3D object printing method and apparatus, 3D printing material

Abstract

The present application provides a three-dimensional object printing method and apparatus, and a three-dimensional printing material. The three-dimensional printing material includes a first liquid material containing a first active component, and the first active component can dissolve at least part of the powder material. It also includes a second liquid material different from the first liquid material, and the second liquid material contains components for promoting the polymerization reaction of the first liquid material. By storing the first liquid material and the second liquid material separately, it helps to improve the storage stability of the liquid material and the inkjet printing fluidity of the liquid material. The formulation of the second liquid material includes a second auxiliary agent, water, a powder release agent, a stripping agent, and a hydrocarbon chain surfactant, which is beneficial to reducing the post-treatment difficulty of the printed three-dimensional object, thereby improving the surface accuracy of the printed object, and is also beneficial to the recovery of the powder in the non-forming area.

Description

Technical Field

[0001] This application relates to the field of 3D printing technology, and particularly to a method and apparatus for printing 3D objects and 3D printing materials. Background Art

[0002] The main process of the additive manufacturing technology for 3D objects is to obtain a digital model of the 3D object, slice and layer the digital model, and perform data processing and conversion on each sliced layer to obtain the printing data for each sliced layer. The printing apparatus manufactures the 3D object layer by layer according to the printing data of the sliced layers and stacks them up.

[0003] In the existing additive manufacturing technology that combines powder and inkjet printing for 3D objects, for example, after the print head sprays a liquid material in the forming area according to the layer printing data of the 3D object on the powder material layer, radiation is provided to cause the liquid material to undergo a polymerization reaction to wrap the powder particles in contact therewith to form a layer of the 3D object. Alternatively, the liquid material contains a radiation absorber, and the radiation absorber absorbs the radiation and converts it into heat energy to melt the powder particles in contact therewith to form a layer of the 3D object. However, in this type of additive manufacturing technology for 3D objects, the sprayed liquid material penetrates into the non-forming area, resulting in the powder particles in the non-forming area adhering and wrapping on the surface of the adjacent 3D object, or causing the powder particles in the non-forming area to melt and adhere to the surface of the 3D object, so that the surface roughness of the final 3D object is high and post-processing is difficult.

[0004] Therefore, in the additive manufacturing technology that combines powder and inkjet printing, how to improve the surface accuracy of 3D objects and reduce the difficulty of post-processing of 3D objects is a technical problem to be solved by those skilled in the art. Summary of the Invention

[0005] The embodiments of this application provide a method and apparatus for printing 3D objects and 3D printing materials, which can improve the storage stability of the liquid material, improve the surface accuracy of 3D objects, and reduce the difficulty of post-processing.

[0006] In a first aspect, this application provides a method for printing a 3D object, the method including:

[0007] Forming a powder material layer with a powder material, the powder material layer including a forming area and a non-forming area;

[0008] Applying a first liquid material and a second liquid material in a first ratio in the forming area of the powder material layer according to the layer printing data, the second liquid material promoting the first liquid material to undergo a polymerization reaction to form a layer entity part of the 3D object;

[0009] According to the layer printing data, the first liquid material and the second liquid material are applied in a second ratio in the non-forming area of the powder material layer to form a layer protection part of the three-dimensional object; wherein the first ratio is greater than the second ratio; the amount of the second liquid material in the unit volume of the forming area is less than the amount of the second liquid material in the unit volume of at least part of the non-forming area, and the amount of the first liquid material in the unit volume of the forming area is greater than the amount of the first liquid material in the unit volume of at least part of the non-forming area.

[0010] In combination with the first aspect, in a feasible embodiment, the first ratio is the volume ratio of the first liquid material to the second liquid material, and the first ratio is (1-10):1; and / or, the second ratio is the volume ratio of the first liquid material to the second liquid material, and the second ratio is (0-0.95):1.

[0011] In combination with the first aspect, in a feasible implementation manner, the layer entity portion and the layer protection portion are located in the same horizontal plane, and the layer entity portion and the layer protection portion are arranged adjacent to each other.

[0012] In combination with the first aspect, in a feasible implementation manner, the amount of the second liquid material per unit volume of the non-forming area gradually decreases as the non-forming area moves away from the forming area.

[0013] In combination with the first aspect, in a possible implementation, the width of the layer protection portion is greater than or equal to the minimum diameter of a droplet of the applied liquid material.

[0014] In combination with the first aspect, in a feasible embodiment, before spraying the first liquid material and the second liquid material in a first ratio within the forming area of the powder material layer according to the layer printing data, and spraying the first liquid material and the second liquid material in a second ratio within the non-forming area of the powder material layer according to the layer printing data, the three-dimensional object printing method further includes:

[0015] The powder material layer is preheated.

[0016] In combination with the first aspect, in a feasible embodiment, the preheating temperature is 5° C.-100° C. lower than the melting point or melting temperature of the powder material.

[0017] In combination with the first aspect, in a feasible embodiment, after applying the first liquid material and the second liquid material in a second ratio in the non-forming area of the powder material layer according to the layer printing data, the three-dimensional object printing method further includes:

[0018] The powder material layer to which the second liquid material is applied is heated.

[0019] Combined with the first aspect, in a feasible implementation, the heating temperature is higher than 70 °C and 5 °C or more below the melting point or melting temperature of the powder material to promote the evaporation of water in the second liquid material, and / or to promote the dissolution of the powder material by the first liquid material and the polymerization reaction of the first liquid material.

[0020] Combined with the first aspect, in a feasible implementation, the energy for preheating and heating includes at least one of radiant energy and thermal energy.

[0021] Combined with the first aspect, in a feasible implementation, the first liquid material includes a first active component that dissolves at least part of the powder material; the second liquid material includes a second auxiliary agent, a powder release agent, a release agent, a hydrocarbon chain surfactant, and water, and the second auxiliary agent is used to promote the polymerization reaction of the first liquid material.

[0022] Combined with the first aspect, in a feasible implementation, based on the total weight of the second liquid material being 100%, the second liquid material includes the following components by weight percentage: 0.1% - 40% of the second auxiliary agent, 30% - 90% of water, 0.01% - 10% of the powder release agent, 1% - 30% of the release agent, and 0.1% - 10% of the hydrocarbon chain surfactant.

[0023] Combined with the first aspect, in a feasible implementation, it satisfies at least one of the following characteristics:

[0024] (1) The second auxiliary agent is selected from at least one of an initiator, a promoter, and a catalyst;

[0025] (2) The powder release agent is selected from at least one of a silicon-containing water-soluble release agent, a silicon-containing water-dispersible release agent, a fluorine-containing water-soluble release agent, and a fluorine-containing water-dispersible release agent;

[0026] (3) The powder release agent is selected from at least one of a silicone oil emulsion, a fluorine-containing nonionic surfactant, and a fluorine-containing anionic surfactant;

[0027] (4) The release agent is selected from a water-soluble polymer and / or a water-dispersible polymer with a glass transition temperature below 40 °C;

[0028] (5) The release agent is selected from at least one of a polyether resin, a polyester resin, a poly(meth)acrylate resin, and a polyurethane resin with a glass transition temperature below 40 °C.

[0029] Combined with the first aspect, in a feasible implementation, the second liquid material further includes the following component by weight percentage: 0.05% - 30% of a co-solvent.

[0030] In combination with the first aspect, in a feasible implementation, the cosolvent is selected from at least one of alcohols, alcohol ethers, amides, pyrrolidones, organic acids, and organic salts.

[0031] In combination with the first aspect, in a feasible implementation, after forming the layer solid part and the layer protection part of the three-dimensional object, the method further includes:

[0032] Repeating the formation of the powder material layer and the application of the first liquid material and the second liquid material, and stacking the obtained multiple sliced layers layer by layer to form a three-dimensional object, where the sliced layer includes a layer solid part and a layer protection part.

[0033] In a second aspect, an embodiment of the present application provides a non-transitory computer-readable storage medium, where the storage medium includes a stored program that controls the device where the storage medium is located to execute the above three-dimensional object printing method when the program runs.

[0034] In a third aspect, an embodiment of the present application provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above three-dimensional object printing method is implemented.

[0035] In a fourth aspect, an embodiment of the present application provides a three-dimensional object printed according to the above three-dimensional object printing method.

[0036] In a fifth aspect, an embodiment of the present application provides a three-dimensional printing material for use in combination with a powder material for three-dimensional printing. The material includes:

[0037] A first liquid material, where the first liquid material includes a first active component that can dissolve at least part of the powder material; and

[0038] A second liquid material. Based on the total weight of the second liquid material being 100%, the second liquid material includes the following components by weight percentage: 0.1% - 40% of a second auxiliary agent, 30% - 90% of water, 0.01% - 10% of a powder release agent, 1% - 30% of a release agent, and 0.1% - 10% of a hydrocarbon chain surfactant; where the second auxiliary agent is used to promote the polymerization reaction of the first liquid material.

[0039] In a sixth aspect, an embodiment of the present application provides a three-dimensional printing material, where the material includes:

[0040] A powder material for forming a powder material layer;

[0041] A first liquid material, the first liquid material comprising a first active component that dissolves at least part of the powder material; and

[0042] A second liquid material, based on 100% of the total weight of the second liquid material, the second liquid material comprising the following components by weight: 0.1% - 40% of a second auxiliary agent, 30% - 90% of water, 0.01% - 10% of a powder release agent, 1% - 30% of a release agent, and 0.1% - 10% of a hydrocarbon chain surfactant; wherein the second auxiliary agent is used to promote the polymerization reaction of the first liquid material.

[0043] Combined with the sixth aspect, in a feasible implementation manner, the powder material layer includes a formed area and an unformed area, the first liquid material and the second liquid material are applied to the formed area in a first ratio, and the first liquid material and the second liquid material are applied to the unformed area in a second ratio, wherein the first ratio is greater than the second ratio.

[0044] Combined with the sixth aspect, in a feasible implementation manner, the first ratio is the volume ratio of the first liquid material to the second liquid material, and the first ratio is (1 - 10):1; and / or, the second ratio is the volume ratio of the first liquid material to the second liquid material, and the second ratio is (0 - 0.95):1.

[0045] Combined with the sixth aspect, in a feasible implementation manner, the amount of the second liquid material per unit volume in the formed area is less than the amount of the second liquid material per unit volume in at least part of the unformed area, and the amount of the first liquid material per unit volume in the formed area is greater than the amount of the first liquid material per unit volume in at least part of the unformed area.

[0046] Combined with the sixth aspect, in a feasible implementation manner, the powder material includes at least one of polystyrene, polyvinyl chloride, polyacrylonitrile, acrylonitrile - styrene - acrylate copolymer, polyamide, polyester, polyurethane, poly(meth)acrylate, polyvinyl fluoride, chlorinated polyolefin, a block and / or graft copolymer containing a segment that can be dissolved by the first active component, polyvinyl alcohol containing hydroxyl groups, cellulose, and modified cellulose.

[0047] Combined with the fifth or sixth aspect, in a feasible implementation manner, the first active component has an active group capable of participating in a polymerization reaction, and the active group includes at least one of a carbon - carbon double bond, a hydroxyl group, a carboxyl group, a heterocyclopropyl group, a carbonate group, an epoxy group, a liquid cyclic lactone structure, and a cyclic acetal structure.

[0048] Combined with the fifth or sixth aspect, in a feasible embodiment, the first liquid material includes a second active component having an active group capable of participating in a polymerization reaction, and the second active component does not dissolve the powder material;

[0049] The second active component includes at least one of isobornyl acrylate, isobornyl methacrylate, lauryl acrylate, lauryl methacrylate, trimethylolpropane formal acrylate, a prepolymer containing a carbon-carbon double bond, a prepolymer containing an epoxy group, a monomer that promotes ring-opening polymerization of the epoxy group, a prepolymer that promotes ring-opening polymerization of the epoxy group, a solid cyclic lactone, and a cyclic amide compound.

[0050] Combined with the fifth or sixth aspect, in a feasible embodiment, based on the total weight of the first liquid material being 100%, the weight percentage of the first active component in the first liquid material is 10% to 95%.

[0051] Combined with the fifth or sixth aspect, in a feasible embodiment, based on the total weight of the first liquid material being 100%, the weight percentage of the second active component in the first liquid material is 5% to 90%.

[0052] Combined with the fifth or sixth aspect, in a feasible embodiment, based on the total weight of the first liquid material being 100%, the first liquid material further includes the following components in weight percentages: first auxiliary agent 0.01% to 30%;

[0053] The first auxiliary agent includes at least one of a high-temperature initiator, a leveling agent, an antifoaming agent, a polymerization inhibitor, an antioxidant, a plasticizer, a dispersant, a pigment, and a dye.

[0054] Combined with the fifth or sixth aspect, in a feasible embodiment, it satisfies at least one of the following characteristics:

[0055] (1) The second auxiliary agent is selected from at least one of an initiator, a promoter, and a catalyst;

[0056] (2) The powder release agent is selected from at least one of a silicon-containing water-soluble release agent, a silicon-containing water-dispersible release agent, a fluorine-containing water-soluble release agent, and a fluorine-containing water-dispersible release agent;

[0057] (3) The powder release agent is selected from at least one of a silicone oil emulsion, a fluorine-containing nonionic surfactant, and a fluorine-containing anionic surfactant;

[0058] (4) The release agent is selected from a water-soluble polymer and / or a water-dispersible polymer having a glass transition temperature lower than 40°C;

[0059] (5) The release agent is selected from at least one of polyether resins, polyester resins, poly(meth)acrylate resins, and polyurethane resins with a glass transition temperature lower than 40°C.

[0060] Combined with the fifth or sixth aspect, in a feasible implementation manner, based on the total weight of the second liquid material being 100%, the second liquid material further includes the following components in terms of weight percentage: cosolvent 0.05%-30%.

[0061] Combined with the fifth or sixth aspect, in a feasible implementation manner, the cosolvent is selected from at least one of alcohols, alcohol ethers, amides, pyrrolidones, organic acids, and organic salts.

[0062] Combined with the fifth or sixth aspect, in a feasible implementation manner, the hydrocarbon chain surfactant is selected from one or more of fatty alcohol polyoxyethylene ethers, sodium alkyl sulfonates, sodium alkyl benzene sulfonates, sodium alkyl sulfates, sodium alkyl ester sulfonates of succinic acid, sodium sulfamates, polyethers, and block copolymers of polyoxyethylene-polyoxypropylene ethers.

