A three-dimensional printing consumable made of continuously fiber-reinforced composite material, its preparation method, three-dimensional printing method and product

Abstract

The present invention belongs to the technical field of additive manufacturing, and particularly relates to a three-dimensional printing consumable of a continuous fiber-reinforced composite material, a preparation method thereof, a three-dimensional printing method, and a product. The present invention adopts a woven tube structure, and embeds a continuous fiber core material into the internal part of a cortical fiber woven tube in a wrapped or interwoven manner, which can improve the interfacial bonding force of the fibers and obtain a three-dimensional printing consumable with excellent mechanical properties. At the same time, by adjusting the types, proportions, weaving structures, relative positions, contents, etc. of the continuous fibers and cortical fibers, a three-dimensional printing consumable with excellent mechanical properties, thermal properties, special functional properties, and processing properties can be obtained, which can significantly improve the properties such as the strength, stiffness, and heat resistance of the printed product, and meet the manufacturing requirements of high-performance structural parts and special functional components. The present invention solves the problems of difficult continuous fiber supply and poor interfacial bonding force in the prior art, and has broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of additive manufacturing, and particularly relates to a three-dimensional printing consumable of a continuous fiber-reinforced composite material, a preparation method thereof, a three-dimensional printing method, and a product. Background Art

[0002] Three-dimensional printing technology, also known as additive manufacturing technology, can directly generate objects with complex shapes from digital models by adding materials layer by layer, greatly shortening the product development cycle and reducing the manufacturing cost, and has become one of the revolutionary technologies in the manufacturing field.

[0003] Currently, the mainstream three-dimensional printing consumables are mainly thermoplastic polymers, and the mechanical properties and heat resistance of the materials are limited, making it difficult to meet the requirements of high-performance structural parts. To improve the performance of three-dimensional printed products, researchers have begun to try to add fillers as reinforcing phases to the polymer matrix. Commonly used fillers include short fibers, glass microspheres, carbon nanotubes, etc. However, the dispersion and orientation of fillers such as short fibers in the matrix are difficult to control, and the reinforcement effect is limited, unable to significantly improve the mechanical properties of the products.

[0004] Compared with short fibers, continuous fibers have higher strength and modulus, and the mechanical properties along the fiber direction are extremely excellent. However, the surface of inorganic continuous fibers is smooth and inert, and it is difficult to form a strong interfacial bond with the polymer matrix, resulting in the inability to fully exert the performance of the composite material. There are two existing routes for the continuous fiber printing process. One is to pre-impregnate continuous fibers to form printing filaments; the other is to feed continuous fibers and polymer fibers through two separate channels during the printing process and then perform laminated composite at the printer print head. However, directly using pre-impregnated continuous fiber printing filaments is limited by the inability to attach enough polymer materials to the continuous fibers, which will cause the structural parts directly printed from them to be prone to cracking; while printing continuous fibers and polymer fibers in a two-channel form, due to the single-sided contact problem between continuous fibers and polymers, the bonding force between continuous fibers and the polymer matrix is also limited, which will affect the overall mechanical properties of the printed parts. Summary of the Invention

[0005] The purpose of the present invention is to provide a three-dimensional printing consumable of a continuous fiber-reinforced composite material, a preparation method thereof, a three-dimensional printing method, and a product. The three-dimensional printing consumable provided by the present invention improves the bonding force between continuous fibers and polymer fibers, thereby improving the mechanical properties of three-dimensional printed products, and at the same time can realize the stable supply and precise positioning of continuous fibers.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A three-dimensional printing consumable made of continuously fiber-reinforced composite material, comprising a continuous fiber core material and a cortical fiber woven tube; the continuous fiber core material is wrapped in the cavity of the cortical fiber woven tube, and / or the continuous fiber core material is interwoven in the tube wall of the cortical fiber woven tube;

[0008] The continuous fiber core material includes one or more of carbon fiber, glass fiber, basalt fiber, polymer fiber, metal fiber, ceramic fiber, and bio-based fiber;

[0009] The cortical fiber used for the cortical fiber woven tube is a polymer fiber.

[0010] Preferably, the cortical fiber includes one or more of polyamide fiber, polypropylene fiber, polyethylene fiber, polylactic acid fiber, polycaprolactone fiber, polyvinyl alcohol fiber, polyether ether ketone fiber, polyimide fiber, polyphenylene sulfide fiber, polycarbonate fiber, polyethylene terephthalate fiber, polyvinyl chloride fiber, blend polymer fiber, and modified polymer fiber;

[0011] The number of tube wall layers of the cortical fiber woven tube is ≥1 layer; the mass ratio of the continuous fiber core layer to the cortical fiber woven tube is 1~80:20~99.

[0012] Preferably, the polymer fiber used in the continuous fiber core material includes one or more of aramid fiber, poly(p-phenylene benzobisoxazole) fiber, polyethylene fiber, polyester fiber, polyimide fiber, and polyamide fiber;

[0013] The metal fiber includes one or more of copper fiber, aluminum fiber, and tungsten fiber;

[0014] The ceramic fiber includes alumina fiber and / or silicon carbide fiber;

[0015] The bio-based fiber includes bamboo fiber and / or flax fiber;

[0016] The continuous fiber core material is a fiber monofilament or a fiber bundle; the number of the continuous fiber core materials is ≥1.

[0017] Preferably, the continuous fiber core material includes functional polymer fibers; the functional polymer fibers include one or more of conductive fibers, flame-retardant fibers, antibacterial fibers, and fluorescent fibers.

[0018] Preferably, when the continuous fiber core material is wrapped in the cavity of the cortical fiber woven tube, the distribution mode of the continuous fiber core material in the cross-section of the three-dimensional printing consumable is central distribution, eccentric distribution, or multi-core distribution;

[0019] When the distribution mode is eccentric distribution, the continuous fiber-reinforced composite material three-dimensional printing consumable further includes auxiliary positioning fibers; the auxiliary positioning fibers and the continuous fiber core material are jointly wrapped in the cavity of the cortical fiber weaving tube; the positional relationship between the auxiliary positioning fibers and the continuous fiber core material is parallel arrangement or mutual winding.

[0020] The present invention also provides a preparation method of the continuous fiber-reinforced composite material three-dimensional printing consumable according to the above scheme, including the following steps:

[0021] Using cortical fibers and a continuous fiber core material as raw materials, weaving according to a preset structure to obtain the continuous fiber-reinforced composite material three-dimensional printing consumable;

[0022] Or using cortical fibers, a continuous fiber core material and auxiliary positioning fibers as raw materials, weaving according to a preset structure to obtain the continuous fiber-reinforced composite material three-dimensional printing consumable;

[0023] The weaving method is braiding or knitting.

[0024] Preferably, the number of spindles for the braiding is 4 to 200, the number of needles for the knitting is 4 to 200, the angle of the braiding or knitting is 5 to 85°, and the arrangement mode of the cortical fibers is annular or spiral.

[0025] Preferably, after the weaving is completed, it further includes subjecting the obtained consumable to sizing treatment and / or surface treatment; the sizing treatment methods include heat treatment, solvent treatment, steam fumigation treatment or ultraviolet light curing treatment;

[0026] The surface treatment method is plasma treatment or preparing a functional layer on the surface of the woven material; the functional layer includes one or more of a lubricating layer, an antioxidant layer, an antistatic layer, a flame retardant layer, a conductive layer and an antibacterial layer.

[0027] The present invention also provides a three-dimensional printing method, including the following steps: performing three-dimensional printing using the continuous fiber-reinforced composite material three-dimensional printing consumable according to the above scheme or the continuous fiber-reinforced composite material three-dimensional printing consumable prepared by the preparation method according to the above scheme.

