Anisotropy enhanced electromagnetic shielding part with orientation structure and ink and 3D printing preparation method thereof

Abstract

The invention discloses an anisotropic enhanced electromagnetic shielding piece with structural orientation, ink of the anisotropic enhanced electromagnetic shielding piece and a 3D printing preparation method of the anisotropic enhanced electromagnetic shielding piece, and belongs to the technical field of electromagnetic shielding materials and 3D printing. And the laying direction of the filiform materials of each layer of plane unit is parallel to the same basic plane. By adjusting the plane units to be perpendicular to the incident direction of electromagnetic waves, the shielding effect in the incident direction is enhanced, meanwhile, basic shielding requirements in other directions are guaranteed, and anisotropic electromagnetic shielding is achieved. In addition, high-length-diameter rigid particles are added to assist the shearing effect of a 3D printing one-way extrusion flow field, ordered arrangement of multi-dimensional nanoparticles is induced, a microscopic oriented conductive network is constructed, and a conductive path is optimized, so that the shielding performance of the material is further enhanced. The anisotropic electromagnetic shielding performance is achieved, and meanwhile the electromagnetic shielding effect of the material is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic shielding materials and direct ink writing (DIW) 3D printing, and more specifically, to an electromagnetic shielding component induced by 3D unidirectional printing flow field and assisted by high long-diameter rigid materials, a preparation method thereof, and printing ink suitable for direct ink writing 3D printing of the electromagnetic shielding component. Background Art

[0002] Modern advanced multifunctional electronic devices such as smartphones are developing in the direction of miniaturization, high integration and high frequency. However, electronic components such as microprocessors and radio frequency chips in smart devices face severe electromagnetic interference (EMI) problems during operation. This is because the rapidly changing electromagnetic field is separated from the device source and propagates through the air, wires or grounding systems, affecting the surrounding electronic equipment, especially in micro-sized spaces. Electromagnetic wave pollution not only disrupts the normal operation of adjacent electronic components, reduces the stability and durability of the equipment, but also poses a threat to human health. Therefore, the development of new high-performance electromagnetic materials and the optimization of shielding structure design are the core strategies to ensure the electromagnetic compatibility, safety and reliability of electronic equipment in multiple frequency bands and multiple scenarios.

[0003] Current electromagnetic shielding materials mainly include metals and their alloy materials and carbon materials. The biggest advantage of metals and alloy materials is their high electrical conductivity. However, metals have the following disadvantages: high weight density, poor flexibility, and easy corrosion. Carbon materials and their composites have attracted much attention in the field of electromagnetic interference shielding due to their advanced electrical properties, excellent flexibility, low production cost, environmental protection, easy manufacturing and chemical inertness. In recent years, people have actively studied composite materials mixed with conductive fillers in polymer materials, especially the use of various carbon-based nanomaterials as single or composite fillers, such as carbon black (Carbon Black, CB), carbon nanotubes (Carbon Nanotubes, CNT), graphene (Graphene, Gr) and carbon fiber (Carbon Fiber, CF). Among them, carbon nanotubes have a fibrous and high aspect ratio structure, and are suitable for use as electromagnetic interference shielding materials in applications that require good conductivity; two-dimensional graphene (Gr) is hybridized and matched with one-dimensional carbon nanotubes (CNT), and Gr acts as a wire concentrator to connect all CNTs, thereby constructing a Gr@CNT multidimensional hybrid network with higher conductivity than CNT at a lower nanofiller loading. The interconnected network structure not only increases the surface area of ​​the material, but also provides a complex propagation path for electromagnetic waves, which helps to improve the electromagnetic wave shielding efficiency.

[0004] However, due to the continuous reduction and spatial distribution of radiation in three-dimensional high-density packaged electronic devices, local electromagnetic interference problems in specific directions have been caused. This problem has posed new challenges to electromagnetic shielding materials, requiring that the materials not only have efficient shielding performance, but also have directional or anisotropic electromagnetic wave management capabilities to meet the shielding needs in complex environments. Therefore, the development of oriented shielding parts is a key research direction to solve this problem.

[0005] Traditional orientation processes often involve multiple stages such as electromagnetic chemical modification, hot rolling, cold rolling, stamping, and electromagnetic induction. The fixed process and difficulty in adjustment limit the diversification and customization potential of products. In addition, traditional orientation processes usually have disadvantages such as energy consumption, non-customizability, application material limitations, or complex processes. Summary of the invention

[0006] The first purpose of the present invention is to provide an anisotropically enhanced electromagnetic shielding component with an oriented structure. By constructing a macroscopic oriented structure through 3D printing technology, the electromagnetic shielding component is given an electromagnetic shielding effect with a specific direction enhancement or anisotropy, solving the problem of local electromagnetic interference in a specific direction, so as to meet the shielding needs in complex environments. At the same time, the introduction of rigid particles with a high aspect ratio enhances the orientation effect of the 3D printing flow field, so that the one-dimensional conductive fibers and the two-dimensional conductive plane are oriented and arranged in a directional manner, and together construct an oriented three-dimensional conductive network structure that is orderly arranged on a microscopic scale, thereby enhancing the electromagnetic shielding effect.

