Three-dimensional object forming method and device, storage medium and computer equipment

Abstract

The invention provides a three-dimensional object forming method and device, a storage medium and computer equipment. According to the three-dimensional object forming method, on the basis that existing powder and ink-jet printing are combined, the first liquid material is applied to the powder material layer according to the layer printing data so as to form the foaming area, and / or the second liquid material is applied to the powder material layer so as to form the non-foaming area; the foaming area and the non-foaming area are arranged adjacently, the non-foaming area limits the foaming range of the foaming area, and the uniformity of the three-dimensional object green body during foaming is guaranteed, so that the structural precision of the three-dimensional object is guaranteed, and the product quality of the three-dimensional object is improved.

Description

TECHNICAL FIELD

[0001] The technical field relates to a three-dimensional object forming method and device, a storage medium and a computer device. BACKGROUND

[0002] The main process of three-dimensional printing technology is to obtain a digital model of a three-dimensional object, slice the digital model, and process and convert data of each slice layer to obtain printing data of each slice layer. A printing device prints each slice layer according to the printing data to manufacture the three-dimensional object. Three-dimensional printing is widely used in the fields of biological tissue engineering, aerospace, energy storage, electronics and devices, vehicle manufacturing, and engineering composites.

[0003] More than 80% of the polymer materials used in three-dimensional printing on the market are hard materials, which limits their application in wearable devices, medical sensors, shoe soles and other industries. Combining foaming materials with three-dimensional printing can prepare flexible lightweight materials. Currently, there are methods for preparing or forming polymer foaming materials using three-dimensional printing technology. According to the different stages of the foaming process, the methods can be divided into pre-forming foaming and post-forming foaming. Pre-forming foaming refers to foaming the material and then three-dimensionally printing the material. This method often causes the pore structure of the material to be damaged during the forming process, thereby reducing the performance of the material itself. Post-forming foaming refers to three-dimensionally printing the material and then foaming the material. This method has the disadvantage that it is difficult to control the foaming ratio and uniformity of the material after forming. Therefore, there is an urgent need to seek a technology that can effectively control the structural precision of a three-dimensional object after three-dimensional printing. SUMMARY

[0004] In order to overcome the above-mentioned defects in the prior art, the purpose of the present application is to provide a three-dimensional forming method and device, a storage medium and a computer device. By setting a non-foaming area around the foaming area, the non-foaming area limits the foaming range of the foaming area, ensures the uniformity of the three-dimensional object green body during foaming, and thus ensures the structural precision of the three-dimensional object and improves the product quality of the three-dimensional object.

[0005] In order to achieve the above-mentioned purpose, the technical solution of the present application is as follows:

[0006] In a first aspect, the present application provides a three-dimensional object forming method, which comprises:

[0007] providing a powder material to form a powder material layer;

[0008] According to layer printing data, a first liquid material is applied to the powder material layer to form a foamed region, and / or a second liquid material is applied to the powder material layer to form a non-foamed region, wherein the foamed region and the non-foamed region are arranged adjacent to each other to form a slice layer of a three-dimensional object preform, wherein the first liquid material is different from the second liquid material;

[0009] Repeat the above steps of forming a powder material layer to forming a slice layer, so that the obtained multiple slice layers are stacked one by one to form a three-dimensional object green body;

[0010] The three-dimensional object blank is subjected to a foaming treatment to foam the foaming area to obtain a three-dimensional object. The foaming temperature of the foaming treatment is higher than the target temperature of the formed object in the foaming area and lower than the target temperature of the formed object in the non-foaming area. The target temperature is selected from at least one of softening temperature and melting point temperature.

[0011] In one specific embodiment, the first liquid material being different from the second liquid material specifically means that: the composition of the first liquid material is different from the composition of the second liquid material, or the amount of the first liquid material sprayed per unit volume is different from the amount of the second liquid material sprayed per unit volume.

[0012] In one specific embodiment, the target temperature T1 of the molded object in the foamed region is lower than the target temperature T2 of the molded object in the non-foamed region, and T2-T1≥5.

[0013] In one specific embodiment, the slice layer of the three-dimensional object preform includes a solid portion, the solid portion comprising foamed and non-foamed regions, or...

[0014] The sliced ​​layer of the three-dimensional object blank includes a solid part and a protective part. The solid part is a foamed area, and the protective part is a non-foamed area.

[0015] In one specific embodiment, the first liquid material includes a first component and a first additive, and the second liquid material includes the first component; wherein...

[0016] The first component includes at least one of a first active component, a first solvent, and an energy absorber. The first active component contains an active group and at least partially dissolves the powder material. The first solvent has a boiling point lower than the melting point or melting temperature of the powder material and at least partially dissolves the powder material. The energy absorber absorbs energy to act on at least a portion of the powder material.

[0017] The first additive includes at least one of a plasticizer, a second solvent, and a first active monomer. The plasticizer is selected from at least one of polyethylene glycol plasticizers, phthalate plasticizers, aliphatic diester plasticizers, phosphate plasticizers, epoxy plasticizers, polymerizable plasticizers, polyphenolic ester plasticizers, chlorinated plasticizers, alkyl sulfonate plasticizers, N-butylbenzenesulfonamides, and polyol esters. The second solvent has a boiling point higher than the melting point or melting temperature of the powder material and at least partially dissolves the powder material. The first active monomer does not dissolve the powder material, and the glass transition temperature of the polymer formed by the polymerization reaction is less than 20°C.

[0018] In one specific embodiment, the second liquid material further includes a first additive, wherein the mass percentage of the first additive in the second liquid material is less than the mass percentage of the first additive in the first liquid material.

[0019] In one specific embodiment, the first liquid material further includes a second component, which includes at least one of water, a second active component, and a non-reactive resin. The second liquid material further includes a second component, wherein the second active component includes at least one of a second active monomer and an oligomer. The second active monomer does not dissolve the powder material and the polymer formed by the polymerization reaction has a glass transition temperature of 20°C to 80°C.

[0020] In one specific embodiment, the first liquid material further includes a second additive, which includes at least one of an initiator, a leveling agent, a defoamer, a polymerization inhibitor, an antioxidant, a dispersant, and a colorant.

[0021] In one specific embodiment, the first liquid material further includes a foaming agent selected from at least one of water, aliphatic hydrocarbons, chlorinated hydrocarbons, chlorofluorocarbons, carbonates (bicarbonates) and their foaming aids, hydrogen peroxide and its foaming aids, hydrides, isocyanate compounds, azo compounds, hydrazine derivatives, urea-amino compounds, azide-amino compounds, nitroso compounds, and triazole compounds.

[0022] In one specific embodiment, the first liquid material further includes a foaming inhibitor, which is selected from at least one of organic acids, acyl halides, acid anhydrides, polyphenols, polyols, nitrogen-containing compounds, sulfur-containing compounds, phosphates, phosphites, aldehydes, and ketones.

[0023] In one specific embodiment, the second liquid material further includes a third auxiliary agent, which is selected from at least one of a crosslinking agent and a third active monomer;

[0024] The crosslinking agent reacts with the powder material or causes a crosslinking reaction between the powder materials, wherein the crosslinking agent is selected from at least one of peroxide, silane compound, dimercapto-triazine compound, diaziridinium group compound, dithiohydroxy compound, sulfur, and sodium disulfide;

[0025] The third active monomer does not dissolve the powder material and the polymer formed by the polymerization reaction has a glass transition temperature greater than 80°C.

[0026] In one specific embodiment, the powder material is selected from at least one of polypropylene, polyethylene, polystyrene, polyvinyl chloride, polyacrylonitrile, acrylonitrile-styrene-acrylate copolymer, polyamide, polyester, polyurethane, polylactic acid, poly(meth)acrylate, poly(meth)acrylate, polyvinyl fluoride, chlorinated polyolefin, polycaprolactone, hydroxyl-containing polyvinyl alcohol, cellulose, and modified cellulose.

[0027] In one specific embodiment, the foaming temperature is higher than the molding temperature of the object being molded in the foaming region.

[0028] In one specific embodiment, the foaming process includes chemical foaming or physical foaming.

[0029] In one specific embodiment, the three-dimensional object blank is chemically foamed, and the three-dimensional object blank is placed in a third liquid material, the third liquid material including a medium liquid, which is a solvent or heat-conducting oil that has no dissolving effect on the three-dimensional object blank.

[0030] Secondly, this application provides a three-dimensional object forming apparatus for implementing any of the three-dimensional object forming methods described above, the three-dimensional object forming apparatus comprising:

[0031] A powder supply component, used to supply powder material to form a powder material layer;

[0032] A forming platform is used to support the powder material layer;

[0033] A material dispenser is used to apply a first liquid material to the powder material layer to form a foamed region according to layer printing data, and / or to apply a second liquid material to the powder material layer to form a non-foamed region, wherein the foamed region and the non-foamed region are arranged adjacent to each other to form a slice layer of a three-dimensional object preform, wherein the first liquid material is different from the second liquid material.

[0034] A foaming unit is used to perform foaming treatment on the three-dimensional object green body, so that the foaming area foams to obtain a three-dimensional object, wherein the foaming temperature of the foaming treatment is higher than the target temperature of the molded object in the foaming area and lower than the target temperature of the molded object in the non-foaming area, and the target temperature is selected from at least one of softening temperature and melting point temperature.

