A layered ceramic based on fused deposition modeling and a preparation method thereof

Abstract

The present invention provides a layered ceramic based on fused deposition modeling and a preparation method thereof, the preparation method comprising the following steps: S1: preparation of printing filaments; S2: modeling and printing; S3: filling: after printing is completed, the printed sample stage is sunk into the slurry, the slurry is brought into the printing layer, the slurry fills the pores of the printing layer and rises, and then the excess slurry is scraped off; S4: solidification: waiting for the slurry to solidify to complete the preparation of the first layer of layered ceramics; S5: continuous printing: continuing fused deposition modeling printing, and offsetting the printing filament from the previous layer, then repeating printing and solidification to complete the preparation of the next layer of layered ceramics until printing is completed; S6: post-processing: drying, degreasing, and sintering to obtain the layered ceramic based on fused deposition modeling. The layered ceramic based on fused deposition modeling prepared by the present invention has strong mechanical properties and high promotion and commercial value.

Description

Technical Field

[0001] The present invention relates to the field of layered ceramic preparation, and in particular to a layered ceramic based on fused deposition molding and a preparation method thereof. Background Art

[0002] Layered ceramics are a new type of composite material. By introducing a weak interface layer with lower strength and poorer interfacial bonding into a high-strength, high-hardness ceramic matrix layer, cracks are deflected and bifurcated when they propagate into this layer, significantly extending the crack propagation path and significantly improving the fracture toughness and fracture work of the ceramic. Research has found that compared to simple layered structures, a "brick-and-mud" layered structure has a longer crack propagation path and better performance: the sheet-like hard material acts as the "bricks," stacked in an interlaced manner; the soft material acts as the "mud," filling the gaps between the hard "bricks." However, due to the limitations of the stacking process, layered ceramics are difficult to form into complex structures.

[0003] Ceramic Fused Deposition Modeling (FDM) printing technology uses a composite filament of ceramic and polymer, which is heated and melted before being extruded through a nozzle and deposited onto a workpiece. This printing method is easy to implement, requires simple equipment, has low printing costs, and can print multi-material composite structures. However, FDM printing is filament-by-filament printing, and the filaments generally only partially overlap, leaving certain gaps. Since the FDM-printed material has good fluidity after heating and melting, it can be extruded. However, after extrusion, it cools and solidifies, and its fluidity decreases rapidly, making it difficult to fully fill the gaps between the filaments. Because ceramics are brittle and sensitive to defects, the gaps between the filaments in FDM-printed materials will result in poor mechanical properties of the resulting material. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing layered ceramics by fused deposition molding, so as to solve the problem that conventional fused deposition molding methods are difficult to fully fill the gaps between wires and have poor mechanical properties in preparing layered ceramics.

[0005] In order to solve the above problems, the present invention provides a method for preparing layered ceramics based on fused deposition modeling, comprising the following steps:

[0006] S1: Printing filament preparation: Select thermoplastic resin, ceramic powder and coupling agent as raw materials, and prepare ceramic / polymer composite filament by screw extrusion;

[0007] S2: Modeling and printing: Generate a target sample model and a target path, print the printing filament by fused deposition modeling, control the printing filament spacing to 0.1-0.2 mm, and press the upper surface of the printing filament into a flat surface to complete the first layer printing;

[0008] S3: Filling: After printing is completed, the printed sample stage is sunk into the slurry, the slurry is brought into the printed layer, the slurry fills the pores of the printed layer and then rises, and then the excess slurry is scraped off; the components of the slurry include slurry ceramic powder, monomer resin, initiator and dispersant;

[0009] S4: solidification: waiting for the slurry processed in step S3 to solidify, completing the preparation of the first layer of layered ceramics;

[0010] S5: Continuous printing: performing fused deposition modeling printing on the basis of the first layer of layered ceramics, and offsetting the printing filament from the previous layer, and then repeating the steps S3 and S4 to complete the preparation of the next layer of layered ceramics until printing is completed;

[0011] S6: Post-processing: Dry the product after printing in step S5, and further degrease and sinter it to obtain a layered ceramic based on fused deposition modeling.

[0012] The present invention provides a preparation method for layered ceramics based on fused deposition modeling, which fully utilizes the characteristics of fused deposition modeling printing. It uses high-strength ceramics as printing filaments, leaves gaps between the printing filaments, and in-situ fills weak interface layer materials to form layered ceramics with a "brick-mud" structure. Compared with traditional FDM printed ceramics, the material is denser and has better mechanical properties.