[0007] The second object of the present invention is to provide a 3D printing preparation method for the above-mentioned electromagnetic shielding component, which utilizes the extrusion process in the ink direct writing (DIW) 3D printing process to realize the orderly arrangement of carbon nanoparticles along the flow field direction combined with the design of the electromagnetic shielding macrostructure, and prints anisotropic carbon-based electromagnetic shielding functional parts that meet the shape of the equipment. The electromagnetic shielding effect of the oriented shielding component is significantly higher than that of the irregular shielding component. The present invention provides one of the oriented samples printed with carbon-based material ink, which can have a shielding effectiveness of up to about 20 dB higher than that of the irregular sample ( Figure 1 ). Furthermore, the 3D printing preparation method of the electromagnetic shielding component adds a high-length-diameter rigid material to assist the 3D printing unidirectional flow field to induce the orderly arrangement of nanoparticles, and the directional arrangement of the conductive network hybridized with nanoparticles. The addition of high-length-diameter rigid materials significantly improves the microscopic orientation of the conductive network. In a solution provided by the present invention, the addition of carbon fibers effectively promotes the directional arrangement of molecular chains and nanoparticles under the shearing action of the flow field, thereby forming a significant microscopic orientation structure ( Figure 2 ).

[0008] The fourth object of the present invention is to provide a 3D printing ink suitable for the preparation of the above-mentioned electromagnetic shielding components, which is composed of a conductive filler with high conductivity, rigid particles with a high aspect ratio, a polymer viscosity regulator with viscosity regulating function, and a solvent.

[0009] To achieve the above object, the present invention provides an anisotropic reinforced electromagnetic shielding component with an oriented structure, comprising: The planar units are stacked layer by layer, and the laying direction of the filamentary materials extruded by 3D printing is parallel to the same base plane. The shielding effect is best along the normal direction of the base plane.

[0010] The electromagnetic shielding component in the above technical solution has two characteristics: (1) 3D printed extruded filamentary materials; (2) in each layer of plane unit, the laying direction of the filamentary materials is consistent and parallel to the same base plane. The shearing effect of the flow field during 3D printing extrusion can inhibit the self-relaxation behavior of the viscosity regulator molecular chain in the ink to a certain extent, bring a certain orientation effect along the extrusion direction, and obtain a microscopic oriented structure. The conductivity of the conductive network in different orientation directions is different, and the regularly arranged conductive network (such as the directional arrangement structure of the present invention) can maximize the conductive performance in certain specific directions. In addition, the order of the material particles is conducive to the formation of a continuous conductive path, reducing the obstruction of the insulating matrix to the current conduction, effectively improving the electron transmission efficiency, and thus improving the conductive performance of the material. The electromagnetic shielding performance of the material is usually closely related to the conductivity. This anisotropic conductive performance has a positive effect on the anisotropic electromagnetic shielding effect. It is worth noting that for shielding electromagnetic waves, materials with directional arrangement show unique advantages, especially when the conductive interface is perpendicular to the propagation direction of the electromagnetic wave. It can at least increase the probability and number of interactions between the electromagnetic wave and the conductive interface, and guide the electromagnetic wave to propagate along an elongated and tortuous path inside the material, thereby enhancing interface scattering and multiple reflections, and promoting more efficient electromagnetic energy conversion and dissipation.

[0011] Preferably, the anisotropic reinforced electromagnetic shielding component with an oriented structure is arranged such that the laying direction is perpendicular to the incident direction of the electromagnetic wave according to the application environment, so as to meet the requirement of shielding enhancement for electromagnetic waves incident in a specific direction, thereby forming an electromagnetic shielding component customized for the application environment.

[0012] Preferably, the application environment includes three-dimensional high-density packaged electronic equipment or other electromagnetic local interference environments with specific directions.

[0013] The present invention provides a 3D printing ink suitable for preparing the electromagnetic shielding component, comprising the following components: Surfactant <10 parts; Carbon fiber 10~50 parts; Other carbon-based functional fillers 60~100 parts; 20-25 parts of viscosity regulator; 300~550 parts of water.

[0014] Preferably, the carbon fiber is a rigid carbon fiber (CF) with a high aspect ratio. The nanomaterial presents a highly ordered arrangement of the crystal planes in its lattice structure, especially exhibiting an obvious "preferred orientation" in a specific direction, so that the constructed network structure as a whole presents a regular directional arrangement feature. For example, 10 to 30 parts of carbon fiber can be added as nanoparticles for the auxiliary flow field, such as 10 parts, 15 parts, 20 parts, 25 parts, 30 parts or any range or point value of CF therebetween.

