provide or supply fluid pressure or pressurized fluid to and from the transfer mechanism to bring about movement of the slurry feed material and / or its components contained within each container, thereby providing pressurized slurry feed material and / or pressurized components. The term “fluid pressure” in this context is intended to cover any suitable fluid pressure of this feature and is broad enough to include vacuum.

[0142] In preferred embodiments, the fluid drive system of the present invention can be selected from the group including pneumatic drive systems, hydraulic drive systems, mechanical movers, and any combination thereof. The pneumatic drive systems used herein preferably include any type of equipment operated by the passage of compressed air. For example, a pneumatic drive system is a system operated by air or other gas under pressure, such as a relatively low-cost yet efficient rotary piston air motor and a portable high-pressure pneumatic cylinder. A hydraulic drive system is preferably a hydraulic drive system incorporating a hydraulic motor, with or without a separate reduction gear. A mechanical mover can be used to transfer slurry feed material to an injection regulating means. The fluid drive system also includes any other electrically operated movers that are appropriately employed for the present invention.

[0143] A single static or dynamic mixer, optionally used in the present invention, is preferably configured to instantaneously mix two or more substantially homogeneous and fluid slurry mixtures in situ, on its own, to form one or a single substantially homogeneous and fluid slurry mixture before being transferred to the print head.

[0144] A single static mixer or motionless mixer is, in essence, a mixer that does not contain any internal moving mechanical parts. A static mixer is a device that includes one or more substantially stationary mixing elements, such as baffles such as blades, plates, or vanes, and mixes a fluid fluid, such as slurry feed material, and / or its components through a conduit to create flow splitting or splitting patterns, thereby achieving mixing in the fluid, such as radial circulation or helical mixing by exchange. Static mixing elements are typically immobile within the conduit, but limited movement of stationary elements is possible as long as they do not substantially contribute to the mixing of the fluid fluid. In a static mixer having multiple static mixing elements, these elements can be arranged in series with respect to each other and / or staggered. A static mixer is preferably selected to produce a mixed fluid flow, i.e., a substantially uniform and fluid slurry mixture, over a short length of the mixer. A dynamic mixer, on the other hand, is the opposite of the static mixer and preferably includes moving parts. A dynamic mixer can mix slurry feedstocks and their components together after they are loaded or while they are being loaded. Other mixers with similar properties may be used instead of the aforementioned mixers, as those skilled in the art can appropriately select.

[0145] A printhead equipped with print nozzles preferably includes a chamber that holds the substantially uniform and fluid slurry mixture immediately before printing or extruding it onto a flat surface. Therefore, considering the slurry feed material of the present invention, the printhead has the advantage of not requiring a heater or the like. In one embodiment, the printhead includes a single printhead, a print bar, and a carriage assembly or mounting block having a plurality of printheads, each having one or more print nozzles arranged in a linear or nonlinear array. The printhead is preferably operably driven by its computing unit and configured to spray, extrude, distribute, deposit, or generally discharge the substantially uniform and fluid slurry mixture, which is received directly from a fluid drive and / or from a single static or dynamic mixer, to produce the preceding components of the gradient functional article. Discharge of the substantially uniform and fluid slurry mixture is a non-contact distribution process utilizing the printhead to form and fire or extrude a continuous or discontinuous flow of the slurry feed material from the print nozzles onto a flat surface or substrate. A static or dynamic mixer can be connected to the printhead via a distribution unit that can be controlled by a separate calculation unit or the same calculation unit.

[0146] In one typical embodiment of the system of the present invention, as can be seen with reference to Figure 10, the containers (i.e., container 1 and container 2) are connected to a fluid drive device.

[0147] The spray adjustment mechanism is positioned between the container and a single static or dynamic mixer connected to the printhead. A calculation unit is preferably responsible for managing the spray adjustment mechanism, the static or dynamic mixer, and the printhead. The spray adjustment mechanism is preferably a mechanical pump.

[0148] In one typical embodiment of the system of the present invention, Figure 11 is essentially the same as the configuration of Figure 10, except that the distribution unit is located between the static or dynamic mixer and the printhead. In this configuration, it is preferable that the calculation unit manages the jet adjustment means (i.e., the mechanical pump), the static or dynamic mixer, the distribution unit, and the printhead.

[0149] In one typical embodiment of the system of the present invention, Figure 12 shows another arrangement using a solenoid valve as a jet regulating means. The solenoid valve is positioned in front of the vessel and connected to a fluid drive unit. A static or dynamic mixer is connected to the vessel and a distribution unit positioned in front of the printhead. A calculation unit preferably manages the solenoid valve, static or dynamic mixer, distribution unit, and printhead.

[0150] The present invention will be specifically described by the following embodiments, but it should be understood that the present invention is not limited to these embodiments.

[0151] The present invention enables a person, such as a technician, to produce FGM articles based on changes from metal A to metal B, metal A to ceramic A, or ceramic A to ceramic B, by direct slurry writing technology (where A and B may be any metal family group or ceramic family group). This versatile method of the present invention can change the material properties of the printed object in three dimensions (see Figures 3A and 3B) rather than in a single direction as disclosed in the prior art and / or conventional manufacturing methods. The present invention enables complete use or optimization by using or utilizing the excellent properties of each material to form unique metal / ceramic composite materials that maintain functionality under extreme conditions.

[0152] The extrusion-based printing of the present invention begins with the engineering design of a CAD model and target material profile based on guidelines provided via a material database (encoded example profiles are shown in Figures 3A and 3B) to form the unique properties of the FGM article. The CAD model is then processed via a pure program to generate Gcode (instructions for the 3D printer to run) for the system of the present invention. This is followed by design post-processing software in which the material profile is integrated with its generated Gcode. The post-processing tool allows the material mixing ratio to be programmed into the Gcode so that the printer can change the mixture composition during the printing process itself.

[0153] A proprietary 3D printer (which is the system of the present invention) may consist of two or more extruders, thereby enabling the mixing of two or more types of materials in the FGM printing of the present invention. The slurry feed material is supplied into a container or tank having pneumatic / hydraulic drive to provide pressure for moving the slurry feed material into a mechanical pump driven by a motor controlled by the printer control unit. The slurry feed material is precisely pumped into a static or dynamic mixer depending on the viscosity of the material to be printed. Since the feed material is slurry formation, in contrast to existing additive methods or techniques where material changes can only be achieved by separate formations (see Figure 1), the mixing of two or more types of materials during printing can be easily scaled up and mixed in-situ during the printing process, as shown in Figure 2.

[0154] The slurry mix print of the present invention relies on the deposition of a solvent-based binder to form a cured print. Therefore, controlling the concentration of the organic polymer binder and the ratio between the binder and the binder particles (i.e., metal and / or ceramic powder) is a critical step to ensure that the printed solution has sufficient static yield strength to maintain its shape after being extruded from the print nozzle. On the other hand, it is still possible to form a uniform slurry mixture during printing, as shown in Figure 2, by mixing using a static mixer (referring to the mixing of fluids without an actively moving part) or a dynamic mixer (including a rotor that mixes fluids via a dynamic shearing mechanism). Static or dynamic mixers have an effective viscosity working range.

[0155] To obtain an effective and homogeneous mixture, the slurry mixture must be prepared so that both types of material raw materials have slight variations in viscosity over a range of shear rates. Different types of powder sizes or shapes result in significant differences in their rheological behavior. Rheological adjustments must be made within each material and in combinations of both mixtures across all variable mixtures. Ideally, they should be in the range of about 30–90 vol% for metals and / or ceramics, about 200–500 g / L and / or 10–70 vol% for the organic polymer binders, and about 1–15 vol% for additives. An effective mixture, which can vary over a wide range of ratios between the two materials, cannot be obtained simply by mixing the two materials together. For example, to obtain a fluid mixture suitable for a print rate of about 10–80 vol%, it may be necessary that raw material A is very viscous and material B is very liquid in its material state. Since both slurries are inherently non-Newtonian fluids, similar shear rates or pumping rates can result in different volumetric flow rates, which can lead to inaccurate mixing ratios programmed by the user. Therefore, in this invention, the rheological profiles of the raw materials (i.e., the components of the slurry feed material) and their mixtures must be achieved and mapped by experimental configuration. These rheological profiles are integrated with the design of the material profiles to form a unique compensation factor that should be included during the post-treatment of the pure Gcode to ensure that the feed volume flow rates of both slurries are consistent so that a uniform mixing ratio is obtained. There is an achievable effective mixing ratio between the two materials, i.e., it is usually in the range of about 10-90%. This allows for the production of metal and ceramic mixtures, i.e., metal A and metal B, metal A (porous mixture) and metal A (non-porous mixture), ceramic A (porous) and ceramic A (non-porous), or ceramic A and ceramic B, depending on the needs and properties of the article to be formed. The mixture of materials flowing through the mixer may be three or more types of materials and is not limited to those shown in any figure.This configuration allows material A and material B to be mixed in the correct ratio during the printing process.

[0156] An example configuration is shown below.

[0157] • Material A (metal / ceramic A with a liquid, low-concentration binder) and Material B (pure binder with a premix of additives). This prevents premature drying of the premixed slurry material during printing using only a single nozzle (to simplify preparation). The precise rheological behavior of the slurry can be adjusted based on the printing conditions, i.e., temperature and humidity.

[0158] • A mixture of both material A (metal) and material B (ceramic) can be precisely varied in three dimensions during printing via printer control software, making it possible to create gradient functional materials that vary in three dimensions, as shown in Figures 3A and 3B. Note that this may also be a mixture of two or more materials, varying in one or more directions and potentially printed in-situ.

[0159] Material A (porous metal / ceramic mixture) is formed by adding a skeletal insoluble material / foaming agent to Material A (concentrated mixture), and Material A can be selected from the group of metals and ceramics. This allows for the printing of unique structures such as shells filled with solid and porous material (see Figure 4). The porosity gradient can be controlled not only as linear or one-dimensional, but also as a parabolic gradient applied across 3D space, as shown in Figure 4 (see Figures 5A and 5B).