[0013] In the filling step S3, the slurry fully fills the pores of the printed layer and then rises. The scraper then scrapes across the sample at a height slightly higher than the current layer height (generally 0.005-0.030mm), allowing the slurry to fully fill the gaps between the printed filaments and scraping off excess slurry, thereby achieving a better filling effect.

[0014] As a preferred embodiment, in step S1, the thermoplastic resin is one or more of polylactic acid, ABS plastic, polycarbonate, nylon, polyethylene, polypropylene, ethylene vinyl acetate polymer, paraffin and stearic acid; the ceramic powder is one or more of silicon carbide, aluminum oxide, zirconium oxide, silicon nitride, boron carbide, aluminum nitride, silicon oxide, yttrium oxide and graphite powder; the coupling agent is one or more of KH550, KH560, KH570 and KH792; and the mass ratio of the thermoplastic resin, ceramic powder and coupling agent is: (1-10): (70-90): (1-3).

[0015] As a preferred solution, in step S1, the screw extrusion process includes the following steps: selecting a thermoplastic resin, a ceramic powder and a coupling agent as raw materials, drying the thermoplastic resin and the ceramic powder together, then ball-milling the ceramic powder and the coupling agent in a solution to obtain a mixed powder, dry-mixing the mixed powder with the thermoplastic resin after drying, obtaining a mixed granular material by twin-screw extrusion granulation, and melt-extruded the mixed granular material by a single screw to obtain a ceramic / polymer composite wire.

[0016] As a preferred solution, the drying conditions are: temperature 50-80°C, time 4-8 hours; the ball milling conditions are: ball milling mixing in water or alcohol; the twin-screw extrusion granulation conditions are: outlet temperature 120-200°C; the single-screw melt extrusion conditions include: heating extrusion parameters: preheating zone 125-135°C, melting zone 135-200°C, forming mold 135-200°C; the diameter of the ceramic / polymer composite wire is 1.75-2.85 mm.

[0017] As a preferred solution, in step S2, the thickness of the first layer printed is 0.1-0.6 mm, and the diameter of the print head of the fused deposition modeling printing is 150%-300% of the layer thickness.

[0018] When the thickness of the first layer is controlled to be 0.1-0.6mm and the diameter of the print head of the fused deposition modeling printing is within the parameter range of 150%-300% of the layer thickness, the deposited filament after the printing filament is extruded from the print head is squeezed into a nearly trapezoidal cross-section, which can ensure that the gap is filled with slurry in the subsequent steps. If the print head diameter is less than 150% of the layer thickness and the cross-section is circular, there will be a filling dead angle, affecting the material performance. If the print head diameter is greater than 300% of the layer thickness, the edge of the filament will have a more serious bulge, affecting the quality of the printed surface. At the same time, when the single layer thickness is within the said range, the layered structure has a better effect. If the single layer is too thick, the layered structure cannot play a toughening role. If the single layer is too thin, it is easy to produce printing defects. Therefore, in combination with the above-mentioned printing steps of the present invention, the above-mentioned printing parameters are controlled within the range, which can cooperate with other steps to further enhance the mechanical properties of the product.

[0019] As a preferred solution, in step S3, the composition of the slurry ceramic powder is consistent with that of the ceramic powder, and the particle size of the slurry ceramic powder is less than 10% of the printing wire spacing; the monomer resin is one or more of HEMA, HDDA, THFA, ACMO, DPHA, OPPEA, A-BPEF, PUA, TMPTA, PPTTA, TPGDA, and IBOA; the initiator is one or more of 907 initiator, 784 initiator, 819 initiator, TPO initiator, ITX initiator, and BDK initiator; the dispersant is one or more of KOS, TEGO, BYK, SOLSPERSE, and VOK series dispersants; the mass ratio of the slurry ceramic powder, monomer resin, initiator, and dispersant is (60-90): (10-40): (0-7): (1-9); and the ambient vacuum state must be maintained during the filling process.

[0020] The particle size of the ceramic powder is designed to be less than 10% of the spacing between the printing wires, so that the ceramic particles can smoothly fill the gaps, thereby achieving better filling effect; the environment is maintained in a vacuum state during the filling process to avoid incomplete slurry filling due to the air in the gap not being discharged in time.

[0021] As a preferred solution, in step S4, the slurry is cured by ultraviolet light or electron beam irradiation.

