Multi-fluid kit for three-dimensional printing, three-dimensional printing kit and three-dimensional printing method

Abstract

The multi-fluid kit for three-dimensional printing may include a wetting agent and a binding agent. The wetting agent may include 0 wt % to about 49.8 wt % of water, about 0.5 wt % to about 30 wt % of a film-forming organic solvent having a boiling point greater than about 100° C. to about 350° C., and about 30 wt % to about 99.5 wt % of an amphiphilic solvent having a boiling point of about 45° C. to less than about 100° C. The amphiphilic solvent may be water miscible and may be present in the wetting agent at a concentration higher than water and at a concentration higher than the film-forming solvent. The binding agent may include about 2 wt % to about 30 wt % of a polymer binder dispersed in an aqueous liquid vehicle.

Description

Technical Field

[0001] The present disclosure relates to three-dimensional printing using wetting agents. Background Art

[0002] Three-dimensional (3D) printing can be an additive printing method for manufacturing 3D physical parts from digital models. 3D printing is commonly used for rapid product prototyping, mold generation, master mold generation, and short run manufacturing. Some 3D printing technologies are considered additive methods because they involve the application of continuous layers of material. This is different from other mechanical processing methods that generally rely on removing materials to produce the final part. Some 3D printing methods use chemical binders or adhesives to bond the building materials together. Other 3D printing methods involve partial sintering, melting, etc. of the building materials. For some materials, partial melting can be achieved using heat-assisted extrusion, and for other materials, curing or fusion can be achieved using, for example, ultraviolet light or infrared light. Summary of the invention

[0003] According to one aspect of the present disclosure, there is provided a multi-fluid kit for three-dimensional printing, comprising: a wetting agent, comprising: 0 wt% to 49.8 wt% of water, 0.2 wt% to 30 wt% of a film-forming organic solvent having a boiling point of greater than 100°C to 350°C, and 30 wt% to 99.5 wt% of an amphiphilic solvent having a boiling point of 45°C to less than 100°C, wherein the amphiphilic solvent is water-miscible and is present in the wetting agent at a concentration higher than water and at a concentration higher than the film-forming solvent. The wetting agent does not include a polymer binder; and a binding agent comprising 2 wt% to 30 wt% of a polymer binder dispersed in an aqueous liquid vehicle, wherein the binding agent is different from the wetting agent.

[0004] According to another aspect of the present disclosure, a three-dimensional printing kit is provided, comprising: a wetting agent comprising: 0 wt % to 49.8 wt % of water, 0.2 wt % to 60 wt % of a film-forming organic solvent having a boiling point of greater than 100° C. to 350° C., and 30 wt % to 99.5 wt % of an amphiphilic water-miscible solvent having a boiling point of 45° C. to less than 100° C., wherein the wetting agent does not include a polymer binder; a binding agent comprising 2 wt % to 30 wt % of a polymer binder dispersed in an aqueous liquid vehicle, wherein the binding agent is different from the wetting agent; and a particle building material comprising 80 wt % to 100 wt % of metal particles, ceramic particles, or both metal particles and ceramic particles.

[0005] According to another aspect of the present disclosure, a three-dimensional printing method is provided, comprising: iteratively applying each building material layer of a granular building material to a powder bed, wherein the granular building material comprises 80 wt % to 100 wt % of metal particles, ceramic particles, or both metal particles and ceramic particles; based on a 3D object model, iteratively and selectively applying a wetting agent to each building material layer, wherein the wetting agent comprises 0 wt % to 49.8 wt % of water, 0.2 wt % to 60 wt % of a component having a boiling point greater than 100° C. to 350° C., and the like. A film organic solvent, and 30 wt % to 99.5 wt % of an amphiphilic water-miscible solvent having a boiling point of 45° C. to less than 100° C., and wherein the wetting agent does not include a polymer binder; and based on the 3D object model, iteratively and selectively applying a bonding agent different from the wetting agent to each build material layer to define respective patterned object layers, the object layers become adhered to each other to form a green body object composed of layers, wherein the bonding agent comprises 2 wt % to 30 wt % of a polymer binder dispersed in an aqueous liquid vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 illustrates an exemplary multi-fluid kit according to the present disclosure;

[0007] Figure 2 illustrates a three-dimensional printing kit according to the present disclosure; and

[0008] Figure 3 is a flow chart illustrating an exemplary 3D printing method according to the present disclosure. DETAILED DESCRIPTION

[0009] Three-dimensional (3D) printing can be an additive method, which can involve applying a continuous layer of particle building material, printing a chemical adhesive or adhesive thereon to bond the continuous layer of particle building material together. In some methods, applying a bonding agent containing an adhesive therein can be used to form a green body object (green body object) and then a fused 3D physical object can be formed therefrom. More specifically, a bonding agent can be selectively applied to a particle building material layer on a support bed to pattern the selected area of ​​the particle building material layer, and then another particle building material layer can be applied thereto. A bonding agent can be applied to another particle building material layer, and these processes can be repeated to form a green part (also referred to as a 3D green body or object), which can then be thermally fused to form a fused 3D object.

[0010] In 3D printing, the binding agent may impact the particle building material layer at a speed and force that can destroy the particle building material layer. Droplets of the binding agent can produce structural defects such as pits by ejecting loose particles and / or irregular aggregates of particles. In addition, the binding agent may exhibit delayed penetration of the particle building material. These printing interactions may cause surface roughness on the printed object and may produce cavities in the green body object that can be formed. The cavity in the green body object may be negatively correlated with the density in the fused 3D object. A green body object with more cavities (regardless of number or volume) may be less dense than a green body object with fewer cavities. The increase in the cavity space of the green body object can reduce the density of the fused 3D object, making the 3D object susceptible to fatigue and / or cracking.