[0028] The present invention also provides a three-dimensional printed article obtained by the three-dimensional printing method according to the above scheme.

[0029] The present invention provides a continuous fiber reinforced composite material for three-dimensional printing, comprising a continuous fiber core material and a cortex fiber woven tube; the continuous fiber core material is wrapped in the cavity of the fiber woven tube, and / or the continuous fiber core material is interwoven in the tube wall of the cortex fiber woven tube; the continuous fiber core material comprises one or more of carbon fiber, glass fiber, basalt fiber, polymer fiber, metal fiber, ceramic fiber and bio-based fiber; the cortex fiber used in the cortex fiber woven tube is polymer fiber. The beneficial effects of the present invention are as follows:

[0030] Improve interfacial bonding strength and enhance mechanical properties: The present invention applies woven tube technology to the preparation of 3D printing consumables for the first time. The present invention embeds continuous fibers into the interior of the cortex fiber woven tube in a wrapped or interwoven manner to achieve stable embedding of the continuous fibers and effective coating of the cortex fibers on the continuous fibers, thereby improving the interfacial bonding strength between the continuous fibers and the cortex fibers and enhancing the mechanical properties of the 3D printing consumables, including tensile strength, bending strength and impact toughness.

[0031] Prevent fiber breakage, achieve stable supply and precise positioning of continuous fibers: In this field, the stable supply and precise positioning of continuous fibers in the 3D printing process is a technical difficulty. When the traditional method uses continuous fibers for 3D printing, the continuous fibers are prone to breakage, entanglement, and displacement, affecting the printing quality. However, the present invention wraps the continuous fiber core material inside the cortex fiber manufacturing tube, or interweaves it in the tube wall of the cortex fiber woven tube, which has a certain displacement margin, can adapt to slight stress changes during the printing process, prevent fiber breakage, entanglement, and displacement, and improve printing quality.

[0032] Improve material compatibility and reduce internal stress: Furthermore, the present invention can optimize the thermal expansion coefficient and melting characteristics of the continuous fiber and the matrix by selecting a cortical fiber material that matches the continuous fiber, reduce internal stress during processing and use, and prevent deformation and cracking of the product.

[0033] Flexible structural design: Furthermore, the present invention is applicable to a combination of various continuous fibers and cortical fibers, and the cortical fiber woven tube can be a multi-layer structure, and the continuous fiber core layer can also be multiple. The parameters such as the number of cortical fiber woven tube layers, the number of continuous fiber core layers, the fiber type and arrangement method can be adjusted according to actual needs. It has a high degree of customization, meets the performance requirements of different application scenarios, and broadens the application range of the material.

[0034] The present invention also provides a preparation method of the continuous fiber-reinforced composite material three-dimensional printing consumable described in the above solution. The preparation method provided by the present invention has a simple process, is easy to control, is suitable for mass production, has a low cost, and helps the wide application of the continuous fiber-reinforced composite material three-dimensional printing consumable. Further, the present invention also realizes the uniform distribution and directional arrangement of fibers by precisely controlling the weaving or knitting parameters, reduces the mechanical property anisotropy, and improves the reliability and consistency of the product.

[0035] The present invention also provides a three-dimensional printing method, specifically using the continuous fiber-reinforced composite material three-dimensional printing consumable described in the above solution for three-dimensional printing. The three-dimensional printing consumable provided by the present invention has appropriate flexibility and stable dimensions, the printing process is smooth, and there is no need to frequently adjust the equipment or interrupt the printing, which improves the printing speed and efficiency and meets the requirements of industrial production; moreover, when using continuous fibers for three-dimensional printing by traditional methods, a specially designed print head, fiber supply system, and control software are required, the equipment cost is high, and the process is complex. However, in the present invention, the continuous fibers are pre-embedded in the consumable, and the printing equipment does not require an additional fiber supply system and can be directly used for existing FDM three-dimensional printers without special modification, which reduces the application threshold, equipment cost, and process complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0037] Figure 1 It is a schematic diagram of the preparation process and structure of the continuous fiber-reinforced composite material three-dimensional printing consumable with a braided tube structure provided by the present invention;

[0038] Figure 2 It is a schematic diagram of the structure of the continuous fiber-reinforced composite material three-dimensional printing consumable with a knitted tube structure provided by the present invention;

[0039] Figure 3 It is a schematic diagram of the preparation process and structure of the continuous fiber-reinforced composite material three-dimensional printing consumable with a multi-layer woven tube structure provided by the present invention, where 1 is the continuous fiber core material, 3 is the braided tube layer (which can be multiple layers), and 4 is the knitted tube layer (which can be multiple layers);

[0040] Figure 4 It is a schematic diagram of the structure of the continuous fiber-reinforced composite material three-dimensional printing consumable with an eccentric distribution of the continuous fiber core material provided by the present invention, where 1 is the continuous fiber core material, 2 is the auxiliary positioning fiber for auxiliary eccentric positioning, 3 is the braided tube layer, and 4 is the knitted tube layer;

[0041] Figure 5 Schematic diagram of the three-dimensional printing consumable structure of the continuous fiber-reinforced composite material with different weaving angles or pitches provided by the present invention. In the figure, the grid density is the pitch;

[0042] Figure 6 Schematic diagram of the heat treatment process. Among them, 5 is the heat preservation layer, 6 is the heating layer, and 7 is the die orifice. Specific implementation manners

[0043] The present invention provides a three-dimensional printing consumable of a continuous fiber-reinforced composite material, including a continuous fiber core material and a cortical fiber weaving tube; the continuous fiber core material is wrapped in the cavity of the fiber weaving tube, and / or the continuous fiber core material is interwoven in the tube wall of the cortical fiber weaving tube;

[0044] The continuous fiber core material includes one or more of carbon fiber, glass fiber, basalt fiber, polymer fiber, metal fiber, ceramic fiber, and bio-based fiber;

[0045] The cortical fiber used for the cortical fiber weaving tube is a polymer fiber.

[0046] In the present invention, unless otherwise specified, all raw material components are commercially available products well-known to those skilled in the art.

[0047] In the present invention, the cortical fiber woven tube uses cortical fibers made of polymer fibers; specifically, the cortical fibers preferably include one or more of polyamide (PA) fibers, polypropylene (PP) fibers, polyethylene (PE) fibers, polylactic acid (PLA) fibers, polycaprolactone (PCL) fibers, polyvinyl alcohol (PVA) fibers, polyetheretherketone (PEEK) fibers, polyimide (PI) fibers, polyphenylene sulfide (PPS) fibers, polycarbonate (PC) fibers, polyethylene terephthalate (PET) fibers, polyvinyl chloride (PVC) fibers, blend polymer fibers, and modified polymer fibers. The polyamide fibers are preferably polyamide 6 fibers; the blend polymer fibers are specifically fibers formed by blending at least two of polyamide, polypropylene, polyethylene, polylactic acid, polycaprolactone, polyvinyl alcohol, polyetheretherketone, polyimide, polyphenylene sulfide, polycarbonate, polyethylene terephthalate, and polyvinyl chloride; the modified polymer fibers are preferably obtained by modifying a polymer matrix with a modifier; the polymer matrix specifically includes one or more of polyamide, polypropylene, polyethylene, polylactic acid, polycaprolactone, polyvinyl alcohol, polyetheretherketone, polyimide, polyphenylene sulfide, polycarbonate, polyethylene terephthalate, and polyvinyl chloride; the modifier preferably includes one or more of inorganic fillers, short fibers, nanomaterials, magnetic particles, and antioxidants; the inorganic fillers preferably include one or more of carbon black, metal oxide powders, and mineral powders; the short fibers preferably include one or more of glass fibers, carbon fibers, and aramid fibers; the nanomaterials preferably include one or more of carbon nanotubes, graphene, and metal nanowires; there are no special requirements for the magnetic particles and antioxidants in the present invention, and those well-known to those skilled in the art can be used; in the present invention, using inorganic fillers as modifiers can enhance the mechanical properties, thermal stability, and wear resistance of the polymer matrix. Using short fibers as modifiers can enhance the tensile strength, impact resistance, and fatigue resistance of the polymer matrix. Using nanomaterials as modifiers can enhance the mechanical, wear resistance, electrical, and thermal properties of the polymer matrix. Adding magnetic particles can endow the polymer matrix with magnetic properties, and adding antioxidants can improve the anti-aging performance of the polymer matrix. In specific embodiments of the present invention, specific polymer fibers can be selected according to process requirements and performance needs. For example, using polypropylene fibers with a lower melting point (melting point 145°C) and polycaprolactone fibers (melting point about 65°C) is suitable for low-temperature processing; using polyetheretherketone (PEEK) fibers with a higher melting point (melting point 343°C) is suitable for high-temperature applications; using a combination of polylactic acid fibers (melting point 170°C) and polyamide 6 fibers (melting point 220°C) can balance the processing temperature and material properties.