[0022] Since the present invention uniquely adopts fused deposition modeling printing first and then fills the printing filament spacing after the fused deposition modeling printing with slurry, ultraviolet light or electron beam irradiation is specially used to accelerate the curing of the filled slurry and printing filament, while also further improving the curing effect. On the premise of printing and filling, the overall structural strength is further strengthened.

[0023] As a preferred solution, in step S5, the offset distance is 20%-80% of the width of the printing wire.

[0024] By designing the offset of the printing filament, the printing and curing process of the present invention creates a layered ceramic with a "brick-and-mortar" structure, further enhancing the mechanical properties of the structure. Designing the offset distance to be 20%-80% of the width of the printing filament can better achieve structural stability.

[0025] As a preferred solution, in step S6, the drying conditions are: heat treatment in an oven for 1-24 hours at a temperature of 80-200°C; the degreasing conditions are: heating to 700-1000°C at a rate of 0.05-0.5°C / min and keeping warm for 1-5 hours.

[0026] The drying process can completely cure the uncured resin and improve the bonding between the layers. At the same time, the heating temperature should be lower than the extrusion temperature of the printing filament to prevent the material from collapsing.

[0027] Another technical problem to be solved by the present invention is to provide a layered ceramic based on fused deposition molding to solve the problem that traditional layered ceramic preparation methods are difficult to form complex structures.

[0028] In order to solve the above problems, the present invention provides a layered ceramic based on fused deposition modeling. The layered ceramic is prepared by the above preparation method and can realize direct forming of three-dimensional models. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic structural diagram of a layered ceramic based on fused deposition molding according to the present invention. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be described clearly and completely below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] The present invention provides a method for preparing layered ceramics based on fused deposition modeling, comprising the following steps:

[0032] S1: Printing filament preparation: Select thermoplastic resin, ceramic powder and coupling agent as raw materials, and prepare ceramic / polymer composite filament by screw extrusion;

[0033] S2: Modeling and printing: Generate a target sample model and a target path, print the printing filament by fused deposition modeling, control the printing filament spacing to 0.1-0.2 mm, and press the upper surface of the printing filament into a flat surface to complete the first layer printing;

[0034] S3: Filling: After printing is completed, the printed sample stage is sunk into the slurry, the slurry is brought into the printed layer, the slurry fills the pores of the printed layer and then rises, and then the excess slurry is scraped off; the components of the slurry include slurry ceramic powder, monomer resin, initiator and dispersant;

[0035] S4: solidification: waiting for the slurry processed in step S3 to solidify, completing the preparation of the first layer of layered ceramics;

[0036] S5: Continuous printing: performing fused deposition modeling printing on the basis of the first layer of layered ceramics, and offsetting the printing filament from the previous layer, and then repeating the steps S3 and S4 to complete the preparation of the next layer of layered ceramics until printing is completed;

[0037] S6: Post-processing: Dry the product after printing in step S5, and further degrease and sinter it to obtain a layered ceramic based on fused deposition modeling.

[0038] Preferably, in step S1, the thermoplastic resin is one or more of polylactic acid, ABS plastic, polycarbonate, nylon, polyethylene, polypropylene, ethylene vinyl acetate polymer, paraffin and stearic acid; the ceramic powder is one or more of silicon carbide, aluminum oxide, zirconium oxide, silicon nitride, boron carbide, aluminum nitride, silicon oxide, yttrium oxide and graphite powder; the coupling agent is one or more of KH550, KH560, KH570 and KH792; the mass ratio of the thermoplastic resin, ceramic powder and coupling agent is: (1-10): (70-90): (1-3).

[0039] Preferably, in step S1, the screw extrusion process includes the following steps: selecting a thermoplastic resin, a ceramic powder and a coupling agent as raw materials, drying the thermoplastic resin and the ceramic powder together, then ball-milling the ceramic powder and the coupling agent in a solution to obtain a mixed powder, dry-mixing the mixed powder with the thermoplastic resin after drying, obtaining a mixed granular material by twin-screw extrusion granulation, and melt-extruded the mixed granular material by a single screw to obtain a ceramic / polymer composite wire.

[0040] Preferably, the drying conditions are: temperature 50-80°C, time 4-8h; the ball milling conditions are: ball milling mixing in water or alcohol; the twin-screw extrusion granulation conditions are: outlet temperature 120-200°C; the single-screw melt extrusion conditions include: heating extrusion parameters: preheating zone 125-135°C, melting zone 135-200°C, forming mold 135-200°C; the diameter of the ceramic / polymer composite wire is 1.75-2.85 mm.