[0011] Accordingly, in one example, the multi-fluid kit may include a wetting agent and a binding agent. The wetting agent may include 0 wt % to about 49.8 wt % of water, about 0.2 wt % to about 30 wt % of a film-forming organic solvent having a boiling point greater than about 100° C. to about 350° C., and about 30 wt % to about 99.5 wt % of an amphiphilic solvent having a boiling point of about 45° C. to less than about 100° C. The amphiphilic solvent may be water miscible and may be present in the wetting agent at a concentration higher than water and at a concentration higher than the film-forming solvent. The binding agent may include about 2 wt % to about 30 wt % of a polymer binder dispersed in an aqueous liquid vehicle. In one example, the film-forming solvent may include aliphatic alcohols, aromatic alcohols, alkyl glycols, glycols, glycol ethers, polyglycol ethers, 2-pyrrolidone, caprolactam, formamide, acetamide, 1,2-butanediol, C3 to C12 alcohols, or mixtures thereof. In another example, the amphiphilic solvent may include ethanol, methanol, 1-propanol, isopropanol, 1-butanol, acetone, methyl ethyl ketone, dimethylformamide, tetrahydrofuran, 1,4-dioxane, acetonitrile or a mixture thereof. In another example, the surface tension of the amphiphilic solvent may be about 20N / m to about 40N / m when measured at 20°C. In a further example, the amphiphilic solvent may be ethanol and the film-forming solvent may be 2-pyrrolidone. In one example, the bonding agent may further include a cosolvent, and the cosolvent in the bonding agent may be the same as the film-forming solvent in the wetting agent. In another example, the wetting agent may be a non-aqueous wetting agent.

[0012] In another example, the three-dimensional printing kit may include a wetting agent, a binding agent, and a particle building material. The wetting agent may include 0 wt % to about 49.8 wt % of water, about 0.2 wt % to about 60 wt % of a film-forming solvent having a boiling point greater than about 100° C. to about 350° C., and about 30 wt % to about 99.5 wt % of an amphiphilic water-miscible solvent having a boiling point of about 45° C. to less than about 100° C. The binding agent may include about 2 wt % to about 30 wt % of a polymer binder dispersed in an aqueous liquid vehicle. The particle building material may include about 80 wt % to 100 wt % of metal particles, ceramic particles, or both metal particles and ceramic particles. In one example, the film-forming solvent may be present in the wetting agent at about 1 wt % to about 15 wt %. In another example, the film-forming solvent may include 1,2-butanediol or other diols or glycols, and the amphiphilic solvent may include ethanol. In yet another example, the particulate building material can include about 90 wt% to 100 wt% metal particles, and the metal particles can have a D50 particle size distribution value of about 3 μm to about 100 μm. In a further example, the amphiphilic solvent can be present in the wetting agent at a higher concentration than water and at a higher concentration than the membrane-forming solvent.

[0013] In another example, the three-dimensional printing method may include iteratively applying each building material layer of a particle building material to a powder bed. The particle building material may include about 80% to 100% by weight of metal particles, ceramic particles, or both metal particles and ceramic particles. The method may further include iteratively and selectively applying a wetting agent to each building material layer based on the 3D object model. The wetting agent may include 0% to about 49.8% by weight of water, about 0.2% to about 60% by weight of a film-forming solvent that may have a boiling point greater than about 100°C to about 350°C, and about 30% to about 99.5% by weight of an amphiphilic water-miscible solvent that may have a boiling point of about 45°C to less than about 100°C. The method may further include iteratively and selectively applying a bonding agent to each building material layer to define each patterned object layer based on the 3D object model, and the object layers may become adhered to each other to form a green body object composed of layers. The binding agent may comprise from about 2% to about 30% by weight of a polymer binder dispersed in an aqueous liquid vehicle. In one example, the method further comprises sintering the green body object comprised of the layers to form a thermally fused article. In a further example, the fused three-dimensional object may have a porosity of from about 0.1% to about 60% by volume.

[0014] When discussing multi-fluid kits, three-dimensional (3D) printing kits, and / or 3D printing methods herein, these discussions may be considered applicable to each other, regardless of whether they are explicitly discussed in the context of that example. Thus, for example, when discussing wetting agents associated with a multi-fluid kit, such disclosure is also relevant to and directly supported in the context of a 3D printing kit, a 3D printing method, and vice versa.

[0015] Unless otherwise specified, the terms used herein will have ordinary meanings in the relevant technical field. In some cases, there are terms that are more specifically defined throughout the specification or included at the end of this specification, whereby these terms may have the meanings as described herein.

[0016] Multi-Fluid Kits

[0017] According to an example of the present disclosure, Figure 1 1 shows a multi-fluid kit 10. The multi-fluid kit may include a wetting agent 100 and a binding agent 200. The wetting agent may include 0 wt % to about 48.8 wt % of water, about 0.2 wt % to about 30 wt % of a film-forming organic solvent that may have a boiling point greater than about 100° C. to about 350° C., and about 30 wt % to about 99.5 wt % of an amphiphilic solvent that may have a boiling point of about 45° C. to less than about 100° C. The amphiphilic solvent may be water miscible and may be present in the wetting agent at a concentration higher than water and at a concentration higher than the film-forming solvent. The binding agent may include about 2 wt % to about 30 wt % of a polymer binder 220 dispersed in an aqueous liquid vehicle 210.

[0018] 3D Printing Kit

[0019] According to another example of the present disclosure, Figure 2A three-dimensional (3D) printing kit 20 is shown in FIG. The 3D printing kit may include a wetting agent 100, a bonding agent 200, and a particulate building material 300. In this example, the wetting agent is applied using a wetting agent fluid injector 110, and the bonding agent is applied using a bonding agent fluid injector 210, both of which may be included on a carriage track 310 or other similar structure. However, it is noted that there may be other application architectures that may be used alternatively as described in more detail herein. In addition, the particulate building material is supported by a building platform in this example, or more generally, by a pre-applied layer of particulate building material (e.g., a portion printed with a bonding agent, a portion printed with a wetting agent, and / or a portion that may remain unprinted). In one example, the wetting agent may include 0 wt % to about 49.8 wt % of water, about 0.2 wt % to about 60 wt % of a film-forming organic solvent having a boiling point greater than about 100° C. to about 350° C., and about 30 wt % to about 99.5 wt % of an amphiphilic water-miscible solvent having a boiling point of about 45° C. to less than about 100° C. The binding agent may include about 2 wt % to about 30 wt % of a polymer binder dispersed in an aqueous liquid vehicle. The particle building material may include about 80 wt % to 100 wt % of metal particles, ceramic particles, or both metal particles and ceramic particles. The wetting agent, the binding agent, or both the wetting agent and the binding agent may be packaged or co-packaged in separate containers with the particle building material, and / or may be combined with the particle building material when printing. The wetting agent and the binding agent may be as described above.