[0063] In the seventh aspect, the embodiments of the present application provide a three-dimensional object printing device, and the device includes:

[0064] A powder supply component that provides a powder material to form a powder material layer, and the powder material layer includes a forming area and a non-forming area;

[0065] A forming platform that supports the formed powder material layer;

[0066] A print head and a controller, and the controller controls the print head to apply a first liquid material and a second liquid material in a first ratio within the forming area of the powder material layer according to layer printing data. The second liquid material promotes the polymerization reaction of the first liquid material to form a layer entity part of the three-dimensional object;

[0067] The controller controls the print head to apply the first liquid material and the second liquid material in a second ratio within the non-forming area of the powder material layer according to layer printing data to form a layer protection part of the three-dimensional object; wherein, the first ratio is greater than the second ratio; the amount of the second liquid material in the unit volume of the forming area is less than the amount of the second liquid material in the unit volume of at least part of the non-forming area, and the amount of the first liquid material in the unit volume of the forming area is greater than the amount of the first liquid material in the unit volume of at least part of the non-forming area.

[0068] In combination with the seventh aspect, in a feasible implementation, the print head includes a first nozzle array and a second nozzle array, wherein the first nozzle array is used to eject a first liquid material and a second liquid material at a first ratio, and the second nozzle array is used to eject the first liquid material and the second liquid material at a second ratio.

[0069] In combination with the seventh aspect, in a feasible implementation, the print head includes a first nozzle array and a second nozzle array, wherein the first nozzle array and the second nozzle array are used to eject a first liquid material and a second liquid material at a first ratio respectively in a forming area, and are used to eject the first liquid material and the second liquid material at a second ratio respectively in a non-forming area.

[0070] In combination with the seventh aspect, in a feasible implementation, the three-dimensional object printing device further includes a lifting mechanism. After each three-dimensional object slice layer including a layer entity part and a layer protection part is formed, the lifting mechanism drives the forming platform to move downward by a distance equal to the thickness of a powder layer.

[0071] In combination with the seventh aspect, in a feasible implementation, the three-dimensional printing device further includes a preheating component, which is placed above the forming platform to preheat the powder material layer.

[0072] In combination with the seventh aspect, in a feasible implementation, the three-dimensional printing device further includes a heating component, which is arranged above the forming platform to heat the powder material layer sprayed with the second liquid material.

[0073] The technical solution of the present application has at least the following beneficial effects:

[0074] The three-dimensional object printing method provided by the present application, by separately storing the first liquid material and the second liquid material and applying them to the forming area and the non-forming area of the powder material layer according to different configuration ratios, not only helps to improve the storage stability of the liquid material and the inkjet printing fluency of the liquid material, but also helps to reduce the temperature of the non-forming area, helps to reduce the effect of the first liquid material on the powder material in the non-forming area, and reduces the post-processing difficulty of the printed three-dimensional object, especially the post-processing of the surface of the three-dimensional object, thereby improving the surface accuracy of the printed object.

[0075] The three-dimensional printing material provided by the present application, wherein the first liquid material and the second liquid material are different types of liquid materials, and the second liquid material contains components for promoting the polymerization reaction of the first liquid material. By separately storing the first liquid material and the second liquid material, it helps to improve the storage stability of the liquid material and the inkjet printing fluency of the liquid material.

[0076] The second liquid material contains water. When energy is provided to the powder material layer applied with the second liquid material, the water is evaporated, increasing the concentration of the second additive, thereby increasing the polymerization reaction rate of the first active component. And when a sufficient amount of water is evaporated, it can carry away the temperature of the powder material in the non-forming area, thus preventing the powder material in the non-forming area from being melted and / or adhered; moreover, using water has lower cost and is more environmentally friendly compared to using other volatile solvents; the second liquid material contains a powder release agent, which helps to improve the surface accuracy of the edge of the forming area when the volume of the second liquid material per unit volume in the forming area of the powder material layer is less than that in the non-forming area; the second liquid material contains a peeling agent. When the second liquid material is sprayed on the non-forming area of the powder material, the peeling agent bonds the powder in the non-forming area at the edge of the forming area together, facilitating the peeling of the powder in the non-forming area and being easily separated from the powder in other non-forming areas during powder recovery. The formulation of the second liquid material is beneficial to reducing the post-processing difficulty of the printed three-dimensional object, thereby improving the surface accuracy of the printed object, and is also beneficial to the recovery of the powder in the non-forming area. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings to be used in the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0078] Figure 1 It is a schematic flowchart of a three-dimensional object printing method provided by an embodiment of the present application;

[0079] Figure 2 It is a schematic flowchart of a three-dimensional object printing method provided by another embodiment of the present application;

[0080] Figure 3a It is a schematic structural diagram of a three-dimensional object to be printed provided by an embodiment of the present application;

[0081] Figure 3b It is a schematic structural diagram of a powder material layer provided by an embodiment of the present application;

[0082] Figures 4a - 4e It is a schematic diagram of the ink drop landing point structure when the first liquid material and the second liquid material are sprayed at a specified ratio provided by an embodiment of the present application;

[0083] Figure 5 It is a schematic flowchart of a three-dimensional object printing method provided by still another embodiment of the present application;

[0084] Figure 6Schematic structural diagram of the three-dimensional object printing device provided by the embodiment of the present application;

[0085] Figures 7a - 7c Partial schematic structural diagram of the liquid supply device in the three-dimensional object printing device provided by the embodiment of the present application;

[0086] Figures 8a - 8c Schematic surface structure diagram of the print head nozzles in the three-dimensional object printing device provided by the embodiment of the present application;

[0087] Figure 9 Schematic diagram of the non-transitory computer-readable storage medium provided by the embodiment of the present application;

[0088] Figure 10 Schematic structural diagram of the computer device provided by the embodiment of the present application. Detailed implementation manners

[0089] In order to better understand the technical solution of the present application, the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0090] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the scope of protection of the present application.

[0091] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0092] It should be understood that the term " / and / " used herein is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after. The terms "spray" and "apply" herein have the same meaning, both indicating that the liquid material in the material storage container is ejected through the print head nozzles.

[0093] The present application describes an additive manufacturing technology that combines powder materials and inkjet printing, and relates to a three-dimensional object printing method, the materials required for printing three-dimensional objects, the printed three-dimensional objects, a computer-readable storage medium storing program instructions, a computer device, and a device for printing three-dimensional objects using the three-dimensional object printing method of the present application, which can improve the surface accuracy of the target three-dimensional object and reduce the post-processing difficulty.

[0094] On the one hand, an embodiment of the present application provides a three-dimensional printing material, which includes:

[0095] Powder material, which is used to form a powder material layer;

[0096] A first liquid material, the first liquid material includes a first active component, and the first active component dissolves at least part of the powder material; and

[0097] A second liquid material. Based on the total weight of the second liquid material being 100%, the second liquid material includes the following components by weight: 0.1% - 40% of a second auxiliary agent, 30% - 90% of water, 0.01% - 10% of a powder release agent, 1% - 30% of a release agent, and 0.1% - 10% of a hydrocarbon chain surfactant; wherein, the second auxiliary agent is used to promote the polymerization reaction of the first liquid material.

[0098] For the three-dimensional printing material provided by the present application, the powder material layer formed by the powder material includes a forming area and a non-forming area. The first liquid material and the second liquid material are different types of liquid materials. The second liquid material contains a second auxiliary agent for promoting the polymerization reaction of the first liquid material. Specifically, the second auxiliary agent promotes the polymerization reaction of the first active component in the first liquid material to form the solid part of the three-dimensional object. By storing the first liquid material and the second liquid material separately, it helps to improve the storage stability of the liquid materials and the inkjet printing fluidity of the liquid materials.

[0099] The second liquid material contains water. When energy is provided to the powder material layer applied with the second liquid material, the water is evaporated, which can increase the concentration of the second auxiliary agent in the second liquid material. Thus, the high-concentration second auxiliary agent in the powder material layer can increase the polymerization reaction rate of the first active component. And when a sufficient amount of water is evaporated, it can take away the temperature of the powder material in the non-forming area of the powder material layer, thereby preventing the powder material in the non-forming area from being melted and / or adhered. Moreover, using water has a lower cost and is more environmentally friendly than using other volatile solvents. The second liquid material also contains a powder release agent, which helps to improve the surface accuracy of the edge of the forming area; the second liquid material also contains a release agent, which helps to separate the powder material in the non-forming area from the solid part formed in the forming area, and is conducive to separating the recycled powder material from the powder in other non-forming areas. The formulation of the second liquid material is beneficial to reducing the post-treatment difficulty of the three-dimensional object obtained by printing, thereby improving the surface accuracy of the printed object, and is also beneficial to the recovery of the powder in the non-forming area.

[0100] In some embodiments, the liquid material can be separately configured as a 3D printing material and combined with a suitable powder material when printing is to be performed. In other embodiments, the liquid material can be combined with the powder material as a 3D printing material, enabling the user to directly use it for printing 3D objects.

[0101] In some embodiments, the powder material is particulate material in powder form, which can be a metal powder material or a non-metal powder material.

[0102] Among them, the non-metal powder material is selected from organic polymer powder materials. The organic polymer powder material does not undergo a polymerization reaction with both the first liquid material and the second liquid material. When the second liquid material contacts the first liquid material under specific ratios and suitable temperature conditions, the second liquid material promotes the first liquid material to undergo a polymerization reaction. Depending on the difference in the ratio of the first liquid material to the second liquid material, the strength of the polymer formed by the polymerization reaction is different, so that the strength of the solid part (corresponding to the forming area) and the protective part (corresponding to the non-forming area) of the 3D object formed by printing is different.

[0103] In some embodiments, the organic polymer powder material can be selected from polypropylene. In practical applications, polypropylene cannot be dissolved by the first liquid material.

[0104] In some embodiments, the organic polymer powder material can be selected from at least one of polystyrene (PS), polyvinyl chloride (PVC), polyacrylonitrile (PAN), acrylonitrile-styrene-acrylate copolymer (ASA), polyamide (PA), polyester, polyurethane (PU), poly(meth)acrylate, polyvinyl fluoride, chlorinated polyolefin, block and / or graft copolymer containing segments soluble in the first active component, polyvinyl alcohol (PVA) containing hydroxyl groups, cellulose, and modified cellulose. In practical applications, these organic polymer powder materials can be dissolved by the first liquid material.

[0105] In some embodiments, the powder material may further include additives, and the additives include at least one of a flow aid and a filler. Among them, the flow aid is used to improve the fluidity of the powder material, and the flow aid can be, for example, silica, talcum powder, etc.; the filler is used to improve the mechanical strength of the 3D object, and the filler can be, for example, graphene, carbon nanotubes, carbon fibers, glass microspheres, glass fibers, kaolin, etc., which are not limited in this embodiment.

[0106] In each embodiment of the present application, the melting point or melting temperature of the organic polymer powder material can be 60°C - 300°C, specifically 60°C, 70°C, 80°C, 100°C, 120°C, 150°C, 180°C, 200°C, 240°C, 280°C, or 300°C, etc. Of course, it can also be other values within the above range, which are not limited herein.

[0107] In each embodiment of the present application, there are no special restrictions on the particle shape and particle size of the powder material. Optionally, the powder material may be spherical, dendritic, flaky, disc-shaped, needle-shaped, rod-shaped, etc. The average particle size of the powder material is 1 μm to 400 μm. For example, it may 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. The average particle size of the powder material is preferably 30 μm to 200 μm. The particle gap in the powder material is approximately 5 nm to 100 μm. For example, it may 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, which is not limited herein. The particle gap of the powder material in each embodiment of the present application is in the range of 5 nm to 100 μm, which is beneficial for the liquid material to quickly penetrate into the interior of the powder material layer through the gap and retain part of it on the surface layer, and even wet the surface of the powder material in the selected area and at least partially dissolve the powder material. It should be noted that the dissolution in each embodiment of the present application refers to all possible cases except complete insolubility.

[0108] In each embodiment of the present application, the first active component may be a substance that only includes one kind of powder material that can be dissolved, or a mixture of substances that include multiple kinds of powder materials that can be dissolved. The solubility of multiple substances in the powder material may be different or the same.

[0109] It should be noted that the dissolution in this embodiment refers to all possible cases except complete insolubility. For example, when 1 g of powder material is placed in 100 g of the active component, at most 1% of the powder material is dissolved. Preferably, the first active component completely dissolves the powder material. The dissolution is not limited to normal temperature, and the dissolution of the active component in the powder material can also be achieved under heating and / or stirring; the dissolution is not limited to one-time dissolution and can also be carried out in batches and stages. For example, when slow dissolution occurs when the active component contacts the powder material, the powder material can be heated to accelerate the dissolution rate. Preferably, the first active component completely dissolves the powder material in contact with the first active component.

[0110] In this specific embodiment, based on the total weight of the liquid material being 100%, the weight percentage of the first active component in the first liquid material is 10% - 95%. For example, it can be 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or 95%. Of course, its weight percentage can also be proportioned according to actual usage conditions and is not limited herein. Preferably, the weight percentage of the first active component in the liquid material is 30% - 95%. In this embodiment, the weight percentage of the first active component in the first liquid material is greater than or equal to 30%. By increasing the proportion of the first active component in the first liquid material, the dissolution rate and dissolution degree of the first active component to the powder material can be improved, thereby improving the mechanical strength of the printed object.

[0111] Specifically, the first active component has active groups that can participate in polymerization reactions. The active groups include at least one of carbon-carbon double bonds, hydroxyl groups, carboxyl groups, thiiranyl groups, carbonate groups, epoxy groups, liquid cyclic lactone structures, and cyclic acetal structures. It should be noted that the first active component does not undergo a polymerization reaction with the powder material.

[0112] The first active component can be selected from at least one of monomers containing carbon-carbon double bonds, compositions containing epoxy groups and promoting the ring-opening polymerization of epoxy groups, cyclic lactones, thiacyclic compounds, carbonate compounds, and cyclic amide compounds.

[0113] Specifically, the monomers containing carbon-carbon double bonds can be (meth)acrylates, vinyl ethers, allyl ethers, styrene, acrylmorpholine, N-vinylpyrrolidone, etc.

[0114] The composition containing epoxy groups and promoting the ring-opening polymerization of epoxy groups can be a composition containing an epoxy diluent and / or a small molecule or prepolymer containing a hydroxyl group, an epoxy diluent and / or a small molecule or prepolymer containing a carboxyl group. The cyclic lactone can be γ-butyrolactone, δ-valerolactone, ε-caprolactone, etc.

[0115] Thiacyclic compounds such as thiirane, thiacyclobutane, etc.

[0116] The carbonate compounds can be dimethyl carbonate, diethyl carbonate, etc.

[0117] The cyclic amide compounds can be caprolactam, etc.

[0118] Exemplarily, 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.