[0041] Preferably, in step S2, the thickness of the first layer printed is 0.1-0.6 mm, and the diameter of the print head of the fused deposition modeling printing is 150%-300% of the layer thickness.

[0042] Preferably, in step S3, the composition of the slurry ceramic powder is consistent with that of the ceramic powder, and the particle size of the slurry ceramic powder is less than 10% of the printing wire spacing; the monomer resin is one or more of HEMA, HDDA, THFA, ACMO, DPHA, OPPEA, A-BPEF, PUA, TMPTA, PPTTA, TPGDA, and IBOA; the initiator is one or more of 907 initiator, 784 initiator, 819 initiator, TPO initiator, ITX initiator, and BDK initiator; the dispersant is one or more of KOS, TEGO, BYK, SOLSPERSE, and VOK series dispersants; and the mass ratio of the slurry ceramic powder, monomer resin, initiator, and dispersant is (60-90): (10-40): (0-7): (1-9).

[0043] Preferably, in step S4, the slurry is cured by ultraviolet light or electron beam irradiation.

[0044] Preferably, in step S5, the offset distance is 20%-80% of the width of the printing wire.

[0045] Preferably, in step S6, the drying conditions are: heat treatment in an oven for 1-24 hours at a temperature of 80-200°C; the degreasing conditions are: heating to 700-1000°C at a rate of 0.05-0.5°C / min and keeping warm for 1-5 hours.

[0046] The present invention also provides a layered ceramic based on fused deposition molding, the structure diagram of the layered ceramic is as follows Figure 1 As shown, the layered ceramic is prepared by the above preparation method.

[0047] The following provides examples combining the above data ranges to further illustrate the above content: Example 1

[0048] This embodiment provides a layered ceramic based on fused deposition modeling and a preparation method thereof, the preparation method comprising the following steps:

[0049] S1: Printing filament preparation: Select thermoplastic resin, ceramic powder and coupling agent as raw materials, put the thermoplastic resin and ceramic powder into an oven for drying at a temperature of 50-80°C for 4-8 hours.

[0050] The thermoplastic resin is any one or more of polylactic acid, ABS plastic, polycarbonate, nylon, polyethylene, polypropylene, ethylene vinyl acetate polymer, paraffin wax, and stearic acid. The ceramic powder is one or more of silicon carbide, aluminum oxide, zirconium oxide, silicon nitride, boron carbide, aluminum nitride, silicon oxide, yttrium oxide, and graphite powder. The coupling agent is any one or more of KH550, KH560, KH570, and KH792. The mass ratio of the thermoplastic resin, ceramic powder, and coupling agent is 1:70:1.

[0051] The ceramic powder and the coupling agent are ball-milled in water or alcohol to mix evenly. The coupling agent accounts for 1% of the powder mass. After mixing, the powder is dried and then dry-blended with the thermoplastic resin to mix evenly. The powder is granulated by twin-screw extrusion at an outlet temperature of 120°C.

[0052] The mixed pellets are melt-extruded through a single screw to obtain ceramic / polymer composite wires with a diameter of 1.75-2.85 mm. Heating extrusion parameters: preheating zone 125°C, melting zone 135°C, forming die 135°C

[0053] S2: Modeling: Generate the target sample model, slice it using slicing software, and generate the printing path;

[0054] FDM printing: The FDM print head prints the current layer with a layer thickness of 0.1mm. The layer thickness should be smaller than the print head diameter during printing, preferably 150% of the layer thickness. The print head is squeezed to make the filament width larger than the print head filament diameter. At the same time, the top surface of the filament is pressed into a flat surface, which is convenient for subsequent scraper paving. The filament spacing should ensure a gap of 0.1mm between the filaments.

[0055] S3: Filling: After printing is completed, the sample stage sinks into the slurry, bringing the slurry into the printing layer. The slurry fully fills the pores of the printing layer and then rises. The scraper then scrapes the sample at a height slightly higher than the current layer height (0.005-0.030mm) to ensure that the slurry fully fills the gaps between the printed filaments and scrapes off excess slurry. Preferably, the printing chamber can be vacuumed to avoid incomplete slurry filling due to the air in the gap not being discharged in time.