[0048] In the present invention, the diameter of the cortical fibers is 10 to 300 μm. In specific embodiments, it can be 15 μm, 25 μm, 50 μm, 100 μm, or 200 μm. The number of layers of the wall of the cortical fiber woven tube is ≥1 layer, that is, the cortical fiber woven tube can be a single-layer structure or a multi-layer nested structure. Specifically, the number of layers of the wall of the cortical fiber woven tube is preferably 1 to 20 layers. In specific embodiments, it can be 2 layers, 3 layers, 5 layers, 10 layers, or 15 layers. In the present invention, when the number of layers of the wall of the cortical fiber woven tube is greater than 1 layer, the types of cortical fibers in each layer and the types of continuous fiber core materials interwoven therein can be the same or different to achieve specific performance combinations and functional requirements.

[0049] In the present invention, the mass ratio of the continuous fiber core material to the cortical fiber woven tube is 1 to 80:20 to 99. In specific embodiments, it can be 10:90, 20:80, 25:75, 30:70, 50:50, 55:45, 70:30, or 80:20.

[0050] In the present invention, the cortical fiber woven tube can specifically be a braided tube and / or a knitted tube. When the number of layers of the wall of the cortical fiber woven tube is greater than 1 layer, the present invention has no special requirements for the specific weaving form of each layer of the woven tube. The weaving methods of each layer can be the same or different. Moreover, when the continuous fiber core material is interwoven in the cortical fiber woven tube, the types of continuous fibers, cortical fibers, braiding angles, and braiding or knitting densities used in each layer can be different to achieve specific performance combinations and functional requirements. For example, in a specific embodiment of the present invention, when the number of layers of the wall of the cortical fiber manufacturing tube is 2 layers and the continuous fiber core layer is interwoven in the wall, the inner wall can be interwoven with carbon fiber bundles and PLA fibers, and the outer wall can be interwoven with glass fibers and PA fibers. The braiding angle of the inner wall can be 30°, and the braiding angle of the outer layer of fibers can be 60°. Figure 1 It is a schematic diagram of the preparation process and structure of a continuous fiber-reinforced composite three-dimensional printing consumable with a braided tube structure according to the present invention. Figure 2 It is a schematic diagram of the structure of a continuous fiber-reinforced composite three-dimensional printing consumable with a knitted tube structure according to the present invention. Figure 3 It is a schematic diagram of the preparation process and structure of a continuous fiber-reinforced composite three-dimensional printing consumable with a multi-layer woven tube structure.

[0051] In the present invention, the continuous fiber core material includes one or more of carbon fiber, glass fiber, basalt fiber, polymer fiber, metal fiber, ceramic fiber, and bio-based fiber; when the continuous fiber core material includes polymer fiber, the polymer fiber includes one or more of aramid fiber, poly(p-phenylene benzobisoxazole) fiber, polyethylene fiber, polyester fiber, polyimide fiber, and polyamide fiber; the metal fiber includes one or more of copper fiber, aluminum fiber, and tungsten fiber; the ceramic fiber includes alumina fiber and / or silicon carbide fiber; the bio-based fiber includes bamboo fiber and / or linen fiber. In a specific embodiment of the present invention, the continuous fiber core material is preferably carbon fiber, glass fiber, carbon fiber-glass fiber hybrid fiber, or basalt-aramid hybrid fiber; the weight ratio of carbon fiber to glass fiber in the carbon fiber-glass fiber hybrid fiber is 1:1; the weight ratio of basalt fiber to aramid fiber in the basalt-aramid hybrid fiber is 1:1.

[0052] In the present invention, the continuous fiber core material preferably includes functional polymer fibers; the functional polymer fibers preferably include one or more of conductive fibers, flame-retardant fibers, antibacterial fibers, and fluorescent fibers; by using functional polymer fibers in the present invention, specific functional characteristics can be imparted to the 3D printing consumables. In an embodiment of the present invention, the functional polymer fibers can be distributed in different fiber layers of the woven tube wall to achieve functional gradients. The 3D printing consumables of continuous fiber-reinforced composite materials provided by the present invention are applicable to combinations of various continuous fibers and cortical fibers, and appropriate material systems can be selected according to requirements, with a high degree of customization, broadening the application scope of the materials.

[0053] In the present invention, the continuous fiber core material is a single fiber or a fiber bundle; the diameter of the single fiber is 2 to 800 μm, and in specific embodiments, it can be 5 μm, 7 μm, 10 μm, 100 μm, 300 μm, or 500 μm; the number of single fibers in the fiber bundle is 1K to 50K, and in specific embodiments, it can be 2K, 5K, 10K, 20K, 30K, or 40K.

[0054] In the present invention, the number of the continuous fiber core materials is preferably ≥1, more preferably 1 to 100, and specifically can be 1, 2, 5, 10, 30, 50, or 80.

[0055] In the present invention, when the continuous fiber core material is wrapped in the cavity of the cortical fiber woven tube, the distribution mode of the continuous fiber core material in the cross-section of the consumable is central distribution, eccentric distribution, or multi-core distribution; in a specific embodiment of the present invention, through multi-core distribution, that is, by introducing multiple bundles of continuous fibers in the same wire by means of stranding or doubling, the performance and functional diversity of the 3D printing consumables can be further improved.

[0056] In the present invention, when the distribution mode is eccentric distribution, the three-dimensional printing consumable of the composite material further includes auxiliary positioning fibers; the auxiliary positioning fibers and the continuous fiber core material are jointly wrapped in the cavity of the cortical fiber woven tube; the positional relationship between the auxiliary positioning fibers and the continuous fiber core material is parallel arrangement or mutual winding; the material of the auxiliary positioning fibers can be selected from the material of the continuous fiber core material or the cortical fibers, which will not be elaborated here; the diameter of the auxiliary positioning fibers is 2 to 800 μm, and in specific embodiments, it can be 5 μm, 10 μm, 100 μm, 300 μm or 500 μm; the structural schematic diagram of the continuous fiber reinforced composite material three-dimensional printing consumable with eccentric distribution of the continuous fiber core material provided by the present invention is shown in Figure 4 .

