Composite material 3D printing equipment and method based on multi-material functional structure

Abstract

A composite material 3D printing device and method based on a multi-material functional structure comprises a broadened yarn presoaking module, a coding electrostatic spraying module and a 3D printing module, an ultra-broadened presoaked printing tow is obtained in a vibration yarn spreading mode, localized distribution of functional filler on continuous fibers is achieved through coding electrostatic spraying, and the 3D printing module is used for conducting 3D printing. And finally, a continuous fiber / functional filler mixed multifunctional composite material structure is formed in a layer-by-layer printing mode, the problem that a functional structure in a multi-material composite material is difficult to distribute in a localized mode can be solved, and then a key technology and equipment are provided for manufacturing of a structure-function integrated composite material.

Description

Technical Field

[0001] The present invention relates to the technical field of fiber-reinforced thermosetting composite material additive manufacturing, and in particular to a composite material 3D printing device and method based on a multi-material functional structure. Background Art

[0002] The existing aerospace equipment has continuously improved its requirements for structural performance due to changes in the service environment. Traditional composite materials have problems such as simple structure and single form, which make it difficult to meet the needs of composite or multifunctional applications. The development of advanced composite materials with integrated structure / function, while ensuring the lightweight and high-strength mechanical properties of composite materials, has attracted widespread attention from the scientific and industrial communities. Nanofillers represented by carbon nanotubes, graphene, and MXENE have extremely broad application prospects in the fields of mechanical enhancement, electrothermal transmission, and electromagnetic shielding due to their unique nanoscale, excellent mechanical properties, and outstanding electrothermal transmission characteristics. Multi-material functional structures aim to meet specific functional application requirements by rationally combining and distributing nano-functional fillers in the composite structure. For example, in terms of heat insulation, a multi-material functional material structure with thermal gradient as the design goal can make the aircraft surface composite material have a gradually changing thermal conductivity under high temperature environment, thereby effectively dispersing and diffusing heat and slowing down the heating rate of the material; in terms of electromagnetic absorption, the rational combination of conductive nanofillers and magnetic fillers (such as ferrites, magnetic nanoparticles) with broadband and high-efficiency electromagnetic absorption effects as the design goal can construct a multifunctional absorbing system with conductivity loss, dielectric loss and magnetic loss, which can optimize the reflection, absorption and attenuation process of electromagnetic waves.

[0003] Traditional additive manufacturing technology mainly focuses on the molding of printed parts combining multiple composite materials, such as the patent application entitled: A multi-degree-of-freedom, multi-material 3D printing device and printing method (publication number CN117301506A). Although these methods have certain advantages in meeting lightweight and specific performance requirements, they have obvious shortcomings in the manufacture of multifunctional composite materials and cannot take into account multiple functional requirements at the same time. For example, it is difficult to achieve the optimal design in the trade-off between mechanical properties, electrothermal characteristics and environmental adaptability, and they can no longer meet the application requirements of composite or multiple functions. Summary of the invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a composite material 3D printing device and method based on a multi-material functional structure, which can achieve precise forming of controllable distribution of multiple materials and meet the effective manufacturing requirements of structural-functional integrated composite materials.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A composite material 3D printing device based on a multi-material functional structure includes a wide-spread yarn prepreg module I, a coded electrostatic spraying module II, and a 3D printing module III. The fiber bundle passes through the wide-spread yarn prepreg module I to achieve wide-spread yarn prepreg, and after the wide-spread yarn prepreg, it enters the coded electrostatic spraying module II for selective spraying. The coded sprayed prepreg tow then passes through the 3D printing module III for cooling, shaping, and printing.

[0007] The wide-spread yarn prepreg module I includes a yarn unwinding device I-1, a vibrating yarn unwinding device I-2 and an impregnation device I-3, wherein the yarn unwinding device I-1 leads the fiber bundle into the vibrating yarn unwinding device I-2, and the fiber bundle widened by the vibrating yarn unwinding device I-2 enters the impregnation device I-3 to achieve wide-spread yarn prepreg.

[0008] The vibration roller of the vibration yarn-unrolling device Ⅰ-2 has a vibration frequency of 10-20 Hz and a vibration amplitude of 6-20 mm.

[0009] The resin tank in the impregnation device I-3 is heated to a temperature of 90-120°C. After heating, the fiber bundle passes through the gap between the rubber roller and the metal roller. By controlling the gap between the two, the fiber content of the prepreg bundle is controlled.