[0056] The slurry is composed of slurry ceramic powder, monomer resin, initiator and dispersant;

[0057] The type of slurry ceramic powder is the same as that of the printing filament ceramic powder, but the particle size of the powder should be less than 10% of the gap, preferably 2%, so that the ceramic particles can fill the gap smoothly;

[0058] The monomer resin is one or more of HEMA, HDDA, THFA, ACMO, DPHA, OPPEA, A-BPEF, PUA, TMPTA, PPTTA, TPGDA, and IBOA;

[0059] The initiator is one or more of 907, 784, 819, TPO, ITX, and BDK;

[0060] The dispersant is one or more of the KOS, TEGO, BYK, SOLSPERSE, and VOK series dispersants;

[0061] The mass ratio of the slurry ceramic powder, monomer resin, initiator and dispersant is 60:10:0:1 (no initiator is added).

[0062] S4: Curing: Irradiate the printed area with ultraviolet light or electron beam to solidify the slurry;

[0063] S5: Continuous printing: The FDM print head continues to print the next layer, and the printing filament is offset from the previous layer by 20%; this process is repeated until printing is completed.

[0064] S6: Post-processing: After printing is completed, heat treatment is carried out in an oven for 1 hour at a temperature of 80°C to completely cure the uncured resin and improve the bonding between the layers. The heating temperature should be lower than the extrusion temperature of the printing filament to prevent the material from collapsing.

[0065] Degreasing: heating to 700℃ at a rate of 0.05℃ / min and keeping warm for 1h;

[0066] Sintering: Select the appropriate sintering method based on the material formula and sintering characteristics. Example 2

[0067] This embodiment provides a layered ceramic based on fused deposition modeling and a preparation method thereof, the preparation method comprising the following steps:

[0068] S1: Preparation of printing filament: Select thermoplastic resin, ceramic powder and coupling agent as raw materials, put the thermoplastic resin and ceramic powder into the oven for drying at a temperature of 80°C for 8 hours.

[0069] The thermoplastic resin is any one or more of polylactic acid, ABS plastic, polycarbonate, nylon, polyethylene, polypropylene, ethylene vinyl acetate polymer, paraffin wax, and stearic acid. The ceramic powder is one or more of silicon carbide, aluminum oxide, zirconium oxide, silicon nitride, boron carbide, aluminum nitride, silicon oxide, yttrium oxide, and graphite powder. The coupling agent is any one or more of KH550, KH560, KH570, and KH792. The mass ratio of the thermoplastic resin, ceramic powder, and coupling agent is 10:90:3.

[0070] The ceramic powder and the coupling agent are ball-milled in water or alcohol to mix evenly. The coupling agent accounts for 10% of the powder mass. After mixing, the powder is dried and then dry-blended with the thermoplastic resin to mix evenly. The powder is granulated by twin-screw extrusion at an outlet temperature of 200°C.

[0071] The mixed pellets were melt-extruded through a single screw extruder to obtain a ceramic / polymer composite wire with a diameter of 2.85 mm. Heating extrusion parameters: preheating zone 135°C, melting zone 200°C, forming die 200°C

[0072] S2: Modeling: Generate the target sample model, slice it using slicing software, and generate the printing path;

[0073] FDM printing: The FDM print head prints the current layer with a layer thickness of 1.0mm. During printing, the layer thickness should be smaller than the print head diameter, preferably 300% of the layer thickness. The print head extrusion makes the printing filament width larger than the print head filament diameter, and the upper surface of the printing filament is pressed into a flat surface, which is convenient for subsequent scraper paving. The spacing between the printing filaments should be such that the gap between the printing filaments is 0.2mm.

[0074] S3: Filling: After printing is completed, the sample stage sinks into the slurry, bringing the slurry into the printing layer. The slurry fully fills the pores of the printing layer and then rises. The scraper then scrapes the sample at a height slightly higher than the current layer height (0.005-0.030mm) to ensure that the slurry fully fills the gaps between the printed filaments and scrapes off excess slurry. Preferably, the printing chamber can be vacuumed to avoid incomplete slurry filling due to the air in the gap not being discharged in time.

[0075] The slurry is composed of slurry ceramic powder, monomer resin, initiator and dispersant;

[0076] The type of slurry ceramic powder is the same as that of the printing filament ceramic powder, but the particle size of the powder should be less than 10% of the gap, preferably 2%, so that the ceramic particles can fill the gap smoothly;

[0077] The monomer resin is one or more of HEMA, HDDA, THFA, ACMO, DPHA, OPPEA, A-BPEF, PUA, TMPTA, PPTTA, TPGDA, and IBOA;

[0078] The initiator is one or more of 907, 784, 819, TPO, ITX, and BDK;

[0079] The dispersant is one or more of the KOS, TEGO, BYK, SOLSPERSE, and VOK series dispersants;

[0080] The mass ratio of the slurry ceramic powder, monomer resin, initiator and dispersant is 90:40:7:9;

[0081] S4: Curing: Irradiate the printed area with ultraviolet light or electron beam to solidify the slurry;

[0082] S5: Continuous printing: The FDM print head continues to print the next layer, and the printing filament is offset from the previous layer by 80%, and this process is repeated until the printing is completed.