[0020] Wetting agents

[0021] Further references Figure 1 and 2 , with respect to a wetting agent 100 that may be present in a multi-fluid kit, a three-dimensional (3D) printing kit, or used in a 3D printing method as described herein, the wetting agent may include both an amphiphilic water-miscible solvent and a film-forming organic solvent. The wetting agent may be used to wet the particle building material prior to applying the binding agent. The wetting agent may act to minimize structural damage to the particle building material and may increase penetration of the binding agent into the particle building material layer.

[0022] Wetting agent can comprise about 30 wt % to about 99.5 wt % of amphiphilic water miscible solvent.In some other examples, wetting agent can comprise about 50 wt % to about 95 wt %, about 60 wt % to about 99 wt %, about 75 wt % to about 95 wt %, about 60 wt % to about 80 wt % or about 55 wt % to about 85 wt % of amphiphilic water miscible solvent.Amphiphilic water miscible solvent as used herein can comprise hydrophilic and lipophilic components.Due to the presence of hydrophilic and lipophilic segments, amphiphilic solvents can easily and very quickly wet the surface of variable properties (hydrophobic and hydrophilic), and can make them be uniformly wetted at a faster rate when subsequently wetted by water-based adhesive formulations.In some examples herein, amphiphilic water miscible solvents can be present in the wetting agent in an amount that can be greater than the amount of film-forming solvent.In another example, amphiphilic water miscible solvents can be present in the wetting agent in an amount that can be greater than the amount of water. In still other examples, the amphiphilic water-miscible solvent may be present in the wetting agent in an amount greater than both the amount of the membrane-forming solvent and the amount of water.

[0023] In one example, the amphiphilic water miscible solvent may include a volatile alcohol, a volatile ketone, a formamide, a water-soluble ether, a water-soluble volatile nitrile, etc. having a weight average molecular weight of about 30MW to about 100MW. In another example, the amphiphilic water miscible solvent may include ethanol, methanol, 1-propanol, isopropanol, 1-butanol, acetone, methyl ethyl ketone, dimethylformamide, tetrahydrofuran, 1,4-dioxane, acetonitrile, or a mixture thereof. In one example, the amphiphilic water miscible solvent may be ethanol. In another example, the amphiphilic water miscible solvent may include ethanol, and the film-forming solvent may include 1,2-butanediol.

[0024] The surface tension of the amphiphilic water miscible solvent can be less than the surface tension of water (72.8 millinewtons / meter at 20°C). In one example, the surface tension of the amphiphilic water miscible solvent can be about 20 millinewtons / meter to about 40 millinewtons / meter when measured at 20°C. In other examples, the surface tension of the amphiphilic water miscible solvent can be about 25 millinewtons / meter to about 35 millinewtons / meter, about 20 millinewtons / meter to about 30 millinewtons / meter, or about 30 millinewtons / meter to about 40 millinewtons / meter. When the amphiphilic water miscible solvent is applied to the particle building material, the low surface tension of the amphiphilic water miscible solvent can allow the amphiphilic water miscible solvent to uniformly wet the particle building material faster than water and can minimize particle displacement. The surface tension of the fluid can be measured by a tensiometer.

[0025] The amphiphilic water-miscible solvent may have a boiling point lower than that of water. In one example, the amphiphilic solvent may have a boiling point that may range from about 45° C. to less than about 100° C. In yet other examples, the amphiphilic solvent may have a boiling point that may range from about 40° C. to about 99.9° C., from about 50° C. to about 95° C., from about 50° C. to about 80° C., or from about 60° C. to about 90° C.

[0026] The wetting agent may further include a film-forming organic solvent of about 0.2% by weight to about 60% by weight. In some more specific examples, the film-forming organic solvent may be included at about 0.5% by weight to about 60% by weight or 0.5% by weight to about 30% by weight. In other examples, the film-forming solvent may be present at about 1% by weight to about 30% by weight, at about 2% by weight to about 12% by weight, at about 5% by weight to about 25% by weight, at about 5% by weight to about 15% by weight, or at about 25% by weight to about 45% by weight.

[0027] The film-forming solvent may include aliphatic alcohols, aromatic alcohols, alkyl glycols, glycols, glycol ethers, polyglycol ethers, 2-pyrrolidone, caprolactam, formamide, acetamide, 1,2-butanediol, other glycols, other glycols, C3 to C12 alcohols or mixtures thereof. In one example, the film-forming solvent may include glycols. In another example, the film-forming solvent may include 2-pyrrolidone. In one example, the amphiphilic solvent may be ethanol, and the film-forming solvent may be 1,2-butanediol, or other glycols or glycols.

[0028] The film-forming solvent may have a boiling point greater than water. In one example, the film-forming solvent may have a boiling point that may range from greater than about 100° C. to about 350° C. In other examples, the film-forming solvent may have a boiling point that may range from about 125° C. to about 300° C., about 125° C. to about 250° C., about 150° C. to about 350° C., about 200° C. to about 350° C., or about 150° C. to about 250° C.

[0029] After the amphiphilic solvent evaporates, the film-forming solvent can produce a hydrophilic film on the surface of the particles of the particle building material. The hydrophilic film can minimize particle displacement during, for example, the application of a binding agent.

[0030] In some instances, the wetting agent can further comprise 0 % by weight to about 49.8 % by weight of water. In other instances, water can exist with 0 % by weight to about 30 % by weight, 0 % by weight to about 20 % by weight, 0 % by weight to about 10 % by weight, 0 % by weight to about 5 % by weight, about 1 % by weight to about 30 % by weight, about 5 % by weight to about 25 % by weight, about 15 % by weight to about 45 % by weight or about 2 % by weight to about 20 % by weight. In some instances again, the wetting agent can be water-free. When present, water can for example be deionized. In many instances, along with the concentration of water reduction, the effectiveness of the wetting agent tends to improve, but may not be all so for each combination of wetting agent and particle construction material.