[0010] The coded electrostatic spraying module II includes an electrostatic spraying controller II-1, a powder pump II-2, a powder barrel II-3, an electrostatic spray gun II-4, a high-voltage power supply II-5, and a heating and converging mechanism II-6. The feed port of the powder pump II-2 sucks powder from the powder barrel II-3, the powder pump II-2 is connected to the electrostatic spraying controller II-1, the discharge port of the powder pump II-2 is connected to the electrostatic spray gun II-4, the electrostatic spray gun II-4 is connected to the high-voltage power supply II-5, and the coded prepreg wire sprayed with powder by the electrostatic spray gun II-4 enters the heating and converging mechanism II-6.

[0011] The electrostatic spray controller II-1 uses a PID algorithm to adjust the output volume, and adjusts the output flow of the conveying gas and the atomizing gas by controlling the stepper motor flow valve. The output conveying gas controls the output powder volume of the powder pump II-2, and then combines with the atomizer to provide an airflow with powder particles for the electrostatic spray gun II-4 in the spraying area.

[0012] The spraying distance is measured by the distance measuring sensor and the signal is transmitted to the electrostatic spray controller Ⅱ-1, which is compared with the set code. The output signal drives the stepper motor to control the position of the electrostatic spray gun Ⅱ-4. The spraying distance is 5-20mm. The high-voltage power supply Ⅱ-5 applies a voltage of 20-30kV and a current of 10-15μA to the electrostatic spray gun Ⅱ-4.

[0013] The heating and converging mechanism II-6 includes a heating device and a converging nozzle connected to the heating device. The coded prepreg yarn is formed into a stable cylindrical shape through the converging nozzle. The power of the heating device is 30-200W, and the heating temperature is 90-180°C.

[0014] The 3D printing module III includes a tension mechanism III-1, a printing extrusion mechanism III-2, and a heating mechanism III-3. The printing filament bundle enters the printing extrusion mechanism III-2 after the tension is adjusted by the tension mechanism III-1. The printing extrusion mechanism III-2 is connected to the heating mechanism III-3.

[0015] The tension mechanism III-1 is composed of a tensioning wheel, a tension sensor, a PLC processor, and a PID control module. When the fiber is stretched, the tension sensor transmits the detected tension signal to the PLC processor. The PLC processor compares the tension signal with the tension setting value and uses the PID control module to calculate. The output signal drives the tensioning wheel to rotate forward and reverse to adjust the tension. The tension setting value is 2-10N.

[0016] The heating power of the heating mechanism III-2 is 30-200W, which can achieve temperature control of 30-300°C. Different printing temperatures are set according to the different resins of the printing filament bundles.

[0017] The printing method using the composite material 3D printing device based on the multi-material functional structure comprises the following steps:

[0018] Step 1, wide spread yarn pre-impregnation: the fiber bundle is first drawn out from the yarn unwinding device Ⅰ-1, and then enters the vibration yarn unwinding device Ⅰ-2 for widening treatment. After being treated by the vibration yarn unwinding device Ⅰ-2, the widened yarn bundle continues to enter the impregnation device Ⅰ-3 to complete the wide spread yarn pre-impregnation process, and obtains a super-widened pre-impregnated yarn bundle with uniform resin distribution for subsequent spraying;

[0019] Step 2, coded electrostatic spraying: the prepreg tow is processed by the electrostatic spraying module II, and the electrostatic spraying controller II-1 generates the corresponding encoder control code according to the structural distribution of the functional filler in the prepreg tow; the powder pump II-2 extracts the required material from the powder cylinder II-3, and uses the electrostatic spray gun II-4 in cooperation with the high-voltage power supply II-5 to accurately and selectively spray the widened prepreg tow. During the spraying process, the fiber tow is sprayed in an alternating manner up and down; after the spraying is completed, the fiber tow is bundled by the heating and bundling mechanism II-6 to form a circular printing tow;

[0020] Step 3, 3D printing: The printed filaments enter the 3D printing module III, are melted and extruded, and then cooled and shaped, and finally the composite material additive manufacturing of multi-material functional structures is completed according to the printing instructions;

[0021] Step 4: Heat treatment: Heat treatment is performed on the printed structure to ensure that the structure is completely cured or releases thermal stress, ensuring further improvement of the performance of the printed composite material.

[0022] In step 1, the resin is a thermoplastic composite 3D printing resin matrix, including polyetherimide (PEI), polyethersulfone (PES), polyetherketone (PEK), polyetheretherketone (PEEK), polysulfone (PSF), or a thermosetting composite 3D printing resin matrix, including epoxy resin, cyanate resin, phenolic resin, bismaleimide resin.