[0160] Here, the definition of porous metal may refer to metal or ceramic / metal foam / ceramic foam. Porous structures can be classified as microporous (<100 μm) and macroporous (>100 μm). In this embodiment, macroporous structures are obtained by controlling the packing structure via pure software (which can be formed in various shapes such as honeycomb, adaptive cube, triangle, star, grilloid, line, concentric circles, Hilbert curve, and lattice structures). The present invention can handle microporous structures by adding a foaming agent or sacrificial material, dissipative material, or skeletal material. This allows for the control of microporous and macroporous structures printed in a single solution by the in-situ mixing of porous and non-porous mixtures. Foaming agents can form random porous structures with minimal control over porous shape and structure. Mixing with the addition of sacrificial / dissipative / skeletal material allows for precise control of porous size, density, and shape.

[0161] The following are non-limiting combinations of building materials, including metals and ceramics. ·Metal-metal (i) Al-Cu (ii) AL-Ni (iii) Ni-Ti (iv)316L-H13 (v) “Ti-6Al-4V”-304L (vi) Low carbon steel-high carbon steel (vii)304-304 porous structure • Metal-ceramic (i) Al-SiC (ii) Al-Al2O3 (iii) Ni-ZrO2 (iv) Cu-SiC

[0162] Ceramic - Ceramic (i) SiC-SiC (different densities) (ii) Al2O3-Al2O3 (porous structure) (iii) Al2O3-SiC (iv) Al2O3-ZrO2

[0163] For FGM articles containing gradual material transitions (see (i)-(v) for metal-metal transitions), the base formulations for each individual material are exemplified in the table below. Such combination changes can be made between 0% and 100% of the gradient transition.

[0164] Table 3: Recommended final mixture composition [Table 3]

[0165] Table 4: Recommended porous composite material mixtures [Table 4]

[0166] The following compositions can be used for the transition between low-carbon steel and high-carbon steel.

[0167] Table 5: Composition of the first mixture [Table 5]

[0168] Table 6: Composition of the second mixture [Table 6]

[0169] In the case of a 304-304 porous structure, the porosity of the structure is controlled by the size of the salt crystals. The following can be used:

[0170] Table 7: Composition of the first mixture [Table 7]

[0171] Table 8: Composition of the second mixture [Table 8]

[0172] The following can be used for the transition between clay and low-carbon steel.

[0173] Table 9: Composition of the first mixture [Table 9]

[0174] Table 10: Composition of the second mixture [Table 10]

[0175] <Other examples / forms> The present invention further discloses slurry feedstock for casting articles at low pressure and room temperature, a method for preparing it, a method for casting articles, and a system therefor. The advantage is that, with the slurry feedstock used in conjunction with a reusable mold, the present invention simplifies conventional casting methods by enabling the casting of metal / ceramic articles without requiring high pressure or metal melting. The present invention primarily focuses on the design and configuration of a novel slurry-based feedstock prepared for metal / ceramic casting at room temperature, as well as a reusable mold. Because the feedstock is in slurry form, it is fluid and mobile, and precise casting volume control into the mold is possible with gravity or minimal pressure, thus further avoiding the risky investment of high-pressure injection systems. Furthermore, the present invention can be used and maintained in a very specific, compact, cost-effective, quick, and simple manner without the use of complex and sophisticated processes, components, or parts.

[0176] As used herein, the term "article" refers to a manufactured article or semi-finished product having any shape, produced from a slurry feed material by mold casting.

[0177] As used herein, the term “slurry” refers to a solid-fluid mixture, including both solid-liquid and solid-gas mixtures. For convenience, with respect to solid-liquid slurries, the present invention discusses them as feed material compositions in which the solid and liquid exist in separate phases. Solid-liquid slurries also include solids and liquids that are introduced into the system of the present invention and are completely or partially separated.

[0178] As used herein, the term “supply material” is defined as a raw material or mixture of raw materials having properties suitable for being supplied to the System, which is capable of producing articles, and is construed to be a component that has not yet been mixed, or is to be further mixed, to produce a mixture suitable for use with the mold.

[0179] As used herein, the term “premix” refers to components that are mixed together to form one part of a slurry mixture.

[0180] As used in this specification, the term "low pressure" refers to a pressure of 2 MPa or less.

[0181] As used herein, the term "room temperature" refers to a temperature at which no additional energy is consumed in the slurry feedstock, or a temperature in the vicinity thereof. In one embodiment, this term refers to a temperature range of approximately 20°C to 30°C.

[0182] As used herein, the terms “preceding part” or “green part” refer to an article or preformed article in a state prior to sintering, which is manufactured by the present invention for further processing by other manufacturing techniques.

[0183] As used herein, the term “brown part” refers to an article manufactured from a preceding or green part that has been subjected to a thermal decomposition treatment and / or solvent debonding treatment to remove binders, sacrificial materials and / or dissipative materials that previously held the supply raw materials together. The brown part may be further heated to completely sinter the part or subjected to sintering in order to manufacture the final or finished part of the article.

[0184] According to one preferred embodiment of the present invention, the slurry feedstock comprises a building material, an organic polymer binder, an additive (which may be optional), and a volatile organic solvent.

[0185] The organic polymer binder is preferably dissolved in a volatile organic solvent to produce an organic polymer binder solution. The additive is preferably added to the construction material to obtain predetermined rheological behavior and print properties. The slurry feed material can essentially be formed by blending the organic polymer binder solution with the construction material mixed with the additive. The resulting slurry feed material can be introduced into a reusable mold and dried by phase inversion at room temperature without external heat supply means.

[0186] The building material of the present invention refers to a powder preferably used to form a slurry feedstock, in which articles are built within the casting system of the present invention. The powder, or particulate material or particles, has a variety of mesh sizes. In one embodiment, the building material has a particle size of about 300 μm or less, preferably less than about 200 μm. The building material is preferably a layering material for use in the casting system of the present invention. The building material may also be in various forms, such as granular powder, fibrous powder, and flaky powder. In a preferred embodiment, the building material is used in an amount of about 10% to about 90% by volume, more preferably about 30% to about 90% by volume.

[0187] The construction material preferably includes metal, ceramic, or any combination thereof. In one embodiment of the present invention, the construction material may be porous, non-porous, or any combination thereof. For example, porous metal means metal particles having significant porosity, e.g., porosity greater than about 0.5 cc / g. The construction material may have pores less than 100 μm (microporous) and / or greater than 100 μm (mesoporous). Non-porous metal, on the other hand, means metal particles with little or no porosity, e.g., porosity less than about 0.05 cc / g. Porous ceramics preferably have porosity with controllable porosity and good mechanical properties. The term "porosity," as used herein, refers to the volume fraction of void space in a porous article, e.g., its porous construction material.

[0188] The porous metals and / or porous ceramics used in the present invention are preferably microporous and can be produced, for example, by direct foaming using a suitable foaming agent, sacrificial material, dissipative material, skeletal material, etc. The porosity can also be controlled by the size of the salt crystals.

[0189] In one preferred embodiment of the present invention, the construction material may consist solely of metal (porous and / or nonporous) or ceramic (porous and / or nonporous). Alternatively, the construction material may include a combination of metal and ceramic in predetermined mixing ratios or volume ratios so as to adequately satisfy the desired properties of the construction material for the article. Examples of such combinations include metal and ceramic; porous metal and ceramic; metal and porous ceramic; porous metal, nonporous metal and ceramic; metal, porous ceramic and nonporous ceramic; porous metal, nonporous metal, porous ceramic and nonporous ceramic, and so on. Various other combinations are possible (e.g., a first metal, a second metal, a first ceramic, a second ceramic, etc.).

[0190] The metal used in the present invention is preferably selected from the group including ferrous metals, nonferrous metals, ferrous metal alloys, and nonferrous metal alloys.

[0191] The ferrous metal is selected from steel, stainless steel, mild steel, cast iron, malleable iron, ductile cast iron, and the like. Preferably, the ferrous metal includes iron, iron-chromium alloys, iron-chromium-nickel alloys, iron-chromium-zinc alloys, iron-chromium-aluminum alloys, iron-chromium-magnesium alloys, iron-chromium-lead alloys, iron-aluminum alloys, iron-zinc alloys, stainless steel, iron-nickel alloys, and combinations thereof. Preferred examples of steel and / or stainless steel include AISI 304, AISI 304L, AISI 316, AISI 316L, AISI 430, AISI 630 (17-4PH), and AISI 631 (17-7PH). Other steels such as A2-A5, D2, H13, M2, and 4140 can also be used in this invention.

[0192] Nonferrous metals are selected from aluminum, aluminum alloys, magnesium, magnesium alloys, zinc, zinc alloys, cadmium, chromium(III), copper, copper(II)-cadmium, lead, cobalt, cobalt-chromium, cobalt-chromium-molybdenum, nickel, nickel alloys, molybdenum, titanium, tantalum, niobium, silver, and gold. Preferred examples of aluminum and / or aluminum alloys include AlSi10Mg, AlSi7Mg, ADC12, and AlMg5Mn. Preferred examples of nickel alloys include alloy 706, alloy 718, alloy 625, and Invar types such as FeNi36 or 64FeNi, or Hastelloy X, Hastelloy C, and Kovar.

[0193] The ceramics used in the present invention are preferably selected from the group including silicate ceramics, oxide ceramics, non-oxide ceramics, bioceramics, and any combination thereof.

[0194] Silicate ceramics preferably include, but are not limited to, clay, cordierite ceramics, steatite, stoneware, pottery, porcelain, kaolin, quartz, silicates, camott, bentonite, mullite, and any combination thereof.

[0195] Oxide ceramics preferably include, but are not limited to, alumina, zirconia including zirconia stabilized in yttria oxide (Y3O2), beryllium oxide, yttrium oxide, titanium oxide, magnesium oxide, calcium oxide, barium oxide, zinc oxide, uranium oxide (UO2), plutonium dioxide (PuO2), yttrium barium copper oxide, spinel, magnetoplanvite, perovskite, cheerite, and any combination thereof.