[0031] In some examples, the wetting agent may further include a colorant. The colorant may include a pigment, a dye, or both a pigment and a dye. In some examples, there is no colorant. However, in other examples, when a colorant is included, a colorant may be included for the purpose of providing a visual clue or indication that the wetting agent has been applied at a given position, or providing an indication or clue as a nozzle health. When the present disclosure relates to printing and subsequently heat-fusing a green body object to form a heat-fused metal object, the colorant will usually burn out during sintering or annealing. Therefore, if used, a small concentration of colorant can be used. If included, the colorant can be present, for example, at most 5 weight %. An exemplary range can be about 0.01 weight % to about 5 weight %, about 0.1 weight % to about 4 weight %, about 0.5 weight % to about 4 weight %, about 1 weight % to about 4 weight %, or about 2 weight % to about 4 weight %, or about 2 weight % to about 4 weight %.

[0032] Binding reagents

[0033] Further references Figure 1 and Figure 2 , with respect to a binding agent 200 that may be present in a multi-fluid kit 10 for 3D printing as described herein, a three-dimensional (3D) printing kit, or used in a 3D printing method as described herein, the binding agent may include a liquid vehicle 210 and a binder 220 to bind the particulate building material together during the construction process to form a green body object. The term "binder" may include any material used to physically bind particles of a particulate building material (e.g., metal particles, ceramic particles, etc.) together or to promote adhesion to the surfaces of adjacent particles in order to prepare a green body part or green body object for subsequent thermal fusion (e.g., sintering, annealing, melting, etc.). During the 3D printing process, the binding agent may be applied to the particulate building material on a layer-by-layer basis. For example, the liquid vehicle of the binding agent is capable of wetting the particulate building material, and the binder may move into the unoccupied space between the particles of the particulate building material.

[0034] The adhesive agent can provide adhesion to the particle building material when applied, or can be activated to provide adhesion after application in some cases. The adhesive can be activated or cured by heating the adhesive (this can be achieved by heating the entire particle building material layer or at least a portion of the adhesive agent that has been selectively applied). If the adhesive is a polymer adhesive, this can occur, for example, around the glass transition temperature of the adhesive. When activated or cured, the adhesive can form a network that adheres or glues the particles of the particle building material together, thereby providing cohesion in the formation and / or conformal of the green body object or its printed layer. A "green" part or green body object or article (or each layer) can refer to any component or mixture of components that have not yet been sintered or annealed, but are sufficient to allow thermal fusion (e.g., processing, moving or otherwise preparing a component for thermal fusion) to be held together.

[0035] Thus, in one example, a green body object may have mechanical strength to withstand extraction from a powder bed and may be subsequently sintered or annealed to form a heat-fused product. Once a green body part or green body object is sintered or annealed, the product may sometimes be referred to as a "brown" product, but is more commonly referred to herein as a "heat-fused" product, part, or object. The term "sintering" refers to the consolidation and physical bonding of particles by solid-state diffusion bonding, partial melting of particles, or a combination of solid-state diffusion bonding and partial melting (after temporary bonding with a bonding agent). The term "annealing" refers to a heating and cooling sequence that controls the heating and cooling processes, such as slow cooling in some cases that can remove internal stresses and / or toughen heat-fused parts or products (or "brown" parts). In some examples, the binder contained in the bonding agent may undergo a pyrolysis or burnout process, wherein the binder may be removed during the sintering or annealing process. This may occur if the thermal energy applied to the green body part or article removes inorganic or organic volatiles and / or other materials that may be present by decomposing or by burning the bonding agent. In other examples, if the binder comprises a metal, such as a reducible metal compound, the metal binder may remain with the heat-fused article after sintering or annealing.

[0036] As mentioned, adhesive can be included in the liquid vehicle so that it is applied to the particle construction material. For example, adhesive can be present in the adhesive agent with about 1 % by weight to about 49.8 % by weight, about 2 % by weight to about 30 % by weight, about 5 % by weight to about 25 % by weight, about 10 % by weight to about 20 % by weight, about 7.5 % by weight to about 15 % by weight, about 15 % by weight to about 30 % by weight, about 20 % by weight to about 30 % by weight, or about 2 % by weight to about 12 % by weight.

[0037] In one example, the adhesive may include polymer particles, such as latex polymer particles. The polymer particles may have an average particle size ranging from about 3 nm to about 1 μm. In other examples, the polymer particles may have an average particle size ranging from about 5 nm to about 700 nm, from about 20 nm to about 500 nm, from about 30 nm to about 400 nm, or from about 50 nm to about 350 nm.

[0038] In one example, the latex particles may include any of a variety of comonomers, and in some cases may include a copolymerized surfactant, such as a polyoxyethylene compound, polyoxyethylene alkylphenyl ether ammonium sulfate, polyoxyethylene alkyl ether sodium sulfate, polyoxyethylene styrenated phenyl ether ammonium sulfate, etc. The comonomer may be derived from a monomer such as styrene, p-methylstyrene, α-methylstyrene, methacrylic acid, acrylic acid, acrylamide, methacrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, methyl methacrylate, hexyl acrylate, hexyl methacrylate, butyl acrylate, butyl methacrylate, ethyl acrylate, ethyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, propyl acrylate, propyl methacrylate, octadecyl acrylate, octadecyl methacrylate, stearyl methacrylate, vinylbenzyl chloride, isobornyl acrylate, tetrahydrofurfuryl acrylate, 2-phenoxyethyl methacrylate, benzyl methacrylate, benzyl acrylate, ethoxylated nonylphenol methacrylate, ethoxylated behenyl methacrylate, polypropylene glycol monoacrylate, isobornyl methacrylate, cyclohexyl methacrylate, cyclohexyl acrylate, tert-butyl methacrylate, n-octyl methacrylate, lauryl methacrylate, tridecyl methacrylate, alkoxylated tetrahydrofurfuryl acrylate, isodecyl acrylate, isobornyl methacrylate, isobornyl acrylate, dimethyl maleate, dioctyl maleate, acetoacetoxyethyl methacrylate, diacetone acrylamide, N-vinyl imidazole, N-vinyl carbazole, N-vinyl caprolactam, or a combination thereof. In some examples, the latex particles may include acrylics. In other examples, the latex particles may include 2-phenoxyethyl methacrylate, cyclohexyl methacrylate, cyclohexyl acrylate, methacrylic acid, a combination thereof, a derivative thereof, or a mixture thereof. In another example, the latex particles can include styrene, methyl methacrylate, butyl acrylate, methacrylic acid, combinations thereof, derivatives thereof, or mixtures thereof.