[0119] The first active component may also be a (meth)acrylate monomer, and the powder material may be poly(meth)acrylate, cellulose, modified cellulose, polyvinyl alcohol containing hydroxyl groups, polyester, polyurethane, modified polyamide, etc. dissolved by the (meth)acrylate monomer.

[0120] The first active component may also be acryloylmorpholine, and the powder material may be polyurethane, cellulose, modified cellulose, polyvinyl alcohol containing hydroxyl groups, etc. that can be partially dissolved by acryloylmorpholine.

[0121] The first active component may also be epichlorohydrin, epoxy diluent, hydroxyethylacrylamide, and the powder material may also be polycarbonate, polyamide, modified polyamide, cellulose ester, cellulose ether, etc. that can be dissolved by epichlorohydrin or epoxy diluent or hydroxyethylacrylamide.

[0122] The first active component may be γ-butyrolactone, and the powder material may also be polyacrylonitrile, cellulose acetate, polymethyl methacrylate, polyvinyl fluoride, polystyrene, etc. that can be dissolved by γ-butyrolactone.

[0123] The first active component may also be ε-caprolactone, and the powder material may also be chlorinated polyolefin, polyurethane, etc. that can be dissolved by ε-caprolactone.

[0124] Furthermore, the first liquid material may further include a second active component having an active group; the second active component does not dissolve the powder material, that is, the second active component completely does not dissolve the powder material. Optionally, the second active component may undergo a polymerization reaction by itself, or can participate in the polymerization reaction together with the first active component.

[0125] In this embodiment, based on the total weight of the first liquid material being 100%, the weight percentage of the second active component in the first liquid material is 5% - 90%. For example, it may be 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%. Of course, its weight percentage can also be proportioned according to actual usage and is not limited here. Preferably, the weight percentage of the second active component in the first liquid material is 20% - 70%. By controlling the proportion of the second active component in the first liquid material, on the premise of ensuring that the first active component dissolves the powder material, the second active component and the first active component form complementary properties, making the three-dimensional object have higher properties than when only containing the first active component, such as reducing the shrinkage rate.

[0126] It should be noted that during the three-dimensional object printing process, the second active component can be filled between the particles of the powder material or into the voids inside the powder particles, reducing the porosity of the formed object and increasing the forming density of the object. Further, the second active component can also form complementary properties with the first active component, enabling the three-dimensional object to have higher properties than when only containing the first active component.

[0127] The second active component includes at least one of isobornyl acrylate, isobornyl methacrylate, lauryl acrylate, lauryl methacrylate, caprolactone acrylate, trimethylolpropane formal acrylate, a prepolymer containing a carbon-carbon double bond, a prepolymer containing an epoxy group, a monomer that promotes the ring-opening polymerization of the epoxy group, a prepolymer that promotes the ring-opening polymerization of the epoxy group, a solid cyclic lactone, and a cyclic amide compound.

[0128] Exemplarily, the prepolymer containing a carbon-carbon double bond can be, for example, an epoxy or (modified) acrylate prepolymer, a polyester acrylate prepolymer, a polyurethane acrylate prepolymer, a pure acrylate prepolymer, etc. The prepolymer containing an epoxy group can be, for example, epoxy resin E-51, epoxy resin E-41, etc.; the cyclic lactone can be, for example, lactide, glycolide, etc. The cyclic lactone itself is a solid and has poor solubility. Some compounds with a cyclic acetal structure, such as trioxane, are solids themselves. Due to their structural differences, (meth)acrylate monomers have different dissolution abilities for polymers. For example, isobornyl acrylate, isobornyl methacrylate, lauryl acrylate, lauryl methacrylate, trimethylolpropane formal acrylate, etc. have poor dissolution effects on polyurethane powders and are basically insoluble.

[0129] Further, the first liquid material further includes a first additive, and the first additive includes at least one of a high-temperature initiator, a leveling agent, an antifoaming agent, a polymerization inhibitor, an antioxidant, a plasticizer, a dispersant, and a colorant. Specifically, based on the total weight of the first liquid material being 100%, the weight percentage of the first additive in the liquid material is 0.1% - 30%, and specifically it can be 0.1%, 1%, 5%, 10%, 15%, 19.5%, 24.5%, 27%, or 30%, etc. Of course, its weight percentage can also be formulated according to the actual usage situation and is not limited here.

[0130] Exemplarily, the weight percentage of the high-temperature initiator in the first liquid material is 0%-10%, specifically it can be 0%, 0.1%, 1%, 3.4%, 5.7%, 6.0%, 7.5%, 8.5%, 9.7% or 10%, etc.; the weight percentage of the leveling agent in the first liquid material is 0.01%-3%, specifically it can be 0.01%, 0.05%, 0.1%, 0.5%, 1.2%, 1.8%, 2.1%, 2.5%, 2.7% or 3%, etc.; the weight percentage of the defoaming agent in the first liquid material is 0.01%-3%, specifically it can be 0.01%, 0.05%, 0.1%, 0.5%, 1.2%, 1.8%, 2.1%, 2.5%, 2.7% or 3%, etc.; the weight percentage of the polymerization inhibitor in the first liquid material is 0.05%-3%, specifically it can be 0.05%, 0.1%, 0.5%, 1.2%, 1.8%, 2.1%, 2.5%, 2.7% or 3%, etc.; the weight percentage of the antioxidant in the first liquid material is 0.05%-3%, specifically it can be 0.05%, 0.1%, 0.5%, 1.2%, 1.8%, 2.1%, 2.5%, 2.7% or 3%, etc.; the weight percentage of the plasticizer in the first liquid material is 0%-25%, specifically it can be 0%, 1%, 5%, 10%, 15%, 17.5%, 20% or 25%, etc.; the weight percentage of the dispersant in the first liquid material is 0%-5%, specifically it can be 0%, 0.1%, 1%, 1.4%, 1.7%, 2.0%, 2.5%, 3.5%, 4.2% or 5%, etc.; the weight percentage of the pigment or dye in the first liquid material is 0-10%, specifically it can be 0%, 0.1%, 1%, 2%, 4%, 5%, 6%, 7%, 9% or 10%, etc. Of course, its weight percentage can also be proportioned according to the actual use situation and is not limited here.

[0131] It should be noted that the high-temperature initiator will not significantly initiate the active components in the first liquid material under normal temperature conditions, such as the first active component or the first active component and the second active component. Therefore, the first liquid material containing the high-temperature initiator is relatively stable at normal temperature and can be stored for 3 to 6 months, or even longer. In this application, the high-temperature initiator is preferably defined as an initiator with a half-life greater than 120°C in 1 hour. The high-temperature initiator will only produce a good initiation effect in a high-temperature environment. However, the tolerance temperature of some polymer powder materials is often lower than the decomposition temperature of the high-temperature initiator. Therefore, a promoter is needed to promote the high-temperature initiator to produce an initiation effect at a lower temperature.

[0132] Specifically, the high-temperature initiator can be selected from at least one of tert-amyl peroxyacetate, tert-amyl peroxybenzoate, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxybenzoate, 3,3-bis(ethyl butyrate), 3,3-bis(tert-butylperoxy)ethyl butyrate, 3,3-bis(tert-amylperoxy)ethyl butyrate, dicumyl peroxide, di-tert-amyl peroxide, di-tert-butyl peroxide, tert-amyl peroxide, tert-butyl peroxide, cumene hydroperoxide, etc.

[0133] The function of the leveling agent is to improve the fluidity of the first liquid material and its wetting performance on the powder material, and at the same time adjust the surface tension of the first liquid material so that it can be normally printed. In this application, as long as the leveling agent used can meet the above performance requirements, there is no restriction on the specific type of leveling agent selected. For example, it can be BYK333, BYK377, BYK1798, BYK-UV3530, BYK-UV3575, BYK-UV3535, etc. of BYK Company, and TEGOwet500, TEGOwet270, TEGOGlide450, TEGORAD2010, TEGORAD2011, TEGORAD2100, TEGORAD2200, etc. of Degussa Company.

[0134] The function of the defoaming agent is to inhibit, reduce, and eliminate the bubbles in the liquid material. In this application, as long as the defoaming agent used can achieve the above effects, there is no restriction on the specific type of defoaming agent selected. For example, it can be BYK055, BYK088, BYK020, BYK025, etc. of BYK Company, and TEGOAirex920, TEGOAirex921, TEGOAirex986, TEGOFoamex810, TEGOFoamexN, etc. of Degussa Company, and Efka7081, Efka7082, etc. of Efka Company.

[0135] The function of the polymerization inhibitor can be to improve the stability of the active components in the first liquid material at high temperatures, and can be to prevent the active components from undergoing polymerization reactions in the non-printing state, thereby improving the storage stability of the liquid material. For example, it can be hydroquinone, p-methoxyphenol, p-benzoquinone, 2-tert-butylhydroquinone, phenothiazine, etc., and it can be GENORAD*16, GENORAD*18, GENORAD*20, GENORAD*22, etc. of Ryan, Tinuvin234, Tinuvin770, Irganox245, Cytec S100, Cytec 130, etc. of BASF, and IrgastabUV10, IrgastabUV22, etc. of Ciba.

[0136] The main function of antioxidants is to delay or inhibit the oxidation of polymers. For example, it can be 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], n-octadecyl 3-(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, tris(nonylphenyl) phosphite, triphenyl phosphite, 2-mercaptobenzimidazole, etc.

[0137] The main function of plasticizers is to improve the toughness of the finished three-dimensional object. For example, it can be dioctyl phthalate, butyl benzyl phthalate, diisononyl phthalate, diisodecyl phthalate, diethyl adipate, dibutyl adipate, diisobutyl adipate, bis(2-butoxyethyl) adipate, bis(2-ethylhexyl) adipate, triethyl citrate, acetyltriethyl citrate, tributyl citrate, acetyltributyl citrate.

[0138] The main function of dispersants is to improve and enhance the dispersion stability of colorants. For example, the specific selection of which dispersant is not restricted. There are many commercially available products at present, such as BYK102, BYK108, BYK110, BYK180, BYK9133, BYK9076, BYK9131, Degussa Dispers655, Dispers675, Dispers688, Dispers750, Dispers670, etc.

[0139] In this application, when neither the first liquid material nor the second liquid material contains a colorant, the polymer formed by the polymerization reaction of the active components is mixed with the powder material at the molecular level, and at this time, it is easy to obtain a colorless or light-colored transparent three-dimensional object.

[0140] When the first liquid material and / or the second liquid material contains a colorant, a colored three-dimensional object can be achieved. The colorant can be a dye or a pigment.

[0141] The pigment can specifically be selected from one or more of C.I. Pigment White 6, C.I. Pigment Red 3, C.I. Pigment Red 5, C.I. Pigment Red 7, C.I. Pigment Red 9, C.I. Pigment Red 12, C.I. Pigment Red 13, C.I. Pigment Red 21, C.I. Pigment Red 31, C.I. Pigment Red 49:1, C.I. Pigment Red 58:1, C.I. Pigment Red 175; C.I. Pigment Yellow 63, C.I. Pigment Yellow 3, C.I. Pigment Yellow 12, C.I. Pigment Yellow 16, C.I. Pigment Yellow 83; C.I. Pigment Blue 1, C.I. Pigment Blue 10, C.I. Pigment Blue B, Phthalocyanine Blue BX, Phthalocyanine Blue BS, C.I. Pigment Blue 61:1, etc.

[0142] The dye can specifically be selected from one or more of C.I. Acid Red 37, C.I. Acid Red 89 (Weak Acid Red 3B, 2BS), C.I. Acid Red 145 (Weak Acid Scarlet GL), C.I. Acid Orange 67 (Weak Acid Yellow RXL), C.I. Acid Orange 116 (Acid Orange AGT), C.I. Acid Orange 156 (Weak Acid Orange 3G), C.I. Acid Yellow 42 (Weak Acid Yellow Rs, Acid Yellow R), C.I. Acid Yellow 49 (Acid Yellow GR200), C.I. Acid Blue 277, C.I. Acid Blue 344, C.I. Acid Blue 350, C.I. Acid Blue 9 (Brilliant Blue FCF), C.I. Green 17, C.I. Acid Green 28, C.I. Acid Green 41, C.I. Acid Green 81, C.I. Acid Violet 17 (Acid Violet 4BNS), C.I. Acid Violet 54 (Weak Acid Brilliant Red 10B), C.I. Acid Violet 48, C.I. Acid Brown 75, C.I. Acid Brown 98, C.I. Acid Brown 165, C.I. Acid Brown 348, C.I. Acid Brown 349, C.I. Acid Black 26, C.I. Acid Black 63, C.I. Acid Black 172, C.I. Acid Black 194, C.I. Acid Black 210, C.I. Acid Black 234, C.I. Acid Black 235, C.I. Acid Black 242, Orasol Red 395 / BL, etc.

[0143] In the second liquid material of the present application, the second auxiliary agent is used to promote the polymerization reaction of the first liquid material, specifically to initiate or catalyze the polymerization reaction of the active components in the first liquid material. Specifically, the second auxiliary agent includes at least one of an initiator, a promoter, and a catalyst; based on the total weight of the second liquid material being 100%, the weight percentage of the second auxiliary agent in the second liquid material is 0.1%-40%, specifically it can be 0.1%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, and of course it can also be other values within the above range, which are not limited herein.

[0144] The initiator is selected from water-soluble or water-dispersible initiators, and can be azodiisobutylamidine hydrochloride, azodiisobimidazoline salt, azodicyanovaleric acid, azodiisopropylimidazoline, sodium persulfate, ammonium persulfate, potassium persulfate, polymethacrylate containing an azo group, self-emulsifying polyurethane containing an azo group, or an aqueous dispersion of some organic peroxides (Reference: Di Zhigang. PVC Initiator - Aqueous Dispersion of Organic Peroxides [J] Polyvinyl Chloride, No. 2, 1995).

[0145] The promoter can be selected from partially water-soluble promoters, such as ferrous lactate, dimethylaniline, tetramethylthiourea, dimethylthiourea, etc. When the first liquid material contains a high-temperature initiator, a promoter is added to the second liquid material to reduce the polymerization temperature of the first liquid material, thereby achieving the effect of improving strength.

[0146] The catalyst can be triethylbenzylammonium chloride, triethylamine, triethanolamine, methyl fluorosulfonate, ethyl fluorosulfonate, methylnitrobenzenesulfonic acid, methyl sulfonate, etc.

[0147] The second liquid material contains water, and the weight percentage of water in the second liquid material is 30%-90%, specifically it can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 80%, 85%, 90%, and of course it can also be other values within the above range, which are not limited herein. The main role of the water contained in the second liquid material is to spray the second liquid material in the non-forming area. The water can reduce the temperature of the powder material in the non-forming area, and during the evaporation process of the water, the evaporated water can also take away the temperature of the powder material in the non-forming area, thereby preventing the powder material in the non-forming area from being melted and / or dissolved by the first liquid material and adhering to the surface of the formed object, affecting the surface accuracy of the object. Moreover, using water has lower cost and is more environmentally friendly compared to using other volatile solvents.