[0057] In the present invention, the diameter of the continuous fiber reinforced composite material three-dimensional printing consumable is 0.1 to 10 mm, and in specific embodiments, it can be 1.75 mm or 2.85 mm

[0058] The present invention also provides a preparation method of the continuous fiber reinforced composite material three-dimensional printing consumable according to the above technical solution, including the following steps:

[0059] Using cortical fibers and a continuous fiber core material as raw materials, weaving according to a preset structure to obtain the continuous fiber reinforced composite material three-dimensional printing consumable;

[0060] Or using cortical fibers, a continuous fiber core material and auxiliary positioning fibers as raw materials, weaving according to a preset structure to obtain the continuous fiber reinforced composite material three-dimensional printing consumable;

[0061] The weaving method is braiding or knitting.

[0062] In the present invention, the number of spindles for weaving is 4 to 200, and in specific embodiments, it can be 10, 30, 50, 100, or 150; the number of needles for knitting is 4 to 200, and in specific embodiments, it can be 10, 30, 50, 100, or 150; the speed of weaving or knitting is 10 to 800 revolutions / min, and in specific embodiments, it can be 20 revolutions / min, 30 revolutions / min, 100 revolutions / min, 300 revolutions / min, or 500 revolutions / min; the angle of weaving or knitting is 5 to 85°, and in specific embodiments, it can be 10°, 30°, 50°, 60°, or 70°; the pitch of weaving is preferably 0.1 to 10 mm. In the present invention, by changing the weaving angle and weaving density, the flexibility, strength, and surface quality of the wire material can be controlled to achieve specific performance combinations and functional requirements; for example, when the weaving angles are set to 30°, 45°, and 60° respectively, a smaller weaving angle (30°) makes the fibers more parallel in the axial direction, increasing the flexibility of the material and being suitable for application scenarios that require bending; a larger weaving angle (60°) makes the fibers interweave more tightly in the radial direction, improving the strength and stability of the material and being suitable for application scenarios that require high strength. Figure 5 Schematic diagram of the structure of a three-dimensional printing consumable for continuous fiber-reinforced composite materials with different weaving angles or pitches.

[0063] In the present invention, the arrangement of the cortical fibers is circular or spiral; during weaving, the tension of the continuous fiber core material is 0.1 to 10 N, and in specific embodiments, it can be 0.5 N, 1 N, 3 N, 5 N, or 8 N; the tension of the cortical fibers is 0.1 to 10 N, and in specific embodiments, it can be 0.5 N, 1 N, 3 N, 5 N, or 8 N. When weaving or knitting, the continuous fiber core material and the cortical fibers are introduced with appropriate tension to ensure the stable supply and arrangement of the fibers; by adjusting the fiber guiding device of the weaving or knitting machine, any position distribution of the continuous fibers in the cross-section of the wire material can be achieved to meet special requirements such as functional gradient and local strengthening.

[0064] The present invention has no special requirements for the specific weaving method, and it can be woven according to the structure of the target three-dimensional printing consumable. Specifically, when the continuous fiber core material is wrapped in the cavity of the cortical fiber weaving tube, the cortical fibers are woven or knitted on the surface of the continuous fiber core material; when the continuous fiber core material is interwoven in the wall of the cortical fiber weaving tube, the cortical fibers and the continuous fiber core material are woven or knitted into a tube; when the distribution mode of the continuous fiber core material is eccentric distribution, the cortical fibers can be woven or knitted on the surfaces of the continuous fiber core material and the auxiliary positioning fibers.

[0065] In the present invention, during the weaving or knitting process, the distribution position of the continuous fiber core material is adjusted by means of core wire configurations such as single-strand, multiple-strand, and ply-strand, etc., to achieve central distribution, eccentric distribution, or multi-core distribution, meeting the requirements of functional gradient and local strengthening.

[0066] In the present invention, after the weaving is completed, it further includes subjecting the obtained consumables to sizing treatment and / or surface treatment; the following will be described in detail respectively.

[0067] In the present invention, the sizing treatment method preferably includes heat treatment, solvent treatment, steam fumigation treatment, or ultraviolet curing treatment; in the specific embodiments of the present invention, the corresponding sizing treatment method is preferably selected according to the characteristics of the polymer fiber used in the cortical fiber weaving tube.

[0068] In the present invention, the heat treatment is applicable to thermoplastic polymer fibers; the temperature of the heat treatment is preferably 50°C below the melting point of the polymer fiber to 10°C above the melting point of the polymer fiber, specifically preferably 50 - 400°C; the time of the heat treatment is 0.1 - 60 min, and in specific embodiments, it can be 10 s, 1 min, 5 min, 10 min, 30 min, or 50 min; in the present invention, when multiple different polymers are used in the cortical fibers, the heat treatment can be carried out in stages, and heat treatment is carried out in sequence according to the melting points of different polymers. In the specific embodiments of the present invention, the heat treatment preferably adopts a tubular heating furnace, the tube wall of the tubular heating furnace is sequentially an inner heating layer and an outer insulation layer from inside to outside, and a die orifice is provided at the outlet end of the tubular heating furnace; the woven material is passed through the tubular heating furnace at a uniform speed for heat treatment, and the speed of the material passing through the tubular heating furnace can be controlled according to the target heat treatment time, specifically it can be 0.1 - 10 m / min. Figure 6 Schematic diagram of the heat treatment process in the present invention.

[0069] In the specific embodiments of the present invention, in order to avoid material degradation or performance decline caused by over-treatment, it is necessary to strictly control the temperature and time of the heat treatment, specifically to select appropriate heat treatment temperature and time according to the melting point of the selected polymer fiber. For example, when the cortical fiber is PP fiber, the heat treatment temperature is preferably 180°C and the heat treatment time is preferably 5 min; when the cortical fiber is PEEK fiber, the heat treatment temperature is preferably 370°C and the heat treatment time is preferably 10 min.

[0070] In the present invention, the solvent treatment is applicable to soluble polymer fibers; the solvent for the solvent treatment is water and / or organic solvents; the organic solvents include one or more of ethanol, acetone, dichloromethane, toluene, and cyclohexanone; when the solvent is a mixed solvent of water and an organic solvent, the volume fraction of the organic solvent in the mixed solvent is preferably greater than or equal to 0.1% and less than 100%, and specifically can be 1%, 5%, 20%, 50%, 80%, or 90%; the temperature of the solvent treatment is from room temperature to 100 °C, and in specific embodiments, it can be 30 °C, 50 °C, or 80 °C; the time of the solvent treatment is 0.1 to 60 min, and in specific embodiments, it can be 1 min, 5 min, 10 min, 30 min, or 50 min. In a specific embodiment of the present invention, when the cortical fiber is a PVA fiber, pure water is preferably used for the solvent treatment, the temperature of the solvent treatment is preferably 85 °C, and the time is preferably 5 min, so as to ensure the appropriate dissolution of the PVA fiber through the above conditions.

[0071] In the present invention, the steam fumigation treatment is applicable to polymer fibers that need to be softened, such as PLA fibers; the steam used for the steam fumigation is specifically water vapor; the temperature of the steam fumigation is 50 to 300 °C, and in specific embodiments, it can be 100 °C or 200 °C; the time is 0.1 to 60 min, and in specific embodiments, it can be 1 min, 5 min, 10 min, 30 min, or 50 min.

[0072] In the present invention, the ultraviolet curing treatment is applicable to photosensitive polymer fibers; the irradiation time of the ultraviolet curing treatment is 0.1 to 60 min, and in specific embodiments, it can be 1 min, 5 min, 10 min, 30 min, or 50 min.