[0039] About liquid vehicle, based on the weight of binding agent as a whole, binding agent can include about 50 % by weight to about 99 % by weight, about 70 % by weight to about 98 % by weight, about 80 % by weight to about 98 % by weight, about 60 % by weight to about 95 % by weight or about 70 % by weight to about 95 % by weight of liquid vehicle. In one example, liquid vehicle can include water as primary solvent, such as the solvent present with maximum concentration when compared with other cosolvents. In another example, liquid vehicle can further include about 0.1 % by weight to about 70 % by weight, about 0.1 % by weight to about 50 % by weight or about 1 % by weight to about 30 % by weight of liquid components other than water. Other liquid components can include organic cosolvents, surfactants, additives, viscosity modifiers, pH regulators, chelating agents, preservatives, etc. that inhibit the growth of harmful microorganisms.

[0040] When present, (one or more) organic co-solvents may include high boiling point solvents and / or humectants, such as aliphatic alcohols, aromatic alcohols, alkyl glycols, glycol ethers, polyglycol ethers, 2-pyrrolidone, caprolactam, formamide, acetamide, C6 to C24 aliphatic alcohols, such as medium (C6-C12) to long (C13-C24) chain length fatty alcohols, or mixtures thereof. (One or more) organic co-solvents may be present in the binding agent at 0 wt % to about 50 wt %. In other examples, the organic co-solvent may be present in the binding agent at about 5 wt % to about 25 wt %, about 2 wt % to about 20 wt %, or about 10 wt % to about 30 wt %.

[0041] Granular building materials

[0042] Further references Figure 2 The particle building material 300 may include about 80% to 100% by weight of metal particles, ceramic particles, or both metal and ceramic particles, based on the total weight of the particle building material. When the particle bed material includes metal particles, the metal particles may be selected from steel, stainless steel, other iron-based alloys, bronze, titanium, titanium alloys, aluminum, aluminum alloys, nickel, nickel alloys, cobalt, cobalt alloys, iron, iron alloys, nickel-cobalt alloys, gold, gold alloys, silver, silver alloys, platinum, platinum alloys, copper, copper alloys, niobium alloys, and the like. The metal included in the alloy may be any of the metals listed above, and / or may also include chromium, vanadium, tungsten, tungsten (tungsten carbide), tantalum, molybdenum, magnesium, and the like, or even non-metals or metalloids such as silicon, boron, germanium, and the like.

[0043] If ceramics are used, the selected ceramic material may include metal oxides, inorganic glasses, carbides, nitrides, borides, etc. In one example, the ceramic particles may include alumina glass, soda-lime glass, borosilicate glass, alumina-silica glass, silicon nitride, silicon dioxide, zirconium dioxide, titanium dioxide, magnesium aluminate, tin oxide, yttrium oxide, hafnium oxide, tantalum oxide, scandium oxide, niobium oxide, vanadium oxide, or a combination thereof.

[0044] When the particle building material includes both metal particles and ceramic particles, the ratio of metal particles to ceramic particles can be about 20:1 to about 1:2 by volume. In other examples, the ratio of metal particles to ceramic particles can be about 10:1 to about 1:1, or about 10:1 to about 4:1. In one example, the particle building material can include metal particles at about 75 volume % to about 100 volume %, and ceramic particles at up to about 25 volume / weight %. In other examples, the particle building material can include metal particles, and ceramic particles may not be present. In still other examples, multiple types of metal particles may be present, or metal particles and a small amount (e.g., about 0.01 weight % to about 5 weight %) of fillers, flow control agents, etc. may be present.

[0045] In one example, the metal particles can be a single-phase metal material composed of one element. In this example, the sintering temperature can be lower than the melting point of the single element. In another example, the metal particles can be composed of two or more elements, which can be in the form of a single-phase metal alloy or a multi-phase metal alloy. In these other examples, sintering can generally occur within a temperature range. Regarding alloys, materials alloyed with metals and non-metals (such as metal-metalloid alloys) can also be used.

[0046] The temperature(s) at which the metal particles and / or ceramic particles of the particle building material are sintered may be higher than the ambient temperature at which the patterning (with the binding agent) is performed (e.g., patterning at about 100°C to about 250°C). In some examples, the metal particles and / or ceramic particles may be sintered at about 500°C to about 3,500°C, depending on the material. Other temperature ranges that may be used may be about 800°C to about 2,500°C, about 1,000°C to about 1,800°C, or about 1,200°C to about 1,600°C, depending on the particle building material metal and / or ceramic selected or formulated for use. For example, stainless steel alloys may be sintered at about 1,100°C to about 1,500°C, while copper alloys may be sintered at substantially lower temperatures, such as about 750°C to about 1,000°C. For example, ceramics such as alumina may be sintered at higher temperatures starting at about 1,400°C, but may be higher or lower temperatures depending, for example, on the material particle size. Again, this depends on the specific material selected.