[0023] The fiber used in step 1 is a mixture of one or more polymer continuous fibers selected from carbon fiber, glass fiber, aramid fiber, basalt fiber, and polyimide fiber.

[0024] In step 2, the functional filler includes one or a mixture of carbon nanotubes, graphene, MXENE, ferrite, and magnetic nanoparticles.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: through the coded electrostatic spraying technology, the functional filler can be implanted as a "gene" into the 3D printing tow, and the distribution of the functional filler in the composite material can be quantitatively controlled by the coded controller. This precise control is difficult to achieve with traditional technology; the vibration yarn spreading technology obtains a prepreg tow with ultra-widened and uniform resin distribution, combined with the symmetrically distributed spray heads for up and down spraying, to ensure the uniform distribution of the functional filler on the 3D printing tow, thereby improving the overall performance of the composite material; multiple spray heads distributed laterally can spray at the same time, significantly improving production efficiency, especially in large-scale production, greatly reducing manufacturing time; by configuring different spray heads to spray different functional fillers, multiple functions can be integrated into the same composite structure, such as realizing conductivity, heat insulation, reinforcement and other functions at the same time, which is difficult to achieve with traditional single-function composite materials.

[0026] The device and method of the present invention can realize the integrated manufacturing of composite material structure and function based on multi-material mixing, so as to meet the application requirements of composite or multi-functional applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is an overall schematic diagram of the printing device of the present invention.

[0028] Figure 2 It is a schematic diagram of the widened prepreg module of the printing device of the present invention.

[0029] Figure 3 It is a schematic diagram of the coded electrostatic spraying module of the printing device of the present invention.

[0030] Figure 4 This is a schematic diagram of a 3D printing module of the printing device of the present invention.

[0031] Figure 5 This is a microscopic effect diagram of the graphene-reinforced glass fiber / epoxy resin composite honeycomb and the graphene incorporated between the filament bundles according to Example 1 of the present invention.

[0032] Figure 6 This is a schematic diagram of the square honeycomb sandwich structure of the composite material of Example 2 of the present invention. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with embodiments and drawings.

[0034] Example 1, reference Figure 1 A composite material 3D printing device based on a multi-material functional structure includes a wide-spread yarn prepreg module I, a coded electrostatic spraying module II, and a 3D printing module III. The fiber bundle passes through the wide-spread yarn prepreg module I to achieve wide-spread yarn prepreg, and after the wide-spread yarn prepreg, it enters the coded electrostatic spraying module II for selective spraying. The coded sprayed prepreg tow then passes through the 3D printing module III for cooling, shaping, and printing.

[0035] Reference Figure 2 The wide-spread yarn prepreg module I includes a yarn unwinding device I-1, a vibrating yarn unwinding device I-2 and an impregnation device I-3, wherein the yarn unwinding device I-1 leads the fiber bundle into the vibrating yarn unwinding device I-2, and the fiber bundle widened by the vibrating yarn unwinding device I-2 enters the impregnation device I-3 to realize wide-spread yarn prepreg; the vibration roller of the vibrating yarn unwinding device I-2 has a vibration frequency of 10-20Hz and a vibration amplitude of 6-20mm; the heating temperature of the resin tank in the impregnation device I-3 is 90-120℃, and the fiber bundle after heating passes through the gap between the rubber roller and the metal roller, and the fiber content of the prepreg bundle is controlled by controlling the gap between the two.

[0036] Reference Figure 3The coded electrostatic spraying module II includes an electrostatic spraying controller II-1, a powder pump II-2, a powder barrel II-3, an electrostatic spray gun II-4, a high-voltage power supply II-5, and a heating and converging mechanism II-6. The powder pump II-2 inlet inhales powder from the powder barrel II-3, the powder pump II-2 is connected to the electrostatic spraying controller II-1, the powder pump II-2 outlet is connected to the electrostatic spray gun II-4, the electrostatic spray gun II-4 is connected to the high-voltage power supply II-5, and the coded prepreg wire sprayed with powder by the electrostatic spray gun II-4 enters the heating and converging mechanism II-6; the electrostatic spraying controller II-1 uses a PID algorithm to adjust the output, and adjusts the output flow of the conveying gas and the atomizing gas by controlling the stepper motor flow valve, and the output conveying gas controls the powder pump II-2. Output powder amount, and then combine with atomizer to provide airflow with powder particles for electrostatic spray gun Ⅱ-4 in the spraying area; the spraying distance is measured by the distance measuring sensor and the signal is transmitted to the electrostatic spray controller Ⅱ-1, which is compared with the set code. The output signal drives the stepper motor to control the position of the electrostatic spray gun Ⅱ-4. The spraying distance is 5-20mm. The high-voltage power supply Ⅱ-5 applies a voltage of 20-30kV and a current of 10-15μA to the electrostatic spray gun Ⅱ-4; the heating and focusing mechanism Ⅱ-6 includes a heating device and a focusing nozzle connected to the heating device. The coded prepreg is molded into a stable cylindrical shape through the focusing nozzle. The power of the heating device is 30-200W and the heating temperature is 90-180℃.