[0073] In the present invention, when the shaping treatment is carried out by means of heat treatment or steam fumigation treatment, it is preferably to cool the obtained material after the shaping treatment; the cooling method is air cooling, water cooling, or segmented cooling; the cooling rate can be adjusted according to the material properties to avoid internal stress and deformation; when the shaping treatment is carried out by means of solvent treatment, it is preferably to dry the obtained material after the shaping treatment, the drying temperature is 20 to 150 °C, and in specific embodiments, it can be 40 °C, 70 °C, 100 °C, or 130 °C; the drying time is 0.1 to 24 h, and in specific embodiments, it can be 1 h, 5 h, 10 h, 15 h, or 20 h; through drying, it can be ensured that the solvent is completely volatilized, and the dimensional stability of the three-dimensional printing consumables is improved.

[0074] In the present invention, through the shaping treatment, the cortical fibers are partially melted, softened or dissolved and then coated with continuous fibers to form a dense structure, thereby improving the structural stability of the three-dimensional printing consumables.

[0075] In the present invention, the surface treatment method is plasma treatment or preparing a functional layer on the surface of the obtained woven consumable; the functional coating includes one or more of a lubricating layer, an antioxidant layer, an antistatic layer, a flame retardant layer, a conductive layer, and an antibacterial layer; the method for preparing the functional layer includes spraying, dip coating, brush coating, or chemical plating. In the present invention, the surface treatment can be carried out after sizing treatment. When sizing treatment is not required, the surface treatment can also be directly carried out on the material obtained after weaving. Through the surface treatment, the present invention can improve the feeding performance, weather resistance, and functional characteristics of the three-dimensional printing consumable.

[0076] In the present invention, after obtaining the three-dimensional printing consumable, winding is further included; the winding is carried out by an automatic winder; the tension of the three-dimensional printing consumable during winding is 0.1 - 100 N. In a specific embodiment, it can be 1 N, 5 N, 10 N, 30 N, 50 N, or 80 N; the present invention uses an automatic winder to wind the prepared three-dimensional printing consumable into a spool, which is convenient for storage and application. During the winding process, the tension of the three-dimensional printing consumable should be kept stable to avoid slack or excessive stretching; the storage environment of the three-dimensional printing consumable is a dry and light-proof environment, and the temperature of the storage environment is -20 - 50 °C. In a specific embodiment, it can be 0 °C, 20 °C, or 40 °C; the relative humidity is 0% - 90%. In a specific embodiment, it can be 10%, 30%, 50%, or 70%; storing in the above environment can prevent the aging or performance degradation of the three-dimensional printing consumable.

[0077] The preparation method of the three-dimensional printing consumable provided by the present invention has the characteristics of wide material selection, flexible and controllable process, excellent performance, etc. The specific parameters of the fiber, such as diameter, tension, weight ratio, etc., all have a large adjustment range and can be selected according to actual needs; the types of continuous fibers and skin fibers are complete, and it can meet the diverse needs of different fields and application scenarios for three-dimensional printing consumables.

[0078] The present invention also provides a three-dimensional printing method, including the following steps: performing three-dimensional printing using the continuous fiber-reinforced composite material three-dimensional printing consumable described in the above solution or the continuous fiber-reinforced composite material three-dimensional printing consumable prepared by the preparation method described in the above solution.

[0079] In the present invention, the parameters of the three-dimensional printing include: the nozzle temperature is 100~400°C, and in specific embodiments, it can be 200°C or 300°C; the printing speed is 1~100 mm / s, and in specific embodiments, it can be 5 mm / s, 10 mm / s, 30 mm / s, 50 mm / s or 80 mm / s; the layer thickness is 0.1~5 mm, and in specific embodiments, it can be 0.5 mm, 1 mm, 2 mm or 3 mm. By reasonably setting the printing parameters, the present invention can achieve a stable and efficient printing process, and prepare three-dimensional printed products with excellent properties such as high strength, high stiffness, heat resistance, and corrosion resistance; in addition, by controlling the distribution and orientation of the fibers in the three-dimensional printing consumables, the directional design of the product performance can be realized to meet special requirements such as multi-axial stress, local strengthening, and functional gradient.

[0080] In specific embodiments of the present invention, it is preferred to install the three-dimensional printing consumables into the feeding system of the three-dimensional printing device, then set the printing parameters, control the feeding speed and direction of the three-dimensional printing consumables to ensure smooth feeding, so that the continuous fibers maintain stability and continuity during the printing process; according to the preset printing path and model, perform three-dimensional printing to prepare three-dimensional printed products with enhanced mechanical properties and specific functions. In specific embodiments of the present invention, the obtained three-dimensional printed products can also be subjected to annealing, surface treatment or other post-treatment processes as needed to improve the product performance.

[0081] The continuous fiber-reinforced composite three-dimensional printing consumables provided by the present invention can be widely used in the preparation of three-dimensional printed products that require high performance and lightweight, such as: in the aerospace field, high-strength and lightweight structural components can be manufactured, such as unmanned aircraft fuselages, satellite components, rocket sections, etc.; in the automotive manufacturing field, high-performance automotive parts can be produced, such as body structural parts, suspension system parts, interior parts, etc., to improve vehicle performance and fuel efficiency; in the medical device field, biodegradable and biocompatible medical supplies can be prepared, such as orthopedic implants, tissue engineering scaffolds, drug controlled release systems, etc.; in the industrial manufacturing field, high-strength and wear-resistant industrial parts can be made, such as gears, bearings, pump casings, etc., to extend the service life and reduce the maintenance cost; in the electronic device field, electronic components, sensors, antennas, etc. with conductive properties can be printed to achieve the integration of the structural and functional functions of electronic devices; in the sports equipment field, high-performance sports equipment can be manufactured, such as bicycle frames, snowboards, rackets, etc., to improve sports performance; in the construction engineering field, building components with special properties can be made, such as seismic supports, heat insulation boards, decorative materials, etc.

[0082] The present invention also provides a three-dimensional printed product obtained by the three-dimensional printing method described in the above solution.

[0083] In the present invention, the three-dimensional printed article has characteristics such as high strength, high modulus, high temperature resistance, flame retardancy, impact resistance, electrical conductivity, antibacterial property, etc., and can be used for a long time in high temperature (-50~400°C), high humidity, and highly corrosive environments with stable performance, and is applicable to fields such as aerospace, automotive manufacturing, medical devices, industrial manufacturing, electronic devices, sports equipment, construction engineering, national defense and military industries.

[0084] In the present invention, the three-dimensional printed article specifically includes one or more of aerospace equipment, automotive parts, medical devices, industrial mechanical parts, electronic components, sports equipment, building components, and military equipment.

[0085] In the present invention, the three-dimensional printed article can be subjected to subsequent processing as needed, such as machining, coating, electroplating, welding, etc., to further expand its application scope.

[0086] In order to further illustrate the present invention, the technical solutions of the present invention will be described in detail below in conjunction with embodiments, but they cannot be understood as limiting the protection scope of the present invention.

[0087] Example 1

[0088] Select 3K continuous carbon fiber as the core material. The single filament diameter of the continuous carbon fiber is 7μm, which has the characteristics of high strength and high modulus. The cortical fiber is selected as polyamide 6 (PA6) fiber with a melting point of 220°C and a fiber diameter of 230μm as the braiding material. The braiding machine is equipped with 16 braiding spindles and the braiding speed is 30 revolutions / min. The continuous carbon fiber is introduced from the center of the braiding machine, and the fiber tension is controlled at 1N to ensure the stable delivery of the fiber. The PA6 fibers are cross-braided at a braiding angle of 45° to form a tubular structure, which tightly wraps around the continuous carbon fiber. The tension of the PA6 fiber is controlled at 0.5N to obtain a continuous fiber-reinforced composite wire.