[0047] The particles may have a D50 particle size of about 0.1 μm to about 150 μm. For example, the metal particles may have a D50 particle size that can range from about 3 μm to about 150 μm, from about 10 μm to about 100 μm, from about 20 μm to about 80 μm, from about 30 μm to about 50 μm, from about 25 μm to about 75 μm, from about 40 μm to about 80 μm, from about 50 μm to about 75 μm, from about 5 μm to about 60 μm, from about 60 μm to about 90 μm, or from about 15 μm to about 85 μm. The ceramic particles may have a D50 particle size that can range from about 0.1 μm to about 50 μm, from about 0.1 μm to about 10 μm, from about 0.1 μm to about 1 μm, from about 0.5 μm to about 25 μm, from about 0.1 μm to about 5 μm, from about 0.5 μm to about 3 μm, from about 0.1 μm to about 2 μm, or from about 0.1 μm to about 1 μm. As used herein, particle size can refer to the diameter value of a spherical particle, or in non-spherical particles, can refer to the equivalent spherical diameter of the particle. The particle size can be Gaussian or quasi-Gaussian (or normally or quasi-normally distributed). A quasi-Gaussian distribution is a distribution curve that can be Gaussian in shape, but can be slightly skewed in one direction or the other (towards the smaller end of the particle size distribution range or towards the larger end of the particle size distribution range). That is, an exemplary quasi-Gaussian distribution of particles can generally be characterized by "D10", "D50", and "D90" particle size distribution values, where D10 refers to the 10th percentile particle size, D50 refers to the 50th percentile particle size, and D90 refers to the 90th percentile particle size. For example, a D50 value of about 25 μm means that about 50% of the particles (by number) have a particle size greater than about 25 μm, and about 50% of the particles have a particle size less than about 25 μm. Particle size distribution values ​​are not necessarily related to a Gaussian distribution curve. In practice, there is usually no true Gaussian distribution because there may be some skewness, but a quasi-Gaussian distribution can still be considered a "Gaussian" distribution used in practice. The particle size distribution can be represented by the D50 particle size, which can be similar to the average particle size, but may be different. In the examples herein, the particle size range can be modified to "average particle size" to provide a particle size distribution range that is sometimes slightly different.

[0048] The shape of the particles can be spherical, irregular spherical, circular, semicircular, disc-shaped, angular, sub-angular, cubic, cylindrical or any combination thereof. In one example, the particles can include spherical particles, irregular spherical particles or round particles. In some examples, the shape of the particles can be uniform or substantially uniform, which can allow the particles to be relatively uniformly melted or sintered.

[0049] 3D Printing Methods

[0050] A flow chart of an exemplary three-dimensional (3D) printing method 400 is shown in FIG4. It is noted that the multi-fluid kit and / or the 3D printing kit used may be, for example, Figure 1 and Figure 2 . The method may include iteratively applying 410 each building material layer of the particle building material to the powder bed. The particle building material may include about 80% to 100% by weight of metal particles, ceramic particles, or both metal particles and ceramic particles. The method may further include iteratively and selectively applying 420 a wetting agent to each building material layer based on the 3D object model. The wetting agent may include 0% to about 49.8% by weight of water, about 0.5% to about 60% by weight of a film-forming organic solvent, and about 30% to about 99% by weight of an amphiphilic water-miscible solvent. The film-forming organic solvent may have a boiling point that can range from greater than about 100°C to about 350°C. The amphiphilic water-miscible solvent may have a boiling point that can range from about 45°C to less than about 100°C. The amphiphilic water-miscible solvent may be present in the wetting agent at a concentration higher than the film-forming organic solvent. The method may further include iteratively and selectively applying 430 a binding agent to each build material layer to define respective patterned object layers based on the 3D object model, the object layers may become adhered to each other to form a green body object composed of layers. The binding agent may include about 2 wt % to about 30 wt % of a polymer binder dispersed in an aqueous liquid vehicle.

[0051] After each layer of particulate building material is printed with a wetting agent and a binding agent thereon, in some cases, each layer of building material may be heated to drive off water and / or other liquid components, and to further solidify the layers of the 3D green body object. Heat may be applied from the top and / or may be provided by the build platform from below the particulate building material. In other examples, the particulate building material may be heated prior to dispensing.

[0052] During the printing process, the build platform may be lowered a distance corresponding to the thickness of the particulate building material spread for the next layer of the green body object or article to be formed, so that another layer of particulate building material can be added thereon, printed with a wetting agent, a binding agent, heated, etc. This process may be repeated on a layer-by-layer basis until a green body object is formed.

[0053] After forming the green body object, in one example, the entire green body object can be moved to a furnace and fused by sintering and / or annealing. The method may include heating the green body object to a debonding temperature (about 300°C to 550°C) to remove the polymer binder via pyrolysis, and then heating the green body object to a sintering temperature of about 600°C to about 3,500°C (which is lower than the melting temperature of the particulate building material). During the sintering process, the building material particles can consolidate into the final part. Sintering the green body object may include heating the green body object to a temperature of about 600°C to about 3,500°C to fuse the individual particles of the particulate building material together and form a thermally fused three-dimensional article. In some examples, the temperature may be about 1,200°C to about 1,400°C, about 1,000°C to about 3,000°C, or about 600°C to about 2,000°C. In one example, the thermally fused three-dimensional article can have a porosity that can range from about 0.1 volume % to about 60 volume % or from about 0.1 volume % to about 40 volume %.

[0054] definition

[0055] It is noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise.

[0056] As used herein, the term "about" when referring to an index value or range allows a certain degree of variability in the value or range, such as within 10% of the value or the range limit, or within 5% in one aspect. The term "about" is also understood to include the range defined by the specified exact numerical value as a numerical sub-range when modifying a numerical range, such as a range of about 1% by weight to about 5% by weight including 1% by weight to 5% by weight as a clearly supported sub-range. As used herein, "kit" can be synonymous with multiple compositions and is understood to include multiple compositions, the compositions comprising multiple components, wherein different compositions can be separately contained in the same one or more containers before and during use (e.g., building a 3D object), but these components can be combined together during the construction process. The container can be any type of vessel, box, or receptacle made of any material.

[0057] As used herein, "green" describes any intermediate structure of a variety of intermediate structures before any particles and particle materials are fused, such as a green body part, a green body body, a green body body object, a green body body layer, etc. As a "green" structure, the particle building materials can be (weakly) bonded together by a binder. Typically, the mechanical strength of the green body is such that the green body can be processed or extracted from the particle building materials on the build platform to be placed in a furnace. It is to be understood that any particle building material that is not patterned with a binding agent is not considered to be part of the "green" structure, even if the particle building material is adjacent to or surrounds the green body object or its layer. For example, unprinted particle building materials can act to support the green body contained therein at the same time, but the particle building material is not part of the green structure unless the particle building material is printed with a binding agent to generate a solidified part before fusion (e.g., sintering, annealing, melting, etc.).

[0058] The terms "fuse", "fusing", "fusion", "thermal fusion", etc. refer to the materials of adjacent particles of a particle building material being joined, for example, by sintering, annealing, melting, etc., and may include adjacent particles being completely fused into the same structure, such as melting together, or may include surface fusion, in which the particles are not completely melted to the liquidus point, but the individual particles of the particle building material are allowed to become bonded to each other, such as forming material bridges between particles at or near contact points.