[0015] Preferably, the aspect ratio of CF (carbon fiber) affects the orientation of the microstructure and the electron transport in the conductive network. The introduction of carbon fiber increases the content of conductive particles, further improves the continuity of the electron transport path, and enhances the conductivity. In addition, it can constrain the rotational freedom of nanoparticles, further optimize the orientation arrangement, and enhance the orientation of the structure. For example, the aspect ratio of CF can range from 80 to 500:1.

[0016] Preferably, in combination with the background technology, carbon-based functional fillers for electromagnetic shielding are selected from carbon materials that tend to have high conductivity, high specific area and thermal stability, such as carbon nanotubes, graphene or graphite powder, and existing carbon-based fillers with equivalent or similar electromagnetic shielding effects. Generally speaking, the above-mentioned carbon-based functional fillers are obtained from the market or prepared by referring to the existing technical literature.

[0017] Preferably, the carbon-based functional filler is a one-dimensional carbon nanotube, carbon fiber and a two-dimensional single-layer, double-layer or multi-layer graphene to construct a multi-dimensional hybrid conductive network with electromagnetic shielding performance. The carbon-based functional filler is a mixture of any two or more of carbon nanotubes, graphene and graphite powder; further preferably, the particle size specification of the carbon-based functional filler is nanometer level.

[0018] Preferably, there is a strong van der Waals force on the surface of the carbon material, and the high specific surface area of ​​the nanomaterial makes the particles easy to aggregate, and the mutual attraction of the particles in the agglomerate is also significantly increased, making it more difficult to disperse. Provide external energy to destroy the forces between carbon molecules and inhibit agglomeration. For example, high-frequency ultrasound, ball milling and other technologies are used to promote the dispersion of carbon nanotubes, and then high-speed centrifugation is used to remove the aggregates that are not fully dispersed; most carbon materials have few surface defects and lack active groups, and their solubility in various solvents is very low. The surface modification increases hydrophilic groups such as hydroxyl and carboxyl to improve the solubility in water or polar solvents; add surfactants to form non-covalent bonds to obtain non-covalent functionalized carbon nanotubes. The surfactant molecules form a protective layer on the surface of the carbon material to avoid direct contact between the carbon material and the solvent, while uniformly dispersing the carbon nanotubes in the medium.

[0019] Preferably, according to the specifically selected carbon-based functional filler, in order to improve the dispersibility of the carbon-based functional filler, the 3D printing ink loaded with the carbon-based functional filler also includes a dispersant. For example, when the carbon-based functional filler is selected as a carbon material, <10 parts of a dispersant can be added to enhance its dispersibility, such as adding 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or any range or point value of a dispersant therebetween; the dispersant selection includes any one or more of cationic hexadecyltrimethylammonium bromide (CTAB), anionic sodium dodecylbenzene sulfonate (SD-BS), sodium dodecyl sulfate (SDS), sodium dodecyl sulfonate, non-ionic OP-10, Triton-100, macromolecular gum arabic (AG), cyclodextrin, and polyvinyl pyrrolidone (PVP).

[0020] Preferably, DIW printing ink is required to have viscoelasticity, thixotropy, shear thinning and other characteristics, while pure carbon dispersion without molecular chain entanglement does not have the above-mentioned ideal shear thinning and viscoelasticity and other characteristics, resulting in excessive liquid fluidity and inability to maintain a stable shape and position during printing. In one embodiment, the viscosity modifier includes any one or more of xanthan gum, guar gum, carboxylated nanocellulose, and sodium alginate.

[0021] On the other hand, the present invention provides a method for preparing the 3D printing ink, which mainly comprises the following steps: (1) Dispersion of carbon-based functional fillers At room temperature of 20-25°C, 60-100 parts of carbon-based functional fillers, 10-50 parts of carbon fibers, 20-25 parts of viscosity regulators and surfactants are added to excess water, mixed, and dispersed by an ultrasonic cell disruptor to obtain a suspension; (2) Preparation of printing ink The suspension obtained in step (1) is concentrated to concentrate the water therein to 300-550 parts, thereby obtaining a 3D printing ink with a high carbon-based filler loading.

[0022] The present invention also provides a method for preparing the above-mentioned high-carbon-based filler-loaded 3D printing ink as a preferred embodiment and reference. It should be noted that the inventive point of this technical solution is mainly that high aspect ratio rigid materials assist flow fields to induce multi-level orientation structures, thereby realizing the printing and preparation of high-performance carbon-based conformal electromagnetic shielding products. Its preparation method is not unique.

[0023] The present invention provides a 3D printing preparation method for the electromagnetic shielding component, which utilizes the extrusion process in the ink direct writing (DIW) 3D printing process to achieve orderly arrangement of carbon nanomaterials along the flow field direction, and adds high long-diameter rigid materials to assist 3D printing of unidirectional flow fields to induce orderly arrangement of nanoparticles, thereby preparing an electromagnetic shielding component with an electromagnetic shielding macroscopic structure.