[0148] The second liquid material contains a powder release agent, and the weight percentage of the powder release agent in the second liquid material is 0.01%-10%; the powder release agent is selected from at least one of a silicon-containing water-soluble release agent, a silicon-containing water-dispersible release agent, a fluorine-containing water-soluble release agent, and a fluorine-containing water-dispersible release agent.

[0149] Specifically, the silicon-containing water-soluble release agent or the silicon-containing water-dispersible release agent is selected from silicone oil emulsions; the fluorine-containing water-soluble release agent or the fluorine-containing water-dispersible release agent can be selected from fluorine-containing nonionic surfactants or fluorine-containing anionic surfactants.

[0150] Exemplarily, the silicone oil emulsion can be a mixture containing a polysiloxane polymer with water as the dispersant.

[0151] The fluorine-containing nonionic surfactant can be a polyoxyethylene ether of a fluorinated fatty alcohol, a polyoxyethylene ether of a fluorinated phenol, a polyoxyethylene ester of a fluorinated carboxylic acid, a polyoxyethylene ether of a fluorinated alkylsulfonyl alkanolamine, or a polyoxyethylene ether of a fluorinated mercaptan.

[0152] The fluorine-containing anionic surfactant can be a fluorinated carboxylate, a fluorinated sulfonate, a fluorinated phosphate, etc.

[0153] The three-dimensional printing material provided in this embodiment is applied to the printing of three-dimensional objects. During the printing process of the three-dimensional object, the amount of the second liquid material per unit volume in the forming area is controlled to be less than the amount of the second liquid material per unit volume in the non-forming area. The main function of the second liquid material in the forming area is to promote the polymerization reaction of the first liquid material to form a polymer. The main function of the second liquid material in the non-forming area is to reduce the temperature of the powder material in the non-forming area and prevent the first liquid material in the forming area from diffusing into the non-forming area, thereby improving the surface accuracy of the formed three-dimensional object.

[0154] The function of the powder release agent contained in the second liquid material is to reduce the surface tension of the powder surface. Further, since the content of the second liquid material sprayed per unit volume in the forming area is less than the amount of the second liquid material per unit volume in the surrounding non-forming area, the surface tension between the powder surfaces or between the powders in the non-forming area around the forming area is less than the surface tension between the powder surfaces or between the powders in the forming area, and the first liquid material in the forming area is not easily diffused to the edge.

[0155] In this application, by controlling the weight percentage of the powder release agent to be 0.01% - 10%, specifically it can be 0.01%, 0.05%, 0.08%, 0.1%, 0.5%, 0.9%, 1.1%, 2.6%, 3.9%, 4%, 5%, 6.6%, 7.9%, 9.9% or 10%, etc., which is not limited herein. Through multiple experiments, it is found that when the weight percentage of the powder release agent is less than 0.01%, it cannot effectively prevent the first liquid material in the forming area from diffusing into the non-forming area. When the weight percentage of the powder release agent is greater than 10%, in this case, it is found that some powder release agents exceeding a certain content will affect the penetration of the first liquid material into the powder material layer and inhibit the effect of the first liquid material in the forming area from diffusing towards the edge, which helps to improve the surface accuracy of the edge of the forming area.

[0156] The second liquid material contains a release agent, and the weight percentage of the release agent in the second liquid material is 1% - 30%, specifically it can be 1%, 2%, 5%, 8%, 12%, 15%, 18%, 19%, 22%, 24%, 25%, 28%, 29% or 30%, etc., which is not limited herein; the release agent is selected from water-soluble polymers and / or water-dispersible polymers with a glass transition temperature lower than 40°C; preferably water-soluble polymers or water-dispersible polymers with a glass transition temperature lower than 0°C, so as to be easily damaged during sandblasting.

[0157] Specifically, the water-soluble polymer or water-dispersible polymer is selected from at least one of polyether resin, polyester resin, poly(meth)acrylate resin, and polyurethane resin.

[0158] It can be understood that when the second liquid material is applied to the non-forming area of the powder material, the release agent bonds the powder materials in the non-forming area at the edge of the forming area together. The release agent helps to separate the powder materials in the non-forming area from the solid part formed in the forming area, and is beneficial to separating the recycled powder materials from the powder materials in other non-forming areas.

[0159] The second liquid material contains a hydrocarbon chain surfactant, and the weight percentage of the hydrocarbon chain surfactant in the second liquid material is 0.1% - 10%, specifically it can be 0.1%, 0.5%, 0.9%, 1.1%, 2.6%, 3.9%, 4%, 5%, 6.6%, 7.9%, 9.9% or 10%, etc., which is not limited herein. Adding an appropriate amount of hydrocarbon chain surfactant to the second liquid material is beneficial to the dissolution or dispersion of the second auxiliary agent, powder release agent, and release agent in water, and is beneficial to forming a uniform liquid.

[0160] Specifically, the hydrocarbon chain surfactant is selected from one or more of fatty alcohol polyoxyethylene ether, sodium alkyl sulfonate, sodium alkyl benzene sulfonate, sodium alkyl sulfate, sodium alkyl succinate sulfonate, sodium aminosulfonate, polyether, and polyoxyethylene polyoxypropylene ether block copolymer.

[0161] In another alternative, the second liquid material further contains a cosolvent, and the weight percentage of the cosolvent in the second liquid material is 0.05%-30%, specifically, it can be 0.05%, 0.1%, 1%, 2%, 5%, 8%, 12%, 15%, 18%, 19%, 22%, 24%, 25%, 28%, 29% or 30%, etc., which is not limited here. The cosolvent is selected from at least one of alcohols, alcohol ethers, amides, pyrrolidones, organic acids and organic salts. Adding an appropriate amount of cosolvent to the second liquid material can effectively increase the solubility of the second auxiliary agent, powder release agent, stripping auxiliary agent, etc. in the second liquid material, and further improve the surface accuracy of the formed three-dimensional object.

[0162] Specifically, the alcohols can be at least one of ethylene glycol, propylene glycol, glycerol, butanediol, diethylene glycol, etc. The alcohol ethers can be at least one of polyethylene glycol 200, polyethylene glycol 400, propylene glycol ether, etc. The amides can be at least one of urea, acetamide, etc. The pyrrolidones can be at least one of pyrrolidone, hydroxyethyl pyrrolidone, N-methylpyrrolidone, etc. The organic acids can be at least one of p-aminobenzoic acid, benzenesulfonic acid, ascorbic acid, etc., and the organic salts can be at least one of sodium benzoate, sodium salicylate, etc.

[0163] Figure 1 It is a schematic flowchart of the three-dimensional object printing method provided by the embodiment of the present application, as Figure 1 shown. On the other hand, the present application provides a three-dimensional object printing method, including the following steps:

[0164] Step S10, forming a powder material layer with the powder material, and the powder material layer includes a forming area and a non-forming area;

[0165] Step S20, applying the first liquid material and the second liquid material in a first ratio in the forming area of the powder material layer according to the layer printing data, and the second liquid material promotes the polymerization reaction of the first liquid material to form a layer entity part of the three-dimensional object;

[0166] Step S30, applying the first liquid material and the second liquid material in a second ratio in the non-forming area of the powder material layer according to the layer printing data to form a layer protection part of the three-dimensional object; wherein, the first ratio is greater than the second ratio; the amount of the second liquid material in the unit volume of the forming area is less than the amount of the second liquid material in the unit volume of at least part of the non-forming area, and the amount of the first liquid material in the unit volume of the forming area is greater than the amount of the first liquid material in the unit volume of at least part of the non-forming area.

[0167] In the above solution, by separately storing the first liquid material and the second liquid material and applying them to the forming area and the non-forming area of the powder material layer according to different configuration ratios, it not only helps to improve the storage stability of the liquid material and the inkjet printing fluidity of the liquid material, but also helps to reduce the temperature of the non-forming area, helps to reduce the effect of the first liquid material on the powder material in the non-forming area, and reduces the post-processing difficulty of the printed three-dimensional object, especially the post-processing of the surface of the three-dimensional object, thereby improving the surface accuracy of the printed object.

[0168] In this application, the powder material is the aforementioned metal powder material or organic polymer powder material; when the powder material is an organic polymer powder material, the organic polymer powder material may not be dissolved by the first liquid material and may not be dissolved by the second liquid material either, or at least part of the organic polymer powder material may be dissolved by the first liquid material but not by the second liquid material, which is specifically related to the specific composition of the first liquid material.

[0169] Specifically, when the powder material is not dissolved by the first liquid material and is not dissolved by the second liquid material either, the reaction mechanism of this implementation method is as follows: in the forming area of the powder material layer, the second liquid material promotes the polymerization reaction of the first liquid material, and the formed polymer wraps the powder material in contact with the first liquid material to form the layer entity part of the three-dimensional object. In the non-forming area of the powder material layer, by controlling the size of the second ratio, the content or concentration of the first liquid material in the non-forming area is diluted, so that an effective polymerization reaction does not occur to form a polymer; or in the non-forming area, a small amount of free polymer formed by the polymerization reaction of the first liquid material cannot effectively wrap the powder material, but can form particles larger than the original powder material particles. In the non-forming area of the powder material layer, the main function of the second liquid material is to reduce the temperature of the powder material in the non-forming area, and / or at the same time prevent the first liquid material in the forming area from diffusing into the non-forming area to form the layer protection part of the three-dimensional object, so as to improve the surface accuracy of the three-dimensional object, reduce the proportion of the first liquid material in the non-forming area so that the polymer cannot effectively wrap the powder material but forms particles larger than the original powder particles, which is beneficial to sandblasting and powder recovery screening, thereby reducing the post-processing difficulty.

[0170] When at least part of the powder material is dissolved by the first liquid material but not by the second liquid material, the reaction mechanism of this embodiment is as follows: in the forming area of the powder material layer, the first liquid material dissolves the powder material in contact therewith, and the second liquid material promotes the polymerization reaction of the first liquid material to form a polymer to form a layer entity part of the three-dimensional object; the formed polymer is blended with the dissolved powder material, and in particular, the dissolved powder material can be mixed at the molecular level to form a polymer alloy, so that there is a good connection between the powder materials, between the powder material and the formed polymer, and between the printed layers, presenting a "sea-island structure" or a homogeneous structure, which can improve the mechanical strength of the three-dimensional object. In the non-forming area of the powder material layer, by controlling the size of the second ratio, the content or concentration of the first liquid material is not sufficient to effectively dissolve the powder material in contact therewith, but can form particles larger than the original powder material particles, and the first liquid material cannot undergo an effective polymerization reaction to form a polymer; or the first liquid material undergoes a polymerization reaction to form a small amount of polymer free in the non-forming area. In the non-forming area of the powder material layer, the main function of the second liquid material is to reduce the temperature of the powder material in the non-forming area and / or simultaneously prevent the first liquid material in the forming area from diffusing into the non-forming area to form a layer protection part of the three-dimensional object, thereby improving the surface accuracy of the three-dimensional object and reducing the post-processing difficulty.

[0171] When the first liquid material and the second liquid material are applied to the powder material layer, the liquid materials can quickly penetrate into the interior of the powder material layer through the gaps and retain part on the surface layer, and even wet the surface of the powder material in the selected area and at least partially dissolve the powder material. It should be noted that the dissolution in the embodiments of the present application refers to all possible situations except complete insolubility.

[0172] It should be noted that the step numbers in the process schematic diagram of the present application do not represent the sequence in the three-dimensional object printing process. In the actual printing process, step S20 can be before step S30, or after step S30; or, step S20 and step S30 can also be executed simultaneously, which is related to the printing method and / or the shape of the object to be printed. Only a few cases are listed in the specification of the present application and not all are described.

[0173] Please refer to Figure 2 together with the following, and elaborate in detail in combination with specific embodiments:

[0174] Before step S10, the method further includes:

[0175] Step S01: Obtain the digital model of the three-dimensional object, slice and layer the digital model of the three-dimensional object to obtain multiple slice layers and slice layer image data, and generate layer printing data according to the slice layer image data. The layer printing data includes layer printing data of the forming area and layer printing data of the non-forming area.

[0176] In a specific implementation manner, the original data of the three-dimensional object can be obtained by scanning and three-dimensional modeling to obtain the digital model of the three-dimensional object. Alternatively, the three-dimensional object model can be designed and constructed to obtain the digital model of the three-dimensional object, and the data format of the digital model is converted, such as converted into formats that can be recognized by slicing software, such as STL format, PLY format, WRL format, etc. Then, the slicing software is used to slice and layer the model to obtain slice layer image data, and the layer image data is processed to obtain layer printing data representing the object. The layer printing data includes layer printing data of the forming area representing the shape information of the object and layer printing data of the non-forming area representing the periphery of the object.

[0177] In this application, the shape of the three-dimensional object to be printed is not limited and can be any shape of object. Figure 3a As shown in the structural schematic diagram of the three-dimensional object to be printed provided by the embodiment of the present application, Figure 3a As shown, in a specific embodiment, the three-dimensional object 1 to be printed can be, for example, a cylinder. After slicing and layering the three-dimensional object 1 to be printed, multiple slice layers of the three-dimensional object are obtained. According to the layer printing data of the forming area 1n in the slice layer, the layer entity part can be printed and formed.

[0178] Step S10: Form a powder material layer using powder material. The powder material layer includes a forming area and a non-forming area.

[0179] In the actual printing process, the forming area 1n of the powder material layer forms the entity part of the three-dimensional object, that is, the contour of the three-dimensional object to be printed and the area within the contour. The non-forming area is the area outside the contour of the three-dimensional object to be printed. In this embodiment, a protective part of the three-dimensional object is formed in the non-forming area of the powder material layer.

[0180] Figure 3b As shown in the structural schematic diagram of the powder material layer provided by the embodiment of the present application, Figure 3b As shown, the area other than the forming area 1n on the powder material layer L0 is the non-forming area. Among them, the area 1n' is at least a part of the non-forming area, located around the forming area 1n, and is called the layer protection part. In other implementation manners, the area 1n' can also be the non-forming area.

[0181] The powder material used in this embodiment is the same as that in the previous 3D printing materials, which will not be elaborated here. Among them, the thickness of the formed 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 thickness of the powder material layer is preferably 50 μm to 150 μm. It can be understood that when the thickness of the powder material layer is relatively thin, an object with higher resolution can be formed, but the time spent in manufacturing the object is greatly extended and the manufacturing cost increases; when the thickness of the powder material layer is relatively thick, the time for the liquid material to infiltrate the powder material is extended, and the resolution of the manufactured object decreases, making it difficult to meet the expectations.