[0059] As used herein, the terms three-dimensional (or 3D) "parts," "objects," "articles," and the like refer to a target object that is typically constructed in two stages, such as forming a green body object and then thermally fusing the green body object to form a thermally fused article. A 3D object that has been heated to a sintering or annealing temperature sufficient to fuse metal and / or ceramic particles may be referred to as a "thermally fused" article, indicating that the object has been fused together, such as by sintering, annealing, melting, etc., to form a strong and rigid part. On the other hand, the terms "green body" or "green" when referring to an object, part, or article indicate that the 3D object has solidified but has not yet been thermally fused.

[0060] As used herein, "applying" when referring to a binding agent or other fluid agent that can be used, for example, refers to placing or arranging a fluid agent (such as a binding agent) on a particulate building material or into a layer of particulate building material to form a 3D green body object. For example, "applying" can refer to "spraying", "squirting", "drip", "spraying", etc.

[0061] As used herein, "jetting" or "ejection" refers to the discharge of a fluid reagent or other composition from a jetting or ejection architecture (e.g., an inkjet architecture). The inkjet architecture may include a thermal architecture or a piezoelectric architecture. In addition, such an architecture may be configured to print different droplet sizes, such as from about 3 picoliters to less than about 10 picoliters, or to less than about 20 picoliters, or to less than about 30 picoliters, or to less than about 50 picoliters, etc.

[0062] As used herein, for convenience, multiple items, structural elements, compositional elements and / or materials may be presented in the same list. However, these lists should be interpreted as if each member of the list is identified as a separate and unique member. Therefore, in the absence of contrary indications, any member of such a list should not be interpreted as a de facto equivalent of any other member of the same list based on presentation in the same group.

[0063] Concentration, size, amount and other numerical data may be presented in range format in this article.It is to be understood that such range format is used only for convenience and brevity, and should be flexibly interpreted as including the numerical value clearly listed as the limit of the range, and also including all independent numerical values ​​or sub-ranges contained in the range, just as clearly listing each numerical value and / or sub-range.For example, the weight ratio range of about 1 wt % to about 20 wt % should be interpreted as including the clearly listed 1 wt % and 20 wt % limits, and including independent weights, such as about 2 wt %, about 11 wt %, about 14 wt %, and sub-ranges, such as about 10 wt % to about 20 wt %, about 5 wt % to about 15 wt %, etc.

[0064] Example

[0065] The following examples illustrate embodiments of the present disclosure. However, it is to be understood that the following examples only illustrate the application of the principles of the present disclosure. Many modifications and alternative multi-fluid kits, three-dimensional printing kits, compositions, methods, systems, etc. can be envisioned without departing from the spirit and scope of the present disclosure. The appended claims are intended to cover such modifications and arrangements.

[0066] Example 1 - Wetting agent formulations

[0067] Various wetting agents incorporating an amphiphilic solvent, a film-forming solvent, and water were prepared as shown in Table 1 below.

[0068] Table 1: Wetting agents

[0069]

[0070] 1 Boiling point: ethanol (78.36°C); 1,2-butanediol (196°C-196.9°C); water (100°C)

[0071] 2 Wetting agents containing more water exhibit higher surface tension, for example, wetting agent 4 containing no water exhibits the lowest surface tension.

[0072] Example 2 – Penetration of the wetting agent into the particle building material

[0073] Droplets of each of the four wetting agents of Table 1 were pipetted onto a 2 mm thick layer of stainless steel 316L powder (D50 ~ 12-13 um) particle building material and visually observed to determine how long it took for the corresponding wetting agent to penetrate the particle layer, e.g., when the wetting agent was not visible as a fluid layer on the particle layer. The collected data is shown in Table 2 below:

[0074] Table 2: Permeation time

[0075] Wetting Agent Formulation ID <![CDATA[ 2 Surface tension (dyne / cm)]]> Time (min) 1 31 4 2 29 1.5 3 27 0.6 4 23 0.5 .

[0076] Wetting agents with lower surface tensions exhibit less intermolecular forces than wetting agents with higher surface tensions and are able to distribute more quickly into the spaces between particles of the particulate building material.

[0077] Example 3 – Adhesive agent penetration with and without wetting agents

[0078] Based on the data collected in Example 2, wetting agent 4 from Table 1 was selected for further evaluation for use in conjunction with a bonding agent formulation and the same stainless steel particle build material. The bonding agent had the formulation shown in Table 3 below.

[0079] Table 3: Binding Reagent Formula

[0080] Components Component Type weight% Proprietary Acrylic Latex Adhesives 12 1,2-Butanediol Solvent 26 Tergitol 15-S7 Surfactants 1 water Solvents margin .

[0081] For this evaluation, an 8 mg drop of binding reagent was pipetted onto the 316L stainless steel particle layer and visually observed to determine how long it took for the binding reagent to penetrate the particle layer (e.g., when the binding reagent was not visible as a fluid layer over the particle layer). The binding reagent penetrated the particle layer after 7 minutes.

[0082] At different locations, 7 mg drops of the wetting reagent were pipetted onto the 316L stainless steel particle layer and visually observed to determine how long it took the wetting reagent to penetrate the particle layer (e.g., when the wetting reagent was not visible as a fluid layer on the particle layer). The wetting reagent penetrated the particle layer in less than 20 seconds.

[0083] At different locations, a drop of 7 mg of wetting reagent was pipetted onto the 316L stainless steel particle layer, and a drop of 8 mg of binding reagent was pipetted onto the 316L stainless steel particle layer at the same location. Again, in this example, the layers were visually observed to determine how long it took for the wetting reagent and binding reagent to penetrate the particle layer (e.g., when the binding reagent and wetting reagent were not visible as a fluid layer on the particle layer). In this case, the binding reagent penetrated the particle layer within 3 minutes due to the wetting assistance of the pre-applied wetting reagent.

[0084] Applying the wetting agent prior to applying the binding agent improves the penetration of the binding agent into the layer of particulate building material. The inclusion of the wetting agent reduces the time it takes for the binding agent to penetrate the layer of particulate building material.