[0196] Non-oxide ceramics preferably include, but are not limited to, carbide ceramics such as titanium carbide, boron carbide, tungsten carbide, and silicon carbide; nitride ceramics such as silicon nitride, boron nitride, and aluminum nitride; nitride ceramics including aluminum oxide nitride, SiAION (ceramics based on the elements silicon (Si), aluminum (Al), oxygen (O), and nitrogen (N)); and any combination thereof.

[0197] The bioceramics are preferably calcium phosphate ceramics and include, but are not limited to, hydroxyapatite (HAP), tricalcium phosphate (TCP), amorphous calcium phosphate (ACP), octacalcium phosphate (OCP), anhydrous dicalcium phosphate (DCPA), dicalcium phosphate dihydrate (DCPD), tetracalcium monoxide phosphate (TetCp), biphase calcium phosphate (BCP), and any combination thereof.

[0198] The construction material of the present invention may include other sinterable materials that do not crack, sag, or delaminate, such as glass powder, acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), and polyether ether ketone (PEEK).

[0199] The organic polymer binder used in the present invention preferably has at least two thermal decomposition temperatures. Thermal decomposition is formed when a decomposition product (i.e., article) containing the organic polymer binder is heated at these temperatures and can act as a reducing agent. The organic polymer binder is preferably selected so as not to inhibit the reaction between powder, i.e., metal and / or ceramic particles. The organic polymer binder is preferably decomposed or evaporated at a temperature below its corresponding thermal decomposition temperature.

[0200] The organic polymer binder is preferably selected from the group consisting of cellulose esters, cellulose ethers, and their derivatives. The organic polymer binder is preferably used at a concentration of about 50 g / L to about 550 g / L, more preferably about 100 g / L to about 500 g / L. In various embodiments of the present invention, the number-average molecular weight of the organic polymer binder is about 150,000 or less, more preferably about 100,000 or less.

[0201] The cellulose ester is preferably selected from the group comprising cellulose acetate, cellulose acetate phthalate, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose butyrate, cellulose triplyrate, cellulose acetate propionate, cellulose propionate, cellulose triplyrate, cellulose nitrate, cellulose acetate propionate, carboxymethylcellulose acetate, carboxymethylcellulose acetate propionate, carboxymethylcellulose acetate butyrate, cellulose acetate butyrate succinate, cellulose propionate butyrate, and mixtures thereof.

[0202] Cellulose ester derivatives can be prepared by esterification of cellulose. Preferred cellulose ester derivatives include cellulose acetate, butyrate, benzoate, phthalate, and anthranilate esters, preferably cellulose acetate phthalate (CAP), cellulose acetate butyrate (CAB), cellulose acetate trimellitate (CAT), hydroxypropyl methylcellulose phthalate (HPMCP), succinoylcellulose, cellulose fluoroate, cellulose carbanillate, and mixtures thereof.

[0203] The cellulose ether is preferably selected from the group comprising methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylhydroxyethylcellulose, methylhydroxypropylcellulose, ethylhydroxyethylcellulose, methylethylhydroxyethylcellulose, hydrophobic modified ethylhydroxyethylcellulose, hydrophobic modified hydroxyethylcellulose, alkylcellulose, hydroxyalkylcellulose, carboxyalkylcellulose, carboxyalkylhydroxyalkylcellulose, and mixtures thereof.

[0204] Cellulose ether derivatives can be prepared by carboxymethylation, carboxyethylation, and carboxypropylation. Preferred examples of cellulose ether derivatives include, but are not limited to, nanocellulose, carboxymethylcellulose (CMC), sodium carboxymethylcellulose (NaCMC), hydroxypropylcellulose (HPC), hydroxyethylcellulose (HEC), hydroxypropylmethylcellulose (HPMC), methylcellulose (MC), ethylcellulose (EC), and tritylcellulose.

[0205] Some organic polymer binders may use cationic cellulose derivatives. Some of these organic polymer binders may include alginates, starches, polysaccharides such as chitin and chitosan, agarose, hyaluronic acid, and their derivatives or copolymers (e.g., graft copolymers, block copolymers, random copolymers), or mixtures thereof.

[0206] The additives used in the present invention may be added to the building material and its organic polymer binder to achieve any desired properties, such as desired physical, mechanical, and thermal properties in the slurry raw material. In preferred embodiments of the present invention, the additives are selected from the group including plasticizers, defoamers, dispersants, sacrificial materials, dissipative materials, skeletal materials, water-soluble inorganic salts, foaming agents, graphene, graphene oxide, flame retardants, toners, release agents, stabilizers, antistatic agents, impact modifiers, colorants, antioxidants, and any combination thereof. The additives are preferably used in amounts of about 1 vol% to about 15 vol%. It is understood that the amount of additives may vary outside the above range depending on the specific type of additive selected in the present invention.

[0207] Preferably, a plasticizer refers to a substance added to the slurry feedstock to improve workability, flexibility, and plasticity. Preferably, the plasticizer includes phthalate esters such as dibutyl phthalate, diaryl phthalate, diethyl phthalate, dimethyl phthalate, dihexyl phthalate, di-2-methoxyethyl phthalate, triphenyl phthalate, (dipropylene glycol) butyl ether, dibutyl tartrate, and diethylene glycol monoricinoleate; natural or synthetic waxes selected from the group consisting of cetyl alcohol, stearyl alcohol, cetostearyl alcohol, beeswax, candelilla wax, shellac wax, carnauba wax, petroleum wax, or mixtures thereof; glycerol, triethyl citrate, acetyl triethyl citrate, ethyl o-benzoyl benzoate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, N-ethyltoluenesulfonamide, o-cresyl p-toluenesulfonate, triethyl phosphate, triphenyl phosphate, and any combination thereof.

[0208] An antifoaming agent is a substance that eliminates foam by reducing the surface tension of the slurry feed material. The antifoaming agent alters the surface properties of metals and ceramics, reducing the interfacial tension of volatile organic solvents and thus removing foam. The antifoaming agent is preferably selected from the group comprising polyethylene glycol, polypropylene glycol copolymer, alkyl polyacrylate, polydimethylsiloxane (silicone oil), ethylene bis-stearamide (EBS), paraffin wax, ester wax, fatty alcohol wax, white oil or vegetable oil, wax having long-chain fatty alcohol, fatty acid soap, ester, polyether-modified polysilicane and trialkane / alkene phosphate, and mixtures thereof.

[0209] The dispersant is preferably a compound selected from the group consisting of silicate compounds, sodium polycarbonate, and alcohols.

[0210] The sacrificial material is preferably a substance that, if present in the green or brown component before sintering, is not present in any significant amount, at least in the same form, within the fully sintered body (i.e., the final component) formed by sintering the brown component until the final article or final component is formed. In one embodiment, the sacrificial material forms a layer on the green or brown component and is later removed, leaving a void. The sacrificial material may include aluminum orthophosphate, which, when heated during the sintering process, first forms a liquid phase within the green or brown component, and then vaporizes or decomposes as one or more gaseous byproducts, leaving the green or brown component. The sacrificial material preferably includes paraffin wax.

[0211] The dissipative material is preferably a material that can function as a mold for casting ceramic and / or metal parts into a three-dimensional form of a tilting functional article, and can then be removed from the ceramic and / or metal parts by melting, dissolving and / or evaporating without damaging the ceramic and / or metal castings. The dissipative material used in the present invention may be a rubber or plastic material selected to achieve desired properties such as having thermal expansion and / or dissipative properties (relative to the ceramic or metal core material).

[0212] In one embodiment, the sacrificial material, dissipative material, or a combination thereof is removed from the preceding part or from the preceding part from which the polymer binder has been detached (i.e., the browned part) by thermal decomposition, solvent debonding, or any combination thereof. Thermal decomposition can preferably be selected from the group including heating, thermal debonding, densification / sintering, partial or complete melting of the dissipative material other than the sacrificial material and / or building material, i.e., metal particles and / or ceramic particles. The solvent debonding may include immersing the preceding part, the browned part, and / or the final part in a solvent that dissolves the sacrificial material and / or dissipative material. It is possible to better control strain and significantly reduce the debonding time. The solvent is, but is not limited to, alternative solvents such as n-hexane, heptane, thinner, acetone, methyl ethyl ketone, carbon tetrachloride, trichloroethylene, methylene chloride, and supercritical carbon dioxide, as well as water.

[0213] The skeletal material is preferably a buttress material for imparting mechanical integrity to the slurry raw material. The skeletal material may be selected from the group including gel-like materials such as chitosan, fibrin, and modified alginates; robust materials such as polycaprolactone and other plastics; and slurries containing ceramics and other powders, hydroxyapatite, or tricalcium phosphate. The skeletal material may also include polycaprolactone, polylactic acid, polyglycolic acid, and poly(lactide-co-glycolide).

[0214] The water-soluble inorganic salts used in the present invention are preferably selected from the group including nitrates, borates, chlorates, perchlorates, sulfates, halide salts, sodium carbonate, potassium carbonate, silicates, phosphates, salts of Group I elements, ammonium salts, and combinations thereof. In one embodiment, the water-soluble inorganic salt includes a rare earth metal chloride.

[0215] A foaming agent (or blowing agent) refers to a component, or combination of components, that can form a foam, preferably generally a bubbly foam, in a slurry raw material, particularly in the metal and / or ceramic building material. The foaming agent may be a solid, liquid, or supercritical material.

[0216] In preferred embodiments of the present invention, the blowing agent is a pyrolytic agent that is liquid or solid at room temperature, has a decomposition temperature lower than the melting temperature of the building material, and decomposes when heated to a temperature higher than the decomposition temperature, generating gases such as nitrogen, carbon dioxide, or ammonia. The blowing agent may be selected from the group including azodicarbonamide and / or its metal salts, hydrazodicarbonamide, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, calcium azide, trihydrazino-sym-triazine, pp'-oxybisbenzenesulfonyl hydrazide, dinitrosopentamethylenetetramine, azobisisobutylodinitrile, toluenesulfonyl hydrazide, p-toluenesulfonyl hydrazide, benzenesulfonyl hydrazide, bisbenzenesulfonyl hydrazide, p,p'-oxybis(benzenesulfonyl hydrazide), azobisisobutyronitrile, barium azodicarboxylate, and combinations thereof. The polysaccharide foaming agent preferably includes arrowroot powder, tapioca starch, potato starch, wheat, rice, and corn powder. The amount of foaming agent can be determined according to the desired expansion coefficient.