[0083] S6: Post-processing: After printing is completed, heat treatment is carried out in an oven for 24 hours at a temperature of 200°C to completely cure the uncured resin and improve the bonding between the layers. The heating temperature should be lower than the extrusion temperature of the printing filament to prevent the material from collapsing.

[0084] Degreasing: heating to 1000℃ at a rate of 0.5℃ / min and keeping warm for 1-5h;

[0085] Sintering: Select the appropriate sintering method based on the material formula and sintering characteristics. Example 3

[0086] This embodiment provides a layered ceramic based on fused deposition modeling and a preparation method thereof, the preparation method comprising the following steps:

[0087] S1: Preparation of printing filament: Select thermoplastic resin, ceramic powder and coupling agent as raw materials, put the thermoplastic resin and ceramic powder into the oven for drying at a temperature of 65°C for 6 hours.

[0088] The thermoplastic resin is any one or more of polylactic acid, ABS plastic, polycarbonate, nylon, polyethylene, polypropylene, ethylene vinyl acetate polymer, paraffin wax, and stearic acid. The ceramic powder is one or more of silicon carbide, aluminum oxide, zirconium oxide, silicon nitride, boron carbide, aluminum nitride, silicon oxide, yttrium oxide, and graphite powder. The coupling agent is any one or more of KH550, KH560, KH570, and KH792. The mass ratio of the thermoplastic resin, ceramic powder, and coupling agent is 5.5:80:2.

[0089] The ceramic powder and the coupling agent are ball-milled in water or alcohol to mix evenly. The coupling agent accounts for 5% of the powder mass. After mixing, the powder is dried and then dry-blended with the thermoplastic resin to mix evenly. The powder is granulated by twin-screw extrusion at an outlet temperature of 160°C.

[0090] The mixed pellets are melt-extruded through a single screw extruder to obtain ceramic / polymer composite wires with a diameter of 1.75-2.85 mm. Heating extrusion parameters: preheating zone 130°C, melting zone 165°C, forming die 165°C

[0091] S2: Modeling: Generate the target sample model, slice it using slicing software, and generate the printing path;

[0092] FDM printing: The FDM print head prints the current layer with a layer thickness of 0.3mm. During printing, the layer thickness should be smaller than the print head diameter, preferably 200% of the layer thickness. The print head extrusion makes the printing filament width larger than the print head filament diameter, and the top surface of the printing filament is pressed into a flat surface, which is convenient for subsequent scraper paving. The spacing between the printing filaments should be such that the gap between the printing filaments is 0.15mm.

[0093] S3: Filling: After printing is completed, the sample stage sinks into the slurry, bringing the slurry into the printing layer. The slurry fully fills the pores of the printing layer and then rises. The scraper then scrapes the sample at a height slightly higher than the current layer height (0.005-0.030mm) to ensure that the slurry fully fills the gaps between the printed filaments and scrapes off excess slurry. Preferably, the printing chamber can be vacuumed to avoid incomplete slurry filling due to the air in the gap not being discharged in time.

[0094] The slurry is composed of slurry ceramic powder, monomer resin, initiator and dispersant;

[0095] The type of slurry ceramic powder is the same as that of the printing filament ceramic powder, but the particle size of the powder should be less than 10% of the gap, preferably 2%, so that the ceramic particles can fill the gap smoothly;

[0096] The monomer resin is one or more of HEMA, HDDA, THFA, ACMO, DPHA, OPPEA, A-BPEF, PUA, TMPTA, PPTTA, TPGDA, and IBOA;

[0097] The initiator is one or more of 907, 784, 819, TPO, ITX, and BDK;

[0098] The dispersant is one or more of the KOS, TEGO, BYK, SOLSPERSE, and VOK series dispersants;

[0099] The mass ratio of the slurry ceramic powder, monomer resin, initiator and dispersant is 75:25:3.5:5;

[0100] S4: Curing: Irradiate the printed area with ultraviolet light or electron beam to solidify the slurry;

[0101] S5: Continuous printing: The FDM print head continues to print the next layer, and offsets the printing filament from the previous layer to align the center of the printing filament with the gap printed in the previous layer (offset 45-55%). This process is repeated until printing is completed.