[0037] Reference Figure 4 The 3D printing module III includes a tension mechanism III-1, a printing extrusion mechanism III-2, and a heating mechanism III-3. The fiber enters the printing extrusion mechanism III-2 after the tension is adjusted by the tension mechanism III-1. The printing extrusion mechanism III-2 is connected to the heating mechanism III-3; the tension mechanism III-1 is composed of a tensioning wheel, a tension sensor, a PLC processor, and a PID control module. When the fiber is tightened, the tension sensor transmits the detected tension signal to the PLC processor. The PLC processor compares the tension signal with the tension setting value and uses the PID control module to calculate. The output signal drives the tensioning wheel to adjust the tension in forward and reverse directions. The tension setting value is 2-10N; the heating power of the heating mechanism III-2 is 30-200W, which realizes the temperature control of 30-300℃. Different printing temperatures are set according to the different resins of the prepreg tow.

[0038] The method of printing a composite material 3D printing device based on a multi-material functional structure is used to prepare a graphene-reinforced glass fiber / epoxy resin composite honeycomb, comprising the following steps:

[0039] Step 1: Wide-spread yarn pre-impregnation: The fiber bundle is first drawn out from the yarn unwinding device Ⅰ-1, and then enters the vibration yarn unwinding device Ⅰ-2 for widening treatment. After being treated by the vibration yarn unwinding device Ⅰ-2, the widened yarn bundle continues to enter the impregnation device Ⅰ-3 to complete the wide-spread yarn pre-impregnation process, achieving a high-efficiency resin impregnation effect while achieving wide-spread yarn, thereby obtaining a pre-impregnated yarn bundle with ultra-widening and uniform resin distribution for subsequent spraying;

[0040] The vibration roller of the vibration yarn spreading device Ⅰ-2 has a vibration frequency of 12 Hz and a vibration amplitude of 10 mm;

[0041] The resin tank in the impregnation device I-3 is heated to 115°C. After heating, the fiber tow passes through the gap between the rubber roller and the metal roller. By controlling the gap between the two, the fiber mass content of the prepreg tow is controlled to be 45%;

[0042] Step 2, coded electrostatic spraying: the prepreg tow is processed by the electrostatic spraying module II, and the electrostatic spraying controller II-1 generates the corresponding encoder control code according to the structural distribution of the mixed multi-materials in the prepreg tow; the powder pump II-2 extracts the required material from the powder cylinder II-3, and uses the electrostatic spray gun II-4 in cooperation with the high-voltage power supply II-5 to accurately and selectively spray the widened prepreg tow. During the spraying process, the fiber tow is sprayed in an alternating manner up and down; after the spraying is completed, the fiber tow is bundled by the heating and bundling mechanism II-6 to form a circular printing tow;

[0043] The spraying distance of the electrostatic spray gun II-4 is 10 mm, and the high voltage power supply II-5 applies a voltage of 20 kV and a current of 10 μA to the electrostatic spray gun II-4;

[0044] The heating device of the heating and converging mechanism II-6 has a power of 200W and a heating temperature of 160°C;

[0045] Step 3, 3D printing: The printed filaments enter the 3D printing module III, are melted and extruded, and then cooled and shaped, and finally the composite material additive manufacturing of multi-material functional structures is completed according to the printing instructions;

[0046] The specific printing parameters are as follows: nozzle diameter 1mm, printing layer height 0.4mm, printing line width 1.2mm, printing temperature 110℃, total size 50mm×50mm×2mm;

[0047] Step 4: Heat treatment: Heat treatment is performed on the printed structure to ensure that the structure is completely cured or releases thermal stress, ensuring further improvement of the performance of the printed composite material.