[0182] In some embodiments, after step S10 and before step S201, the printing method further includes:

[0183] Step S11, preheating the powder material layer.

[0184] It can be understood that providing heat energy on the formed powder material layer to preheat the powder material, and the preheating temperature is 5 °C - 100 °C lower than the melting point or melting temperature of the powder material. By preheating the powder material, it can effectively promote the polymerization reaction of the first liquid material applied in the forming area subsequently, prevent the first liquid material in the forming area from diffusing into the non-forming area, and affect the surface accuracy of the formed object; and / or, promote the evaporation of some components (such as water) in the second liquid material applied in the forming area subsequently, increase the concentration of the additives in the second liquid material in the forming area, and further accelerate the polymerization reaction rate of the first liquid material.

[0185] In some embodiments, the preheating energy includes at least one of radiant energy and thermal energy, and specifically, it can be preheated by infrared radiation, visible light irradiation, etc.

[0186] In order to effectively improve the inkjet printing efficiency, during the printing process, the first liquid material and the second liquid material can be inkjet printed in the same scanning direction.

[0187] Step S20, the specific implementation manner can be:

[0188] Step S201, in the same scanning direction, apply the first liquid material and the second liquid material in the forming area of the powder material layer at a first ratio according to the layer printing data of the forming area, and the second liquid material promotes the polymerization reaction of the first liquid material to form the layer solid part of the three-dimensional object.

[0189] In some embodiments, the first liquid material and the second liquid material are stored independently and applied to the forming area and the non-forming area of the powder material layer in different configuration ratios, which not only helps to improve the storage stability of the liquid material, but also improves the inkjet printing fluidity of the liquid material.

[0190] In the embodiments of the present application, the first liquid material includes a first active component, and the weight ratio of the first active component in the first liquid material is 10%-95%. The first active component dissolves at least part of the powder material.

[0191] Specifically, the first active component has active groups that can participate in polymerization reactions. The active groups include at least one of carbon-carbon double bonds, hydroxyl groups, carboxyl groups, thiiranyl groups, carbonate groups, epoxy groups, liquid cyclic lactone structures, and cyclic acetal structures. The first active component can be selected from at least one of monomers containing carbon-carbon double bonds, compositions containing epoxy groups and promoting the ring-opening polymerization of epoxy groups, cyclic lactones, thiirane compounds, carbonate compounds, and cyclic amide compounds. It should be noted that the first active component does not undergo a polymerization reaction with the powder material. Specific examples can be seen in the introduction of the three-dimensional printing materials mentioned above and will not be elaborated here.

[0192] The second liquid material includes the following components by weight ratio: 0.1%-40% of a second auxiliary agent, 30%-90% of water, 0.01%-10% of a powder release agent, 1%-30% of a release agent, and 0.1%-10% of a hydrocarbon chain surfactant; wherein, the second auxiliary agent is used to promote the polymerization reaction of the first liquid material, specifically to initiate or catalyze the polymerization reaction of the first active component in the first liquid material.

[0193] Specifically, the second auxiliary agent includes at least one of an initiator, a promoter, and a catalyst; the initiator is selected from water-soluble or water-dispersible initiators; the promoter can be selected from partially water-soluble promoters; the catalyst can be triethylbenzylammonium chloride, triethylamine, triethanolamine, methyl fluorosulfonate, ethyl fluorosulfonate, methyl nitrobenzenesulfonic acid, methyl sulfonate, etc.

[0194] The powder release agent is selected from at least one of a silicon-containing water-soluble release agent, a silicon-containing water-dispersible release agent, a fluorine-containing water-soluble release agent, and a fluorine-containing water-dispersible release agent. After many experiments, it is found that the powder release agent can reduce the surface tension of the powder surface. An appropriate amount of the powder release agent will affect the penetration of the first liquid material into the powder material layer and inhibit the effect of the first liquid material in the forming area from spreading to the edge, which helps to improve the surface accuracy of the edge of the forming area.

[0195] The release agent is selected from water-soluble polymers and / or water-dispersible polymers with a glass transition temperature below 40°C; preferably water-soluble polymers or water-dispersible polymers with a glass transition temperature below 0°C. Specifically, the water-soluble polymer or water-dispersible polymer is selected from at least one of polyether resins, polyester resins, poly(meth)acrylate resins, and polyurethane resins. The release agent helps to separate the powder material in the non-formed area from the solid part formed in the formed area, and is beneficial to separating the recycled powder material from the powder in other non-formed areas.

[0196] The hydrocarbon chain surfactant is selected from one or more of fatty alcohol polyoxyethylene ether, sodium alkyl sulfonate, sodium alkyl benzene sulfonate, sodium alkyl sulfate, sodium alkyl sulfosuccinate, sodium aminosulfonate, polyether, and polyoxyethylene-polyoxypropylene block copolymer. Adding an appropriate amount of hydrocarbon chain surfactant to the second liquid material is beneficial to the dissolution or dispersion of the second auxiliary agent, powder release agent, and release agent in water, and is beneficial to forming a homogeneous liquid.

[0197] The second liquid material contains water. The main function of water is to spray the second liquid material in the non-formed area. Water can reduce the temperature of the powder material in the non-formed area, and during the evaporation of water, the evaporated water can also take away the temperature of the powder material in the non-formed area, thereby preventing the powder material in the non-formed area from being melted and / or dissolved by the first liquid material and adhering to the surface of the formed object, affecting the surface accuracy of the object. Moreover, using water has a lower cost and is more environmentally friendly than using other volatile solvents.

[0198] In another alternative, the second liquid material further contains a cosolvent with a weight percentage of 0.05%-30%. The cosolvent is selected from at least one of alcohols, alcohol ethers, amides, pyrrolidones, organic acids, and organic salts. Adding an appropriate amount of cosolvent to the second liquid material can effectively increase the solubility of the second auxiliary agent, powder release agent, release auxiliary agent, etc. in the second liquid material, and further improve the surface accuracy of the formed three-dimensional object.

[0199] Specifically, the first ratio is the ratio of the amount of the first liquid material applied in the formed area of the powder material layer to the amount of the second liquid material applied. It should be noted that the "amount" is a measure of the amount of the first liquid material and the second liquid material, and can be volume, weight, or the number of ink drops, which is not limited in this application.

[0200] In the specific implementation manner, the first ratio is the volume ratio of the first liquid material to the second liquid material, and the first ratio is (1 - 10):1. Specifically, the first ratio can be 1:1, 2:1, 3:1, 5:1, 6:1, 7:1, 8:1, 10:1, etc. In the forming area of the powder material layer, by controlling the magnitude of the first ratio, the second liquid material promotes the rapid polymerization reaction of the first liquid material to obtain a layer entity part of a three-dimensional object with specified material properties. When the second liquid material is insufficient, the polymerization reaction rate of the first liquid material is slow and the reaction is incomplete. Eventually, the strength of the three-dimensional object is reduced, and since the first liquid material does not fully participate in the polymerization reaction to form a polymer, the excessive first liquid material easily penetrates into the non-forming area, affecting the forming accuracy of the object. When the second liquid material is excessive, the second liquid material easily reduces the temperature of the powder material in the forming area, reducing the polymerization reaction rate of the first liquid material and / or reducing the dissolution rate of the first liquid material for dissolving the powder material.

[0201] Correspondingly, for step S30, the specific implementation manner can be:

[0202] Step S301, in the same scanning direction as step S201, apply the first liquid material and the second liquid material in the non-forming area of the powder material layer according to the layer printing data of the non-forming area at a second ratio to form a layer protection part of the three-dimensional object; wherein, the first ratio is greater than the second ratio; the amount of the second liquid material per unit volume in the forming area is less than the amount of the second liquid material per unit volume in at least part of the non-forming area, and the amount of the first liquid material per unit volume in the forming area is greater than the amount of the first liquid material per unit volume in at least part of the non-forming area.

[0203] The second ratio is the ratio of the amount of the first liquid material applied in the non-forming area of the powder material layer to the amount of the second liquid material applied. In this application, the first ratio is greater than the second ratio, that is, when the first liquid material and the second liquid material are mixed, the proportion of the first liquid material in the mixture in the first ratio is greater than the proportion of the first liquid material in the mixture in the second ratio.

[0204] In the specific implementation manner, the second ratio is the volume ratio of the first liquid material to the second liquid material, and the second ratio is (0 - 0.95):1. The second ratio can specifically be 0, 0.05:1, 0.1:1, 0.2:1, 0.5:1, 0.7:1, 0.8:1, 0.95:1, etc. When the second ratio is 0, it means that only the second liquid material is applied in the non-forming area of the powder material layer. At this time, the application amount of the second liquid material in the non-forming area only needs to satisfy that the amount of the second liquid material applied per unit volume in the non-forming area is greater than the amount of the second liquid material applied per unit volume in the forming area. Among them, the second liquid material is mainly used to reduce the temperature of the powder material in the non-forming area and / or prevent the first liquid material in the forming area from penetrating into the non-forming area, so as to improve the surface accuracy of the formed three-dimensional object.

[0205] When the second ratio is greater than 0, it means that the first liquid material and the second liquid material are applied in the non-forming area of the powder material layer. Among them, the second liquid material is mainly used to reduce the temperature of the powder material in the non-forming area and / or reduce the concentration of the first liquid material in the non-forming area through the second liquid material, so as to prevent the powder material in the non-forming area from being bonded to the surface of the three-dimensional object by high-temperature melting or dissolved by the first liquid material, and / or prevent the first liquid material in the forming area from penetrating into the non-forming area, so as to improve the surface accuracy of the formed three-dimensional object. It can be understood that since the amount of the second liquid material per unit volume in the non-forming area is greater than the amount of the second liquid material per unit volume in the forming area, the endothermic evaporation of some components can effectively reduce the temperature of the powder material in the non-forming area, prevent the powder material in the non-forming area from adhering to the surface of the formed three-dimensional object, and can improve the surface accuracy of the three-dimensional object.

[0206] In the specific implementation process, the present application controls the amount of the first liquid material in the non-forming area of the powder material layer. When the second ratio is greater than 0.95:1, the polymer formed by the second liquid material promoting the polymerization reaction of the first liquid material in the non-forming area has sufficient strength. The polymer formed in the non-forming area adheres to the surface of the object, which will reduce the surface accuracy of the formed three-dimensional object and increase the difficulty of post-treatment.

[0207] In the above implementation manner, the amount of the second liquid material per unit volume in the forming area is less than the amount of the second liquid material per unit volume in the non-forming area. In the forming area, the main function of the second liquid material is to promote the polymerization reaction of the first liquid material to form a polymer. The polymer formed in the forming area is blended with the dissolved powder material, especially reaching a molecular-level mixing with the dissolved powder material to form a polymer alloy, which can improve the mechanical strength of the three-dimensional object.

[0208] In the non-forming area, the main function of the second liquid material is to reduce the temperature of the powder material in the non-forming area; in the non-forming area, the second liquid material can also prevent the first liquid material in the forming area from diffusing into the non-forming area. Specifically, since the content of the second liquid material sprayed per unit volume in the forming area is less than that in the surrounding non-forming area per unit volume, under the action of the powder release agent in the second liquid material, the surface tension between the powder surfaces or between the powders in the non-forming area around the forming area is less than the surface tension between the powder surfaces or between the powders in the forming area, and the first liquid material in the forming area is not likely to diffuse to the edge. That is, it is difficult for the first liquid material to penetrate into the powder material in the non-forming area to dissolve the powder material in the non-forming area, which helps to reduce the effect of the first liquid material on the powder material in the non-forming area; moreover, since the second liquid material contains water, when a sufficient amount of water is evaporated, it can take away the temperature of the powder material in the non-forming area, thereby helping to reduce the temperature of the non-forming area, and preventing the powder material in the non-forming area from adhering to the surface of the formed layer entity part (corresponding to the forming area) at high temperature, so that an interface can be formed between the formed layer entity part and the layer protection part, and the layer protection part will not fuse with the layer entity part, improving the surface accuracy of the formed three-dimensional object.

[0209] Moreover, the proportion of the first liquid material in the liquid material applied to the non-forming area is low. The polymer formed by the first liquid material cannot effectively wrap the powder material, but can form particles larger than the original powder material particles, which is beneficial to sandblasting and recycling the powder material, reducing the post-processing difficulty of the printed three-dimensional object, especially the post-processing of the surface of the three-dimensional object, and then improving the surface accuracy of the printed object.

[0210] Figures 4a - 4e Schematic diagram of the ink drop landing point structure when the first liquid material and the second liquid material provided in the embodiment of the present application are sprayed at a specified ratio, as Figures 4a - 4e shown Figure 4aIn the x direction is the scanning direction of the print head, and in the y direction is the stepping direction of the print head. Each small square represents the minimum printing unit of the printer. In 3D printing, the minimum printing unit is called a voxel, and in a 2D plane, the minimum printing unit is called a pixel. Each dashed box in the figure represents a mixing unit. The first liquid material A and the second liquid material B are ejected in proportion in the mixing unit. For example, in the mixing unit X1, the first liquid material A and the second liquid material B are ejected into different voxels respectively and mixed in a volume ratio of 5:4. When the first liquid material A contacts the second liquid material B, the second liquid material B promotes the polymerization reaction of the first liquid material A. For example, in the mixing unit X2, the first liquid material A and the second liquid material B are mixed in a volume ratio of 1:1. For example, in the mixing unit X3, the first liquid material A and the second liquid material B are mixed in a volume ratio of 0.8:1. In this specific embodiment, the mixing unit is an area where the first liquid material A and the second liquid material B can be ejected in a specified proportion to achieve basic uniform mixing, and the actual size of the area is not limited here.

[0211] During the printing process, based on this mixing unit, the first liquid material and the second liquid material are ejected in a specified proportion. During the printing of a layer entity part of a 3D object, the mixing unit can be a single form or combined with other forms of mixing units, which is not limited here.