[0035] Thirdly, this application provides a non-transitory computer-readable storage medium, the non-transitory computer-readable storage medium including a stored program that, when the program is executed, controls the device where the storage medium is located to perform any of the three-dimensional object forming methods described above.

[0036] Fourthly, this application provides a computer device, the computer device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement any of the three-dimensional object forming methods described above.

[0037] The technical solution provided in this application can achieve the following beneficial effects:

[0038] This application provides a method and apparatus for forming a three-dimensional object, a storage medium, and a computer device. A first liquid material is applied to a powder material layer to form a foamed region, and / or a second liquid material is applied to a powder material layer to form a non-foamed region. The foamed region and the non-foamed region are arranged adjacent to each other. The non-foamed region limits the foaming range of the foamed region, ensuring the uniformity of the three-dimensional object green body during foaming, thereby ensuring the structural accuracy of the three-dimensional object and improving the product quality of the three-dimensional object.

[0039] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0040] Figure 1 A schematic flowchart illustrating the three-dimensional object forming method provided in the embodiments of this application;

[0041] Figure 2 A schematic diagram of the structure of a three-dimensional object blank to be printed provided in an embodiment of this application;

[0042] Figure 3 This is a schematic diagram of the structure of the powder material layer provided in the embodiments of this application;

[0043] Figure 4 This is a schematic diagram of the structure of the three-dimensional object forming device according to an embodiment of this application;

[0044] Figure 5 This is a schematic diagram of the structure of a non-transitory storage medium according to an embodiment of this application;

[0045] Figure 6 This is a schematic diagram of the structure of a computer device according to an embodiment of this application.

[0046] Explanation of reference numerals in the attached figures:

[0047] 1-Powder material; 2-Powder supply component; 21-Powder spreader; 22-Lifter; 23-Powder storage chamber; 231-Support plate; 3-Forming platform; 4-Lifting mechanism; 5-Preheating component; 6-Material distributor; 61-First printhead; 62-Second printhead; 7-Energy supply device; 8-Controller; 81-Storage medium; 811-Program; 9-Guide rail; 11-Foaming section; 11 n - Foamed area; 12 - Non-foamed area; 12 n - Non-foamed area; 100 - Computer equipment; 101 - Processor; 102 - Memory; 103 - Computer program; L0 - Powder material layer.

[0048] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Specific Implementation

[0049] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0050] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0051] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0052] It should be noted that the directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this application are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this application.

[0053] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0054] Figure 1The flowchart of the three-dimensional object forming method provided in this embodiment is as follows: Figure 1 As shown, this embodiment provides a method for forming a three-dimensional object, including the following steps:

[0055] Step 101: Provide powder material to form a powder material layer;

[0056] Step 102: Apply a first liquid material to the powder material layer to form a foamed region according to the layer printing data, and / or apply a second liquid material to the powder material layer to form a non-foamed region. The foamed region and the non-foamed region are arranged adjacent to each other to form a slice layer of a three-dimensional object green body, wherein the first liquid material is different from the second liquid material.

[0057] Step 103: Repeat the above steps of forming powder material layer to forming slice layer, so that the obtained multiple slice layers are stacked one by one to form a three-dimensional object green body;

[0058] Step 104: Foaming treatment is performed on the three-dimensional object blank to foam the foaming area and obtain the three-dimensional object. The foaming temperature of the foaming treatment is higher than the target temperature of the molded object in the foaming area and lower than the target temperature of the molded object in the non-foaming area. The target temperature is selected from at least one of softening temperature and melting point temperature.

[0059] In this application, a first liquid material is applied to a powder material layer to form a foamed region, and / or a second liquid material is applied to a powder material layer to form a non-foamed region. The foamed region and the non-foamed region are arranged adjacent to each other. The non-foamed region limits the foaming range of the foamed region, ensuring the uniformity of the three-dimensional object green body during foaming, thereby ensuring the structural accuracy of the three-dimensional object and improving the product quality of the three-dimensional object.

[0060] The following is a detailed explanation of specific implementation methods:

[0061] Prior to step 101, the three-dimensional object forming method further includes:

[0062] Obtain the digital model of the object to be printed, slice and layer the digital model of the object to obtain multiple slice layers and slice layer image data, and generate layer printing data based on the slice layer image data. The layer printing data includes layer printing data of foamed areas and / or layer printing data of non-foamed areas.

[0063] In specific implementation methods, the original data of the object to be printed can be obtained by scanning and 3D modeling to obtain a digital model of the object to be printed. Alternatively, a 3D model of the object to be printed can be designed and constructed to obtain a digital model of the object to be printed. The digital model is then converted into a data format, such as STL, PLY, or WRL, which can be recognized by slicing software. The slicing software is then used to slice the model into layers to obtain slice layer image data. The layer image data is then processed to obtain layer printing data representing the object. The layer printing data includes information representing the shape of the object to be printed and / or information representing the color of the object to be printed.

[0064] It should be noted that the shape of the object to be printed is not limited; it can be any shape. Figure 2 This is a schematic diagram of the structure of a three-dimensional object blank to be printed provided in an embodiment of this application, such as... Figure 2 As shown, in a specific embodiment, the three-dimensional object blank to be printed can be, for example, a cylinder. When the entire three-dimensional object needs to be foamed, the foamed part 11 is the solid part of the three-dimensional object blank, and the non-foamed part 12 is the protective part of the three-dimensional object blank. After the foaming process, the protective part can be removed, leaving only the solid part, thus obtaining the desired three-dimensional object. When only part of the three-dimensional object needs to be foamed, both the foamed part 11 and the non-foamed part 12 are solid parts of the three-dimensional object blank, and after the foaming process, the desired three-dimensional object is obtained.

[0065] Step 101: Provide powder material to form a powder material layer;

[0066] In a specific implementation, the powder material is a powdered material particle. Optionally, the powder material is selected from at least one of polypropylene, polyethylene, polystyrene, polyvinyl chloride, polyacrylonitrile, acrylonitrile-styrene-acrylate copolymer, polyamide, polyester, polyurethane, polylactic acid, poly(meth)acrylate, poly(meth)acrylate, polyvinyl fluoride, chlorinated polyolefin, polycaprolactone, hydroxyl-containing polyvinyl alcohol, cellulose, and modified cellulose.

[0067] In this embodiment, the melting point or melting temperature of the powder material can be between 60°C and 300°C. There are no special limitations on the particle shape and size of the powder material. When forming a powder material layer, the powder material provided in this embodiment exhibits sufficient flowability to meet usage requirements, the gaps between the powder materials can be filled by the applied liquid material, and the applied liquid material can wet the surface of the powder material.

[0068] Optionally, depending on the manufacturing process of the powder material, the powder material in this embodiment can be spherical, dendritic, flake-like, disc-like, needle-like, or rod-like. The average particle size of the powder material is 1 μm to 400 μm, for example, it can be 1 μm, 5 μm, 10 μm, 30 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, or 400 μm, and the average particle size of the powder material is preferably 30 μm to 200 μm. The interparticle spacing in the powder material is approximately 5 nm to 100 μm, for example, it can be 5 nm, 10 nm, 100 nm, 250 nm, 500 nm, 1 μm, 5 μm, 10 μm, 25 μm, 50 μm, 75 μm, or 100 μm, and is not limited here. In this embodiment, the particle gaps of the powder material are in the range of 5nm to 100μm. When liquid material is selectively applied to the powder material layer, the liquid material can quickly penetrate into the interior of the powder material layer through the gaps and remain on the surface, thereby wetting the surface of the powder material in the selected area.

[0069] Optionally, the thickness of the powder material layer is 10 μm to 500 μm, for example, it can be 10 μm, 25 μm, 50 μm, 75 μm, 100 μm, 125 μm, 150 μm, 200 μm, 300 μm, 400 μm, or 500 μm. The preferred thickness of the powder material layer is 50 μm to 150 μm. Understandably, when the powder material layer is thinner, a higher resolution three-dimensional object can be formed, but the time required to manufacture the three-dimensional object is greatly increased, and the manufacturing cost increases; when the powder material layer is thicker, the time for the liquid material to wet the powder material is longer, and the resolution of the manufactured three-dimensional object decreases, making it difficult to achieve the desired result.

[0070] The powder material in this application may also include additives, including at least one of flow aids and fillers. Flow aids are used to improve the flowability of the powder material, and may be, for example, silica or talc. Fillers are used to improve the mechanical strength of the three-dimensional object, and may be, for example, graphene, carbon nanotubes, glass fiber, or kaolin, etc., and are not limited in this embodiment.

[0071] In some embodiments, after step 101 and before step 102, the three-dimensional object forming method further includes:

[0072] Preheated powder material layer.

[0073] Understandably, providing heat energy to preheat the powder material layer and increasing its temperature helps improve the penetration rate of the powder material when applying the first liquid material and / or the second liquid material to the powder material layer in step 102. The preheating temperature is related to the properties of the powder material used. Preferably, the preheating temperature is lower than the melting point or melting temperature of the powder material to prevent the powder material from sticking together and to facilitate the penetration of the first liquid material and / or the second liquid material into the gaps between the powder material particles.

[0074] In some implementations, the energy used for preheating includes at least one of radiant energy and thermal energy, specifically through infrared radiation, visible light irradiation, etc.