[0089] The continuous fiber-reinforced composite wire is passed through a tube furnace with a temperature set at 230°C at a speed of 2m / min for heat treatment, and the heat treatment time is 10s. This temperature is slightly higher than the melting point of PA6 to ensure that the polymer fiber surface layer melts and adheres to each other to form a dense composite structure. After leaving the furnace, it immediately enters the cooling zone and is quickly shaped by air cooling. The cooled three-dimensional printing consumable is wound onto a spool using an automatic winding machine. The winding speed is synchronized with the heat treatment speed and maintains a constant tension to avoid wire relaxation or deformation. The finally obtained three-dimensional printing consumable has a uniform surface, no obvious bubbles or defects, a uniform diameter of about 1.75mm, and the mass ratio of the continuous fiber core material to the cortical fiber weaving tube is 20:80.

[0090] The mechanical property test results show that the tensile strength of the obtained 3D printing consumables reaches 1500 MPa, and the flexural strength reaches 1200 MPa, which is significantly higher than that of pure polyamide materials.

[0091] When the 3D printing consumables are applied to a commercial FDM 3D printer, the maximum temperature of the print head can reach 280 °C. The printing parameters are set as nozzle temperature 250 °C, printing speed 2 - 50 mm / s, and layer thickness 0.2 - 3 mm. During the printing process, the wire feeding is smooth, without blockage or fiber breakage. The obtained printed products have high strength and high stiffness, and good surface quality, meeting the requirements of high-performance structural parts.

[0092] Example 2

[0093] 1K continuous glass fiber is selected as the core material, and the single filament diameter of the continuous glass fiber is 9 μm. The cortical fiber is PVA fiber soluble in water, with a diameter of 15 μm, as the weaving material. The number of knitting needles is 8, and the knitting speed is 20 revolutions per minute. The continuous glass fiber is introduced from the center of the knitting machine, and the fiber tension is controlled at 0.8 N to ensure the stable conveyance of the fiber. The PVA fibers are cross-knitted at a knitting angle of 30° to form a tubular structure, tightly covering the glass fiber. The tension of the PVA fiber is controlled at 0.4 N to obtain a continuous fiber-reinforced composite wire.

[0094] The continuous fiber-reinforced composite wire is immersed in a solvent tank of pure water at an immersion temperature of 85 °C for 5 minutes. The PVA fiber is partially dissolved in pure water, becoming viscous, tightly bonding and moderately covering the surface of the continuous glass fiber. Subsequently, the wire is taken out of the solvent and placed in a ventilated environment to allow the residual solvent to volatilize naturally. To ensure complete volatilization and shaping of the solvent, it is placed in a blast drying oven at 50 °C for 2 hours. The obtained 3D printing consumables after drying have a smooth surface and a uniform diameter of about 2 mm, and the mass ratio of the continuous fiber core material to the cortical fiber weaving tube is 25:75.

[0095] The mechanical property test results show that the tensile strength of the obtained 3D printing consumables reaches 800 MPa, and the flexural strength is 600 MPa.

[0096] The 3D printing consumables are applied to an FDM 3D printer with a nozzle diameter of 1.2 mm. The print head is suitable for water-soluble materials. The printing parameters are set as nozzle temperature 220 °C, printing speed 30 mm / s, and layer thickness 0.25 mm. The printing process is smooth, the product is well formed, and after printing, it can be washed with water to remove the residual PVA, improving the purity and performance of the product.

[0097] Example 3

[0098] The continuous fiber core material is a 12K basalt-aramid hybrid fiber bundle. The weight ratio of basalt fiber to aramid fiber is 1:1, and the diameter of each fiber monofilament is 10 μm. The cortical fiber is made of PLA fiber with a melting point of 170 °C and a fiber diameter of 25 μm. As the braiding material, the number of braiding layers is 2. The number of inner-layer braiding needles of the braiding machine is 16, the outer layer is 24, and the braiding speed is 30 revolutions / min. The basalt-aramid hybrid fiber is introduced from the center of the braiding machine, and the fiber tension is controlled at 0.6 N to ensure the stable delivery of the fiber. The inner-layer PLA fiber is braided at a braiding angle of 40° to form an inner-layer braided tube, which tightly wraps the core material. Then, outside the inner-layer braided tube, PLA fiber is used again to braid at a braiding angle of 50° to form an outer-layer braided tube, further enhancing the structural stability, and a continuously fiber-reinforced composite wire is obtained.

[0099] The continuously fiber-reinforced composite wire is placed in a steam fumigation box. The steam temperature is set at 180 °C, and the fumigation time is 10 min. Under the action of high-temperature steam, the PLA fiber softens, melts, wraps and penetrates between the continuous fibers, forming a dense composite structure. After the fumigation is completed, the wire is taken out and naturally cooled at room temperature to complete the shaping process. The finally obtained 3D printing consumable has a uniform surface, uniform color, and a diameter of about 2.5 mm. The mass ratio of the continuous fiber core material to the cortical fiber woven tube is 55:45.

[0100] The mechanical property test results show that the tensile strength of the obtained 3D printing consumable reaches 1000 MPa, and the bending strength is 800 MPa.

[0101] This 3D printing consumable is applied to a commercial FDM 3D printer. The printing parameters are set as nozzle temperature 200 °C, printing speed 35 mm / s, and layer thickness 0.6 mm. The printing process is stable, the product has high precision, high strength and heat resistance, combines the excellent properties of basalt fiber and aramid fiber, and is suitable for high-performance application fields.

[0102] Example 4

[0103] Other conditions are the same as those in Example 1, except that:

[0104] The continuous fiber core material is replaced with 12K carbon fiber (fiber monofilament diameter 7 μm, tensile strength 4900 MPa) and 24K glass fiber (fiber monofilament diameter 13 μm, tensile strength 3450 MPa). The weight ratio of carbon fiber to glass fiber is 1:1; the braiding angle of PA6 fiber is 60°. The tensile strength of the obtained 3D printing consumable is 1600 MPa, the bending strength is 1300 MPa, and the impact strength is 85 kJ / m², combining high strength and high toughness.

[0105] Example 5

[0106] Other conditions are the same as those in Example 1, except that:

[0107] The continuous fiber core material is replaced with 16K basalt fiber (fiber monofilament diameter is 11μm, tensile strength is 4800MPa) and Kevlar aramid fiber (fiber monofilament diameter is 12μm, tensile strength is 3600 MPa), and the weight ratio of basalt fiber to Kevlar aramid fiber is 1:1.

[0108] The cortical fiber is PEEK fiber, with a diameter of 50μm and a braiding angle of 45°; the heat treatment temperature is 370°C and the treatment time is 10min.

[0109] The heat distortion temperature of the obtained 3D printing consumable is 280°C, and the impact strength is 90 kJ / m 2 , showing outstanding heat resistance and high impact resistance at the same time.

[0110] Example 6

[0111] Other conditions are the same as those in Example 1, except that:

[0112] The braiding angle of the PA6 fiber is changed to 30° or 60°. The results show that when the braiding angle is 30°, the flexibility of the 3D printing consumable can be improved, which is suitable for application scenarios that require bending.

[0113] When the braiding angle is 60°, the fibers can be intertwined more tightly in the radial direction, improving the strength and stability of the 3D printing consumable, which is suitable for applications that require high strength.

[0114] Example 7

[0115] Other conditions are the same as those in Example 1, except that:

[0116] The cortical fiber is changed to PCL fiber, with a fiber diameter of 75μm, a heat treatment temperature of 60°C, and a time of 5min.