[0024] In the above scheme, on the one hand, the shearing effect of the flow field during 3D printing extrusion can inhibit the self-relaxation behavior of the viscosity regulator molecular chain in the ink to a certain extent, bring about a certain orientation effect along the extrusion direction, and obtain a microscopic oriented structure (particles with a high aspect ratio are usually more easily oriented under this shearing effect).

[0025] Secondly, during the processing, rigid particles with high aspect ratio (such as carbon fiber and nanotubes) are more likely to be arranged along the direction of external force. Reason 1: Due to the high aspect ratio of the particles, their surface energy is very high, but because their rigid materials cannot entangle and agglomerate, the energy of the system is reduced. They tend to be arranged along the direction of external force to reduce the overall energy state of the system. This is an entropy-driven process. Reason 2: Directed arrangement can reduce the collision and flow resistance between particles during the flow process and achieve the lowest system energy. Reason 3: During the DIW process, as the flow channel continues to decrease, the shear rate continues to increase. If the rigid particles with high aspect ratio perpendicular to the flow field direction enter the flow channel with high shear rate, one end of the particle is located in the high flow rate area and the other end is located in the low flow rate area. According to Strouhal's law in fluid mechanics, the high-speed flowing fluid part will exert a greater thrust on one side of the particle, while the low-speed flowing part will exert a smaller thrust on the other side. This phenomenon of uneven force on both sides will produce a lateral shear force, causing the particles to deflect in the direction of lower flow velocity. When the flow velocities at both ends of the particles are the same, they stop rotating and are oriented along the flow direction. Under the action of the flow field, rigid nanomaterials with a high aspect ratio can use the flow field as the central axis to induce the surrounding graphene sheets or other two-dimensional carbon materials to align or deflect through van der Waals forces, electrostatic forces or mechanical interlocking during rotation or movement, thereby achieving the purpose of assisting flow field-induced orientation.

[0026] Preferably, the extrusion volume rate is used as an indicator to measure the DIW extrusion pressure and the printing movement speed, and the shear rate flow rate distribution is monitored and adjusted. When the movement speed is constant, as the extrusion pressure increases, the volume flow rate increases, and the shear rate increases as the flow channel continues to shrink, and the shear rate of each flow layer is the maximum at the end of the flow channel. According to the positive correlation between the Weissenberg parameter and the shear rate, the self-relaxation behavior of the molecular chain at the end of the extrusion is suppressed, so that the molecular chain drives the nanoparticles to be oriented along the shear direction.

[0027] Preferably, the 3D printing preparation method of the electromagnetic shielding component specifically includes: Step 1: Load ink into the 3D printing system The prepared ink is transferred to a special printing syringe, and a suitable extrusion needle is selected according to the printing requirements. The diameter ranges from microns to hundreds of microns to ensure printing accuracy. This component is fixed in the 3D printing equipment and the pneumatic control system inside the equipment is activated to ensure that the ink can be smoothly and stably delivered accurately during the printing process, preparing for refined printing operations.

[0028] Step 2: Setting printing parameters After installation is complete, control the printing accuracy by adjusting the following printing parameters.

[0029] Printing speed: 1~20 mm / s; Extrusion pressure: 0.1~0.5 MPa; Platform temperature: 20~25℃; Initial distance between needle and receiving platform: 0.5~1.5 mm; Distance between adjacent wires: 0.3~2 mm.

[0030] Step 3: Design of printing structure After setting the appropriate printing parameters, each filamentary material is precisely deposited in a pre-set direction and pattern through precise algorithms and software control. The filaments are laid along the horizontal axis through the regional coating program design, turn 180° at the edge of the printing layer, and continue to advance in the adjacent but opposite parallel direction again, and so on, until the first layer is built, forming a basic structure with consistent directionality. Next, the second layer is stacked in a strictly set directional pattern to lay the filaments. This goes on and on until the top layer, and the entire microstructure is orderly arranged through the workpiece to reflect and utilize the anisotropy of the material on a macro scale.

[0031] In step 2 of the present invention, it is worth noting that the setting of printing parameters affects the printing accuracy and the formation of multi-level orientation. Printing speed: 1~20 mm / s. If the printing speed is too low, the time cost will increase. If the printing speed is too high, the continuity of ink extrusion may be destroyed, resulting in problems such as line discontinuity, blurred patterns, or weak adhesion between layers. Extrusion pressure: 0.1~0.5 MPa. Properly increasing the pressure can increase the fluid shear rate, promote a more orderly arrangement of nanoparticles in the material, and improve the printing quality. However, too high a pressure will squeeze out too much ink, which will not only lead to uneven layer thickness and reduced accuracy, but may also damage the overall structure of the printed part; platform temperature: -20~25℃, because some printed structural parts collapse under the action of gravity, the solvent can be freeze-dried by low-temperature cooling of the platform to enhance the internal structural stability of the workpiece and the retention of the three-dimensional shape; the initial distance between the needle and the receiving platform: 0.5~1.5 mm, if the distance from the platform is too high, the wire strip will break before it contacts the platform, and if the distance from the platform is too low, the extrusion will be blocked, affecting the complete formation of the wire strip; the distance between adjacent wire strips: 0.3~2 mm, if the interval between the program-designed wire strips is too large, electromagnetic waves will escape from the gap, and if the interval is too small, it will easily cause adjacent wire strips to squeeze each other, which will not only interfere with the uniform deposition of the material, but may also destroy the predetermined thickness of each layer, thereby reducing the dimensional accuracy and surface flatness of the printed product.