[0217] The graphene used as an additive in the present invention is preferably a polycyclic aromatic compound in which multiple carbon atoms are covalently bonded. The covalently bonded carbon atoms form a 6-membered carbon ring as a repeating unit, and may further include 5-membered carbon rings and / or 7-membered carbon rings. In the present invention, graphene is not limited to monolayer graphene, but also includes, for example, multigraphene having up to 10 monolayer graphene layers. Graphene preferably includes pure or natural graphene in addition to modified graphene such as graphene oxide or amide-modified graphene.

[0218] Graphene oxide, also known as "graphite acid" and "graphite oxide," may include structures in which oxygen-containing functional groups, such as carboxyl groups, hydroxyl groups, or epoxy groups, are bonded to graphene in varying proportions, but may be obtained by treating graphite with a strong oxidizing agent. In one embodiment of the present invention, graphene oxide includes a nanocomposite containing graphene oxide. Graphene oxide also includes reduced graphene oxide, i.e., graphene oxide in a reduced form, such as graphene oxide that has been subjected to a reduction treatment and is partially or substantially reduced. Reduced graphene oxide also refers to graphene oxide in which the percentage of oxygen has been reduced by a reduction treatment.

[0219] Other additives, such as flame retardants, toners, release agents, stabilizers, antistatic agents, impact modifiers, colorants, antioxidants, and release agents, can be used in this invention.

[0220] The volatile organic solvent is chemically inert to the building material, but is preferably evaporated or released during or after casting by the system of the present invention. The volatile organic solvent is necessary to completely dissolve components of the slurry feedstock other than the building material (e.g., organic polymer binders) and also functions as a wetting agent. Furthermore, it is desirable to use a volatile organic solvent that promotes variability (variation) of the building material (i.e., metals and ceramics) in the composition of the article, the structure including the packing pattern, or any combination thereof, and has a relatively high flash point and relatively low odor. The volatile organic solvent is preferably a solvent with a low vapor pressure greater than about 0.133 mbar or 13.3 Pa (0.1 mmHg) at about 20°C.

[0221] The volatile organic solvent is preferably used in an amount of about 1% to about 50% by volume. In one embodiment of the present invention, an appropriate amount of the volatile organic solvent should be used in the organic polymer binder, taking into consideration the preferred or desired concentration of the solution obtained as a second premix, which is an organic polymer binder solution.

[0222] The volatile organic solvent is preferably selected from the group comprising acetone, butanone, ketones including methyl ethyl ketone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone, aliphatic hydrocarbons, aromatic hydrocarbons, methanol, ethanol, propanol, alcohols including isopropyl alcohol, and butanol, methyl formate, ethylene carbonate, propylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate, 1,2-dimethoxyethane, γ-butyrolactone, ethyl acetate, isopropyl acetate, ethyl ether, methyl tert-butyl ether, tetrahydrofuran, diozan, nitromethane, acetonitrile, methylcyclohexane, n-heptane, n-hexane, cyclohexane, dipropylene glycol n-butyl ether, and mixtures thereof.

[0223] In various embodiments of the present invention, the building material mixed with the additive preferably forms a first premix, and the organic polymer binder, together with or dissolved in a volatile organic solvent (i.e., the organic polymer binder solution), preferably forms a second premix. The first and second premixes are preferably mixed to form a substantially homogeneous and fluid slurry mixture, which is then preferably subjected to casting in a mold cavity. The mold is then substantially immersed in a solidification bath for producing a precursor of an article by phase inversion, thereby extracting the volatile organic solvent from the article to control or manipulate the porosity or pores formed in the resulting article (i.e., the precursor) to the smallest possible extent. The second premix is ​​preferably in an amount of about 10% to about 90% by volume, more preferably about 10% to about 70% by volume.

[0224] The mixing preferably forms or produces a substantially homogeneous and fluid slurry mixture that is supplied to the system for manufacturing the preceding parts of the articles. The substantially homogeneous and fluid slurry mixture of the present invention may refer to a composition that is homogeneously mixed having substantially one morphological phase in the same state, such that at least two random samples of the composition have roughly or substantially the same amounts, concentrations and distributions of its components (e.g., building materials, organic polymer binders, additives, and / or volatile organic solvents). The substantially homogeneous and fluid slurry mixture of the present invention also means encompassing compositions that are fluid under gravity and / or have components (e.g., building materials, organic polymer binders, additives, and / or volatile organic solvents) that can be introduced (pumped). Furthermore, the substantially homogeneous and fluid slurry mixture indicates the performance of a composition that is transported by gravity or by conventional mechanical, hydraulic, or pneumatic pumping means from a storage container such as a vessel.

[0225] In one preferred embodiment, a substantially homogeneous and fluid slurry mixture comprises two or more substantially homogeneous and fluid slurry mixtures. As schematically shown in Figures 20 and 21, two or more substantially homogeneous and fluid slurry mixtures are instantaneously mixed in situ with or without the use of a static or dynamic mixer to form one substantially homogeneous and fluid slurry mixture. Preferably, the two or more substantially homogeneous and fluid slurry mixtures comprise two substantially homogeneous and fluid slurry mixtures, each comprising a first premix and a second premix. For example, two substantially homogeneous and fluid slurry mixtures, i.e., a first substantially homogeneous and fluid slurry mixture and a second substantially homogeneous and fluid slurry mixture. The first substantially homogeneous and fluid slurry mixture comprises a first premix comprising a metal, which is a building material, mixed with a dispersant, which is preferably an additive, and a second premix comprising a cellulose ester, which is the organic polymer binder, dissolved in acetone, which is a volatile organic solvent. A second substantially homogeneous and fluid slurry mixture comprises a first premix containing a ceramic, which is a building material, mixed with a blowing agent, which is preferably an additive, and a second premix containing cellulose ether, which is the organic polymer binder, dissolved in butanone, which is a volatile organic solvent. The resulting first and second substantially homogeneous and fluid slurry mixtures are mixed in the single static or dynamic mixer to form a single substantially homogeneous and fluid slurry mixture before being poured into a mold.

[0226] The term "in-situ" is understood to mean the location where mixing takes place or provides the mixing, or on-site mixing. Therefore, to form slurry feedstock at the mixing site, constructor materials, organic polymer binders, additives, and / or volatile organic solvents are generally co-injected (co-delivered) or supplied together to a single static or dynamic mixer (target site) and mixed or assembled at the co-injection site within the single static or dynamic mixer.

[0227] The terms “instantaneous” or “momentary” will also be understood to mean the time required to prepare the slurry feedstock in a single static or dynamic mixer by mixing the building materials, organic polymer binders, additives, volatile organic solvents, building materials mixed with additives, and / or volatile organic solvents (i.e., organic polymer binder solution) together with or dissolved in them. In this invention, such instantaneous mixing may occur in a time of one to several seconds. Compared to the total processing time, mixing in terms of seconds can be considered very rapid or instantaneous.

[0228] It should be further understood that the term “single static or dynamic mixer” as used herein refers to a single unit of static or dynamic mixer, rather than multiple non-operationally coupled random mixers as in the prior art.

[0229] In various embodiments of the present invention, the organic polymer binder is debonded from the preceding component, preferably by a thermal decomposition treatment based on the thermal decomposition temperature, a solvent debonding treatment, or a combination thereof. The thermal decomposition treatment may be selected from the group including heating, thermal debonding, densification / sintering, partial or complete melting, and / or potentially post-densification annealing, of components other than the constructing material, i.e., metal particles and / or ceramic particles, to relieve or further increase residual stress in the preceding component. In some embodiments, the thermal decomposition treatment by heating may be performed at room temperature, or at a lower temperature and shorter time than normal heat treatment times and temperatures, for example, at about 60°C to about 200°C for about 10 minutes to about 10 hours to achieve the effect.

[0230] The solvent debonding treatment of the preceding component may include contacting the preceding component with a solvent to extract a soluble binder (along with any additives) from the main body. Suitable solvents for solvent debonding according to the present invention include preferably acetone, methyl ethyl ketone, heptane, carbon tetrachloride, trichloroethylene, methylene chloride, and alternative solvents such as supercritical carbon dioxide and water.

[0231] The thermal decomposition treatment and / or the solvent debinding treatment of the precursor parts are followed by a sintering treatment to produce the final parts of the article.

[0232] According to a preferred embodiment of the present invention, the following may be practically used to obtain the precursor parts (or green parts).

[0233] Table 11: Composition of the first mixture [Table 11]

[0234] Table 12: Composition of the second mixture [Table 12]

[0235] Referring to FIG. 22, a method for preparing a slurry feedstock for use in casting an article preferably includes the following steps. (a) A preparation step of preparing a construction material containing a metal, a ceramic, or any combination thereof, (a-1) A step of supplying a construction material that is porous, non-porous, or any combination thereof, and (a-2) The preparation step including a step of supplying the construction material in an amount of 10% to 90% by volume, (b) A preparation step of preparing an organic polymer binder selected from the group consisting of cellulose esters, cellulose ethers, and derivatives thereof, (b-2) The preparation step including a step of providing the organic polymer binder at a concentration of 50 g / L to 550 g / L, (c) A preparation step of preparing an additive selected from the group consisting of a plasticizer, an antifoaming agent, a dispersant, a sacrificial material, a dissipative material, a skeletal material, a water-soluble inorganic salt, a foaming agent, graphene, graphene oxide, a flame retardant, a toner, a mold release additive, a stabilizer, an antistatic agent, an impact modifier, a colorant, an antioxidant, and any combination thereof, (d) Preparation steps for preparing volatile organic solvents, (e) A forming step of mixing the mixed building materials and additives to form a first premix, (f) A forming step of mixing the dissolved organic polymer binder with a volatile organic solvent to form a second premix, (g) A forming step of mixing a first premix and a second premix to form a substantially homogeneous and fluid slurry mixture to be subjected to casting in a mold cavity substantially immersed in a solidification tank for producing a preceding part of the article by phase inversion, wherein a volatile organic solvent is extracted from the article to adjust, control or manipulate the porosity or pores formed in the resulting article (i.e., the preceding part) to the smallest possible extent.