[0075] Step 102: Apply a first liquid material to the powder material layer to form a foamed region according to the layer printing data, and / or apply a second liquid material to the powder material layer to form a non-foamed region. The foamed region and the non-foamed region are arranged adjacent to each other to form a slice layer of a three-dimensional object green body, wherein the first liquid material is different from the second liquid material.

[0076] Figure 3 This is a schematic diagram of the structure of the powder material layer provided in the embodiments of this application, as shown below. Figure 3 As shown, in a specific embodiment, at the nth layer, a first liquid material is applied to the powder material layer L0 according to the layer printing data to form a foamed region 11. n And / or, apply a second liquid material to the powder material layer L0 to form a non-foamed region 12. n Foaming area 11 n Non-foamed area 12 n Adjacent slice layers are arranged to form a three-dimensional object blank. It should be noted that in some slice layers, when both foamed regions 11n and non-foamed regions 12n are included, the foamed regions 11n and non-foamed regions 12n are arranged adjacently. In other slice layers, there may be only foamed regions 11n, or only non-foamed regions 12n; in this case, in two adjacent slice layers, at least a portion of the foamed regions 11n and at least a portion of the non-foamed regions 12n are arranged adjacently. The slice layers of the three-dimensional object blank include a solid portion, and the solid portion includes the foamed regions 11n, 12n, 12n, and 12n. n Non-foamed area 12 n In other embodiments, the sliced ​​layer of the three-dimensional object preform includes a solid portion and a protective portion, wherein the solid portion is the foamed region 11. n The protective part is the non-foamed area 12 nFurthermore, the protective portion has a horizontal width of 0.1 mm or more to ensure sufficient support strength. In other embodiments, a certain gap may exist between the foamed and non-foamed areas, and the gap between the foamed and non-foamed areas contains powder material that has not been applied with liquid material, which can be removed after the three-dimensional object is formed.

[0077] The first liquid material differs from the second liquid material, specifically in that: the composition of the first liquid material differs from the composition of the second liquid material, or the amount of the first liquid material sprayed per unit volume differs from the amount of the second liquid material sprayed per unit volume. It should be noted that the composition of the first liquid material differs from the composition of the second liquid material in that: the specific types of substances in the first liquid material differ from the specific types of substances in the second liquid material, and / or, the mass percentage of the specific substances in the first liquid material differs from the mass percentage of the specific substances in the second liquid material. Because the first liquid material differs from the second liquid material, the target temperature T1 of the molded object in the foamed region is different from the target temperature T2 of the molded object in the non-foamed region. The target temperature is selected from at least one of the softening temperature and melting point temperature. For molded objects made of non-crystalline polymers, the target temperature is the softening temperature; for molded objects made of crystalline polymers, the target temperature is the melting point temperature. Furthermore, the target temperature T1 of the molded object in the foamed region is lower than the target temperature T2 of the molded object in the non-foamed region, and satisfies T2-T1≥5, ensuring that the non-foamed region cannot foam in subsequent foaming processes, thereby ensuring sufficient support strength is provided to the foamed region.

[0078] The following description uses the example of the composition of the first liquid material being different from that of the second liquid material. In one embodiment, the first liquid material includes a first component and a first additive. The first component includes at least one of a first active component, a first solvent, and an energy absorber. The first active component contains active groups and at least partially dissolves the powder material. The boiling point of the first solvent is lower than the melting point or melting temperature of the powder material and at least partially dissolves the powder material. The energy absorber absorbs energy to act on at least a portion of the powder material.

[0079] It should be noted that the first liquid material and the second liquid material are collectively referred to as liquid materials. The first component of the liquid material can at least partially dissolve or melt the powder material, and / or, the first component of the liquid material undergoes thermal polymerization and / or photopolymerization, and / or, the first component of the liquid material undergoes a polymerization reaction with the powder material. The first component of the liquid material can be flexibly changed according to actual needs, as long as it can ultimately solidify the powder material sprayed with the liquid material. For example, the first component of the liquid material can contain an energy absorber, which absorbs the provided energy and converts the energy into heat energy, thereby melting and solidifying the powder material in contact with it or promoting the dissolution of the powder material in contact with it by the liquid material; or, the first component of the liquid material can contain a first active component, which contains active groups that can undergo polymerization reactions, and part of the first active component can at least partially dissolve the powder material. Under the provision of energy, such as radiation energy or heat energy, an initiator initiates a polymerization reaction of the first active component, thereby entangled and solidifying the dissolved powder molecules; or, the liquid material has an active component that reacts with the powder material, and under the provision of energy, an initiator initiates a polymerization reaction between the liquid material and the powder material.

[0080] When the total mass of the first liquid material is 100%, and the first component includes the first active component and / or the first solvent, the mass percentage of the first active component and / or the first solvent in the first liquid material is 10% to 80%, for example, it can be 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, etc., preferably 30% to 60%; when the first component includes an energy absorber, the mass percentage of the energy absorber in the first liquid material is 0.1% to 10%, for example, it can be 0.1%, 1%, 2%, 3%, 4%, 5%, 10%, etc., and its mass percentage can also be adjusted according to the actual use, which is not limited here. For example, the first component may include only the first active component; or the first component may include only the first solvent; or the first component may include only the energy absorber; or the first component may include the first active component and the first solvent; or the first component may include the first active component and the energy absorber; or the first component may include the first solvent and the energy absorber; or the first component may include the first active component, the first solvent and the energy absorber; the specific composition of the first component may be selected according to the actual use and is not limited here.

[0081] The first active component contains an active group and at least partially dissolves the powder material. The active group is a polymerizable functional group or a functional group that undergoes a polymerization reaction with the powder material. The active group may include at least one of the following: carbon-carbon double bond, hydroxyl group, carboxyl group, thiocyclopropane group, carbonate group, epoxy group, liquid cyclic lactone structure, and cyclic acetal structure. The first active component can be selected from monomers containing carbon-carbon double bonds, such as (meth)acrylates, vinyl ethers, allyl ethers, styrene, acrylamide, hydroxyethyl acrylamide, N-vinylpyrrolidone, etc.; compositions containing epoxy groups and promoting the ring-opening polymerization of epoxy groups can be epoxy diluents and / or small molecules or prepolymers containing hydroxyl groups, epoxy diluents and / or small molecules or prepolymers containing carboxyl or amino groups; cyclic lactones can be γ-butyrolactone, δ-valerolactone, ε-caprolactone, etc.; thioheterocyclic compounds can be thioheterocyclopropane, thioheterocyclobutane, etc.; carbonate compounds can be dimethyl carbonate, diethyl carbonate, etc.; cyclic amide compounds such as caprolactam, etc.

[0082] For example, the first active component can be styrene or γ-butyrolactone, and the powder material can be polystyrene that can be dissolved by styrene or γ-butyrolactone. The first active component can also be a (meth)acrylate monomer, and the powder material can be poly(meth)acrylate, cellulose, modified cellulose, hydroxyl-containing polyvinyl alcohol, polyester, polyurethane, modified polyamide, etc., that can be dissolved by (meth)acrylate monomers. The first active component can also be acryloylmorpholine, and the powder material can be polyurethane, cellulose, modified cellulose, hydroxyl-containing polyvinyl alcohol, etc., that can be partially dissolved by acryloylmorpholine. The first active component can also be epichlorohydrin, epoxy diluent, hydroxyethylacrylamide, and the powder material can also be polycarbonate, polyamide, modified polyamide, cellulose ester, cellulose ether, etc., that can be dissolved by epichlorohydrin, epoxy diluent, or hydroxyethylacrylamide. For example, hydroxyethylacrylamide can effectively dissolve nylon 12 powder at 170°C. The first active component can be γ-butyrolactone, and the powder material can also be polyacrylonitrile, cellulose acetate, polymethyl methacrylate, polyvinyl fluoride, and polystyrene, etc., which can be dissolved by γ-butyrolactone. Alternatively, the first active component can be ε-caprolactone, and the powder material can also be chlorinated polyolefins, polyurethane, etc., which can be dissolved by ε-caprolactone.

[0083] The boiling point of the first solvent is lower than the melting point or melting temperature of the powder material and at least partially dissolves the powder material. Since the boiling point of the first solvent is lower than the melting point or melting temperature of the powder material, the first solvent is more likely to evaporate when it is lower than the melting point or melting temperature of the powder material. The first solvent can be selected from water, low-boiling-point alkanes, low-boiling-point cycloalkanes, benzene, toluene, hexafluoroisopropanol, tetrahydrofuran, dichloromethane, chloroform, alcohols, ketones, ethers, acids, etc.

[0084] For example, the first solvent may be water, and the powder material may be polyvinyl alcohol. The first solvent may be acetone, and the powder material may be a poly(meth)acrylate. The first solvent may be tetrahydrofuran, and the powder material may be polyurethane. The first solvent may be formic acid, and the powder material may be a polyamide. The first solvent may be hexafluoroisopropanol, and the powder material may be polyurethane and polyamide, etc. In some embodiments, a mixture of multiple solvents may be used, and the mixed solvents can be selected to dissolve the powder material based on the principle of similar solubility parameters.

[0085] Energy absorbers can absorb energy such as ultraviolet light, infrared light, microwaves, or other electromagnetic radiation waves to generate high-temperature heat to act on at least a portion of the powder material. Energy absorbers can be selected from carbon black, graphite, endothermic dyes such as compounds containing phthalocyanine or naphthalene phthalocyanine groups, nano-metal particles, nano-oxides, iron nanoparticles, polymers containing conjugated bonds, nano-cesium tungsten bronze dispersions, ultraviolet absorbers, etc. In some specific embodiments, energy absorbers often appear in the form of dispersions, such as black pigments, dye dispersions, nano-dispersions, etc. Further, black pigments, dyes or dye dispersions, nano-dispersions, etc., are dispersed in aqueous solutions or other solutions to better disperse in the liquid material, thereby facilitating ejection from the printhead.