[0048] Reference Figure 5 , Figure 5The graphs show the microscopic effects of the graphene-reinforced glass fiber / epoxy resin composite honeycomb and the graphene incorporated between the filament bundles of this embodiment. It can be seen that the method of the present invention can achieve uniform nanoparticles; after adding 3wt% and 5wt% of modified graphene respectively, the thermal conductivity of the composite material increased by 110.3% and 114.3%, and the fracture toughness of the composite material increased by 39% and 43.2%.

[0049] Example 2, a composite material 3D printing device based on a multi-material functional structure is the same as Example 1.

[0050] A printing method based on a composite material 3D printing device with a multi-material functional structure is used to prepare a microwave-absorbing aramid fiber / epoxy resin composite material grid, comprising the following steps:

[0051] Step 1, which is different from step 1 of embodiment 1, is as follows: an ultrasonic vibration yarn spreading method is used to obtain an aramid prepreg printing tow with ultra-widened and uniform epoxy resin distribution; the vibration roller has a vibration frequency of 10 Hz and a vibration amplitude of 6 mm; the resin tank in the impregnation device Ⅰ-3 is heated to 110°C, and after heating, the tow passes through the gap between the rubber roller and the metal roller, and the fiber mass content of the prepreg tow is controlled to be 40% by controlling the gap between the two;

[0052] Step 2 is different from step 2 of embodiment 1 in that: the spraying distance of the electrostatic spray gun II-4 is 5 mm, the voltage applied to the electrostatic spray gun II-4 by the high voltage power supply II-5 is 25 kV, and the current is 12 μA; the heating temperature of the heating and converging mechanism II-6 is 170° C.;

[0053] Step three is different from step three of Example 1 in that the specific printing parameters are as follows: the nozzle diameter is 1 mm, the single layer thickness of the aramid layer is 0.2 mm, the printing line width is 1.5 mm, the printing temperature is 160°C, and the total size is 200 mm × 60 mm × 12 mm, where the thickness includes a 10 mm square honeycomb interlayer and a 1 mm skin.

[0054] Reference Figure 6 , Figure 6 This is a schematic diagram of the square honeycomb sandwich structure of the composite material of this embodiment. It can be seen that the composite grid structure prepared by the method of the present invention has both excellent mechanical properties and good electromagnetic properties. The shear strength of the square honeycomb sandwich structure of the composite material in the L direction is 2.08Mpa. In the wave absorption test, the metamaterial shows a broadband absorption of 8-18.1GHz (greater than 90%), which proves the feasibility and effectiveness of the present invention.

Claims

1. A composite material 3D printing device based on a multi-material functional structure, characterized in that: The invention comprises a wide-spread yarn preimpregnation module (I), a coded electrostatic spraying module (II) and a 3D printing module (III). The fiber bundle is preimpregnated with the wide-spread yarn by the wide-spread yarn preimpregnation module (I). After the wide-spread yarn preimpregnation, the fiber bundle enters the coded electrostatic spraying module (II) for selective spraying. The coded sprayed preimpregnated fiber bundle is then cooled and shaped and printed by the 3D printing module (III).

2. The device according to claim 1, characterized in that: The wide-spread yarn prepreg module (I) comprises a yarn unwinding device (I-1), a vibrating yarn unwinding device (I-2) and an impregnation device (I-3), wherein the yarn unwinding device (I-1) leads a fiber bundle into the vibrating yarn unwinding device (I-2), and the fiber bundle widened by the vibrating yarn unwinding device (I-2) enters the impregnation device (I-3) to achieve wide-spread yarn prepreg; The vibration roller of the vibration yarn unwinding device (I-2) has a vibration frequency of 10-20 Hz and a vibration amplitude of 6-20 mm; The resin tank in the impregnation device (I-3) is heated to a temperature of 90-120°C. After heating, the fiber bundle passes through the gap between the rubber roller and the metal roller. By controlling the gap between the two, the fiber content of the prepreg bundle is controlled.