[0117] The obtained 3D printing consumable only requires a printing temperature of 70°C and can be combined with a continuous fiber core material that cannot withstand high-temperature processing for printing.

[0118] Example 8

[0119] Other conditions are the same as those in Example 2, except that:

[0120] The step of using water for sizing treatment is omitted, and the continuously fiber-reinforced composite wire obtained by braiding is used as a consumable for direct 3D printing. The results show that the obtained consumable can be directly used for printing, but the feeding stability decreases slightly, manifested as a slight decrease in the surface smoothness of the printed product compared with Example 2, and occasional material jamming occurs, but it can still fully meet the printing requirements.

[0121] Example 9

[0122] In this example, a three-dimensional printing consumable made of continuously fiber-reinforced composite material with an eccentric structure was prepared. That is, in the cross-section of the consumable, the continuous fiber core is deviated from the central position to meet specific functional requirements, such as improving the local performance of the product or realizing functional gradient.

[0123] 3K continuous carbon fiber was selected as the core material, with a single fiber diameter of 7μm, having excellent characteristics of high strength and high modulus; the polymer fiber of the cortex was selected as PA6 fiber, with a melting point of 220°C and a fiber diameter of 20μm, as the braiding material. To achieve the eccentric structure, the braiding machine for the braided tube was modified, and the core material inlet was moved from the central position to the eccentric position. Specifically, by adjusting the angle and position of the core material inlet tube, it was made to approach the edge of the braiding area, so that the continuous carbon fiber was introduced into the side position of the braided tube during the braiding process. In addition, a PA6 fiber was incorporated into the core material to assist in keeping the continuous carbon fiber in the eccentric position. The braiding machine is equipped with 16 braiding spindles, and the braiding speed is set at 30 revolutions per minute. The continuous carbon fiber is introduced from the eccentric inlet tube at a constant tension of 1N, and the PA6 fiber is cross-braided at a braiding angle of 45°, and the fiber tension is controlled at 0.5N to form a tubular structure, which tightly wraps around the carbon fiber to obtain a three-dimensional printing consumable made of continuously fiber-reinforced composite material. Due to the offset of the core material inlet position, the continuous carbon fiber is located in the edge area of the braided tube, forming an eccentric fiber-reinforced structure.

[0124] The braided material was heat-treated in a tube furnace with a temperature set at 230°C at a speed of 2m / min, and the heat treatment time was 10s. This temperature is slightly higher than the melting point of PA6 to ensure that the polymer fiber is completely melted. The molten PA6 fiber wraps and penetrates into the carbon fiber and the surrounding area to form a dense composite structure. After leaving the furnace, it immediately enters the cooling zone, and the air cooling method is adopted to quickly shape the consumable. Since the continuous carbon fiber is deviated from the central position in the cross-section of the consumable, after cooling and shaping, a three-dimensional printing consumable with asymmetric fiber distribution in the cross-section is formed.

[0125] The cooled three-dimensional printing consumable is wound onto a spool using an automatic winding machine. The winding speed is synchronized with the heat treatment speed and maintains a constant tension to avoid wire relaxation or deformation. The finally obtained three-dimensional printing consumable has a smooth surface and a uniform diameter of about 1.75mm. The mass ratio of the continuous fiber core material to the cortical fiber weaving tube is 35:65, and the characteristic of eccentric fiber distribution can be observed in the cross-section.

[0126] The mechanical property test results show that the tensile strength of the obtained eccentric three-dimensional printing consumable along the fiber-reinforced region direction reaches 1400 MPa, slightly lower than that of the three-dimensional printing consumable with continuously fiber-reinforced distributed in the center, but still significantly higher than that of the pure polyamide material; the bending property shows anisotropy, and the stiffness and strength in the fiber-reinforced region are higher.

[0127] Apply this eccentric three-dimensional printing consumable to a commercial FDM three-dimensional printer, and the maximum temperature of the print head can reach 280 °C. The printing parameters are set as nozzle temperature 250 °C, printing speed 40 mm / s, and layer thickness 0.6 mm. During the printing process, it is necessary to pay attention to the feeding direction of the wire material to ensure that the fiber-reinforced region faces the direction where the product needs to be strengthened. The three-dimensional printing consumable feeds smoothly without clogging or fiber breakage. The final printed product has higher strength and stiffness in the fiber-reinforced region and is suitable for structural parts that require local strengthening. By adjusting the printing path and the feeding direction of the consumable, the directional design of the mechanical properties of the product can be achieved. In this embodiment, through the transformation of the braiding equipment and the adjustment of the process parameters, an eccentric continuously fiber-reinforced three-dimensional printing consumable is successfully prepared. This method broadens the application scope of the present invention, provides new possibilities for the performance design and optimization of three-dimensional printed products, and has important application value.

[0128] Example 10

[0129] In this embodiment, a continuous fiber-reinforced composite three-dimensional printing consumable with a multi-layer nested structure is prepared. The inner continuous fiber core material uses a 12K carbon fiber bundle, specifically the T700S carbon fiber with a fiber monofilament diameter of 7 μm, its tensile strength is 4900 MPa, tensile modulus is 230 GPa, and elongation at break is 2.1%. The outer continuous fiber core material uses a 24K glass fiber bundle, the fiber monofilament diameter is 13 μm, the supplier is Owens Corning E-glass fiber, the tensile strength is 3450 MPa, the tensile modulus is 73 GPa, and the elongation at break is 4.7%. The inner polymer fiber selects PLA fiber, the fiber diameter is 20 μm, and the melting point is 170 °C. The outer polymer fiber selects PA6 fiber, the fiber diameter is 20 μm, and the melting point is 220 °C.

[0130] Using a multi-layer knitting machine, a 12K carbon fiber bundle is introduced into the inner core material position of the knitting machine through a fiber guiding device with a tension of 1N. Subsequently, PLA fibers are knitted at a tension of 0.5N through 16 knitting needles at a knitting angle of 30° to form a tubular structure, enabling the carbon fibers and PLA fibers to interweave and form an inner embedded structure. Then, outer layer knitting is carried out. Based on the completion of the inner layer knitting, a 24K glass fiber bundle is introduced into the outer layer knitting area through a fiber guiding device with a tension of 1N and advances synchronously with the inner layer filaments. Then, PA6 fibers are knitted at a tension of 0.5N through 24 knitting needles at a knitting angle of 60° to cover the outside of the inner layer, enabling the glass fibers and PA6 fibers to interweave and form an outer embedded structure, resulting in a composite wire.

[0131] Sizing treatment is carried out by means of a staged heat treatment method. The knitted composite wire is passed through a tubular heating furnace at a speed of 1m / min. The heating temperature in the first stage is set at 180°C (10°C above the melting point of PLA), the heating length is 1m, and the heating time is about 1min. The purpose is to melt the inner layer of PLA fibers, coat and penetrate between the carbon fibers. In the second stage, the heating temperature is raised to 230°C (10°C above the melting point of PA6), the heating length is 1m, and the heating time is about 1min. The purpose is to melt the outer layer of PA6 fibers, coat and penetrate between the glass fibers. Then, it immediately enters a segmented cooling system for cooling. The first cooling section cools from 230°C to 150°C, with a length of 1m and a cooling time of about 1min. The second cooling section cools from 150°C to room temperature, with a length of 1m and a cooling time of about 1min. The purpose of segmented cooling is to gradually reduce the temperature, reduce internal stress, and prevent the wire from deforming. To endow the 3D printing consumables with flame retardant properties, surface treatment is carried out. The cooled wire is passed through a dip coating device to coat a flame retardant coating on the wire surface. The coating material is a halogen-free flame retardant solution (the solvent is deionized water and the flame retardant concentration is 10%), and the dip coating time is 5s. Subsequently, the coated wire enters a tunnel drying oven with the temperature set at 100°C and the drying time of 30min to ensure that the solvent is completely volatilized and the coating adheres evenly.