[0032] The above step three mentions printing electromagnetic shielding parts with different macroscopic orientations. The orderly arrangement of the entire microstructure reflects and utilizes the anisotropy of the material on a macroscopic scale through the workpiece. For different orientations of electromagnetic shielding, such as random orientation, the continuity of the conductive network is low due to the randomness of the conductive path; for uniaxial orientation, that is, orderly arrangement along a specific direction, such as an electromagnetic field parallel to the orientation direction, the material can more effectively reflect and absorb electromagnetic waves; multi-axis orientation, orderly arrangement in multiple directions, is suitable for application scenarios that require all-round protection. In one of the technical solutions, the 3D printing program is designed to print shielding parts in horizontal, multi-axis orientation, and vertical directions along the axial direction.

[0033] One of the inventive points of the present invention is to provide a feasible solution for improving electromagnetic shielding by using high-length rigid materials to assist 3D printing with unidirectional flow field induced orientation. The use of ink direct writing 3D printing technology for matching printing can realize the printing and preparation of anisotropic shielding parts. 3D printing not only meets personalized customization, but also provides an induced oriented flow field. Nanoparticles are arranged in a directional manner under high shear rates in the flow field, achieving orderly arrangement of crystal grains and crystal faces, orderly arrangement of conductive paths constructed by crystals, and orderly arrangement of network gaps formed by conductive paths, which effectively extends the propagation path of electromagnetic waves and increases the frequency of interaction between electromagnetic waves and interfaces, thus achieving effective management of electromagnetic waves. ( Figure 2 ) Using the above-mentioned high-carbon-based filler-loaded 3D printing ink and its supporting direct writing 3D printing preparation method, the carbon fiber-assisted flow field oriented electromagnetic shielding product samples prepared have a thickness of 2.5 mm. The electromagnetic shielding effectiveness (SE) of the non-oriented workpiece is 45.5 dB, while the materials with parallel orientation and vertical orientation structures are increased to 73.9 dB and 58.3 dB respectively. ( Figure 1 ) It should be emphasized that the electromagnetic shielding components that use a high aspect ratio rigid auxiliary flow field to guide the orientation of carbon nanoparticles have shown significant superiority in shielding effectiveness compared to carbon-based material workpieces manufactured under the current technical level. This innovative method can achieve a more excellent electromagnetic shielding effect while maintaining the same or even reducing the material thickness. For example, Shailaja Pande et al. used solvent casting and a combination of solvent casting and compression molding technology to manufacture uniformly dispersed MWCNT / PC composites. At a thickness of 2 mm, the shielding value was 43 dB. Ding-Xiang Yan et al. achieved an electromagnetic interference shielding composite material based on reduced graphene oxide and polystyrene through high-pressure solid phase compression molding. At a thickness of 2.5 mm, the shielding value was 45.1 dB. The electromagnetic shielding component made of carbon fiber (CF) reinforced polyacrylamide / wood fiber composite board using mechanical grinding assisted hot pressing has an optimal shielding value of 41.03 dB. At the same time, a search found that the relevant literature reports and patents on the preparation of shielding parts using 3D printing technology did not mention that 3D printing unidirectional flow field induced nanoparticle orientation arrangement and carbon fiber assisted flow field induced nanoparticle orientation can enhance electromagnetic shielding, indicating that technical personnel in this field have never envisioned the use of 3D printing technology to prepare multi-level oriented electromagnetic shielding parts.

[0034] The present invention has at least the following beneficial effects: 1. The anisotropic electromagnetic shielding product provided by the present invention has an electromagnetic shielding performance that has greatly exceeded the commercial electromagnetic shielding standard of 20dB; it also has the characteristics of light weight and high temperature resistance, which is in line with the current development trend of miniaturization of electronic equipment, high concentration of electronic components, and high frequency.

[0035] 2. The present invention is based on the continuous unidirectional extrusion of non-Newtonian fluids in 3D printing, and its extrusion flow field has a certain shearing effect, which is very suitable for the construction of micro-oriented structures. At the same time, rigid carbon fiber (CF) particles with a high aspect ratio are introduced to limit the free movement of nanoparticles through micron-level confinement, thereby assisting the orderly arrangement of nanoparticles under the shearing effect of the DIW 3D unidirectional printing flow field. The micro-oriented structure formed by this orderly arrangement can effectively solve the "pile-up" of local electromagnetic waves. The micro-oriented structure is coupled with the 3D printing structure design to construct a multi-level ordered oriented structure from micro to macro. The anisotropic regulation of EMI performance by 3D printing is realized.