[0086] The first additive includes at least one of a plasticizer, a second solvent, and a first active monomer. The mass percentage of the first additive in the first liquid material is 10% to 80%, based on the total mass of the first liquid material as 100%. For example, it can be 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, etc. The mass percentage can also be adjusted according to the actual use, and is not limited here.

[0087] The function of plasticizers is to lower the glass transition temperature of polymers, thereby lowering the softening temperature of the polymers. Furthermore, plasticizers are immiscible with powdered materials but readily miscible with a third liquid material. Plasticizers can be at least one of the following: polyethylene glycol plasticizers, phthalate plasticizers, aliphatic diester plasticizers, phosphate ester plasticizers, epoxy compound plasticizers, polymeric plasticizers, polyphenolic ester plasticizers, chlorinated plasticizers, alkyl sulfonate plasticizers, N-butylbenzenesulfonamides, and polyol esters.

[0088] The second solvent has a boiling point higher than the melting point or melting temperature of the powder material and at least partially dissolves the powder material. Because the boiling point of the second solvent is higher than the melting point or melting temperature of the powder material, the second solvent is less likely to evaporate below the melting point or melting temperature of the powder material, and the second solvent can remain in the green body of the three-dimensional object. The second solvent may be selected from at least one of hydroxyethylpyrrolidone, pyrrolidone, methylpyrrolidone, ethylene glycol, propylene glycol, butanediol, hexahydronaphthalene, decahydronaphthalene, butyrolactone, caprolactone, dimethylformamide, benzyl alcohol, phenol, and dimethyl sulfoxide.

[0089] For example, the second solvent may be hydroxyethylpyrrolidone or pyrrolidone, and the powder material may be a polyamide; the second solvent may be N,N-dimethylformamide, and the powder material may be polyurethane. In some specific embodiments, a second solvent that is easily precipitated from the three-dimensional green body during or after foaming is selected.

[0090] The polymer formed by the polymerization reaction of the first active monomer has a glass transition temperature of less than 20°C. Furthermore, the first active monomer differs from the first active component; it cannot dissolve the powder material. By controlling the mass ratio of the first active monomer in the first liquid material, the target temperature of the molded object in the foamed region where the first liquid material is applied to the powder material layer can be controlled, thereby ensuring that the target temperature of the molded object in the foamed region is lower than the target temperature of the molded object in the non-foamed region. The first active monomer can be selected from nonylphenol ethoxy (4) monoacrylate, 2-phenoxyethyl acrylate, phenol ethoxy (3) monoacrylate, tetrahydrofuran acrylate, ethoxyethoxyethyl acrylate, octyldecyl acrylate, isodecyl acrylate, lauryl acrylate, etc.

[0091] Optionally, the first liquid material further includes a second component, which includes at least one of water, a second active component, and a non-reactive resin. The second active component includes at least one of a second active monomer and an oligomer. Based on the total mass of the first liquid material being 100%, the mass percentage of water in the first liquid material is 0% to 70%, specifically 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, etc., and its mass percentage can be adjusted according to actual usage, without limitation here. The mass percentage of the second active monomer in the first liquid material is 0% to 75%, specifically 0%, 10%, 20%, 30%, 40%, 50%, 60%, 75%, etc., and its mass percentage can be adjusted according to actual usage, without limitation here. The proportions of the oligomer in the first liquid material shall be determined according to the actual application and are not limited here; the mass percentage of the oligomer in the first liquid material shall be 0% to 30%, specifically 0%, 5%, 10%, 15%, 20%, 30%, etc., and its mass percentage shall be determined according to the actual application and is not limited here; the mass percentage of the non-reactive resin in the first liquid material shall be 0% to 30%, specifically 0%, 5%, 10%, 15%, 20%, 30%, etc., and its mass percentage shall be determined according to the actual application and is not limited here.

[0092] For example, when the first component includes only an energy absorber, the second component may include water to disperse the energy absorber.

[0093] The second active component includes at least one of a second active monomer and an oligomer. The second active monomer cannot dissolve the powder material, and the polymer formed by the polymerization reaction has a glass transition temperature of 20°C to 80°C. By controlling the proportion of the second active component in the first liquid material, while ensuring that the first active component dissolves the powder material, the second active component and the first active component complement each other in terms of performance, giving the three-dimensional green body higher performance than when only the first active component is present, such as reduced shrinkage and increased strength.

[0094] It should be noted that during the printing of 3D object preforms, the second active component can fill the voids between or within the powder particles, reducing the porosity of the formed object and increasing its density. Furthermore, it can complement the properties of the first active component, giving the 3D object preform higher performance than when only the first active component is present.

[0095] The second active component can be at least one of o-phenylphenoxyethyl acrylate, stearic acid acrylate, 4-tert-butylcyclohexyl acrylate, cyclic trimethylolpropane acetal (meth)acrylate, prepolymers containing carbon-carbon double bonds, prepolymers containing epoxy groups, monomers that promote ring-opening polymerization of epoxy groups, prepolymers that promote ring-opening polymerization of epoxy groups, solid cyclic lactones, and cyclic amide compounds. For example, prepolymers containing carbon-carbon double bonds can be epoxy or (modified) acrylate prepolymers, polyester acrylate prepolymers, polyurethane acrylate prepolymers, pure acrylate prepolymers, etc. Prepolymers containing epoxy groups can be, for example, epoxy resin E-51, epoxy resin E-41, etc.; cyclic lactones can be, for example, lactide, glycolide, etc., and cyclic lactones themselves are solids with poor solubility. Some compounds with cyclic acetal structures, such as trioxymethylene, are themselves solids. Due to their structural differences, (meth)acrylate monomers have varying abilities to dissolve polymers. For example, o-phenylphenoxyethyl acrylate, stearic acid acrylate, 4-tert-butylcyclohexyl acrylate, and cyclic trimethylolpropane acetal methacrylate have poor dissolving effects on polyurethane powders and are basically insoluble.

[0096] Non-reactive resins can be alkyd resins, polyester resins, polyurethane resins, (meth)acrylate resins, etc.

[0097] Optionally, the first liquid material further includes a second additive, which includes at least one of an initiator, a leveling agent, a defoamer, a polymerization inhibitor, an antioxidant, a dispersant, and a colorant. Specifically, based on the total mass of the first liquid material as 100%, the mass percentage of the second additive in the first liquid material is 0.1% to 30%, specifically 0.1%, 1%, 5%, 10%, 15%, 19.5%, 24.5%, 27%, or 30%, etc., and its mass percentage can be adjusted according to actual usage, which is not limited here.

[0098] For example, the initiator has a mass percentage of 0% to 10% in the first liquid material, specifically 0%, 0.1%, 1%, 3.4%, 5.7%, 6.0%, 7.5%, 8.5%, 9.7%, or 10%, etc.; the leveling agent has a mass percentage of 0.01% to 3% in the first liquid material, specifically 0.01%, 0.05%, 0.1%, 0.5%, 1.2%, 1.8%, 2.1%, 2.5%, 2.7%, or 3%, etc.; the defoamer has a mass percentage of 0.01% to 3% in the first liquid material, specifically 0.01%, 0.05%, 0.1%, 0.5%, 1.2%, 1.8%, 2.1%, 2.5%, 2.7%, or 3%, etc.; and the polymerization inhibitor has a mass percentage of 0.05% to 3% in the first liquid material, specifically 0.05%. The mass percentages of the following components in the first liquid material are as follows: 0.1%, 0.5%, 1.2%, 1.8%, 2.1%, 2.5%, 2.7%, or 3%, etc.; the mass percentage of the antioxidant in the first liquid material is 0.05% to 3%, specifically 0.05%, 0.1%, 0.5%, 1.2%, 1.8%, 2.1%, 2.5%, 2.7%, or 3%, etc.; the mass percentage of the dispersant in the first liquid material is 0% to 5%, specifically 0%, 0.1%, 1%, 1.4%, 1.7%, 2.0%, 2.5%, 3.5%, 4.2%, or 5%, etc.; the mass percentage of the colorant in the first liquid material is 0% to 10%, specifically 0%, 0.1%, 1%, 2%, 4%, 5%, 6%, 7%, 9%, or 10%, etc. The mass percentages can also be adjusted according to the actual application and are not limited here.

[0099] Specifically, the initiator may be selected from at least one of the following: tert-amyl peroxide acetate, tert-amyl peroxide benzoate, tert-butyl peroxide 3,5,5-trimethylhexanoate, tert-butyl peroxide benzoate, ethyl 3,3-bis(tert-butylperoxy)butyrate, ethyl 3,3-bis(tert-amylperoxy)butyrate, dicumyl peroxide, di-tert-amyl peroxide, di-tert-butyl peroxide, tert-amyl peroxide, tert-butyl peroxide, cumene hydroperoxide, and 2,2,4-trimethylpentyl butyl peroxide.