[0085] Example 4 – Comparison of printing of binding agent applied to particulate build material with and without wetting agent

[0086] Using a proprietary HP powder bed 3-D printing test bench, printing was performed on a 22 μm thick stainless steel 316L particle building material layer with a binding agent and a wetting agent and binding agent from Example 2. Visual inspection of the particle building material with a binding agent and / or wetting agent applied thereon. The layer with a binding agent (excluding wetting agent) printed thereon looked darker than the layer with wetting agent and binding agent printed thereon. After microscopic examination at 50 times magnification using a Keyence VHX-5000_ digital microscope, the surface of the particle building material layer with a binding agent (excluding wetting agent) showed a textured appearance, while the layer with wetting agent and binding agent printed thereon appeared smooth. When observed at 500 times magnification, the particle building material layer with a binding agent (excluding wetting agent) appeared to include vein-like valleys throughout the layer.

Claims

1. A multi-fluid kit for three-dimensional printing, comprising: A wetting agent, the wetting agent consisting of: 0% to 49.8% by weight of water, 0.2 wt % to 30 wt % of a film-forming organic solvent having a boiling point of greater than 100° C. to 350° C., wherein the film-forming organic solvent comprises an aliphatic alcohol, an aromatic alcohol, a glycol ether, a polyglycol ether, 2-pyrrolidone, caprolactam, formamide, acetamide or a mixture thereof, and 30% to 99.5% by weight of an amphiphilic solvent having a boiling point of 45°C to less than 100°C, wherein the amphiphilic solvent is water miscible and is present in the wetting agent at a concentration greater than water and at a concentration greater than the film-forming organic solvent, wherein the amphiphilic solvent has a surface tension of 20 to 40 millinewtons per meter when measured at 20°C; and A binding agent comprising 2% to 30% by weight of a polymer binder dispersed in an aqueous liquid vehicle.

2. The multi-fluid kit of claim 1, wherein the film-forming organic solvent comprises a glycol.

3. The multi-fluid kit of claim 2, wherein the film-forming organic solvent comprises an alkyl glycol. The multi-fluid kit of claim 3 , wherein the film-forming organic solvent comprises 1,2-butanediol.

5. The multi-fluid kit of claim 1, wherein the film-forming organic solvent comprises a C3 to C12 alcohol.

6. The multi-fluid kit of claim 1, wherein the amphiphilic solvent comprises ethanol, methanol, 1-propanol, isopropanol, 1-butanol, acetone, methyl ethyl ketone, dimethylformamide, tetrahydrofuran, 1,4-dioxane, acetonitrile, or a mixture thereof.

7. The multi-fluid kit of claim 1, wherein the amphiphilic solvent is ethanol and the film-forming organic solvent is 2-pyrrolidone. 8 . The multi-fluid kit according to claim 1 , wherein the binding reagent further comprises a co-solvent, and the co-solvent in the binding reagent is the same as the film-forming organic solvent in the wetting reagent.

9. The multi-fluid kit of claim 1, wherein the wetting reagent is a non-aqueous wetting reagent.

10. A three-dimensional printing kit, comprising: A wetting agent, the wetting agent consisting of: 0% to 49.8% by weight of water, 0.2 wt % to 60 wt % of a film-forming organic solvent having a boiling point of greater than 100° C. to 350° C., wherein the film-forming organic solvent comprises an aliphatic alcohol, an aromatic alcohol, a glycol ether, a polyglycol ether, 2-pyrrolidone, caprolactam, formamide, acetamide or a mixture thereof, and 30% to 99.5% by weight of an amphiphilic solvent having a boiling point of 45°C to less than 100°C, wherein the amphiphilic solvent is water miscible, and wherein the surface tension of the amphiphilic solvent is from 20 to 40 millinewtons per meter when measured at 20°C; a binding agent comprising 2% to 30% by weight of a polymer binder dispersed in an aqueous liquid vehicle; and A particulate building material comprising 80% to 100% by weight of metal particles, ceramic particles, or both metal particles and ceramic particles.

11. The three-dimensional printing kit of claim 10, wherein the film-forming organic solvent is present in the wetting agent at 1 wt% to 15 wt%.

12. The three-dimensional printing kit of claim 10, wherein the film-forming organic solvent comprises a glycol and the amphiphilic solvent comprises ethanol.

13. The three-dimensional printing kit according to claim 12, wherein the film-forming organic solvent comprises 1,2-butanediol.

14. The three-dimensional printing kit of claim 10, wherein the particulate building material comprises 90 wt% to 100 wt% metal particles, and the metal particles have a D50 particle size distribution value of 3 μm to 100 μm.

15. The three-dimensional printing kit of claim 10, wherein the amphiphilic solvent is present in the wetting reagent at a higher concentration than water and at a higher concentration than the film-forming organic solvent.

16. A three-dimensional printing method, comprising: iteratively applying respective build material layers of a particulate build material comprising 80% to 100% by weight of metal particles, ceramic particles, or both metal particles and ceramic particles to the powder bed; Based on the 3D object model, iteratively and selectively applying a wetting agent to each build material layer, wherein the wetting agent comprises 0 wt % to 49.8 wt % water, 0.2 wt % to 60 wt % of a film-forming organic solvent having a boiling point of greater than 100° C. to 350° C., and 30 wt % to 99.5 wt % of an amphiphilic solvent having a boiling point of 45° C. to less than 100° C., wherein the film-forming organic solvent comprises an aliphatic alcohol, an aromatic alcohol, a glycol ether, a polyglycol ether, 2-pyrrolidone, caprolactam, formamide, acetamide, or a mixture thereof, and wherein the amphiphilic solvent is water miscible and has a surface tension of 20 to 40 millinewtons per meter when measured at 20° C.; and Based on the 3D object model, a binding agent is iteratively and selectively applied to each build material layer to define respective patterned object layers, which become adhered to each other to form a green body object composed of layers, wherein the binding agent comprises 2 wt % to 30 wt % of a polymer binder dispersed in an aqueous liquid vehicle.

17. The method of claim 16, further comprising sintering the green body object comprised of layers to form a thermally fused article.

18. The method of claim 17, wherein the fused three-dimensional object has a porosity of 0.1 vol% to 60 vol%.

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