[0102] S6: Post-processing: After printing is completed, heat treatment is carried out in an oven for 12 hours at a temperature of 140°C to completely cure the uncured resin and improve the bonding between the layers. The heating temperature should be lower than the extrusion temperature of the printing filament to prevent the material from collapsing.

[0103] Degreasing: heating to 850℃ at a rate of 0.25℃ / min and keeping warm for 3h;

[0104] Sintering: Select the appropriate sintering method based on the material formula and sintering characteristics.

[0105] The following provides a set of more specific embodiments based on actual data, operation methods, and experimental tests to further expand on the above embodiments: Example 4

[0106] This embodiment provides a layered ceramic based on fused deposition modeling and a preparation method thereof, the preparation method comprising the following steps:

[0107] S1: Printing filament preparation

[0108] The ceramic powder is composed of silicon carbide (particle size 0.4um), boron carbide (particle size 1um), and graphite powder (particle size 2um) in a mass ratio of 10:0.5:1; the thermoplastic resin is polylactic acid; the coupling agent is KH550

[0109] The mass ratio of the thermoplastic resin, ceramic powder and coupling agent is 5:80:2;

[0110] The ceramic powder and coupling agent are ball-milled in water and dried, then dry-blended with a thermoplastic resin and pelletized using a twin-screw extruder. Heating and extrusion parameters: preheating zone 125-135°C, melting zone 135-200°C, and forming die 135-200°C.

[0111] S2: Modeling: Generate the target sample model, slice it using slicing software, and generate the printing path;

[0112] FDM printing: The FDM print head prints the current layer with a print head diameter of 0.6mm and a layer thickness of 0.2mm; the gap between the printing filaments is controlled to 0.15mm;

[0113] S3: Filling: After printing is completed, the sample stage sinks into the slurry, bringing the slurry into the printing layer, holds it for 10 seconds and then rises. The scraper then scrapes across the sample at a height slightly higher than the current layer height by 0.01mm, allowing the slurry to fully fill the gaps between the printed filaments and scraping off excess slurry.

[0114] The ceramic powder is composed of silicon carbide (particle size 0.4 μm), boron carbide (particle size 1 μm), and graphite powder (particle size 2 μm) in a mass ratio of 2:0.1:9;

[0115] The light-curing resin is composed of HDDA and TMPTA in a mass ratio of 8:2.

[0116] The dispersant is BYK-111;

[0117] 71 parts of ceramic powder, 28 parts of light-curing resin, and 1 part of dispersant were mixed in a homogenizer and then mixed with a three-roll mill to obtain a base layer and interface layer slurry;

[0118] S4: Curing: electron beam curing, accelerating voltage is 200kV; exposure dose is 80kGy;

[0119] S5: Continuous printing: The FDM print head continues to print the next layer, and the printing filament is offset from the previous layer by 50%;

[0120] Repeat printing, filling, and curing, and select the base layer or interface layer slurry to print the next layer until the sample printing is completed;

[0121] S6: Post-treatment: heating to 800°C at a rate of 0.1°C / min and keeping at that temperature for 2 hours;

[0122] The layered ceramic product was obtained by hot pressing and sintering at 1900°C and 30 MPa pressure in a vacuum atmosphere for 1 hour.

[0123] The layered ceramic product prepared in Test Example 4 has a strength of 450-500 MPa and a fracture toughness of 4.5-5.5 MPa∙m 1 / 2 In comparison, the layered ceramic product obtained by FDM printing and hot pressing sintering using the same powder has a strength of only 250-300 MPa and a fracture toughness of 3.0-3.5 MPa∙m 1 / 2 By comparison with the prior art, it is proved that the structural strength and fracture toughness of the layered ceramic product prepared by the present invention are superior.

[0124] The above embodiments further demonstrate that the layered ceramics prepared by the fused deposition modeling method of the present invention have higher product strength and fracture toughness, solving the problem that the conventional fused deposition modeling method is difficult to fully fill the gaps between wires and has poor mechanical properties when preparing layered ceramics.