[0100] The function of leveling agents is to improve the fluidity of liquid materials and their wetting properties on powder materials, while adjusting the surface tension of the liquid materials to enable normal printing. In this application, the specific leveling agent used is not limited as long as it meets the above performance requirements. For example, it can be BYK333, BYK377, BYK1798, BYK-UV3530, BYK-UV3575, BYK-UV3535, etc. from BYK Corporation, or TEGO wet 500, TEGO wet 270, TEGOGlide450, TEGO RAD 2010, TEGO RAD 2011, TEGO RAD 2100, TEGO RAD 2200, etc. from TEGO Corporation.

[0101] The function of defoamers is to inhibit, reduce, and eliminate air bubbles in liquid materials. In this application, as long as the defoamer used can achieve the above-mentioned effect, the specific choice of defoamer is not limited. For example, it can be BYK055, BYK088, BYK020, BYK025, etc. from BYK Corporation; TEGO Airex 920, TEGO Airex 921, TEGO Airex 986, TEGO Foamex 810, TEGO Foamex N, etc. from DIGIC Corporation; Efka 7081, Efka7082, etc. from Efka Corporation.

[0102] The role of polymerization inhibitors can be to improve the stability of active components in liquid materials at high temperatures, to prevent polymerization reactions of active components in non-printing states, and to improve the storage stability of liquid materials. Examples include hydroquinone, p-hydroxyanisole, p-benzoquinone, 2-tert-butylhydroquinone, phenothiazine, and N-nitroso-N-phenylhydroxylamine aluminum; Rion's GENORAD*16, GENORAD*18, GENORAD*20, and GENORAD*22; BASF's Tinuvin 234, Tinuvin 770, Irganox 245, Cytec S100, and Cytec 130; and Ciba's Irgastab UV10 and Irgastab UV 22.

[0103] The main function of antioxidants is to delay or inhibit polymer oxidation. Examples of antioxidants include 2,6-di-tert-butyl-4-methylphenol, pentaerythritol β-tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 4-[(4,6-dioctylthio-1,3,5-triazin-2-yl)amino]-2,6-di-tert-butylphenol, dilauryl thiodipropionate, tri(nonylphenyl) phosphite, triphenyl phosphite, and 2-mercaptobenzimidazole.

[0104] The main function of dispersants is to improve and enhance the dispersion stability of colorants. There are no restrictions on the specific type of dispersant chosen; many commercially available products are available, such as BYK102, BYK108, BYK110, BYK180, BYK9133, BYK9076, BYK9131, and Dispers 655, Dispers 675, Dispers 688, Dispers 750, and Dispers 670.

[0105] In this application, when neither the first liquid material nor the second liquid material contains a colorant, it is easy to obtain a colorless or light-colored transparent three-dimensional object.

[0106] When the first liquid material and / or the second liquid material contains a colorant, a colored three-dimensional object can be realized. The colorant can be a dye or a pigment. Specifically, the pigment can be selected from one or more of the following: CIPigment White 6, CIPigment Red 3, CIPigment Red 5, CIPigment Red 7, CIPigment Red 9, CIPigment Red 12, CIPigment Red 13, CIPigment Red 21, CIPigment Red 31, CIPigment Red 49:1, CIPigment Red 58:1, CIPigment Red 175; CIPigment Yellow 63, CIPigment Yellow 3, CIPigment Yellow 12, CIPigment Yellow 16, CIPigment Yellow 83; CIPigment Blue 1, CIPigment Blue 10, CIPigment Blue B, Phthalocyanine Blue BX, Phthalocyanine Blue BS, CIPigment Blue 61:1, etc.

[0107] The dyes can be specifically selected from CI Acid Red 37, CI Acid Red 89 (Weak Acid Red 3B, 2BS), CI Acid Red 145 (Weak Acid Scarlet GL), CI Acid Orange 67 (Weak Acid Yellow RXL), CI Acid Orange 116 (Acid Orange AGT), CI Acid Orange 156 (Weak Acid Orange 3G), CI Acid Yellow 42 (Weak Acid Yellow Rs, Acid Yellow R), CI Acid Yellow 49 (Acid Yellow GR200), CI Acid Blue 277, CI Acid Blue 344, CI Acid Blue 350, and CI Acid Blue 9 (Brilliant Blue FCF). CI Green 17, CI Acid Green 28, CI Acid Green 41, CI Acid Green 81, CI Acid Violet 17 (Acid Violet 4BNS), CI Acid Violet 54 (Weak Acid Brilliant Red 10B), CI Acid Violet 48, CI Acid Brown 75, CI Acid Brown 98, CI Acid Brown 165, CI Acid Brown 348, CI Acid Brown 349, CI Acid Black 26, CI Acid Black 63, CI Acid Black 172, CI Acid Black 194, CI Acid Black 210, CI Acid Black 234, CI Acid Black 235, CI Acid Black 242, etc.

[0108] Optionally, the first liquid material further includes a foaming agent. Based on the total mass of the first liquid material (100%), the mass percentage of the foaming agent in the first liquid material is 0% to 10%, specifically 0%, 0.1%, 1%, 3.4%, 5.7%, 6.0%, 7.5%, 8.5%, 9.7%, or 10%, etc. Its mass percentage can also be adjusted according to actual usage and is not limited here. The foaming agent can be selected from at least one of water, aliphatic hydrocarbons, chlorinated hydrocarbons, chlorofluorocarbons, carbonates (bicarbonates) and their foaming aids, hydrogen peroxide and its foaming aids, hydrides, isocyanate compounds, azo compounds, hydrazine derivatives, urea-amino compounds, azide-amino compounds, nitroso compounds, and triazole compounds. The foaming conditions of the foaming agent and its foaming aid system should meet the requirement that the foaming temperature is higher than the target temperature of the molded object in the foamed region and lower than the target temperature of the molded object in the non-foamed region. In some embodiments, some solvents do not volatilize at the molding temperature but vaporize at the foaming temperature, and can be considered as both solvents and foaming agents.

[0109] Optionally, the first liquid material also includes a foaming inhibitor to ensure that the foaming agent is passivated during the molding process, thus extending the foaming initiation time. Based on the total mass of the first liquid material as 100%, the mass percentage of the foaming inhibitor in the first liquid material is 0% to 10%, specifically 0%, 0.1%, 1%, 3.4%, 5.7%, 6.0%, 7.5%, 8.5%, 9.7%, or 10%, etc. Its mass percentage can also be adjusted according to actual usage, and is not limited here. Foaming inhibitors can be selected from organic acids such as maleic acid and fumaric acid, acyl halides such as stearoyl chloride and phthaloyl chloride, acid anhydrides such as maleic anhydride and phthalic anhydride, polyphenols such as hydroquinone and naphthol, polyols such as glycerol, nitrogen-containing compounds such as aliphatic amines, amides, oximes and isocyanates, sulfur-containing compounds such as thiols, thiophenols, thioureas, sulfides and sulfones, phosphates and phosphites, aldehydes and ketones such as cyclohexanone, acetaldehyde and acetone.

[0110] For example, the second liquid material includes a first component. Taking the total mass of the second liquid material as 100%, when the first component includes a first active component and / or a first solvent, the mass percentage of the first active component and / or the first solvent in the second liquid material is 20% to 90%, for example, it can be 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, etc.; when the first component includes an energy absorber, the mass percentage of the energy absorber in the second liquid material is 0.1% to 10%, for example, it can be 0.1%, 1%, 2%, 3%, 4%, 5%, 10%, etc., and its mass percentage can also be adjusted according to actual usage, which is not limited here. The composition of the first component of the second liquid material can be the same as or different from the composition of the first component of the first liquid material. The specific types of the first component are described above and will not be repeated here. Furthermore, when both the first liquid material and the second liquid material include a first active component, the glass transition temperature of the polymer formed by the polymerization reaction of the first active component of the first liquid material is lower than the glass transition temperature of the polymer formed by the polymerization reaction of the first active component of the second liquid material, so as to ensure that the target temperature of the molded object in the foamed region is lower than the target temperature of the molded object in the non-foamed region.

[0111] Optionally, the second liquid material may include a first additive, the first additive having a lower mass percentage in the second liquid material than in the first liquid material. By controlling the type and content of the first additive, it can be ensured that the target temperature of the molded object in the foamed region is at least 5°C lower than the target temperature of the molded object in the non-foamed region. The specific types of the first additive are described above and will not be repeated here.

[0112] Optionally, the second liquid material may include a second component. The specific types of the second component are described above and will not be repeated here. Taking the total mass of the second liquid material as 100%, the mass percentage of water in the second liquid material is 0% to 70%, specifically 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, etc., and its mass percentage can be adjusted according to actual application, without limitation here. The mass percentage of the second active component in the first liquid material is 0% to 75%, specifically 0%, 10%, 20%, 30%, 40%, 50%, 60%, 75%, etc., and its mass percentage can be adjusted according to actual application, without limitation here. The mass percentage of the non-reactive resin in the first liquid material is 0% to 30%, specifically 0%, 5%, 10%, 15%, 20%, 30%, etc., and its mass percentage can be adjusted according to actual application, without limitation here.

[0113] Optionally, the second liquid material may include a second additive. The specific types of the second additive are described above and will not be repeated here. Taking the total mass of the second liquid material as 100%, the mass percentage of the second additive in the second liquid material is 0% to 30%, specifically 0.1%, 1%, 5%, 10%, 15%, 19.5%, 24.5%, 27%, or 30%, etc. The mass percentage can also be adjusted according to the actual application and is not limited here.