3. The device according to claim 1, characterized in that: The coded electrostatic spraying module (II) comprises an electrostatic spraying controller (II-1), a powder pump (II-2), a powder barrel (II-3), an electrostatic spray gun (II-4), a high-voltage power supply (II-5), and a heating and converging mechanism (II-6). The powder pump (II-2) inlet inhales the powder barrel (II-3) powder, the powder pump (II-2) is connected to the electrostatic spraying controller (II-1), the powder pump (II-2) outlet is connected to the electrostatic spray gun (II-4), the electrostatic spray gun (II-4) is connected to the high-voltage power supply (II-5), and the coded prepreg wire sprayed with powder by the electrostatic spray gun (II-4) enters the heating and converging mechanism (II-6); The electrostatic spray controller (II-1) uses a PID algorithm to adjust the output volume, and adjusts the output flow of the conveying gas and the atomizing gas by controlling the stepping motor flow valve. The output conveying gas controls the output powder volume of the powder pump (II-2), and then combines with the atomizer to provide an airflow with powder particles for the electrostatic spray gun (II-4) in the spraying area; The spraying distance is measured by a distance measuring sensor and the signal is transmitted to the electrostatic spraying controller (Ⅱ-1), which is compared with the set code. The output signal drives the stepper motor to control the position of the electrostatic spray gun (Ⅱ-4). The spraying distance is 5-20mm. The high-voltage power supply (Ⅱ-5) applies a voltage of 20-30kV and a current of 10-15μA to the electrostatic spray gun (Ⅱ-4); The heating and converging mechanism (II-6) includes a heating device and a converging nozzle connected to the heating device. The coded prepreg yarn is shaped into a stable cylindrical shape through the converging nozzle. The power of the heating device is 30-200W and the heating temperature is 90-180°C.

4. The device according to claim 1, characterized in that: The 3D printing module III includes a tension mechanism (III-1), a printing extrusion mechanism (III-2), and a heating mechanism (III-3). The printing filament bundle enters the printing extrusion mechanism (III-2) after the tension is adjusted by the tension mechanism (III-1). The printing extrusion mechanism (III-2) and the heating mechanism (III-3) are connected; The tension mechanism (III-1) is composed of a tension wheel, a tension sensor, a PLC processor, and a PID control module. When the fiber is stretched, the tension sensor transmits the detected tension signal to the PLC processor. The PLC processor compares the tension signal with the tension setting value and uses the PID control module to calculate. The output signal drives the tension wheel to rotate forward and reverse to adjust the tension. The tension setting value is 2-10N. The heating power of the heating mechanism (III-2) is 30-200W, achieving temperature control of 30-300°C. Different printing temperatures are set according to the different resins of the printing filament bundles.

5. A printing method using a composite material 3D printing device based on a multi-material functional structure according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1, wide-spread yarn pre-impregnation: the fiber bundle is first drawn out from the yarn unwinding device (Ⅰ-1), and then enters the vibration yarn unwinding device (Ⅰ-2) for widening treatment. After being treated by the vibration yarn unwinding device (Ⅰ-2), the widened yarn bundle continues to enter the impregnation device (Ⅰ-3) to complete the wide-spread yarn pre-impregnation process, and obtains a super-widened pre-impregnated yarn bundle with uniform resin distribution for subsequent spraying; Step 2: coded electrostatic spraying: the prepreg tow is processed by the electrostatic spraying module (II), and the electrostatic spraying controller (II-1) generates a corresponding encoder control code according to the structural distribution of the functional filler in the prepreg tow; the powder pump (II-2) extracts the required functional filler from the powder cylinder (II-3), and the electrostatic spray gun (II-4) is used in conjunction with the high-voltage power supply (II-5) to accurately and selectively spray the widened prepreg tow. During the spraying process, the fiber tow is sprayed in an alternating manner up and down; After spraying is completed, the fiber bundle is bundled by a heating and bundling mechanism (II-6) to form a circular printing bundle; Step 3, 3D printing: the printed filaments enter the 3D printing module (III), are melted and extruded, and then cooled and shaped, and finally the composite material additive manufacturing of multi-material functional structure is completed according to the printing instructions; Step 4: Heat treatment: Heat treatment is performed on the printed structure to ensure that the structure is completely cured or releases thermal stress, ensuring further improvement of the performance of the printed composite material.

6. The method according to claim 5, characterized in that: The resin in step 1 is a thermoplastic composite 3D printing resin matrix, including polyetherimide (PEI), polyethersulfone (PES), polyetherketone (PEK), polyetheretherketone (PEEK) or polysulfone (PSF), or a thermosetting composite 3D printing resin matrix, including epoxy resin, cyanate resin, phenolic resin or bismaleimide resin.

7. The method according to claim 5, characterized in that: The fiber used in step 1 is a mixture of one or more polymer continuous fibers selected from carbon fiber, glass fiber, aramid fiber, basalt fiber, and polyimide fiber.

8. The method according to claim 5, characterized in that: In step 2, the functional filler includes one or a mixture of carbon nanotubes, graphene, MXENE, ferrite, and magnetic nanoparticles.

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