[0036] 3. The present invention uses 3D printing technology based on additive manufacturing to build any customized geometric shape by stacking layer by layer, which can quickly and efficiently realize the integrated customization of complex structures. It has the advantages of low cost of printing model replacement, high precision, short cycle, and material saving in additive manufacturing, and has obvious processing advantages. The structural design of shielding parts is crucial for the effective management of electromagnetic waves. For example, the design of Faraday cages, multi-layer shielding, shielding canopies, etc. can all achieve improvements in electromagnetic shielding performance.

[0037] 4. The DIW printing process of the electromagnetic shielding component provided by the present invention not only retains the flexibility and accuracy of the technology in customized design, but also ingeniously uses the printing process to induce a special flow field inside the material, thereby achieving directional arrangement of nano-filling materials. This is an unprecedented innovation.

[0038] 5. The carbon fiber (CF) provided by the present invention assists in orientation. The directional arrangement of rigid materials with high aspect ratio drives the nanoparticles within a certain range to undergo directional deflection, constructs microscopic orientation, and improves electromagnetic shielding. In addition, the addition of carbon fiber conductive particles does not destroy the continuity of the conductive network and promotes the interface interaction of other carbon materials.

[0039] 6. The 3D printing ink filler provided by the present invention is a carbon-based material. In addition to overcoming the shortcomings of metal materials such as easy corrosion, high density, and difficult processing in electromagnetic shielding applications, this type of printing ink has excellent electrical conductivity, good chemical stability, and flexibility, making it a potential material for solving the current electromagnetic wave interference situation. It is particularly worth mentioning that the flexible characteristics of carbon-based materials make it possible to design complex curved surfaces, wearable devices, or application scenarios that need to adapt to dynamic deformation, which is an advantage that traditional rigid shielding materials cannot achieve.

[0040] 7. The 3D printing ink and preparation method thereof provided by the present invention have simple operation process, do not involve chemical reaction, are safe and non-toxic, and are easy to promote.

[0041] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a bar graph of electromagnetic shielding performance of electromagnetic shielding components with different orientation structures of the present invention; Figure 2 It is a microscopic electron microscope image of the electromagnetic shielding element with a parallel orientation structure of the present invention; Figure 3 It is a schematic diagram of the structure of the electromagnetic shielding member with different orientation structures of the present invention; Figure 4It is a structural schematic diagram of an electromagnetic shielding component with no orientation structure; Figure 5 This is a microscopic electron microscope image of an electromagnetic shielding component with no orientation structure; Figure 6 It is a schematic diagram of the principle structure of the electromagnetic shielding element of the multi-axial orientation structure of the present invention; Figure 7 This is a schematic diagram of the application structure of the electromagnetic shielding component customized for the electromagnetic environment of the present invention. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below with reference to examples so that those skilled in the art can implement the invention with reference to the description.

[0044] However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention. Those skilled in the art can refer to the content of the present invention and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art, and they are all deemed to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications described in the present invention without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention. Although it is believed that those of ordinary skill in the art fully understand the following terms, the following definitions are still stated to help illustrate the subject matter disclosed in the present invention.

[0045] It should be understood that the terms such as “having”, “including” and “comprising” used in the present invention do not exclude the existence or addition of one or more other elements or combinations thereof.

[0046] The present invention provides an anisotropically reinforced electromagnetic shielding component with an oriented structure, comprising: The planar units are stacked layer by layer, and the laying direction of the filamentary materials extruded by 3D printing is parallel to the same base plane. The shielding effect is best along the normal direction of the base plane.

[0047] like Figure 6 The figure shows the principle structure diagram of anisotropic enhanced electromagnetic shielding with a multi-axis oriented structure. The laying direction of the wire strips in a single-layer plane unit is the same, and the laying direction of the wire strips between each layer of plane units is not exactly the same. Each layer of plane units is parallel to the same reference plane unit in space. When the incident electromagnetic wave is incident in the normal direction of the plane unit, the best shielding effect can be achieved. The same is true for anisotropic enhanced electromagnetic shielding components with parallel orientation structures.

[0048] The printing ink of the present invention is composed of the following components by mass: Surfactant <10 parts Carbon fiber 10~50 parts Other carbon-based functional fillers 60~100 parts; 20-25 parts of viscosity regulator; 300~550 parts of water.

[0049] In one embodiment, for example, 10 to 30 parts of carbon fibers can be added as nanoparticles to assist the flow field, for example, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts or any range or point value therebetween can be added.

[0050] In one of the embodiments, the carbon-based functional filler is a one-dimensional carbon nanotube, carbon fiber and a two-dimensional single-layer, double-layer or multi-layer graphene to construct a multi-dimensional hybrid conductive network with electromagnetic shielding performance. The carbon-based functional filler is a mixture of any two or more of carbon nanotubes, graphene and graphite powder; further preferably, the particle size specification of the carbon-based functional filler is nanometer level.