[0114] Optionally, the second liquid material may include a third additive. Based on the total mass of the second liquid material (100%), the third additive comprises 0% to 20% of the second liquid material by mass, specifically 0.1%, 1%, 5%, 10%, 15%, 19.5%, 20%, etc. Its mass percentage can also be adjusted according to actual application, and is not limited here. The third additive is selected from at least one of a crosslinking agent and a third active monomer. The crosslinking agent comprises 0% to 10% of the second liquid material by mass, specifically 0.1%, 1%, 5%, 10%, etc.; the third active monomer comprises 0% to 20% of the second liquid material by mass, specifically 0.1%, 1%, 5%, 10%, 15%, 19.5%, 20%, etc. Of course, its mass percentage can also be adjusted according to actual application, and is not limited here.

[0115] Crosslinking agents can undergo crosslinking reactions with powder materials or induce crosslinking reactions between powder materials under certain conditions. Crosslinking agents can be selected from peroxides, silane compounds, dimercapto-triazine compounds, diacylpyridinium compounds, dithiohydroxy compounds, sulfur, sodium disulfide, etc. In some embodiments, peroxides can act as both initiators and crosslinking agents.

[0116] The third active monomer can increase the target temperature of the molded object. The third active monomer cannot dissolve the powder material, and the glass transition temperature of the polymer formed by the polymerization reaction is greater than 80°C. The third active monomer can be selected from at least one of the following: isobornyl acrylate, dicyclopentenyl acrylate, cyclohexyl methacrylate, isobornyl methacrylate, hydroxypentanoic acid polydiacrylate, dipropylene glycol diacrylate, tricyclodecanedimethyl diacrylate, neopentyl glycol diacrylate, and pentaerythritol triacrylate.

[0117] Following step 102, the molding method further includes:

[0118] The powder material layer to which the first liquid material and / or the second liquid material are applied is heated.

[0119] Understandably, heat energy is provided to the powder material layer on which liquid material is applied to heat the powder material layer on which liquid material is applied, and the heating temperature is higher than 70°C and lower than the melting point or melting temperature of the powder material by more than 5°C; in this embodiment, by heating the powder material layer on which liquid material is applied, the curing and molding of the powder material layer on which liquid material is applied can be further promoted.

[0120] In some specific implementations, the heating energy includes at least one of radiation energy and thermal energy, specifically through infrared radiation, visible light irradiation, etc.

[0121] Step 103: Repeat the above steps of forming powder material layer to forming slice layer, so that the obtained multiple slice layers are stacked one by one to form a three-dimensional object green body;

[0122] Understandably, the digital model of the object to be printed is sliced ​​and layered to obtain at least one slice layer. During the printing process of the 3D object blank, each slice layer is stacked layer by layer until all slice layers are printed to form the 3D object blank. Otherwise, it is necessary to repeatedly form powder material layers and spray liquid material to form slice layers based on the layer printing data, and then stack them layer by layer to form the 3D object blank.

[0123] Step 104: Foaming treatment is performed on the three-dimensional object green body to foam the foaming area and obtain the three-dimensional object. The foaming temperature of the foaming treatment is higher than the target temperature of the molded object in the foamed area and lower than the target temperature of the molded object in the non-foamed area. The target temperature is selected from at least one of softening temperature and melting temperature.

[0124] In a specific embodiment, after obtaining the three-dimensional object blank, the blank is subjected to a foaming treatment, which can be either chemical foaming or physical foaming. The foaming temperature during the foaming treatment is higher than the molding temperature of the object in the foaming area to avoid foaming during the printing process. Chemical foaming refers to the first liquid material containing a chemical foaming agent, which decomposes upon heating to produce gas or releases gas through a chemical reaction. Physical foaming refers to the first liquid material containing a physical foaming agent, which vaporizes upon heating to produce gas, or the first liquid material not containing a foaming agent, where a supercritical fluid containing gases such as carbon dioxide or nitrogen, after being treated under high temperature and pressure, acts as the foaming agent. For example, after obtaining the three-dimensional object blank, it is heated to a first temperature and then immersed in a supercritical fluid. After immersion, the blank is cooled to a second temperature and left to stand. The foaming process is completed after the standing period. The foaming temperature during the foaming process is higher than the target temperature of the molded object in the foamed area but lower than the target temperature of the molded object in the non-foamed area. The target temperature is selected from at least one of the softening temperature and the melting temperature. Specifically, for molded objects made of non-crystalline polymers, the target temperature is the softening temperature, and for molded objects made of crystalline polymers, the target temperature is the melting point temperature. This allows the foamed area to foam while the non-foamed area does not. The non-foamed area can limit the foaming range of the foamed area, ensuring the uniformity of the three-dimensional object green body during foaming, thereby ensuring the structural accuracy of the three-dimensional object and improving the product quality of the three-dimensional object.

[0125] Optionally, when chemically foaming the three-dimensional object preform, the three-dimensional object preform is placed in a third liquid material, which includes a solvent or a heat-conducting oil medium liquid that has no dissolving effect on the three-dimensional object preform. For example, water can be selected as the medium liquid when the foaming temperature is below 100°C; heat-conducting oil can be selected as the medium liquid when the foaming temperature is above 100°C.

[0126] Furthermore, the third liquid material may also include a foaming aid, which helps to lower the temperature required for the foaming agent to foam. Foaming aids can be selected from organic acids such as stearic acid, lauric acid, and salicylic acid; zinc compounds such as zinc oxide, zinc octanoate, zinc nitrate, and zinc fatty acid soaps; lead compounds such as lead carbonate, lead phthalate, lead phosphite, tribasic lead sulfate, dibasic lead phosphite, lead stearate, and lead oxide; cadmium compounds such as cadmium octanoate, cadmium hexanoate, cadmium laurate, cadmium myristate, and cadmium fatty acid soaps; urea and its derivatives; and amino compounds such as urea, ethanolamine, ammonia, and diethylguanidine.

[0127] After the foaming process is completed, if the non-foamed areas are protective parts, the non-foamed areas need to be removed to obtain a three-dimensional object.

[0128] In this application, the following embodiments and comparative examples are printed according to the aforementioned three-dimensional object forming method. It should be noted that the printing steps of the embodiments and comparative examples are the same.

[0129] The following are examples of the composition of some materials in the embodiments and comparative examples of this application:

[0130] Example 1:

[0131] The composition of the liquid material for 3D printing provided in this embodiment is shown in Table 1.

[0132] Table 1. Composition of the liquid material for 3D printing provided in Example 1

[0133]

[0134] The powder material provided in this embodiment is polyurethane (TPU), the foaming temperature for foaming the three-dimensional object preform is 90℃~100℃, and the third liquid material is water.

[0135] Example 2:

[0136] The composition of the liquid material for 3D printing provided in this embodiment is shown in Table 2.

[0137] Table 2 Composition of the liquid material for 3D printing provided in Example 2

[0138]

[0139]

[0140] The powder material provided in this embodiment is polyurethane (TPU). The three-dimensional object preform is placed in hot air for foaming treatment, and the foaming temperature is 90℃~100℃.

[0141] Example 3:

[0142] The composition of the liquid material for 3D printing provided in this embodiment is shown in Table 3.

[0143] Table 3. Composition of the liquid material for 3D printing provided in Example 3

[0144]

[0145] The powder material provided in this embodiment is polyurethane (TPU), the foaming temperature for foaming the three-dimensional object preform is 90℃~100℃, and the third liquid material is water.

[0146] Example 4:

[0147] The composition of the liquid material for 3D printing provided in this embodiment is shown in Table 4.

[0148] Table 4. Composition of the liquid material for 3D printing provided in Example 4

[0149]

[0150] The powder material provided in this embodiment is polyurethane (TPU), the foaming temperature for foaming the three-dimensional object preform is 90℃~100℃, and the third liquid material is water.

[0151] Example 5:

[0152] The composition of the liquid material for 3D printing provided in this embodiment is shown in Table 5.

[0153] Table 5. Composition of the liquid material for 3D printing provided in Example 5

[0154]

[0155]

[0156] The powder material provided in this embodiment is polyurethane (TPU), the foaming temperature for foaming the three-dimensional object preform is 100℃~110℃, and the third liquid material is heat transfer oil.

[0157] Example 6:

[0158] The composition of the liquid material for 3D printing provided in this embodiment is shown in Table 6.

[0159] Table 6. Composition of the liquid material for 3D printing provided in Example 6

[0160]

[0161] The powder material provided in this embodiment is polyamide (PA12), and the foaming temperature for foaming the three-dimensional object preform is 130℃~160℃. The third liquid material is an oil containing salicylic acid. It should be noted that the decomposition temperature of the foaming agent dinitrosopyramethylenetetramine is generally above 200℃. Adding the foaming aid salicylic acid can reduce the decomposition temperature to below 160℃, thereby avoiding deformation of the object caused by heating the three-dimensional object preform to above 200℃.

[0162] In Examples 1-6, the foaming agent does not react or vaporize under the printing temperature conditions; in Examples 1-4 and 6, the foaming agent will decompose and generate gas after reaching the foaming temperature; in Example 5, when the three-dimensional object blank is heated to above 100°C, the water in the first liquid material vaporizes and generates gas, causing expansion.

[0163] Comparative Example 1:

[0164] The composition of the liquid material for 3D printing provided in this comparative example is shown in Table 7.