[0212] Figure 4b It is a schematic diagram of the ink droplet landing point structure of another first liquid material and second liquid material; the x direction represents the scanning direction, and the Z direction represents the ink droplet stacking direction. In this specific embodiment, the first liquid material A and the second liquid material B are ejected in a specified proportion at the same voxel position, such as Figure 4b As shown, during the inkjet printing process, the first liquid material A and the second liquid material B are ejected in a volume ratio of 1:1 at the same voxel position V voxel , and the ink droplets are stacked in the Z direction. Or, as Figure 4c As shown, during the inkjet printing process, the first liquid material A and the second liquid material B are ejected in a volume ratio of 2:1 at the same voxel position V voxel , and the ink droplets are stacked in the Z direction. Two ink droplets of the first liquid material A with the same volume are ejected at the same voxel position. Or, as Figure 4d As shown, during the inkjet printing process, the first liquid material A and the second liquid material B are ejected in a volume ratio of 2:1 at the same voxel position V voxel , and the ink droplets are stacked in the Z direction. The volume of a single ink droplet of the first liquid material A at the same voxel position is twice the volume of a single ink droplet of the second liquid material B. Or, as Figure 4e As shown, the x direction is the scanning direction of the print head, and the y direction is the stepping direction of the print head. During the inkjet printing process, the first liquid material A and the second liquid material B are ejected in a volume ratio of 1:1 at the same voxel position V voxel, the ink droplets are arranged on the horizontal plane within the same voxel. In this application, the first liquid material and the second liquid material are sprayed in the forming area and the non-forming area at a specified ratio. The way of the ink droplet landing point can also be a combination of the above various ways, which is not limited here.

[0213] Since after the three-dimensional object printing is completed, the powder material in the non-forming area needs to be removed from around the target object, this application preferably reduces the range of the non-forming area where the liquid material is sprayed to improve the recycling rate of the powder material.

[0214] In this embodiment, on the premise of ensuring that the layer protection part plays the aforementioned role, the width d of the layer protection part is greater than or equal to the minimum diameter of the droplets of the applied liquid material. For example, if the diameter of the smallest droplet during the inkjet process is 10um, then d in this embodiment is greater than or equal to 10um.

[0215] In another alternative embodiment, in the non-forming area, along the direction away from the forming area, the amount of the second liquid material in the unit volume of the non-forming area gradually decreases. Thereby reducing the amount of the second liquid material sprayed in the non-forming area and reducing the three-dimensional object printing cost.

[0216] In each specific embodiment of this application, in order to improve the strength of the formed three-dimensional object, reduce the possibility of the powder material in the non-forming area adhering to the surface of the three-dimensional object formed by printing, and improve the peelability of the powder material in the non-forming area adhering to the surface of the three-dimensional object, so that a clear interface can be formed between the layer solid part and the layer protection part of the three-dimensional object, it is defined that the amount of the second liquid material in the unit volume of the forming area is less than the amount of the second liquid material in the unit volume of at least part of the non-forming area, and the amount of the first liquid material in the unit volume of the forming area is greater than the amount of the first liquid material in the unit volume of at least part of the non-forming area.

[0217] Further, after step S20 and step S30, more specifically, after performing step S201 and step S301, the printing method further includes: step S40, heating the powder material layer applied with the second liquid material.

[0218] Understandably, heat energy is provided to the powder material layer applied with the second liquid material to heat the powder material layer applied with the second liquid material, and the heating temperature is higher than 70°C and 5°C or more lower than the melting point or melting temperature of the powder material; in this specific embodiment, by heating the powder material layer applied with the second liquid material, the polymerization reaction of the first liquid material in the forming area can be further promoted, preventing the first liquid material in the forming area from diffusing into the non-forming area and affecting the surface accuracy of the formed object; and / or promoting the evaporation of some components in the second liquid material (such as the evaporation of water), increasing the concentration of the second auxiliary agent in the second liquid material in the forming area to further accelerate the polymerization reaction rate of the first liquid material. Since the amount of the second liquid material per unit volume in the non-forming area is greater than that in the forming area, the endothermic evaporation of some components can effectively reduce the temperature of the powder material in the non-forming area, preventing the powder material in the non-forming area from adhering to the surface of the formed three-dimensional object and improving the surface accuracy of the three-dimensional object.

[0219] In some specific embodiments, the heating energy includes at least one of radiant energy and thermal energy, and specifically, heating can be performed by infrared radiation, visible light irradiation, etc.

[0220] During the printing process of the three-dimensional object, after step S40, the printing method further includes:

[0221] Step S50, confirming whether the formed layer of the current three-dimensional object is the last layer. If not, repeat the steps of forming the powder material layer to forming the formed layer above to stack the obtained multiple formed layers layer by layer to form a three-dimensional object.

[0222] Understandably, the digital model of the three-dimensional object is sliced and layered to obtain at least one slice layer. During the printing process of the three-dimensional object, each formed layer is stacked layer by layer until all slice layers are printed to form the target three-dimensional object. Otherwise, it is necessary to repeat forming the powder material layer and jetting the first liquid material and the second liquid material according to the layer printing data to form the layer entity part and the layer protection part, where the layer entity part and the layer protection part constitute the formed layer, and the formed layers are stacked layer by layer to form a three-dimensional object.

[0223] During the three-dimensional object printing process, applying a second liquid material in the forming area can promote the polymerization reaction of the first liquid material, and the first liquid material dissolves at least part of the powder material to form a layer solid part of the three-dimensional object. In the non-forming area, the second liquid material does not promote or slowly promotes the polymerization reaction of the first liquid material to form a layer protection part of the three-dimensional object. The main function of applying the second liquid material in the non-forming area is to prevent the first liquid material in the forming area from penetrating into the non-forming area, thereby preventing the penetrated first liquid material from reacting with the powder material in the non-forming area and affecting the surface accuracy of the formed object; and / or, preventing the powder material in the non-forming area from being melted and adhered to the surface of the formed object and affecting the surface accuracy of the object; there is no residue of small molecule substances in the printed three-dimensional object, and no small molecule substances are precipitated during use, which can meet the requirements of safety and environmental protection.

[0224] Figure 5 It is a schematic flowchart of a three-dimensional object printing method provided for another embodiment of this application. The difference between this embodiment and Figure 2 is that during the printing process, the first liquid material A and the second liquid material B are inkjet printed in different scanning directions, and the second liquid material B is sprayed first and then the first liquid material A is sprayed.

[0225] Specifically, after step S11, the printing method includes:

[0226] Step S202, in the first scanning direction, apply the second liquid material in the forming area of the powder material layer at a first ratio according to the layer printing data of the forming area, and apply the second liquid material in the non-forming area of the powder material layer at a second ratio according to the layer printing data of the non-forming area;

[0227] Then, execute step S40 to heat the powder material layer applied with the second liquid material;

[0228] After that, execute step S302. In the second scanning direction, apply the first liquid material in the forming area of the powder material layer at a first ratio according to the layer printing data of the forming area. The second liquid material promotes the polymerization reaction of the first liquid material to form a layer solid part of the three-dimensional object; apply the first liquid material in the non-forming area of the powder material layer at a second ratio according to the layer printing data of the non-forming area to form a layer protection part of the three-dimensional object; wherein, the first scanning direction is opposite to the second scanning direction, and the first ratio is greater than the second ratio; the amount of the second liquid material in the unit volume of the forming area is less than the amount of the second liquid material in at least part of the unit volume of the non-forming area, and the amount of the first liquid material in the unit volume of the forming area is greater than the amount of the first liquid material in at least part of the unit volume of the non-forming area.

[0229] In this specific embodiment, the first liquid material and the second liquid material are applied in different scanning directions respectively. The second liquid material is applied first, and after heating the powder material layer applied with the second liquid material, the first liquid material is applied. In this way, before the first liquid material is ejected, at least part of the evaporable components in the second liquid material are evaporated. The amount of the second liquid material in the non-forming area is large, and the evaporated components take away the temperature of the powder material in the non-forming area, so that the temperature of the powder material in the non-forming area is reduced, and the concentration of other components in the second liquid material is increased, which can promote the polymerization reaction rate of the first liquid material and improve the surface accuracy of the formed object.

[0230] In this application, according to the three-dimensional printing materials provided above and the Figure 2 three-dimensional object printing method described above, the following examples and comparative examples are printed. It should be noted that the printing steps of the examples and comparative examples are the same.

[0231] Example 1:

[0232] Using polypropylene particles as the powder material, the liquid material formula is as follows:

[0233]

[0234] Note: The water-soluble polyester resin does not react during the forming process, and its Tg is 10°C.

[0235] Example 2:

[0236] Using polyurethane particles as the powder material, the liquid material formula is as follows:

[0237]

[0238]

[0239] Note: The Tg of the aqueous acrylate emulsion is -10°C.

[0240] Example 3:

[0241] Using polyurethane particles as the powder material, the liquid material formula is as follows:

[0242]

[0243] Note: The Tg of the aqueous polyurethane is 0°C.

[0244] Example 4:

[0245] Using polyurethane particles as the powder material, the liquid material formula is as follows:

[0246]

[0247]

[0248] Note: The Tg of the aqueous acrylate emulsion is -10°C.

[0249] Example 5:

[0250] Using polyamide particles as the powder material, the liquid material formulation is as follows:

[0251]

[0252] Note: The Tg of the aqueous acrylate emulsion is -10°C.

[0253] Example 6:

[0254] Using polyamide particles as the powder material, the liquid material formulation is as follows:

[0255]

[0256]

[0257] Note: The Tg of the aqueous acrylate emulsion is -10°C.

[0258] Example 7:

[0259] Using polyamide particles as the powder material, the liquid material formulation is as follows:

[0260]

[0261] Note: The Tg of the aqueous acrylate emulsion is -10°C.

[0262] Example 8: Using cellulose acetate as the powder material, the liquid material formulation is as follows:

[0263]

[0264] Note: The Tg of the aqueous acrylate emulsion is 40°C.

[0265] Example 9:

[0266] Using the three-dimensional printing material in Example 5 in combination with Figure 2 the three-dimensional object printing method in which, the preheating temperature is 175°C, the heating temperature is 180°C, and in the inkjet printing process, for each voxel V voxel 8 drops of ink are used for printing, the volume of each single ink drop is basically the same, the first ratio is 4:4, indicating that 4 drops of the first liquid material ink drops and 4 drops of the second liquid material ink drops are respectively ejected in each voxel in the forming area; the second ratio is 0:8, indicating that no first liquid material is ejected in the non-forming area, and only 8 drops of the second liquid material ink drops are ejected in each voxel in the non-forming area.

[0267] Example 10:

[0268] Using the three-dimensional printing material in Example 5 in combination with Figure 2 the three-dimensional object printing method in, where the preheating temperature is 175 °C, the heating temperature is 180 °C, and in the inkjet printing process, for each individual voxel V voxel 8 drops of ink are used for printing, the volume of each individual ink drop is basically the same, the first ratio is 7:1, which can be expressed as ejecting 7 drops of the first liquid material ink drop and 1 drop of the second liquid material ink drop in each individual voxel in the forming area; the second ratio is 3:5, which can be expressed as ejecting 3 drops of the first liquid material ink drop and 5 drops of the second liquid material ink drop in each individual voxel in the non-forming area.

[0269] Example 11

[0270] Using the three-dimensional printing material in Example 5 in combination with Figure 2 the three-dimensional object printing method in, where the preheating temperature is 175 °C, the heating temperature is 180 °C, and in the inkjet printing process, in the forming area, for each individual voxel V voxel 8 drops of ink are used for printing, and in the non-forming area, for each individual voxel V voxel 4 drops of ink are used for printing, the volume of each individual ink drop is basically the same, the first ratio is 6:2, which can be expressed as ejecting 6 drops of the first liquid material ink drop and 2 drops of the second liquid material ink drop in each individual voxel in the forming area; the second ratio is 1:3, which can be expressed as ejecting 1 drop of the first liquid material ink drop and 3 drops of the second liquid material ink drop in each individual voxel in the non-forming area.

[0271] Comparative Example 1:

[0272] Using polyurethane particles as the powder material, the liquid material formula is as follows:

[0273]

[0274] Comparative Example 2:

[0275] Using polyurethane particles as the powder material, and using the first liquid material in Example 2 as the liquid material formula.

[0276] Comparative Example 3:

[0277] Using polyurethane particles as the powder material, and using the first liquid material in Example 4 as the formula of the first liquid material for spraying, the second liquid material formula is as follows:

[0278]

[0279] Note: The Tg of the aqueous acrylate emulsion is -10 °C.

[0280] Comparative Example 4:

[0281] Using polyamide particles as the powder material, the first liquid material of Example 5 is used alone as the jetting liquid formulation;

[0282] Comparative Example 5:

[0283] Using polyamide particles as the powder material, the first liquid material of Example 5 is used as the first liquid material formulation of the jetting liquid, and the second liquid material formulation is as follows:

[0284]

[0285]

[0286] Note: The Tg of the aqueous acrylate emulsion is -10°C.

[0287] Comparative Example 6:

[0288] Using polyamide particles as the powder material, the first liquid material of Example 5 is used as the first liquid material of the jetting liquid, and the second liquid material formulation is as follows:

[0289]

[0290] Note: The Tg of the aqueous acrylate emulsion B is 90°C.

[0291] Comparative Example 7:

[0292] Using polyamide particles as the powder material, the first liquid material of Example 5 is used as the first liquid material of the jetting liquid, and the second liquid material formulation is as follows:

[0293]

[0294] Comparative Example 8:

[0295] Using the three-dimensional printing material in Example 5 in combination with Figure 2 the three-dimensional object printing method in, where the preheating temperature is 175°C, the heating temperature is 180°C, and 4 drops of ink are used for printing in a single voxel V voxel during the inkjet printing process. The volume of each single ink drop is basically the same. The first ratio is 1:1, indicating that 2 drops of the first liquid material ink drops and 2 drops of the second liquid material ink drops are respectively jetted in a single voxel in the forming area; the second ratio is 1:1, indicating that 2 drops of the first liquid material ink drops and 2 drops of the second liquid material ink drops are respectively jetted in a single voxel in the non-forming area.

[0296] Comparative Example 9:

[0297] Using the three-dimensional printing material in Example 5 in combination with Figure 2Three-dimensional object printing method, wherein the preheating temperature is 175 °C, the heating temperature is 180 °C, and in the forming area during the inkjet printing process, each voxel V voxel uses 12 drops of ink for printing, and in each voxel V in the non-forming area voxel uses 8 drops of ink for printing, the volume of each ink drop is basically the same, the first ratio is 11:1, indicating that 11 drops of the first liquid material ink drops and 1 drop of the second liquid material ink drop are respectively ejected in each voxel in the forming area; the second ratio is 3:5, indicating that 3 drops of the first liquid material ink drops and 5 drops of the second liquid material ink drop are respectively ejected in each voxel in the non-forming area.