[0132] Finally, an automatic winding machine is used to wind the processed multi-layer nested 3D printing consumables into a spool, and the winding tension is controlled at 20N. The spool is placed in a dry and light-proof storage environment at a temperature of 20°C and a relative humidity maintained below 50% to prevent material aging or performance degradation. The diameter of the prepared multi-layer nested 3D printing consumables is 2.5mm, and the weight ratio of each fiber is: carbon fiber accounts for 20%, glass fiber accounts for 30%, PLA polymer accounts for 25%, and PA6 polymer accounts for 25%.

[0133] The mechanical property test results show that the tensile strength of the obtained multi-layer nested 3D printing consumables reaches 1800 MPa, the tensile modulus is 150 GPa, the flexural strength is 1500 MPa, the flexural modulus is 120 GPa, and the impact strength is 80 kJ / m². The thermal property test shows that the heat distortion temperature (HDT) of the 3D printing consumables is 200 °C, and the glass transition temperature (T g ) is 85 °C. In terms of functional characteristics, the flame retardant performance reaches the UL94V-0 level, and the corrosion resistance is excellent. There is no obvious performance decline after soaking in acid and alkali solutions for 24 h.

[0134] In 3D printing applications, an FDM 3D printer was used. The nozzle diameter was 1.5 mm, the heating nozzle temperature was set at 240 °C, the printing bed temperature was 80 °C, the printing speed was 30 mm / s, and the layer thickness was 0.8 mm. The prepared multi-layer nested 3D printing consumables were installed in the feeding system of the printer to ensure smooth feeding of the wire. The printing parameters were set to adapt to the characteristics of the multi-layer nested 3D printing consumables, the printing model was loaded, and printing was started. Due to the high strength and high modulus of the multi-layer nested 3D printing consumables, the printing speed and nozzle temperature were adjusted during the printing process to prevent warping caused by overheating or too fast cooling of the material. After printing was completed, the product was cooled to room temperature and then taken out. The mechanical properties of the printed product are excellent, and the tensile strength can reach more than 1500 MPa, meeting the requirements of high-strength applications. In terms of thermal properties, the product maintains dimensional stability in a high-temperature environment of 150 - 200 °C and is suitable for the manufacture of high-temperature resistant components. The flame retardant performance is good, making it suitable for fields with high fire protection requirements.

[0135] As can be seen from the above embodiments, the combination method of materials and the adjustment of process parameters have an important impact on the performance of the final product. In terms of materials, the types and combinations of fibers can effectively control the strength, toughness, and heat resistance of the wire.

[0136] Although the above embodiments have described the present invention in detail, they are only a part of the embodiments of the present invention, not all embodiments. Other embodiments can be obtained based on these embodiments without creative efforts, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A three-dimensional printing consumable for continuously fiber-reinforced composite materials, characterized in that, It includes a continuous fiber core material and a cortical fiber woven tube; the continuous fiber core material is wrapped in the cavity of the cortical fiber woven tube, and / or the continuous fiber core material is interwoven in the tube wall of the cortical fiber woven tube; The continuous fiber core material includes one or more of carbon fiber, glass fiber, basalt fiber, polymer fiber, metal fiber, ceramic fiber, and bio-based fiber; The cortical fiber used for the cortical fiber woven tube is a polymer fiber; the cortical fiber woven tube is a braided tube and / or a knitted tube; the braiding or knitting angle is 5 - 85°; The number of tube wall layers of the cortical fiber woven tube is ≥1 layer; the mass ratio of the continuous fiber core material to the cortical fiber woven tube is 1 - 80:20 - 99; When the continuous fiber core material is wrapped in the cavity of the cortical fiber woven tube, the distribution mode of the continuous fiber core material in the cross-section of the 3D printing consumable is eccentric distribution, and the 3D printing consumable of the continuous fiber reinforced composite material also includes auxiliary positioning fibers; the auxiliary positioning fibers and the continuous fiber core material are jointly wrapped in the cavity of the cortical fiber woven tube, and the positional relationship between the auxiliary positioning fibers and the continuous fiber core material is parallel arrangement or mutual winding.

2. The continuous fiber-reinforced composite material three-dimensional printing consumable according to claim 1, wherein The cortical fiber includes one or more of polyamide fiber, polypropylene fiber, polyethylene fiber, polylactic acid fiber, polycaprolactone fiber, polyvinyl alcohol fiber, polyether ether ketone fiber, polyimide fiber, polyphenylene sulfide fiber, polycarbonate fiber, polyethylene terephthalate fiber, polyvinyl chloride fiber, blend polymer fiber, and modified polymer fiber.

3. The continuous fiber reinforced composite material three-dimensional printing consumable according to claim 1, characterized in that, The polymer fiber used in the continuous fiber core material includes one or more of aramid fiber, poly(p-phenylene benzobisoxazole) fiber, polyethylene fiber, polyester fiber, polyimide fiber, and polyamide fiber; The metal fiber includes one or more of copper fiber, aluminum fiber, and tungsten fiber; The ceramic fiber includes alumina fiber and / or silicon carbide fiber; The bio-based fiber includes bamboo fiber and / or flax fiber; The continuous fiber core material is a fiber monofilament or a fiber bundle; the number of the continuous fiber core material is ≥1.

4. The three-dimensional printing consumable of the continuous fiber-reinforced composite material according to claim 1, characterized in that, The continuous fiber core material includes functional polymer fibers; the functional polymer fibers include one or more of conductive fibers, flame-retardant fibers, antibacterial fibers, and fluorescent fibers.

5. The preparation method of the three-dimensional printing consumable of the continuous fiber-reinforced composite material according to any one of claims 1 to 4, characterized in that, It includes the following steps: Using the cortical fiber and the continuous fiber core material as raw materials, weaving according to a preset structure to obtain the 3D printing consumable of the continuous fiber reinforced composite material; Or using the cortical fiber, the continuous fiber core material, and the auxiliary positioning fiber as raw materials, weaving according to a preset structure to obtain the 3D printing consumable of the continuous fiber reinforced composite material; The weaving method is braiding or knitting; the braiding or knitting angle is 5 - 85°.

6. The preparation method according to claim 5, characterized in that, The number of spindles for braiding is 4 - 200, the number of needles for knitting is 4 - 200, and the arrangement mode of the cortical fiber is circular or spiral.

7. The preparation method according to claim 5, characterized in that, After the weaving is completed, it also includes performing sizing treatment and / or surface treatment on the obtained consumable; the sizing treatment methods include heat treatment, solvent treatment, steam fumigation treatment, or ultraviolet curing treatment; The surface treatment method is plasma treatment or preparing a functional layer on the surface of the woven material; the functional layer includes one or more of a lubricating layer, an antioxidant layer, an antistatic layer, a flame retardant layer, a conductive layer, and an antibacterial layer.

8. A three-dimensional printing method, characterized in that, It includes the following steps: performing three-dimensional printing using the continuous fiber-reinforced composite three-dimensional printing consumable described in any one of claims 1 to 4 or the continuous fiber-reinforced composite three-dimensional printing consumable prepared by the preparation method described in any one of claims 5 to 7.

9. A three-dimensional printed article obtained by the three-dimensional printing method according to claim 8.

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