[0165] Table 7 shows the composition of the liquid material for 3D printing provided in Comparative Example 1.

[0166]

[0167] The powder material provided in this comparative example is polyurethane (TPU), the foaming temperature for foaming the three-dimensional object preform is 90℃~100℃, and the third liquid material is water.

[0168] Comparative Example 2:

[0169] The composition of the liquid material for 3D printing provided in this comparative example is shown in Table 8.

[0170] Table 8 shows the composition of the liquid material for 3D printing provided in Comparative Example 2.

[0171]

[0172]

[0173] The powder material provided in this comparative example is polyurethane (TPU). The three-dimensional object preform is placed in hot air for foaming treatment, and the foaming temperature is 140℃~150℃.

[0174] Comparative Example 3:

[0175] The composition of the liquid material for 3D printing provided in this comparative example is shown in Table 9.

[0176] Table 9 shows the composition of the liquid material for 3D printing provided in Comparative Example 3:

[0177]

[0178] The powder material provided in this comparative example is polyurethane (TPU), the foaming temperature for foaming the three-dimensional object preform is 90℃~100℃, and the third liquid material is water.

[0179] Comparative Example 4:

[0180] The composition of the liquid material for 3D printing provided in this comparative example is shown in Table 10.

[0181] Table 10 shows the composition of the liquid material for 3D printing provided in Comparative Example 4:

[0182]

[0183]

[0184] The powder material provided in this comparative example is polyurethane (TPU), the foaming temperature for foaming the three-dimensional object preform is 90℃~100℃, and the third liquid material is water.

[0185] Comparative Example 5:

[0186] The composition of the liquid material for 3D printing provided in this comparative example is shown in Table 11.

[0187] Table 11 shows the composition of the liquid material for 3D printing provided in Comparative Example 5:

[0188]

[0189] The powder material provided in this comparative example is polyurethane (TPU), the foaming temperature for foaming the three-dimensional object preform is 80℃~90℃, and the third liquid material is heat transfer oil.

[0190] Comparative Example 6:

[0191] The composition of the liquid material for 3D printing provided in this comparative example is shown in Table 12.

[0192] Table 12 shows the composition of the liquid material for 3D printing provided in Comparative Example 6:

[0193]

[0194] The powder material provided in this embodiment is polyamide (PA12). The three-dimensional object preform is placed in hot air for foaming treatment, and the foaming temperature is 130℃~160℃.

[0195] Using the materials provided in Examples 1-6 and Comparative Examples 1-6, 12 samples were obtained using the three-dimensional object forming method described above, labeled S1-S6 and Ref1-Ref6 respectively. The 12 samples were tested using the following testing methods, and the test results are shown in Table 13.

[0196] Size and density tests:

[0197] Before foaming, samples S1 to S6 and Ref2 to Ref4 are all cuboids with a length of 80.00 mm, a width of 30.00 mm, and a height of 30.00 mm. The foamed portion with the first liquid material applied is a cuboid with a length of 80.00 mm, a width of 20.00 mm, and a height of 20.00 mm. The remaining portion is formed by applying the second liquid material to form a non-foamed portion. The non-foamed portion with the second liquid material applied at least partially surrounds the foamed portion. Before foaming, Ref1 and Ref5 to Ref6 are also cuboids with a length of 80.00 mm, a width of 20.00 mm, and a height of 20.00 mm.

[0198] After foaming the green blanks of the above samples S1~S6 and Ref1~Ref6, the length, width, and height of the above samples S1~S6 and Ref1~Ref6 are measured, and the difference between the sample and the green blank is calculated, wherein:

[0199] △L = Sample length - Green blank length;

[0200] △W = Sample width - Green blank width;

[0201] △D = Sample height - Green body height;

[0202] The density of samples S1 to S6 and Ref1 to Ref6 was measured using the water level method.

[0203] Table 13. Molding performance test results of the liquid materials for 3D printing provided in Examples 1-6 and Comparative Examples 1-6

[0204]

[0205]

[0206] As shown in Table 13, Examples 1-6 and Comparative Example 1 show that the ΔW and ΔD values ​​of Examples 1-6 containing the second liquid material are smaller, indicating that foaming in the width and height directions of the sample is suppressed. The non-foaming area where the second liquid material is applied can limit the directional foaming of the sample, ensuring the uniformity of the foaming of the three-dimensional object green body, thereby ensuring the structural accuracy of the three-dimensional object and improving the product quality of the three-dimensional object. The foaming effects of Examples 2 and 3 are lower than those of Examples 1 and 4 because the first active monomer in the first additive has a certain foaming suppression effect compared to the second solvent. Example 5 has a poor foaming effect because it uses water as a foaming agent. Although Comparative Example 2 contains the second liquid material, the foaming temperature is higher than the softening temperature of the molded object in the non-foaming area where the second liquid material is applied, and close to the melting point temperature of the powder material, which means that the non-foaming area where the second liquid material is applied cannot limit the foaming range of the foaming area. Although Comparative Example 3 contains the second liquid material... In Comparative Example 4, although a second liquid material is present, it contains a significant amount of the first active monomer, and the mass percentage of the first additive in the second liquid material is greater than that in the first liquid material. Furthermore, the first liquid material contains a third additive, causing the target temperature of the foaming area where the first liquid material is applied to rise. Consequently, the non-foaming areas where the second liquid material is applied cannot limit the foaming range of the foaming area. In Comparative Example 5, water is used as the foaming agent, but the foaming temperature of the foaming treatment is low, failing to reach the foaming temperature of the foaming agent, thus resulting in minimal foaming. In Comparative Example 6, due to the lack of the foaming additive salicylic acid, the decomposition effect of dinitrospentamethylenetetramine is not significant, therefore the foaming effect is not obvious.

[0207] This application also provides a three-dimensional object forming apparatus for implementing any of the methods described above. Figure 4 This is a schematic diagram of the structure of a three-dimensional object forming device provided in a specific embodiment of this application, such as... Figure 4 As shown, the device includes:

[0208] Powder supply component 2 is used to supply powder material to form powder material layer L0;

[0209] Forming platform 3 is used to support the powder material layer L0;

[0210] Material dispenser 6 is used to apply a first liquid material to the powder material layer L0 according to layer printing data to form a foamed region, and / or to apply a second liquid material to the powder material layer L0 to form a non-foamed region, wherein the foamed region and the non-foamed region are arranged adjacent to each other to form a slice layer of a three-dimensional object green body, wherein the first liquid material is different from the second liquid material.

[0211] A foaming unit (not shown in the figure) is used to perform foaming treatment on the three-dimensional object green body, so that the foaming area foams to obtain a three-dimensional object. The foaming temperature of the foaming treatment is higher than the target temperature of the molded object in the foaming area and lower than the target temperature of the molded object in the non-foaming area. The target temperature is selected from at least one of softening temperature and melting temperature.

[0212] In this embodiment, the powder supply component 2 includes a powder storage chamber 23, a lifting device 22, and a powder spreader 21. The powder storage chamber 23 is used to store powder material 1. The powder storage chamber 23 has a movable support plate 231 inside. The lifting device 22 is connected to the support plate 231 and can drive the support plate 231 to rise or fall in the Z direction. The powder spreader 21 is used to spread the powder material 1 in the powder storage chamber 23 onto the forming platform 3 to form a powder material layer L0. The commonly used powder spreader 21 can be a powder spreading roller or a scraper.

[0213] The material dispenser 6 is an inkjet printhead, which can be a single-channel or multi-channel printhead. The material dispenser 6 has a first printhead 61 and a second printhead 62. The first printhead 61 is used to apply a first liquid material, and the second printhead 62 is used to apply a second liquid material. In other embodiments, the number of printheads depends on the type of liquid material used and the amount of liquid material to be applied. For example, when the liquid material includes functional materials of different colors, different colored liquid materials are ejected through different printheads or different channels of the same printhead. For instance, when the amount of liquid material to be applied is large and the volume of a single ink droplet is insufficient, multiple printheads or multiple channels can be used simultaneously to eject the same type of material to improve printing efficiency.

[0214] Energy supply device 7 is used to provide energy to the powder material layer L0, so that the powder material layer L0 with applied liquid material is solidified and formed to obtain a slice layer of three-dimensional object green body.

[0215] The energy supplied by the energy supply device 7 can be radiant energy or thermal energy, and the energy supply device can be selected from at least one of ultraviolet lamps, infrared lamps, microwave emitters, heating wires, heating plates, and heating plates. It should be noted that the specific type of energy supply device 7 selected is related to the type of liquid material. When the liquid material undergoes a photopolymerization reaction, the energy supply device 7 provides radiant energy, such as ultraviolet radiation, to initiate the photopolymerization reaction of active groups through ultraviolet radiation. When the liquid material undergoes a thermal polymerization reaction, the energy supply device 7 provides thermal energy, such as infrared lamps, microwaves, heating wires, heating plates, or heating plates, to initiate the thermal polymerization reaction of active groups through thermal energy.

[0216] Optionally, the three-dimensional object forming device further includes a lifting mechanism 4, which is connected to the forming platform 3 and drives the forming platform 3 to rise or fall in the vertical direction.

[0217] Optionally, the three-dimensional object forming apparatus further includes a preheating component 5, which is used to preheat the powder material layer L0. The preheating component 5 may be selected from at least one of ultraviolet lamp, infrared lamp, microwave emitter, heating wire, heating plate, and heating element.