[0298] Comparative example 10

[0299] Adopts the three-dimensional printing material in Example 5 and uses it in combination Figure 2 Three-dimensional object printing method, wherein the preheating temperature is 175 °C, the heating temperature is 180 °C, and in the forming area during the inkjet printing process, each voxel V voxel uses 8 drops of ink for printing, and in each voxel V in the non-forming area voxel uses 4 drops of ink for printing, the volume of each ink drop is basically the same, the first ratio is 4:4, indicating that 4 drops of the first liquid material ink drops and 4 drops of the second liquid material ink drop are respectively ejected in each voxel in the forming area; the second ratio is 1:3, indicating that 1 drop of the first liquid material ink drop and 3 drops of the second liquid material ink drop are respectively ejected in each voxel in the non-forming area.

[0300] Performance test:

[0301] 1. Performance test of the first liquid material:

[0302] The first liquid materials prepared in Examples 1 to 8 and the liquid material prepared in Comparative Example 1 are respectively placed in an oven at normal temperature of 25 °C and 70 °C for baking, and the test results are shown in Table 1.

[0303] Table 1. Storage stability test of the first liquid material

[0304]

[0305] It can be seen from the test data in Table 1 that the first liquid materials provided in Example 1, Examples 3 - 5, and Example 8 do not contain high-temperature initiators, the first liquid materials provided in Example 2, Example 6, and Example 7 contain high-temperature initiators, and the first liquid material provided in Comparative Example 1 contains a low-temperature initiator. According to the experimental test data, when the first liquid material does not contain an initiator, the storage stability of the first liquid material is good; when the first liquid material contains a low-temperature initiator, it is likely to cause the storage stability of the first liquid material to deteriorate; when the first liquid material contains a high-temperature initiator at a temperature that induces the low-temperature initiator to act, it will not affect the storage stability of the first liquid material. The high-temperature initiators in Example 6 and Example 7 are different from those in Example 2 and can be relatively stable at room temperature, which can ensure the storage stability of the first liquid material.

[0306] 2. Performance testing of three-dimensional objects

[0307] According to the powder material provided in Example 1, it is used in combination at a preheating temperature of 150 °C Figure 2 in the three-dimensional object printing method (the ratio of the first liquid material to the second liquid material) to print a sample. The powder materials provided in Examples 2 - 4 and Comparative Examples 1 - 3 are used in combination at a preheating temperature of 110 °C Figure 2 in the three-dimensional object printing method to print a sample; the powder materials provided in Examples 5 - 7, Examples 9 - 11, and Comparative Examples 4 - 10 are used in combination at a preheating temperature of 175 °C Figure 2 in the three-dimensional object printing method, and the powder material provided in Example 8 is used in combination at a preheating temperature of 150 °C Figure 2 in the three-dimensional object printing method. Among them, in Examples 1 to 8, Comparative Example 3, Comparative Example 5, Comparative Example 6, and Comparative Example 7, the total volume of the ink in a single voxel in the forming area and the non-forming area of the three-dimensional object printing method is the same. Taking the volume of a single ink droplet to be basically the same as an example, the number of ink droplets in a single voxel in the forming area and the non-forming area is the same. Taking 8 ink droplets of the liquid material being ejected in a single voxel as an example, the volume ratio of the first liquid material to the second liquid material in the forming area is 6:2; the volume ratio of the first liquid material to the second liquid material in the non-forming area is 2:6, and samples are printed. Samples are printed according to the three-dimensional object printing method with 8 ink droplets of the liquid material being ejected in a single voxel in the forming area in Comparative Example 1, Comparative Example 2, and Comparative Example 4.

[0308] 2.1) Tensile strength test of the sample:

[0309] The samples are subjected to a tensile strength test according to the plastic tensile property determination standard of GB / T1040.2 - 2006.

[0310] 2.2) Elongation at break test of the sample:

[0311] The measurement was carried out according to the standard of GB / T 1040.2-2006 "Determination of Tensile Properties of Plastics".

[0312] The test results of the tensile strength and elongation at break of the specimens are shown in Table 2:

[0313] Table 2. Test results of tensile strength and elongation at break of specimens

[0314] Specimen Tensile strength (MPa) Elongation at break (%) Example 1 3.54 52 Example 2 10.30 325 Example 3 12.12 263 Example 4 10.60 332 Example 5 36.20 61 Example 6 39.50 49 Example 7 33.61 37 Example 8 15.23 15 Example 9 34.13 67 Example 10 37.02 57 Example 11 36.12 60 Comparative Example 1 9.32 306 Comparative Example 2 1.83 56 Comparative Example 3 10.26 331 Comparative Example 4 7.89 7 Comparative Example 5 35.21 62 Comparative Example 6 37.41 44 Comparative Example 7 35.61 56 Comparative Example 8 20.89 27 Comparative Example 9 17.69 17 Comparative Example 10 33.67 66

[0315] 2.3) Test on the dimensional stability and roughness of the specimens:

[0316] The target length of the specimen is 70.00 mm, the target width is 10.00 mm, and the target thickness is 3.00 mm. Measure the width, thickness and length of the actually printed specimen, and calculate the difference between the measured value and the target value, where:

[0317] △W width = measured width value - target width value;

[0318] △D thickness = measured thickness value - target thickness value;

[0319] △L length = measured length value - target length value;

[0320] Measure the roughness value of the printed specimen using a surface roughness tester.

[0321] The test results of the dimensional stability and roughness of the specimens are shown in Table 3:

[0322] Table 3. Test results of the dimensional stability and roughness of specimens

[0323] Specimen △W (mm) △D (mm) △L (mm) Roughness value (um) Example 1 －0.16 0.10 －0.29 60 Example 2 －0.05 －0.12 －0.10 86 Example 3 0.05 －0.03 －0.61 74 Example 4 0.03 0.13 －0.24 71 Example 5 0.06 0.11 －0.51 26 Example 6 －0.02 0.05 －0.21 34 Example 7 －0.07 －0.05 －0.22 37 Example 8 －0.06 0.10 －0.22 41 Example 9 －0.08 －0.10 －0.66 25 Example 10 －0.02 0.04 －0.38 30 Example 11 0.04 0.02 －0.46 27 Comparative Example 1 －0.31 0.51 －1.32 187 Comparative Example 2 －0.37 0.46 －1.36 175 Comparative Example 3 －0.23 0.55 －1.41 121 Comparative Example 4 －0.67 0.60 －2.06 123 Comparative Example 5 －0.24 －0.31 －0.71 41 Comparative Example 6 0.43 0.39 1.01 351 Comparative Example 7 －0.15 －0.11 －1.37 45 Comparative Example 8 2.23 0.72 0.96 235 Comparative Example 9 －0.15 0.09 －0.67 44 Comparative Example 10 2.31 1.01 1.21 240

[0324] In Table 2, the material formulations of Example 2 and Comparative Example 2 use the same first liquid material, and the second liquid material containing a promoter is not added to the liquid material provided in Comparative Example 2. Through testing, it is found that the tensile strength and elongation at break of the specimens in Example 2 are significantly better than those in Comparative Example 2. This is because the high-temperature initiator in the first liquid material of Example 2 needs to introduce the second liquid material containing a promoter to have a better initiation polymerization effect; while in Comparative Example 2, the second liquid material containing a promoter is not added, and the first liquid material does not effectively polymerize after being mixed with the powder material, so the mechanical properties of the specimens are poor.

[0325] In Example 2, the first liquid material and the second liquid material are applied on the powder material layer, while in Comparative Example 2, the second liquid material is not applied. It can be seen from Table 3 that the values of △W, △D, △L and roughness in Comparative Example 2 are larger, indicating that the combined use of the first liquid material and the second liquid material has a significant improvement effect on the dimensional stability and roughness of the three-dimensional object.

[0326] In both Example 4 and Comparative Example 3, the same polyurethane powder and the same first liquid material are used. Among them, the weight ratio of the powder release agent in the second liquid material provided in Example 4 is 2%, and the weight ratio of the powder release agent in the second liquid material provided in Comparative Example 3 is 15% (exceeding 10%). It can be seen from Table 3 that the values of △W, △D, △L, and roughness in Comparative Example 3 are larger than those in Example 4. This shows that when the powder release agent exceeds a certain content, the differential effect on the solid part and the protective part is not obvious, thus making the effect of the second liquid material not obvious.

[0327] In Table 2, the same first liquid material is used in both Example 5 and Comparative Example 4. The second liquid material in Example 5 contains an initiator, while the second liquid material containing an initiator is not added in Comparative Example 4. Therefore, the tensile strength and elongation at break of Example 5 are significantly stronger than those of Comparative Example 4. The values of △W, △D, △L, and roughness of the sample printed in Comparative Example 4 are larger than those in Example 5, indicating that applying the first liquid material and the second liquid material containing an initiator on the powder material layer has a certain effect on dimensional stability and roughness.

[0328] The same first liquid material is used in both Example 5 and Comparative Example 5. Among them, the second liquid material provided in Comparative Example 5 does not contain a powder release agent. It can be seen from Table 3 that compared with Comparative Example 4 and Comparative Example 5, Comparative Example 5 has a certain improvement effect on dimensional stability and roughness, but there is still a certain gap compared with Example 5, indicating that adding an appropriate amount of powder release agent to the second liquid material has an improvement effect on the dimensional stability and roughness of the three-dimensional object.

[0329] The same first liquid material is used in both Example 5 and Comparative Example 6. Among them, the glass transition temperature Tg point of the release agent (aqueous acrylate emulsion) in the second liquid material provided in Comparative Example 6 is 90°C, exceeding 40°C; while the glass transition temperature Tg point of the release agent (aqueous acrylate emulsion) in the second liquid material provided in Example 5 is -10°C, lower than 40°C. The values of △W and △D of the sample printed in Comparative Example 6 are positive, but the roughness is much larger than that in Example 5. This shows that after the release agent with a high glass transition temperature wraps the powder material particles, it is easy to adhere to the surface of the sample, resulting in a positive deviation value and a rougher surface. Therefore, it is necessary to control the glass transition temperature of the release agent in the second liquid material to be lower than 40°C.

[0330] The same first liquid material is used in both Example 5 and Comparative Example 7. Among them, the second liquid material provided in Comparative Example 7 does not contain a release agent. The values of △W, △D, △L, and roughness of the sample printed in Comparative Example 7 are close to those of the sample in Example 5, but there is still a certain gap with Example 5. It shows that including a release agent in the second liquid material has a certain improvement effect on the dimensional stability and roughness of the sample.

[0331] Example 5, Example 9, Example 10, Example 11, Comparative Example 8, Comparative Example 9, and Comparative Example 10 all use the same powder material and liquid material, but adopt different printing methods.

[0332] In Comparative Example 8, its tensile strength and elongation at break are much lower than those in Example 5, Example 9, Example 10 and Example 11. This may be because the amount of ink in Comparative Example 8 is relatively small and the first liquid material is relatively low, and its △W, △D, and △L are all larger than the target values. During the molding process, the protective part of the non-molding area is adhered to the solid part to form a molding layer.

[0333] The tensile strength and elongation at break of Comparative Example 9 are much lower than those of Examples 5, 9, 10, and 11. This is because there is too much first liquid material and too little second liquid material in Comparative Example 9. There is not enough second liquid material to promote the polymerization reaction of the first liquid material, resulting in insufficient polymerization of the first liquid material. Therefore, its tensile strength and elongation at break are much lower.

[0334] In comparative example 10, although the volume ratio of the first liquid to the second liquid in the molding area and the volume ratio of the first liquid to the second liquid in the non-molding area are within the range, the amount (volume) of the second liquid material per unit volume of the molding area is greater than the amount (volume) of the second liquid material per unit volume of the non-molding area. In addition, the overall ink volume of the first liquid material is relatively large, so △W, △D, and △L are all larger than the target values, and the roughness is greater.

[0335] On the other hand, Figure 6 A schematic diagram of the structure of a three-dimensional object printing device provided in an embodiment of the present application is shown in FIG. Figure 6 As shown, an embodiment of the present application further provides a three-dimensional object printing device for implementing the above-mentioned three-dimensional object printing method, the printing device comprising:

[0336] A powder supply component 2, which provides powder material to form a powder material layer L0, wherein the powder material layer includes a forming area and a non-forming area;

[0337] Forming platform 3, supporting the formed powder material layer L0;

[0338] The print head 26 ejects the first liquid material A and the second liquid material B;

[0339] A controller 9 controls a print head 26 to apply a first liquid material A and a second liquid material B in a first ratio within a forming region of the powder material layer according to the layer printing data, wherein the second liquid material B promotes a polymerization reaction of the first liquid material A to form a layer solid portion of the three-dimensional object;

[0340] The controller 9 controls the print head 26 to apply the first liquid material A and the second liquid material B in a second ratio within the non-forming area of the powder material layer, so as to form a layer protection part of the three-dimensional object; wherein, the first ratio is greater than the second ratio; the amount of the second liquid material B per unit volume in the forming area is less than the amount of the second liquid material B per unit volume in at least part of the non-forming area, and the amount of the first liquid material A per unit volume in the forming area is greater than the amount of the first liquid material A per unit volume in at least part of the non-forming area.

[0341] In this embodiment, the powder supply component 2 includes a powder storage cavity 23, a lifting component 22 and a powder spreading device 21. The powder storage cavity is used to store the powder material 0. There is a movable support plate 231 inside the powder storage cavity 23. The lifting component 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 spreading device 21 is used to spread the powder material 0 in the powder storage cavity 23 onto the forming platform 3 to form a powder material layer L0. The commonly used powder spreading device 21 can be a powder spreading rod or a squeegee.

[0342] The print head 26 includes a first nozzle array 26a and a second nozzle array 26b. Among them, the first nozzle array 26a is used to eject the first liquid material A, and the second nozzle array 26b is used to eject the second liquid material B; or the first nozzle array 26a is used to eject the first liquid material A and the second liquid material B mixed in a first ratio, and the second nozzle array 26b is used to eject the first liquid material A and the second liquid material B mixed in a second ratio.

[0343] In this application, the first liquid material A and the second liquid material B are two different liquid materials, which are separately stored in different material storage devices, such as ink cartridges, and the first liquid material and the second liquid material are respectively transported through different liquid material delivery pipelines. For the specific components of the first liquid material A and the second liquid material B, please refer to the introduction in the aforementioned three-dimensional printing materials, which will not be elaborated here.

[0344] In one embodiment, the first liquid material A and the second liquid material B are ejected in proportion, which can be mixed in proportion before the first liquid material A and the second liquid material B are transported to the respective nozzle arrays of the print head 26 for ejection, and then the mixed liquid material is ejected onto the forming area or the non-forming area of the powder material layer.