[0236] Preferably, this method further comprises a forming step of forming two or more substantially homogeneous and fluid slurry mixtures, each containing a first premix and a second premix, respectively, and a forming step of instantaneously mixing the two or more substantially homogeneous and fluid slurry mixtures in situ using a static or dynamic mixer to form one substantially homogeneous and fluid slurry mixture.

[0237] As described in a previous paragraph, the organic polymer binder is debonded from the preceding part by either or both a thermal decomposition treatment and / or a solvent debonding treatment, and a subsequent sintering treatment produces a final part of an article containing a building material in which the composition, filling pattern, or any combination thereof is selectively changed, gradually changing over the volume of the final part in one or more directions.

[0238] This method is presented as a numbered sequence for clarity, but the numbering does not necessarily describe the order of the steps. It should be understood that some of these steps may be omitted, performed in parallel, or carried out without requiring strict adherence to a particular order.

[0239] Referring to Figures 23 and 24, the method for casting an article preferably includes the following steps: (a) A supply process for supplying slurry feed material, (a-1) A preparation step of preparing a building material comprising a metal, a ceramic, or any combination thereof, (a-1-3) A step of supplying the construction material which is porous, non-porous, or any combination thereof, (a-1-4) The preparation step includes a step of supplying construction materials in an amount of 10% to 90% by volume, (a-2) A preparation step for preparing an organic polymer binder selected from the group comprising cellulose esters, cellulose ethers, and their derivatives, (a-2-2) The preparation step includes a step of providing an organic polymer binder at a concentration of 50 g / L to 550 g / L, (a-3) A preparation step of preparing additives selected from the group including plasticizers, defoamers, dispersants, sacrificial materials, dissipative materials, skeletal materials, water-soluble inorganic salts, foaming agents, graphene, graphene oxide, flame retardants, toners, release agents, stabilizers, antistatic agents, impact modifiers, colorants, antioxidants, and any combination thereof, (a-4) The supply step includes a preparation step of preparing a volatile organic solvent, (b) A forming step of mixing the mixed building materials and additives to form a first premix,

[0240] (c) A forming step of mixing the dissolved organic polymer binder with a volatile organic solvent to form a second premix, (d) A forming step of mixing the first premix and the second premix to form a substantially homogeneous and fluid slurry mixture, (e) A step of subjecting the substantially homogeneous and fluid slurry mixture to casting in a mold, (f) A step of substantially immersing a mold having a cavity filled with a substantially homogeneous and fluid slurry mixture in a solidification tank to extract a volatile organic solvent by phase inversion to produce a precursor part of the article, (g) A debonding step in which an organic polymer binder is debonded from the preceding component by either or both of a thermal decomposition treatment and a solvent debonding treatment, (h) The process comprises subjecting a preceding part (i.e., a brown part) from which an organic polymer binder has been debonded or removed to a sintering process in order to produce a final part of an article.

[0241] Preferably, this method further comprises a forming step of forming two or more substantially homogeneous and fluid slurry mixtures, each containing a first premix and a second premix, respectively, and a forming step of instantaneously mixing the two or more substantially homogeneous and fluid slurry mixtures in situ using a static or dynamic mixer to form one substantially homogeneous and fluid slurry mixture.

[0242] This method is presented as a numbered sequence for clarity, but the numbering does not necessarily describe the order of the steps. It should be understood that some of these steps may be omitted, performed in parallel, or carried out without requiring strict adherence to a particular order.

[0243] In one preferred embodiment of the present invention, the system used for casting articles preferably comprises one or more vessels, (reusable) molds, solidification tanks, decoupling means, and optionally, a single static or dynamic mixer.

[0244] One or more containers, or containers, tanks, or vessels, are preferably configured to separately contain slurry supply materials and / or their components, as described in a previous paragraph. The above containers are preferably airtight. The containers may be made from metal, plastic, or a combination thereof, in various shapes and sizes.

[0245] In one embodiment, each container holds the building material, organic polymer binder, additives, and volatile organic solvent in an individual, separate manner. For example, four separate containers are provided, each adapted to store the building material, organic polymer binder, additives, and volatile organic solvent. These four containers are specifically configured for in-situ mixing of the components of the slurry feedstock.

[0246] In another embodiment, the metal and ceramic of the construction material are housed in different separate containers. For example, metal particles are stored in a first container and ceramic particles in a second container. The metal and ceramic of the construction material can be further stored in many separate containers depending on, for example, the properties of the particular metal or ceramic (e.g., physical properties, chemical properties, rheological properties, etc.), the type of metal and / or ceramic (e.g., metal A, metal B, ceramic A, ceramic B, porous metal A, porous metal B, porous ceramic A, porous ceramic B, etc.), and the desired final properties of the article. In another embodiment of the present invention, the construction material can be mixed with additives that form a first premix and stored in one container, and an organic polymer binder can be dissolved together with or in a volatile organic solvent that forms a second premix and stored in another container. These two containers are configured to supply such mixtures (i.e., premixed construction material and additives, as well as pre-dissolved organic polymer binder in a volatile organic solvent) to the static or dynamic mixer.

[0247] In yet another embodiment, the first container is configured to store a slurry shared feedstock that is a substantially uniform and fluid slurry mixture containing a construction material mixed with one type of additive and the organic polymer binder solution, and the second container is configured to store another additive mixed with the organic polymer binder solution. The first container and the second container are preferably arranged to vary the microporosity of the article in order to obtain any desired or targeted filling pattern. In this regard, the other additive is a sacrificial material and / or a dissipative material. The arrangement of the containers described above may not be applicable to changes in microporosity.

[0248] A reusable mold is configured to mold the substantially uniform and fluid slurry mixture that is essentially received or introduced from one or more containers within its cavity. The cavity is preferably used to obtain an article having a desired shape. The cavity is preferably formed concentrically, internally, and centrally within the body of the mold. In one embodiment, the mold has an effectively continuous mold wall or casting surface of any desired shape surrounding the cavity. The cavity can be of any shape including regular or irregular polygonal shapes, such as bell shape, truncated pyramid shape, and spherical segment shape with two bases.

[0249] The shape of the mold wall is often rectangular or square, but can be circular or any other symmetric or asymmetric shape to manufacture an article with a corresponding cross-sectional shape. If desired, the surrounding mold wall can be adjustable in length and / or shape by providing end walls that are slidable between a pair of parallel side walls, for example, to vary the cross-sectional area and shape of the cavity defined by the walls. In such a configuration, the end walls may not be integral with the side wall portions, but the combined mold walls composed of the end walls and the side wall portions are effectively continuous and the walls fit closely together to avoid leakage of molten metal.

[0250] In one preferred embodiment, the mold comprises a first component in which a cavity is recessed or formed. The first component of the mold may be defined by two subcomponents having surfaces that face each other and are joined along a central dividing plane to form a single component of the first component. Preferably, the two subcomponents include a female and a male component that are seamlessly joined or fitted together and can be held in place with or without locking means such as pins and latches. The two subcomponents of the first component may be disassembled or removable to remove or detach the resulting preceding component from the empty cavity.

[0251] The first component of the mold is preferably made from or a material selected from the following: silicone, ceramic, concrete, thermoplastic, high-density polyethylene, medium-density polyethylene, low-density polyethylene, cross-linked polyethylene, polytetrafluoroethylene, polyethylene terephthalate, UV-curing resins including polypropylene, polycarbonate, polylactide, epoxy resin, acrylonitrile butadiene, styrene, glass fiber, nylon, and any combination thereof. Other substances that are insoluble in ketone and alcohol solvents can also be used in the present invention. In one embodiment, the first component of the mold is obtained, manufactured, or prepared by additive manufacturing or three-dimensional (3D) printing.

[0252] The first component of the mold may be permeable or impermeable. If permeable, the first component may have a peripheral wall having a permeable wall portion. Although the term permeable is used herein, the entire peripheral wall of the first component does not necessarily have to be permeable; instead, only a portion of it in which gas flow is desired may be permeable. The permeable wall portion can be made from ceramic, silicone (depending on the properties of the material), or a microstructure printed on the mold, which is an engineered design structure. The permeable first component is essentially configured to allow a phase change to occur between non-solvent particles in the solidification bath and the solvent in the slurry mixture, so that controllable pores are formed in the article during the drying process.

[0253] The mold of the present invention may further include a second component. Preferably, the second component, which is a single component, is configured to removably enclose the first component. The second component may be tubular or elongated outer casing, slidably engaging with the outer wall of the first component so that the first component can be inserted into a snug fit. The second component may enclose or cover part or substantially all of the first component. The second component may or may not be liquid-resistant to the first component. In one embodiment, the second component of the mold may allow a liquid, for example from a solidification tank, to enter and come into contact with a substantially homogeneous, fluid slurry mixture introduced into the first component and / or its cavity, thereby initiating phase inversion.

[0254] The second part may be manufactured from the same material as the first part. In one embodiment, the second part is obtained, manufactured, or prepared by additive manufacturing or 3D printing. To increase, improve, or enhance the strength and structural integrity of the second part, solid silicone can be applied to the second part of the mold.

[0255] The second part of the mold may be permeable or impermeable. If permeable, the second part may have a peripheral wall having a permeable wall portion. Although the term permeable is used herein, the entire peripheral wall of the second part does not necessarily have to be permeable; instead, only the portion where gas flow is desired may be permeable. The permeable wall portion can be made from ceramic, silicone (depending on the properties of the material), or a microstructure printed on the mold, which is an engineered design structure. The permeable second part is essentially configured to allow a phase change to occur between non-solvent particles in the solidification bath and the solvent in the slurry mixture, creating controllable pores in the article during the drying process.