[0125] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A method for preparing layered ceramics based on fused deposition modeling, characterized in that: The following steps are involved: S1: Printing filament preparation: Select thermoplastic resin, ceramic powder and coupling agent as raw materials, and prepare ceramic / polymer composite filament by screw extrusion; S2: Modeling and printing: Generate a target sample model and a target path, print the printing filament by fused deposition modeling, control the printing filament spacing to 0.1-0.2 mm, and press the upper surface of the printing filament into a flat surface to complete the first layer printing; S3: Filling: After printing is completed, the printed sample stage is sunk into the slurry, the slurry is brought into the printed layer, the slurry fills the pores of the printed layer and then rises, and then the excess slurry is scraped off; the components of the slurry include slurry ceramic powder, monomer resin, initiator and dispersant; S4: solidification: waiting for the slurry processed in step S3 to solidify, completing the preparation of the first layer of layered ceramics; S5: Continuous printing: performing fused deposition modeling printing on the basis of the first layer of layered ceramics, and offsetting the printing filament from the previous layer, and then repeating the steps S3 and S4 to complete the preparation of the next layer of layered ceramics until printing is completed; S6: Post-processing: Dry the product after printing in step S5, and further degrease and sinter it to obtain a layered ceramic based on fused deposition modeling.

2. The method for preparing a layered ceramic by fused deposition modeling according to claim 1, wherein: In step S1, the thermoplastic resin is one or more of polylactic acid, ABS plastic, polycarbonate, nylon, polyethylene, polypropylene, and ethylene vinyl acetate polymer; the ceramic powder is one or more of silicon carbide, aluminum oxide, zirconium oxide, silicon nitride, boron carbide, aluminum nitride, silicon oxide, and yttrium oxide; the coupling agent is one or more of KH550, KH560, KH570, and KH792; and the mass ratio of the thermoplastic resin, ceramic powder, and coupling agent is: (1-10): (70-90): (1-3).

3. The method for preparing layered ceramics based on fused deposition modeling according to claim 1, characterized in that: In step S1, the screw extrusion process includes the following steps: selecting a thermoplastic resin, a ceramic powder and a coupling agent as raw materials, drying the thermoplastic resin and the ceramic powder together, then ball-milling the ceramic powder and the coupling agent in a solution to obtain a mixed powder, dry-mixing the mixed powder with the thermoplastic resin after drying, obtaining a mixed granular material by twin-screw extrusion granulation, and melt-extruded the mixed granular material by a single screw to obtain a ceramic / polymer composite wire.

4. The method for preparing layered ceramics based on fused deposition modeling according to claim 3, characterized in that: The drying conditions are: temperature 50-80°C, time 4-8 hours; the ball milling conditions are: ball milling mixing in water or alcohol; the twin-screw extrusion granulation conditions are: outlet temperature 120-200°C; the single-screw melt extrusion conditions include: heating extrusion parameters: preheating zone 125-135°C, melting zone 135-200°C, forming mold 135-200°C; the diameter of the ceramic / polymer composite wire is 1.75-2.85 mm.

5. The method for preparing layered ceramics based on fused deposition modeling according to claim 3, characterized in that: In step S2, the thickness of the first layer printed is 0.1-0.6 mm, and the diameter of the print head of the fused deposition modeling printing is 150%-300% of the layer thickness.

6. The method for preparing layered ceramics based on fused deposition modeling according to claim 1, characterized in that: In step S3, the composition of the slurry ceramic powder is consistent with that of the ceramic powder, and the particle size of the slurry ceramic powder is less than 10% of the printing wire spacing; the monomer resin is one or more of HEMA, HDDA, THFA, ACMO, DPHA, OPPEA, A-BPEF, TMPTA, PPTTA, TPGDA, and IBOA; the initiator is one or more of 907 initiator, 784 initiator, 819 initiator, TPO initiator, ITX initiator, and BDK initiator; the dispersant is one or more of KOS, TEGO, BYK, SOLSPERSE, and VOK series dispersants; the mass ratio of the slurry ceramic powder, monomer resin, initiator, and dispersant is (60-90): (10-40): (0-7): (1-9); and the environment needs to be maintained in a vacuum state during the filling process.

7. The method for preparing layered ceramics based on fused deposition modeling according to claim 1, characterized in that: In the step S4, the slurry is cured by ultraviolet light or electron beam irradiation.

8. The method for preparing layered ceramics based on fused deposition modeling according to claim 1, characterized in that: In step S5, the offset distance is 20%-80% of the width of the printing wire.

9. The method for preparing layered ceramics based on fused deposition modeling according to claim 1, characterized in that: In step S6, the drying conditions are: heat treatment in an oven for 1-24 hours at a temperature of 80-200°C; the degreasing conditions are: heating to 700-1000°C at a rate of 0.05-0.5°C / min and keeping warm for 1-5 hours.

10. A layered ceramic based on fused deposition modeling, characterized in that: The layered ceramic is prepared by the preparation method according to any one of claims 1 to 9.

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