[0345] Figure 7a It is a partial structural schematic diagram of the liquid supply device in the three-dimensional object printing device provided by the embodiment of this application, as Figure 7aAs shown, in one embodiment, the first liquid material A is stored in the ink cartridge 21a and is transported to the mixing container 25a or 25b through the pump 22a via the ink tube 23a. The second liquid material B is stored in the ink cartridge 21b and is transported to the mixing container 25a or 25b through the pump 22b via the ink tube 23b. In the mixing container 25a, the first liquid material A and the second liquid material B are mixed in a first ratio, and in the mixing container 25b, the first liquid material A and the second liquid material B are mixed in a second ratio. The switches 24a and 24b are respectively used to control the ink supply of the first liquid material A and the second liquid material B to the mixing container 25a or the mixing container 25b. The specific types of the switches 24a and 24b are not limited, as long as they can control the ink supply of the first liquid material A and the second liquid material B to the designated mixing container, for example, it can be an electromagnetic valve.

[0346] Figure 7b The partial structural schematic diagram of the liquid supply device in the three-dimensional object printing device provided by the embodiment of the present application is as Figure 7b As shown, in another embodiment, the first liquid material A is stored in the ink cartridge 21a and is transported to the mixing container 25a through the pump 22a via the ink tube 23a, and is transported to the mixing container 25b through the pump 22c via the ink tube 23c. The second liquid material B is stored in the ink cartridge 21b and is transported to the mixing container 25a through the pump 22b via the ink tube 23b, and is transported to the mixing container 25b through the pump 22d via the ink tube 23d. In the mixing container 25a, the first liquid material A and the second liquid material B are mixed in a first ratio, and in the mixing container 25b, the first liquid material A and the second liquid material B are mixed in a second ratio. The mixture of the first liquid material A and the second liquid material B mixed in the first ratio supplies ink to the first nozzle array 26a, and the mixture of the first liquid material A and the second liquid material B mixed in the second ratio supplies ink to the second nozzle array 26b, thereby realizing inkjet printing in the forming area and the non-forming area of the powder material layer to obtain the layer entity part and the layer protection part of the three-dimensional object.

[0347] In the embodiment of the present application, the first liquid material A and the second liquid material B are sprayed in proportion. It can also be that the first liquid material A and the second liquid material B respectively supply ink to different nozzle arrays of the print head 26 through different ink supply pipelines, and the liquid materials are sprayed on the powder layer in different proportions.

[0348] Figure 7c The partial structural schematic diagram of the liquid supply device in the three-dimensional object printing device provided by the embodiment of the present application is as Figure 7cAs shown, in yet another embodiment, the first liquid material A is stored in the ink cartridge 21a and is delivered to the first nozzle array 26a of the print head via the ink tube 23a by the pump 22a. The second liquid material is stored in the ink cartridge 21b and is delivered to the second nozzle array 26b of the print head via the ink tube 23b by the pump 22b.

[0349] The controller controls the first nozzle array 26a and the second nozzle array 26b of the print head 26 to eject the first liquid material A and the second liquid material B respectively on the forming area of the powder material layer at a first ratio according to the layer printing data, and controls the first nozzle array 26a and the second nozzle array 26b to eject the first liquid material A and the second liquid material B respectively on the non-forming area of the powder material layer at a second ratio according to the layer printing data. The first liquid material A and the second liquid material B come into contact on the powder material layer.

[0350] Figure 8a It is a schematic diagram of the surface structure of the nozzle holes of the print head in the three-dimensional object printing device provided by the embodiment of the present application. As Figure 8a shown, the first nozzle array 26a and the second nozzle array 26b can be an integrated multi-channel print head, or two multi-channel print heads. The multi-channel print head 26 includes at least two rows of nozzle holes, such as 2 rows, 3 rows, 4 rows, etc. In a specific embodiment, the print head 26 has 4 rows of nozzle holes, and each row of nozzle holes can be independently controlled.

[0351] Figure 8b It is another schematic diagram of the surface structure of the nozzle holes of the print head provided by the embodiment of the present application. As Figure 8b shown, the first nozzle array 26a and the second nozzle array 26b can be single-channel print heads, and the print head 26 is a single-channel print head.

[0352] Figure 8c It is still another schematic diagram of the surface structure of the nozzle holes of the print head provided by the embodiment of the present application. As Figure 8c shown, the first nozzle array 26a and the second nozzle array 26b can also be an integrated single-channel and multi-channel print head. In a specific embodiment, the print head 26 is an integrated single-channel and multi-channel print head, and each nozzle hole can be independently controlled, such as controlling whether each nozzle hole ejects ink, and / or the size of the ink droplets ejected by each nozzle hole can be variable.

[0353] In the present application, by storing the first liquid material and the second liquid material separately in different ink cartridges and delivering them through different ink transmission pipelines, the storage stability of the liquid materials can be improved, the polymerization reaction of the first liquid material can be prevented, the ink supply smoothness of the liquid materials can be ensured, and at the same time, the nozzle holes of the print head can be prevented from being blocked and the print head can be damaged.

[0354] Optionally, the three-dimensional object printing device further includes a preheating component 53, which is disposed above the forming platform 3. The preheating component 53 is used to provide radiant energy or thermal energy to preheat the powder material layer L0, which helps the second liquid material in the forming area to promote the polymerization reaction of the first liquid material to form a polymer, and helps the evaporation of the evaporable components in the second liquid material in the non-forming area to take away the temperature of the powder material in the non-forming area. The preheating component can be selected from at least one of an ultraviolet lamp, an infrared lamp, a microwave emitter, a heating wire, a heating sheet, and a heating plate, and the specific selection is not limited.

[0355] Optionally, the three-dimensional object printing device further includes heating components 51 and 52, which are used to heat the powder layer sprayed with the second liquid material after the print head sprays the second liquid material. The heating components can be selected from at least one of an ultraviolet lamp, an infrared lamp, a microwave emitter, a heating wire, a heating sheet, and a heating plate; it should be noted that the specific form of the heating component selected is related to the type of the first active component in the first liquid material or the types of the first active component and the second auxiliary agent. When the first active component in the first liquid material undergoes a photopolymerization reaction, the heating component provides radiant energy such as ultraviolet light radiation at this time, and the first active component is induced to undergo a photopolymerization reaction through the ultraviolet light radiation; when the first active component in the first liquid material undergoes a thermal polymerization reaction, the heating component provides thermal energy such as an infrared lamp, a microwave, a heating wire, a heating sheet, and a heating plate at this time, and the first active component in the first liquid material is induced to undergo a thermal polymerization reaction through the thermal energy.

[0356] Optionally, the three-dimensional object printing device further includes a lifting mechanism 4, which is connected to the forming platform 3 and drives the forming platform 3 to move up or down in the vertical direction. During the printing process, after each three-dimensional object slice layer including a layer solid part and a layer protection part is formed, the lifting mechanism 4 drives the forming platform 3 to move downward by a distance equal to the thickness of a powder layer.

[0357] In this embodiment, the preheating component 53 is installed above the forming platform 3, which can be installed on the top of the forming chamber. The heating components 51, the print head 26, and the heating component 52 can be installed on the guide rail 11 in sequence and can move on the guide rail 11.

[0358] The three-dimensional object printing device may further include a temperature monitor (not shown in the figure), and the temperature monitor is used to monitor the temperature of the powder material layer.

[0359] Furthermore, the controller 9 is further used to control the operation of at least one of the powder supply component 2, the preheating component 53, the heating components 51 and 52, and the temperature monitor. For example, the temperature monitor feeds back the monitored temperature to the controller 9, and the controller controls the magnitudes of the energy provided by the preheating component 53 and / or the heating components 51 and 52 according to the information fed back by the temperature monitor.

[0360] The embodiments of the present application also provide a non-transitory computer-readable storage medium, such as Figure 9 shown, the storage medium 91 includes a stored program 911, which controls the device where the storage medium 91 is located to execute the above three-dimensional object printing method when the program runs.

[0361] The embodiments of the present application also provide a computer device, such as Figure 10 shown, the computer device in 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 printing method in the embodiment. To avoid repetition, it will not be elaborated here one by one.

[0362] The computer device can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The computer device may include, but is not limited to, a processor and a memory. Those skilled in the art can understand that the computer device may include more or fewer components than shown in the figure, or combine certain components, or different components. For example, the computer device may also include input / output devices, network access devices, a bus, etc.

[0363] The so-called processor may be a central processing unit (CPU), or may also be 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. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0364] The memory may be an internal storage unit of the computer device, such as the hard disk or memory of the computer device. The memory may also be an external storage device of the computer device, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the computer device. Further, the memory may also include both the internal storage unit and the external storage device of the computer device. The memory is used to store the computer program and other programs and data required by the computer device. The memory may also be used to temporarily store the data that has been output or will be output.

[0365] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present application shall be included within the scope of protection of the present application.

Claims

1. A three-dimensional printing material, which is used in combination with a powder material for three-dimensional printing, and is characterized in that, The materials include: A first liquid material, the first liquid material includes a first active component, and the first active component can dissolve at least part of the powder material; and A second liquid material. Based on the total weight of the second liquid material being 100%, the second liquid material includes the following components by weight percentage: 0.1% - 40% of a second auxiliary agent, 30% - 90% of water, 0.01% - 10% of a powder release agent, 1% - 30% of a release agent, and 0.1% - 10% of a hydrocarbon chain surfactant; wherein, the second auxiliary agent is used to promote the polymerization reaction of the first liquid material; the release agent is selected from water-soluble polymers and / or water-dispersible polymers with a glass transition temperature lower than 40°C.

2. A three-dimensional printing material, characterized in that, The materials include: A powder material, which is used to form a powder material layer; A first liquid material, the first liquid material includes a first active component, and the first active component dissolves at least part of the powder material; and A second liquid material. Based on the total weight of the second liquid material being 100%, the second liquid material includes the following components by weight percentage: 0.1% - 40% of a second auxiliary agent, 30% - 90% of water, 0.01% - 10% of a powder release agent, 1% - 30% of a release agent, and 0.1% - 10% of a hydrocarbon chain surfactant; wherein, the second auxiliary agent is used to promote the polymerization reaction of the first liquid material; the release agent is selected from water-soluble polymers and / or water-dispersible polymers with a glass transition temperature lower than 40°C.

3. The three-dimensional printing material according to claim 2, wherein The powder material layer includes a formed area and an unformed area. The first liquid material and the second liquid material are applied to the formed area at a first ratio, and the first liquid material and the second liquid material are applied to the unformed area at a second ratio, wherein the first ratio is greater than the second ratio.

4. The three-dimensional printing material according to claim 3, wherein The first ratio is the volume ratio of the first liquid material to the second liquid material, and the first ratio is (1 - 10):1; and / or, the second ratio is the volume ratio of the first liquid material to the second liquid material, and the second ratio is (0 - 0.95):

1.

5. The three-dimensional printing material according to claim 3, characterized in that, The amount of the second liquid material per unit volume in the formed area is less than the amount of the second liquid material per unit volume in at least part of the unformed area, and the amount of the first liquid material per unit volume in the formed area is greater than the amount of the first liquid material per unit volume in at least part of the unformed area.

6. The three-dimensional printing material according to claim 2, characterized in that, The powder material includes at least one of polystyrene, polyvinyl chloride, polyacrylonitrile, acrylonitrile-styrene-acrylate copolymer, polyamide, polyester, polyurethane, poly(meth)acrylate, polyvinyl fluoride, chlorinated polyolefin, block and / or graft copolymer containing segments soluble in the first active component, polyvinyl alcohol containing hydroxyl groups, cellulose, and modified cellulose.

7. The three-dimensional printing material according to claim 1 or 2, characterized in that, The first active component has active groups capable of participating in polymerization reactions, and the active groups include at least one of carbon-carbon double bonds, hydroxyl groups, carboxyl groups, heterocyclic propyl groups, carbonate groups, epoxy groups, liquid cyclic lactone structures, and cyclic acetal structures.

8. The three-dimensional printing material according to claim 1 or 2, characterized in that, The first liquid material includes a second active component having an active group capable of participating in a polymerization reaction, and the second active component does not dissolve the powder material; The second active component includes at least one of isobornyl acrylate, isobornyl methacrylate, lauryl acrylate, lauryl methacrylate, trimethylolpropane formal acrylate, a prepolymer containing a carbon-carbon double bond, a prepolymer containing an epoxy group, a monomer promoting ring-opening polymerization of the epoxy group, a prepolymer promoting ring-opening polymerization of the epoxy group, a solid cyclic lactone, and a cyclic amide compound.

9. The three-dimensional printing material according to claim 1 or 2, characterized in that Based on the total weight of the first liquid material being 100%, the weight percentage of the first active component in the first liquid material is 10% - 95%.

10. The three-dimensional printing material according to claim 8, characterized in that, Based on the total weight of the first liquid material being 100%, the weight percentage of the second active component in the first liquid material is 5% - 90%.

11. The three-dimensional printing material according to claim 1 or 2, characterized in that, Based on the total weight of the first liquid material being 100%, the first liquid material further includes the following components by weight percentage: 0.01% - 30% of a first auxiliary agent; the first auxiliary agent includes at least one of a high-temperature initiator, a leveling agent, an antifoaming agent, a polymerization inhibitor, an antioxidant, a plasticizer, a dispersant, a pigment, and a dye.

12. The three-dimensional printing material according to claim 1 or 2, characterized in that It satisfies at least one of the following characteristics: (1) The second auxiliary agent is selected from at least one of an initiator, a promoter, and a catalyst; (2) The powder release agent is selected from at least one of a silicon-containing water-soluble release agent, a silicon-containing water-dispersible release agent, a fluorine-containing water-soluble release agent, and a fluorine-containing water-dispersible release agent; (3) The powder release agent is selected from at least one of a silicone oil emulsion, a fluorine-containing nonionic surfactant, and a fluorine-containing anionic surfactant; (4) The release agent is selected from at least one of a polyether resin, a polyester resin, a poly(meth)acrylate resin, and a polyurethane resin having a glass transition temperature lower than 40°C.

13. The three-dimensional printing material according to claim 1 or 2, characterized in that, Based on the total weight of the second liquid material being 100%, the second liquid material further includes the following components by weight percentage: 0.05% - 30% of a cosolvent.

14. The three-dimensional printing material according to claim 13, wherein, The cosolvent is selected from at least one of alcohols, alcohol ethers, amides, pyrrolidones, organic acids, and organic salts.

15. The three-dimensional printing material according to claim 1 or 2, characterized in that, The hydrocarbon chain surfactant is selected from one or more of fatty alcohol polyoxyethylene ether, sodium alkyl sulfonate, sodium alkyl benzene sulfonate, sodium alkyl sulfate, sodium alkyl sulfosuccinate, sodium amidosulfonate, polyethers, and polyoxyethylene-polyoxypropylene block copolymers.

16. A three-dimensional object, characterized in that, The three-dimensional object is printed using the three-dimensional printing material according to any one of claims 1 - 15.

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