[0051] In one embodiment, the viscosity modifier is selected from any one or more of xanthan gum, guar gum, carboxylated nanocellulose, and sodium alginate.

[0052] In one embodiment, according to the specific selection of the carbon-based functional filler, in order to improve the dispersibility of the carbon-based functional filler, the 3D printing ink loaded with high carbon-based fillers also includes a dispersant. For example, when the carbon-based functional filler is selected as a carbon material, <10 parts of a dispersant can be added to enhance its dispersibility, such as adding 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or any range or point value of a dispersant therebetween; the dispersant selection includes any one or more of cationic hexadecyltrimethylammonium bromide (CTAB), anionic sodium dodecylbenzene sulfonate (SD-BS), sodium dodecyl sulfate (SDS), sodium dodecyl sulfonate, non-ionic OP-10, Triton-100, macromolecular gum arabic (AG), cyclodextrin, and polyvinyl pyrrolidone (PVP).

[0053] In one embodiment, the carbon-based functional filler is 60-80 parts, for example, 60 parts, 61 parts, 62 parts, 63 parts, 64 parts, 65 parts, 66 parts, 67 parts, 68 parts, 69 parts, 70 parts, 71 parts, 72 parts, 73 parts, 74 parts, 75 parts, 76 parts, 77 parts, 78 parts, 79 parts, 80 parts or any range or point value therebetween; the viscosity modifier is 20-25 parts, for example, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts or any range or point value therebetween; the water is 300-550 parts, for example 300 parts, 310 parts, 320 parts, 330 parts, 340 parts, 350 parts, 360 parts, 370 parts, 380 parts, 390 parts, 400 parts, 410 parts, 420 parts, 430 parts, 440 parts, 450 parts, 460 parts, 470 parts, 480 parts, 490 parts, 500 parts, 510 parts, 520 parts, 530 parts, 540 parts, 550 parts, or any range or point value therebetween.

[0054] On the other hand, the present invention provides a method for preparing the 3D printing ink and a specific 3D printing process, which mainly includes the following steps: (1) Dispersion of carbon-based functional fillers At room temperature, according to the weight percentage, 60-80 parts of carbon-based functional filler, 20-30 parts of carbon fiber, 20-25 parts of viscosity regulator and surfactant are added to excess water, mixed, and dispersed by ultrasonic cell disruptor to obtain a suspension; (2) Preparation of printing ink The suspension obtained in step (1) is concentrated while being stirred at a constant speed, and the water is concentrated to 300-550 parts, and the prepared 3D printing ink is transferred into a sealed container.

[0055] (3) Loading ink into the 3D printing system The ink prepared in step (2) is transferred to a special printing syringe, and a suitable extrusion needle is selected according to the printing requirements, with a diameter ranging from microns to hundreds of microns to ensure printing accuracy. The component is fixed in the 3D printing device of ink direct writing 3D printing technology and the pneumatic control system inside the device is activated to ensure that the ink can be smoothly and stably accurately transported during the printing process, preparing for refined printing operations.

[0056] (4) Setting of printing parameters After installation is complete, control the printing accuracy by adjusting the following printing parameters.

[0057] Printing speed: 1~20 mm / s, Extrusion pressure: 0.1~0.5 MPa, Platform temperature: 20~25℃ Initial distance between needle and receiving platform: 0.5~1.5 mm Distance between adjacent wires: 0.3~2 mm (5) Design of printing structure After setting the appropriate printing parameters, each filamentary material is precisely deposited in a pre-set direction and pattern through precise algorithms and software control. The filaments are laid along a specific angle through regional coating program design, turn 180° at the edge of the printing layer, and continue to advance in an adjacent but opposite parallel direction, and so on, until the first layer is built, forming a basic structure with consistent direction. Next, the second layer is accumulated and the filaments are laid in strict accordance with the set direction. This goes back and forth until the top layer.