[0256] In a preferred embodiment of the present invention, the first component of the mold can be prepared by a silicone mold manufacturing process used to form a negative silicone mold for the physical article to be cast. The silicone mold is cast and subjected to a cleaning process using a permeable silicone compound (i.e., a mixture of room temperature vulcanized (RTV) silicone / platinum curing silicone and a fine salt having a particle size of 5-10 μm or less) to form a permeable silicone mold having a pore size of 5-10 μm. This allows for phase inversion between the casting slurry mixture and the non-solvent. The second component of the mold is an externally permeable mold which can be coated with a solid silicone wall to increase the rigidity of the mold and extend its reusability.

[0257] In another preferred embodiment of the present invention, the mold can be fabricated by a 3D printing process using a fuse deposition (FDM) method with a variety of thermoplastic resins, such as HDPE, LDPE, PETG, PP, PC, or a thermoplastic resin insoluble in ketone and alcohol solvents; by stereolithography (SLA) using a UV-based resin resistant to ketone groups; or by a direct ink writing method that forms a permeable mold using a permeable silicone formulation. In the case of the FDM and SLA methods, the permeable mold can be obtained by embedding it in microchannels of the mold design and realizing it using 3D printing.

[0258] According to one embodiment of the present invention, in the manufacture of an article, it is cast into a single integrated part from at least two different substantially homogeneous and fluid slurry mixtures of different material components (e.g., material A and material B in Figures 2 and 3). At least two different substantially homogeneous and fluid slurry mixtures are supplied into a mold and hardened into a casting whose shape is defined by the shape of the cavity surrounded by the mold. The casting operation may be carried out so as to achieve a clear and sharp interface between the different substantially homogeneous and fluid slurry mixtures, or so as to occur in the interface zone where a constant mixing of the two different substantially homogeneous and fluid slurry mixtures takes place.

[0259] In casting operations that result in a clearly defined interface, the first cast portion of the article is hardened to such an extent that it is substantially uniform and free from the mixing of fluid slurry mixtures.

[0260] In castings where an interface region is formed between the cast portions of an article, the hardening and cooling of the first cast portion may continue as long as a limited mixing of a substantially uniform and fluid slurry mixture can occur, or a predetermined melting, softening, or any other modification can occur in the already cast portion. Active or quiescent cooling of the initially cast substantially uniform and fluid slurry mixture may be carried out in a directed manner so that the hardened region moves through the casting and eventually reaches that side of the cast portion where additional casting will take place.

[0261] The solidification tank is preferably configured to produce a precursor of the article by phase inversion by immersing a mold filled with a substantially homogeneous and fluid slurry mixture for a certain period (e.g., 6, 12, and 24 hours). During phase inversion, volatile organic solvents in the substantially homogeneous and fluid slurry mixture are preferably extracted from the article to adjust, control, or manipulate the porosity or pores formed in the resulting article (i.e., the precursor) to the smallest possible extent. By controlling the cellulose binder concentration and volume mixture between the binder and the building material, i.e., the metal / ceramic powder content, porous and / or non-porous articles can be cast, which is not possible with conventional casting methods.

[0262] The solidification tank in which the phase inversion of the slurry feed material stored in the mold cavity occurs is preferably a non-solvent liquid (or solidification liquid). The non-solvent liquid can be selected from the group including water, distilled water, pure water, and any combination thereof. Other non-solvent liquids can also be used in the present invention as organic polymer binders. The solidification tank is preferably provided in a container suitable for receiving and immersing the mold therein. In one embodiment, the container housing the solidification tank can receive and accommodate one or more molds simultaneously. The container may have a retaining frame that is removablely mounted inside the container. The retaining frame having suitable locking members is preferably configured to fix or hold the mold in a designated position within the solidification tank. The retaining frame may further include adjustable mounting parts so that the frame can be raised above the solidification tank to retrieve the mold, and horizontal to the bottom of the container to immerse the mold.

[0263] The debonding means is preferably a post-processing unit that refers to a mechanism for debonding or removing an organic polymer binder from a preceding part recovered from its mold. In a preferred embodiment, the debonding means includes either or both a pyrolysis unit for performing a pyrolysis treatment, and a solvent debonding unit for performing a solvent debonding treatment, after which a sintering treatment for producing a final part of the article is performed. The debonding means may also include a sintering unit.

[0264] A single static or dynamic mixer, optionally used in the present invention, is preferably configured to instantaneously mix two or more substantially homogeneous and fluid slurry mixtures in situ, on its own, to form one or a single substantially homogeneous and fluid slurry mixture before being transferred to a mold.

[0265] A single static mixer or motionless mixer is, in essence, a mixer that does not contain any internal moving mechanical parts. A static mixer is a device that includes one or more substantially stationary mixing elements, such as baffles such as blades, plates, or vanes, and mixes a fluid fluid, such as slurry feed material, and / or its components through a conduit to create flow splitting or splitting patterns, thereby achieving mixing in the fluid, such as radial circulation or helical mixing by exchange. Static mixing elements are typically immobile within the conduit, but limited movement of stationary elements is possible as long as they do not substantially contribute to the mixing of the fluid fluid. In a static mixer having multiple static mixing elements, these elements can be arranged in series with respect to each other and / or staggered. A static mixer is preferably selected to produce a mixed fluid flow, i.e., a substantially uniform and fluid slurry mixture, over a short length of the mixer. A dynamic mixer, on the other hand, is the opposite of the static mixer and preferably includes moving parts. A dynamic mixer can mix slurry feedstocks and their components together after they are loaded or while they are being loaded. Other mixers with similar properties may be used instead of the aforementioned mixers, as those skilled in the art can appropriately select.

[0266] In one embodiment, the slurry mix print of the present invention relies on the deposition of a solvent-based binder to form a cured article. Therefore, controlling the concentration of the organic polymer binder and the ratio between the binder and the binder particles (i.e., metal and / or ceramic powder) is a crucial step in ensuring that the cast article has sufficient static yield strength to maintain its shape once it is placed in or deposited in the mold.

[0267] To obtain an effectively homogeneous mixture, the slurry mixture must be prepared such that both types of material raw materials have only slight variations in viscosity over a range of shear rates.

[0268] Different types of powder sizes or shapes result in significant differences in their rheological behavior. Rheological adjustments must be made within each material and in combinations of both mixtures across all variable mixtures. Ideally, they should be in the range of about 30–90 vol% for metals and / or ceramics, about 50–500 g / L and / or 2.5–70 vol% for the organic polymer binders, and about 1–15 vol% for additives. Effective mixtures, which can vary over a wide range of ratios between the two materials, cannot be obtained simply by mixing the two materials together. For example, to obtain a fluid mixture suitable for a casting rate of about 10–80 vol%, it may be necessary for raw material A to be very viscous and material B to be very liquid in its material state. Since both slurries are essentially non-Newtonian fluids, similar shear rates or pumping rates can result in different volumetric flow rates, which can lead to inaccurate mixing ratios programmed by the user. Therefore, in this invention, the rheological profiles of the raw materials (i.e., the components of the slurry feedstock) and their mixtures must be achieved and mapped by experimental configurations. These rheological profiles are integrated with the material profile design to form a unique compensation factor that should be included during the post-processing of the pure Gcode to ensure that the feed volume flow rates of both slurries are consistent, so that a uniform mixing ratio is obtained. There is an effective mixing ratio that can be achieved between the two materials, namely, it is usually in the range of about 10-90%. This allows for the production of metal and ceramic mixtures, i.e., metal A and metal B, metal A (porous mixture) and metal A (non-porous mixture), ceramic A (porous) and ceramic A (non-porous), or ceramic A and ceramic B, depending on the needs and properties of the article to be formed. The mixture of materials flowing through the mixer may be three or more materials, and is not limited to those shown in any figure. This configuration allows material A and material B to be mixed in precise proportions during the casting process.

[0269] An example configuration is shown below. Material A (metal / ceramic A with a liquid, low-concentration binder) and Material B (pure binder with a premix of additives). Material A (porous metal / ceramic mixture) is formed by adding a skeletal insoluble material / foaming agent to Material A (concentrated mixture), and Material A can be selected from the group of metals and ceramics. This allows for the casting of unique structures such as solid, porous shells filled with porous material (see Figure 4). The following are non-limiting combinations of building materials, including metals and ceramics. ·Metal-metal (i) Al-Cu (ii) AL-Ni (iii) Ni-Ti (iv)316L-H13 (v) “Ti-6Al-4V”-304L (vi) Low carbon steel-high carbon steel (vii)304-304 porous structure • Metal-ceramic (i) Al-SiC (ii) Al-Al2O3 (iii) Ni-ZrO2 (iv) Cu-SiC

[0270] Ceramic - Ceramic (i) SiC-SiC (different densities) (ii) Al2O3-Al2O3 (porous structure) (iii) Al2O3-SiC (iv) Al2O3-ZrO2 The following compositions can be used for the transition between low-carbon steel and high-carbon steel.

[0271] Table 13: Composition of the first mixture [Table 13]

[0272] Table 14: Composition of the second mixture [Table 14]

[0273] In the case of a 304-304 porous structure, the porosity of the structure is controlled by the size of the salt crystals. The following can be used:

[0274] Table 15: Composition of the first mixture [Table 15]

[0275] Table 16: Composition of the second mixture [Table 16]

[0276] The following can be used for the transition between clay and low-carbon steel.

[0277] Table 17: Composition of the first mixture [Table 17]

[0278] Table 18: Composition of the second mixture [Table 18]

[0279] <Further Embodiments / Aspects> A novel 3D printing system using a unique composition of a metal and / or ceramic powder-binder slurry mixture is introduced as a supply material. The binder used in the metal and / or ceramic mixture consists of organic polymer binders from the group of cellulose esters, cellulose ethers and their derivatives. It is dissolved in an organic solvent as a base binder at a concentration of 10-70 volume%, and solid particles consisting of one or more metal and / or ceramic powders at a concentration of 30-90 volume%, are bonded with additives (dispersants, rheology modifiers, defoamers, or foaming agents) to form the metal and / or ceramic powder binder slurry mixture.