[0218] In this embodiment, the material dispenser 6 and the energy supply device 7 can be installed sequentially on the guide rail 9 and can move on the guide rail 9.

[0219] The three-dimensional object forming apparatus may also include a temperature monitor (not shown in the figure) for monitoring the temperature of the powder material layer L0.

[0220] Furthermore, the three-dimensional object forming apparatus also includes a controller 8, which controls the operation of at least one of the powder supply component 2, the material distributor 6, the energy supply device 7, the preheating component 5, and the temperature monitor. For example, the temperature monitor feeds back the monitored temperature to the controller 8, and the controller controls the amount of energy supplied by the preheating component 5 and the energy supply device 7 based on the information fed back by the temperature monitor.

[0221] The foaming unit is used to foam the green three-dimensional object, causing the foaming area to expand and thus obtaining the three-dimensional object. The foaming unit can be selected according to the type of foaming process, and can be any foaming device known in the art, without limitation here.

[0222] This application also provides a non-transitory computer-readable storage medium, such as... Figure 5 As shown, the storage medium 81 includes a stored program 811, which controls the device where the storage medium 81 is located to execute the above-described three-dimensional object forming method when the program is running.

[0223] This application also provides a computer device, such as...Figure 6 As shown, the computer device 100 of this embodiment includes: a processor 101, a memory 102, and a computer program 103 stored in the memory 102 and executable on the processor 101. When the processor 101 executes the computer program 103, it implements the three-dimensional object forming method in the embodiment. To avoid repetition, it will not be described in detail here.

[0224] Computer device 100 can be a desktop computer, laptop, handheld computer, cloud server, or other computing device. The computer device may include, but is not limited to, processor 101 and memory 102. Those skilled in the art will understand that... Figure 6 This is merely an example of computer device 100 and does not constitute a limitation on computer device 100. It may include more or fewer components than shown, or combine certain components, or different components. For example, computer device may also include input / output devices, network access devices, buses, etc.

[0225] The processor 101 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0226] The memory 102 can be an internal storage unit of the computer device 100, such as a hard disk or RAM of the computer device 100. The memory 102 can also be an external storage device of the computer device 100, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the computer device 100. Furthermore, the memory 102 can include both internal and external storage units of the computer device 100. The memory 102 is used to store computer programs and other programs and data required by the computer device. The memory 102 can also be used to temporarily store data that has been output or will be output.

[0227] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for forming a three-dimensional object, characterized in that, The method includes the following steps: Provide powder material to form a powder material layer; According to layer printing data, a first liquid material is applied to the powder material layer to form a foamed region, and / or a second liquid material is applied to the powder material layer to form a non-foamed region, wherein the foamed region and the non-foamed region are arranged adjacent to each other to form a slice layer of a three-dimensional object preform, wherein the first liquid material is different from the second liquid material; Repeat the above steps of forming a powder material layer to forming a slice layer, so that the obtained multiple slice layers are stacked one by one to form a three-dimensional object green body; The three-dimensional object blank is subjected to a foaming treatment to foam the foaming area to obtain a three-dimensional object. The foaming temperature of the foaming treatment is higher than the target temperature of the formed object in the foaming area and lower than the target temperature of the formed object in the non-foaming area. The target temperature is selected from at least one of softening temperature and melting point temperature.

2. The method according to claim 1, characterized in that, The first liquid material is different from the second liquid material in that: the composition of the first liquid material is different from the composition of the second liquid material, or the amount of the first liquid material sprayed per unit volume is different from the amount of the second liquid material sprayed per unit volume.

3. The method according to claim 1, characterized in that, The target temperature T1 of the molded object in the foamed region is lower than the target temperature T2 of the molded object in the non-foamed region, and T2-T1≥5.

4. The method according to claim 1, characterized in that, The sliced ​​layer of the three-dimensional object preform includes a solid portion, which comprises foamed and non-foamed regions, or... The sliced ​​layer of the three-dimensional object blank includes a solid part and a protective part. The solid part is a foamed area, and the protective part is a non-foamed area.

5. The method according to claim 1, characterized in that, The first liquid material includes a first component and a first additive, and the second liquid material includes the first component; wherein, The first component includes at least one of a first active component, a first solvent, and an energy absorber. The first active component contains an active group and at least partially dissolves the powder material. The first solvent has a boiling point lower than the melting point or melting temperature of the powder material and at least partially dissolves the powder material. The energy absorber absorbs energy to act on at least a portion of the powder material. The first additive includes at least one of a plasticizer, a second solvent, and a first active monomer. The plasticizer is selected from at least one of polyethylene glycol plasticizers, phthalate plasticizers, aliphatic diester plasticizers, phosphate plasticizers, epoxy plasticizers, polymerizable plasticizers, polyphenolic ester plasticizers, chlorinated plasticizers, alkyl sulfonate plasticizers, N-butylbenzenesulfonamides, and polyol esters. The second solvent has a boiling point higher than the melting point or melting temperature of the powder material and at least partially dissolves the powder material. The first active monomer does not dissolve the powder material, and the glass transition temperature of the polymer formed by the polymerization reaction is less than 20°C.

6. The method according to claim 5, characterized in that, The second liquid material further includes a first additive, wherein the mass percentage of the first additive in the second liquid material is less than the mass percentage of the first additive in the first liquid material.

7. The method according to claim 5, characterized in that, The first liquid material further includes a second component, which includes at least one of water, a second active component, and a non-reactive resin. The second liquid material further includes a second component, wherein the second active component includes at least one of a second active monomer and an oligomer. The second active monomer does not dissolve the powder material and the polymer formed by the polymerization reaction has a glass transition temperature of 20°C to 80°C.

8. The method according to claim 5, characterized in that, The first liquid material further includes a second additive, which includes at least one of an initiator, a leveling agent, a defoamer, a polymerization inhibitor, an antioxidant, a dispersant, and a colorant.

9. The method according to claim 5, characterized in that, The first liquid material further includes a foaming agent selected from at least one of water, aliphatic hydrocarbons, chlorinated hydrocarbons, chlorofluorocarbons, carbonates (bicarbonates) and their foaming aids, hydrogen peroxide and its foaming aids, hydrides, isocyanate compounds, azo compounds, hydrazine derivatives, urea-amino compounds, azide-amino compounds, nitroso compounds, and triazole compounds.

10. The method according to claim 9, characterized in that, The first liquid material further includes a foaming inhibitor, which is selected from at least one of organic acids, acyl halides, acid anhydrides, polyphenols, polyols, nitrogen-containing compounds, sulfur-containing compounds, phosphates, phosphites, aldehydes, and ketones.

11. The method according to claim 5, characterized in that, The second liquid material further includes a third auxiliary agent, which is selected from at least one of a crosslinking agent and a third active monomer; The crosslinking agent reacts with the powder material or causes a crosslinking reaction between the powder materials, wherein the crosslinking agent is selected from at least one of peroxide, silane compound, dimercapto-triazine compound, diaziridinium group compound, dithiohydroxy compound, sulfur, and sodium disulfide; The third active monomer does not dissolve the powder material and the polymer formed by the polymerization reaction has a glass transition temperature greater than 80°C.

12. The method according to claim 1, characterized in that, The powder material is selected from at least one of polypropylene, polyethylene, polystyrene, polyvinyl chloride, polyacrylonitrile, acrylonitrile-styrene-acrylate copolymer, polyamide, polyester, polyurethane, polylactic acid, poly(meth)acrylate, poly(meth)acrylate, polyvinyl fluoride, chlorinated polyolefin, polycaprolactone, hydroxyl-containing polyvinyl alcohol, cellulose, and modified cellulose.

13. The method according to claim 1, characterized in that, The foaming temperature is higher than the molding temperature of the object being molded in the foaming region.

14. The method according to claim 1, characterized in that, The foaming process includes chemical foaming or physical foaming.

15. The method according to claim 14, characterized in that, The three-dimensional object blank is chemically foamed and placed in a third liquid material, the third liquid material including a medium liquid, which is a solvent or heat-conducting oil that has no dissolving effect on the three-dimensional object blank.

16. The method according to claim 15, characterized in that, The third liquid material further includes a foaming agent selected from at least one of organic acids, zinc compounds, lead compounds, cadmium compounds, urea and its derivatives, and amino compounds.

17. A three-dimensional object forming apparatus for implementing the method of any one of claims 1-16, characterized in that, The device includes: A powder supply component, used to supply powder material to form a powder material layer; A forming platform is used to support the powder material layer; A material dispenser is used to apply a first liquid material to the powder material layer to form a foamed region according to layer printing data, and / or to apply a second liquid material to the powder material layer to form a non-foamed region, wherein the foamed region and the non-foamed region are arranged adjacent to each other to form a slice layer of a three-dimensional object preform, wherein the first liquid material is different from the second liquid material. A foaming unit is used to perform foaming treatment on the three-dimensional object green body, so that the foaming area foams to obtain a three-dimensional object, wherein the foaming temperature of the foaming treatment is higher than the target temperature of the molded object in the foaming area and lower than the target temperature of the molded object in the non-foaming area, and the target temperature is selected from at least one of softening temperature and melting point temperature.

18. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium includes a stored program that, when the program is executed, controls the device on which the storage medium is located to perform the three-dimensional object forming method according to any one of claims 1-16.

19. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the three-dimensional object forming method according to any one of claims 1-16.

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