[0280] In one embodiment of the present invention, the term "construction material" refers to a solid particle material or a powder of the material. The material is mixed as part of the preparation of the feedstock material. The solid particle size may be in the range of 0.1 to 100 μm. The material refers to at least one metal and / or ceramic or a mixture of two or more construction materials used in the preparation of the "feedstock" or "slurry mixture," and can be used interchangeably. The binder here refers to the cellulose group consisting only of esters, ethers, and derivatives.

[0281] Here, cellulose derivatives of ethers and their ester groups should be understood as one of the bio-based polymers having ether and ester functional groups linked to their main molecular chain.

[0282] Cellulose ethers are high molecular weight compounds produced by substituting the hydrogen atoms of the hydroxyl groups in the anhydrous glucose units of cellulose with R, which belongs to alkyl groups or substituted alkyl groups. Examples of cellulose ethers include methylcellulose and ethylcellulose.

[0283] Cellulose esters are generally water-insoluble polymers with good film-forming properties and are classified into organic and inorganic groups. Various types of organic cellulose esters can be used, such as cellulose acetate (CA), cellulose acetate phthalate (CAP), cellulose acetate propionate, cellulose acetate butyrate (CAB), cellulose acetate trimellitate (CAT), and hydroxypropyl methylcellulose phthalate (HPMCP). Inorganic cellulose esters that can be used are cellulose nitrate and cellulose sulfate.

[0284] In a preferred embodiment, the molecular weight of the binder is less than Mw 100,000. The slurry mixture is first prepared by dissolving the binder in a concentration range of 20 to 70 g per 100 ml of solvent (i.e., purity ≥ 95%).

[0285] The base binder can be a single type of binder from a group, a similar or mixture of two or more binders from different groups with different molecular weights, or a blend of two or more similar binders from different groups with different molecular weights as a base binder formulation. Mixtures of binders with different molecular weights or different types of binders can achieve the desired rheology and curing control. Similarly, the solvent selected to dissolve the binder can be a single type or a mixture of different solvents, depending on the mixture composition in the base binder formulation.

[0286] The solvent used to dissolve the binder is preferably a volatile organic solvent solution, depending on the composition of the base binder formulation. Ketones and esters are preferred volatile organic solvents.

[0287] A ketone refers to any class of organic compound characterized by having a carbonyl group in which a carbon atom is covalently bonded to an oxygen atom. The remaining two bonds are to other carbon atoms or hydrocarbon radicals (R). Examples of ketones include acetone, cyclohexanone, diacetone alcohol, and the like.

[0288] Esters have the general formula RCOOR', where R represents a hydrogen atom, an alkyl group, or an aryl group, and R' may be an alkyl group or an aryl group, but not a hydrogen atom. If R' is a hydrogen atom, the compound is a carboxylic acid. Examples of esters include methyl formate and ethyl lactate.

[0289] Other suitable organic solvents include nitromethane, acetonitrile, methyl glycol, tetrahydrofuran, alcohols, ethers, aromatic solvents, aliphatic solvents, and diaoxanes.

[0290] To obtain desired rheological behavior and print properties, additives such as plasticizers, defoamers, or foaming agents can be added to the formulation. Foaming agents allow the user to control the concentration of the printed object through mixing to form the desired porosity during the printing process. By adding and mixing foaming agents in situ, the porosity of metal parts can also be controlled during the printing process. The same techniques can be applied to control the viscosity of the binder, the strength of the binder for green parts, the structural and mechanical properties, and the curing rate during the printing process. Solid particles, in this case metal and / or ceramic powders, can be prepared by wetting and dispersing a base binder solution with pre-mixed additives to form a slurry mixture. The mixture is prepared under controlled conditions, i.e., under vacuum and / or inert gas conditions.

[0291] Phthalate plasticizers appear colorless, have a slight odor, and exhibit limited solubility in water, but are miscible with various organic solvents. Phthalate esters are produced by esterification of phthalic anhydride, which is obtained by the oxidation of orthoxylene.

[0292] Phthalates have a basic structure of benzenedicarboxylic acid with two side chains (R and R') that can be alkyl, benzyl, phenyl, cycloalkyl, or alkoxy groups. The defining characteristics of each phthalate ester and its decomposition pattern are determined by the length of the dialkyl side chain. If the phthalate ester is more branched, more isomers are available and it is likely to be hydrophobic. Examples of phthalate plasticizers include dibutyl phthalate, diaryl phthalate, diethyl phthalate, dimethyl phthalate, and di-2-methoxyethyl phthalate.

[0293] The plasticizer is present in an amount of 2 to 10% by weight relative to the total mass of the binder. In addition to the plasticizer formulations specified above, specific examples of plasticizers include N-ethyltoluenesulfonamide, o-cresyl p-toluenesulfonate, dibutyl tartrate, acetyltriethyl citrate, triethyl citrate, and glycerol. ,workman Chill o- Benzoyl Benzoate The following may be selected: ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, and others.

[0294] Here, a plasticizer refers to a component that enhances the plasticity or fluidity of a substance. In some embodiments, the component may be introduced as an organic solvent, which begins to function as a plasticizer as the organic solvent evaporates. The binder composition comprises a plasticizer and at least one organic solvent, and therefore, if the organic solvent begins to function as a plasticizer, the binder composition also contains a plasticizer. In other words, cellulose acetate is plasticized in solution. In some embodiments, the plasticizer may be the same as at least one of the organic solvents. In other embodiments, the plasticizer is different from any of the organic solvents.

[0295] Antifoaming agents or dispersants, also called surfactants (e.g., aryl or alkyl phosphates), can be added as additives to promote the suspension of solid or liquid particles in a liquid (e.g., colloid or emulsion), improving particle separation and preventing sedimentation or aggregation. Other examples of dispersants include triethyl phosphate and triphenyl phosphate.

[0296] This embodiment of solid microparticles in the form of metallic material refers to a group consisting of one or more combinations of the following elements: Stainless steel: 17-4PH, 304, 304L, 310, 316, 316L, 420, 440, 430L, etc. Titanium and titanium alloys: Ti64, Ti-6Al-4V, Ti64ELI, etc. Aluminum and aluminum alloys: AlSi10Mg, AlSi7Mg, ADC12, AlMg5Mn, etc. Nickel and nickel alloys: 718, 625, Hastelloy® X, Kovar, Invar 36, Hastelloy® C, etc. Other metals: A2, D2, H13, M2, 4140, CoCr, CoCrMo, copper alloys, bronze, magnesium, carbon steel, chromoly steel, Fe-3%Si, Fe-50%Ni, Fe-50%Co, W, WC-5Co, WC-1-Co, etc.

[0297] This embodiment of solid microparticles in the form of ceramic material refers to a group consisting of one or more combinations of the following elements:

[0298] Calcium phosphate ceramics: hydroxyapatite (HAp), tricalcium phosphate (TCP), amorphous calcium phosphate (ACPs), and biphasic calcium phosphate (BCPs) Oxide ceramics: Aluminum oxide, beryllium oxide, zirconium dioxide, yttria-stabilized zirconia (YSZ) Silicate ceramics: porcelain, aluminum silicate, kaolin, magnesium silicate, mullite Carbide ceramics: Boron carbide, silicon carbide, tungsten carbide Nitride ceramics: silicon nitride, aluminum silicon oxynitride, aluminum nitride, and mixtures thereof.

[0299] The particle mesh size is preferably less than 200.

[0300] Here, we will explain the use of supplied raw materials.

[0301] The feed material is placed in a sealed storage tank 12, ready to be supplied to an extrusion-based 3D printer capable of distributing the slurry mixture layer by layer to form 3D objects, as shown in Figure 25. The storage tank 12 is pressurized 15 to transfer the feed material to a pump 14, which may be a progressive cavity pump, peristaltic pump, or syringe, driven by a printer control unit 16. A nozzle 18 moves and distributes the feed material to form the green parts 20.

[0302] The green parts 20 can be cured at room temperature or with additional ventilation 22. The green parts 20 can be printed on any hot plate 24. A heating chamber at 30-100°C can also accelerate the curing process. The printed green parts 20 have sufficient holding power to facilitate handling.

[0303] The printer, as shown in Figure 26, is configured with two or more slurry metal and / or ceramic mixtures that are fed through separate nozzles 18A, 18B, and can form unique multi-material or separate continuous gradient material structures after post-processing.

[0304] Another configuration for slurry mixture-based printing can be carried out by in-situ mixing, as shown in Figure 27. The first feed material 26 and the second feed material 28 are supplied before mixing in a mixer 30 having the following configuration: First configuration: First supply: Binder solution Second supply material: Metal and / or ceramic powder solution Second structure: First supply material: Metal-binder slurry mixture Second supply material: Ceramic-binder slurry mixture

[0305] Two feed materials 26 and 28 are supplied to the mixer 30 during the printing process. Post-curing of the green parts 20 may be required, depending on their size, to ensure a fully cured structure before proceeding to the post-processing steps.

[0306] Post-processing of the printed material includes a debonding treatment 32 to form a brown part 34 and a sintering treatment 36 to form a final sintered part 38. The thermal debonding treatment 32 and the sintering treatment 36 can be carried out in a controlled environment by a single heat treatment or two separate treatments, according to a specific temperature profile for the type of material being treated based on the type of metal and / or ceramic particles. The thermal debonding and sintering profiles are shown in Figure 29. During thermal debonding, the green part is heated to the thermal decomposition temperature of the binder, and the holding time can be varied depending on the size of the part to ensure complete removal of the binder. Subsequently, a sintering treatment is performed to fuse the metal and / or ceramic particles at a specific temperature depending on the type of material to be treated. Further post-processing treatments such as heat treatment, surface finishing, or machining may be performed.

[0307] [Example 1] Stainless steel 17-4PH is prepared using 60 vol% 17-4PH metal powder with an average particle size of 15 μm and a 40 vol% binder solution. A binder solution of cellulose acetate is prepared at a concentration of 40 g per 100 ml of acetone solvent.

[0308] The binder solution contains 10% by volume of an additive consisting of a mixture of a plasticizer, an antifoaming agent, and a dispersant.

[0309] Figure 30 shows the basic print configuration under non-heating conditions. This configuration produced the green component 20 shown in Figure 31. After post-processing, sintered stainless steel 38 was obtained as shown in Figure 32.

[0310] [Example 2] A ceramic mixture is prepared using 70 vol% kaolin and 30 vol% binder solution. 40 g of cellulose acetate is prepared in 100 ml of acetone solvent. Figure 33 shows the basic print configuration under non-heating conditions. This configuration produces the green component 20 shown in Figure 34. After post-processing, a sintered ceramic 38 is obtained as shown in Figure 35.

[0311] Therefore, a feedstock for 3D printing is introduced. The feedstock is made from a mixture of metal and / or ceramic slurry. The feedstock can be printed directly to obtain the intended 3D object.

[0312] While the subject matter of the present invention has been described with reference to specific embodiments, various modifications and changes may be made to these embodiments without departing from the broader scope of the embodiments of the present disclosure. Such embodiments of the subject matter of the present invention are referred to herein, individually or collectively, by the term “invention,” but where two or more inventions are actually disclosed, the scope of this application is not intended to be arbitrarily limited to any single disclosure or inventive concept.

[0313] The embodiments illustrated herein are described in sufficient detail to enable those skilled in the art to carry out the disclosed teachings.

[0314] Other embodiments may be used and derived from them so as to involve structural and logical substitutions and modifications without departing from the scope of this disclosure. Therefore, the detailed description should not be constrained, and the scope of the various embodiments, along with the entire scope of the equivalents to which such claims are granted, is defined solely by the appended claims.

[0315] As used herein, the term "or" may be interpreted either comprehensively or exclusively. Furthermore, resources, operations, or structures described as examples herein may be multiple examples. Moreover, the boundaries between various resources, operations, modules, engines, and datastores are somewhat arbitrary, and specific operations are shown in the context of specific exemplary configurations. Other assignments of functions are conceivable and may fall within the scope of various embodiments of the invention. In general, structures and functions presented as separate resources in example configurations may be implemented as combined structures or resources. Similarly, structures and functions presented as single resources may be implemented as separate resources. These and other variations, modifications, additions, and improvements fall within the scope of embodiments of the invention represented by the appended claims. Accordingly, this specification and the drawings should be considered illustrative rather than restrictive.

[0316] The foregoing description is provided for illustrative purposes and refers to specific embodiments. However, the above illustrative discussion is not intended to be exhaustive or to strictly limit possible embodiments to the disclosed forms. Many modifications and variations are possible in light of the above teachings. The embodiments have been selected and described to best illustrate the principles involved and their practical applications, thereby enabling the best use of various embodiments with various modifications suitable for specific uses as conceivable by those skilled in the art.

[0317] In this specification, terms such as "first," "second," etc., are used to describe various elements, but it should be understood that these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, as long as it does not deviate from the scope of this embodiment, the first contact can be called the second contact, and similarly, the second contact can be called the first contact. Both the first and second contacts are contacts, but they are not the same contact.

[0318] The terms used in the description of the example embodiments herein are for illustrative purposes only and are not intended to limit the use of any particular example embodiment. Where used in the description of the example embodiments and the accompanying examples, the singular forms “a,” “an,” and “the” also include the plural form unless the context explicitly states otherwise. Where used herein, the terms “and / or” refer to any and all possible combinations of one or more of the enumerated items relating to the example, and shall be understood to encompass them. Where used herein, the terms “including” and / or “including” identify the presence of the described features, integers, processes, operations, elements, and / or components, but shall not exclude the presence or addition of one or more other features, integers, processes, operations, elements, and / or components, and / or groups thereof.

[0319] Where used herein, the term "if" may be interpreted, depending on the context, as meaning "at the time" or "afterward" or "in response to a decision" or "in response to detection." Similarly, the phrases "if a decision is made" or "if (the described condition or event) is detected" may be interpreted, depending on the context, as meaning "after a decision" or "in response to a decision," or "after (the described condition or event) is detected" or "in response to (the described condition or event) detection."

Claims

1. A method for three-dimensional (3D) printing of a tilting functional article on an extrusion base, The system includes a process for supplying slurry feed material, The process of supplying the slurry raw material is as follows: A process of preparing building materials including metals, ceramics, or any combination thereof, A step of preparing an organic polymer binder selected from the group including cellulose esters, cellulose ethers, and their derivatives, A step of preparing additives selected from the group including plasticizers, defoamers, dispersants, sacrificial materials, dissipative materials, skeletal materials, water-soluble inorganic salts, foaming agents, graphene, graphene oxide, flame retardants, toners, release agents, stabilizers, antistatic agents, impact modifiers, colorants, antioxidants, and any combination thereof, The process includes preparing a volatile organic solvent, The process of preparing the aforementioned construction materials is as follows: A step of supplying the construction material, which is porous, non-porous, or any combination thereof, The process includes supplying the aforementioned construction material in an amount of 10% to 90% by volume, The step of preparing the aforementioned organic polymer binder is: The process includes providing the organic polymer binder at a concentration of 150 g / L to 550 g / L. The step of supplying the slurry supply material includes a step of adjusting the supply of the slurry supply material, The method further comprises the step of forming two or more substantially homogeneous and fluid slurry mixtures, each comprising a first premix and a second premix. The first premix described above is formed by mixing the mixed building materials and the additives, The previous second premix is ​​formed by mixing the dissolved organic polymer binder with the volatile organic solvent, Furthermore, the above method, after forming the two or more slurry mixtures, A step of mixing the two or more slurry mixtures to form a substantially homogeneous and fluid slurry mixture, The process includes a printing step in which the slurry mixture of the aforementioned one type is printed using a printer, The printing process includes printing the one type of slurry mixture with the printer, during which the printer changes the composition of the one type of slurry mixture, while printing the one type of slurry mixture as a leading part of the gradient functional article. Furthermore, the method includes a step of debonding the organic polymer binder from the preceding component by either or both of a thermal decomposition treatment and a solvent debonding treatment, The process includes subjecting the preceding part, from which the organic polymer binder has been detached, to a sintering process to produce the final part containing the building material, in which the composition, filling pattern, or any combination thereof, selectively and gradually changes over the volume of the final part of the functionally graded article in one or more directions. A method characterized by the following:

2. The building material in the first premix in each of the two or more slurry mixtures is different The method according to feature 1.

3. In the step of forming the one slurry mixture, The two or more slurry mixtures are instantaneously mixed in situ using a static or dynamic mixer to form the single slurry mixture. The method according to 1 or 2, characterized by the features described above.

4. The step of providing a support structure for an overhang or cantilever portion of the tilting functional article, the support structure comprising a substantially uniform and fluid support mixture formed of a support material, The method according to feature 1.

5. A system for three-dimensional (3D) printing of tilting functional articles on an extrusion base, Equipped with one or more containers for holding slurry supply material, The slurry supply material is, A building material comprising metals, ceramics, or any combination thereof, being porous, non-porous, or any combination thereof, in an amount of 10% to 90% by volume, An organic polymer binder selected from the group including cellulose esters, cellulose ethers, and their derivatives, having a concentration of 150 g / L to 550 g / L, Additives selected from the group including plasticizers, defoamers, dispersants, sacrificial materials, dissipative materials, skeletal materials, water-soluble inorganic salts, foaming agents, graphene, graphene oxide, flame retardants, toners, release agents, stabilizers, antistatic agents, impact modifiers, colorants, antioxidants, and any combination thereof, A volatile organic solvent is provided, The building material and the additive are mixed to form a first premix, and the organic polymer binder is dissolved in the volatile organic solvent to form a second premix. These are then mixed to form two or more substantially homogeneous and fluid slurry mixtures. The aforementioned system, A means for adjusting the injection of the slurry supply material contained in one or more containers, selected from the group including solenoid valves, mechanical pumps, and combinations thereof, A calculation unit comprising a control unit configured to generate a control signal for the injection adjustment means, wherein the control unit is connected to a database comprising a predetermined set of materials and rheology profiles used to operationally influence the final part of the tilting functional article, A fluid drive selected from the group including pneumatic drive devices, hydraulic drive devices, mechanical move devices, and any combination thereof, is configured to provide fluid pressure to the slurry supply material contained in one or more containers or the injection adjustment means, and to cause movement of the slurry supply material contained in the connected one or more containers, thereby providing pressurized slurry supply material, A static or dynamic mixer that mixes two or more slurry mixtures to form a substantially uniform, fluid slurry mixture, The system further comprises a print head which is driven operably by the calculation unit and is configured to produce a leading part of the tilting functional article by spraying the one type of slurry mixture and printing it while changing the mixture composition of the one type of slurry mixture during the printing process, thereby printing the one type of slurry mixture as a leading part of the tilting functional article, The organic polymer binder is debonded from the preceding component by either or both a thermal decomposition treatment and a solvent debonding treatment, and a subsequent sintering treatment produces the final component containing the building material, in which the composition, filling pattern, or any combination thereof is selectively and gradually changed over the volume of the final component in one or more directions. A system characterized by the following features.

6. The building material in the first premix in each of the two or more slurry mixtures is different The system according to claim 5, characterized in that it is the same as described in claim 5.

7. The system according to claim 5 or 6, wherein the static or dynamic mixer instantaneously mixes the two or more slurry mixtures in situ to form the one slurry mixture before it is moved to the print head.

8. The one or more containers contain a support material that forms a substantially uniform and fluid support mixture for printing a support structure for the overhang or cantilever portion of the tilting functional article through the print head or other print heads, The system according to claim 5 or 6, characterized in that it is the same as described above.

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