[0058] In step (4) of the present invention, it is worth noting that the setting of printing parameters affects the printing accuracy and the formation of multi-level orientation. Printing speed: 1~20 mm / s. If the printing speed is too low, the time cost will increase. If the printing speed is too high, the continuity of ink extrusion may be destroyed, resulting in problems such as line discontinuity, blurred pattern or poor adhesion between layers. In one embodiment, for example, the printing speed is 1 mm / s, 2 mm / s, 3 mm / s, 4 mm / s, 5 mm / s, 6 mm / s, 7 mm / s, 8 mm / s, 9 mm / s, 10 mm / s, 11 mm / s, 12 mm / s, 13 mm / s, 14 mm / s, 15 mm / s, 16 mm / s, 17 mm / s, 18 mm / s, 19 mm / s, 20 mm / s; Extrusion pressure: 0.1~0.5 MPa. In one embodiment, for example, the extrusion pressure is 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.25 MPa, 0.3 MPa, 0.35 MPa, 0.4 MPa, 0.45 MPa, 0.5 MPa, or any range or point value between them, appropriately increasing the pressure can increase the fluid shear rate, promote a more orderly arrangement of nanoparticles in the material, and improve the printing quality.However, too high a pressure will cause excessive extrusion of ink, which will not only lead to uneven layer thickness and decreased accuracy, but may also damage the overall structure of the printed part; platform temperature: -20~25°C. Since some printed structural parts collapse under the action of gravity, the solvent can be freeze-dried by low-temperature cooling the platform to enhance the internal structural stability of the workpiece and the retention of the three-dimensional shape. In one embodiment, for example, the platform temperature is -20°C, -15°C, -10°C, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C or any range or point value therebetween; the initial distance between the needle and the receiving platform: 0.5~1.5 mm. If the distance from the platform is too high, the filament will break before it contacts the platform. If the distance from the platform is too low, the extrusion will be blocked, affecting the complete formation of the filament. In one embodiment, for example, the platform distance is 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm, 3.5 mm, 3.6 mm, 3.7 mm, 3.8 mm, 3.9 mm, 4.1 mm, 4.2 mm, 4.3 mm, 4.4 mm, mm, 1.5 mm or any range or point value therebetween; distance between adjacent wire strips: 0.3-2 mm. If the interval between the wire strips is too large, the electromagnetic waves will escape from the gap; if the interval is too small, the adjacent wire strips will be easily squeezed against each other, which will not only interfere with the uniform deposition of the material, but also may destroy the predetermined thickness of each layer, thereby reducing the dimensional accuracy and surface flatness of the printed product. In one embodiment, for example, the distance between adjacent wire strips is 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm or any range or point value therebetween.

[0059] The above step (5) mentions printing electromagnetic shielding parts with different macroscopic orientations. The orderly arrangement of the entire microstructure reflects and utilizes the anisotropy of the material on a macroscopic scale through the workpiece. For different orientations of electromagnetic shielding, such as random orientation, the continuity of the conductive network is low due to the randomness of the conductive path; for uniaxial orientation, that is, orderly arrangement along a specific direction, such as in an electromagnetic field parallel to the orientation direction, the material can more effectively reflect and absorb electromagnetic waves; multi-axial orientation, orderly arrangement in multiple directions, is suitable for application scenarios that require all-round protection. In one embodiment, the 3D printing program is designed to print electromagnetic shielding parts in horizontal, multi-axial orientation, and vertical directions along the axial direction. Example

[0060] 1. Raw materials Multi-walled carbon nanotubes (CNT, average length: 1.5 μm, average diameter: 9.5 nm) were provided by Nanocyl SA, Belgium; graphene (Gr, average thickness range: 3.4-8 nm, average flake size: 5×50 μm) was provided by Tanfeng Graphene Technology Co., Ltd., Suzhou, China; carbon fibers (CF, diameter: 0.075-0.4 μm, average length: 5-50 μm); carboxylated cellulose nanofibers (CNF, carboxyl content: 1.2 mmol / g, chain length range: 1-3 μm, average diameter: 7 nm) were purchased from Qihong Technology Co., Ltd., Guilin, China; polyvinylpyrrolidone (PVP, average molecular weight: 101,200-110,000) was provided by Macklin Co. Ltd, China; and deionized water was provided by Cologne Chemical Reagent Factory, China. All chemicals were used directly without purification.

[0061] 2. Test methods It should be noted that the electromagnetic shielding performance test of the following application example uses an Agilent N5230A vector network analyzer to test a 3D printed disc with a thickness of less than 2.5 mm and a diameter of about 12 mm. The test band is the X-band (8.2~12.4 GHz). Using formulas (1)-(6), the relevant electromagnetic properties of the EMI shielding material are calculated through scattering parameters.

[0062] Where R, T, and A represent the reflection coefficient, transmission coefficient, and absorption coefficient, respectively; SE A , SE R and SE m stands for absorption attenuation, reflection attenuation and multiple internal reflection attenuation respectively; SE total and SSE represent the total EMI SE value and specific shielding value; Represents the apparent density, according to the formula: =m / V, where m and V are the weight and apparent volume of the 3D printed model, respectively. total >10 dB, SE m Can be ignored.

[0063] Example 1 A 3D printing preparation method for an electromagnetic shielding component having a parallel orientation structure, comprising: (1) Dispersion of carbon-based functional fillers At room temperature, 80 parts of carbon-based functional fillers, 20 parts of carbon fibers, 20 parts of carboxylated nanocellulose and 10 parts of PVP were added to excess water and mixed according to their mass fractions. The mixture was dispersed for 120 min using an ultrasonic cell disruptor with an ultrasonic power of 1500 W to obtain a suspension. The aspect ratio of the carbon fibers used was 8 to 10:1.

[0064] (2) Preparation of printing ink The suspension obtained in step (1) was concentrated in a water bath at 80° C., with constant stirring during the process, and the water was concentrated to 550 parts, and the prepared 3D printing ink was transferred to a sealed container.

[0065] (3) Loading ink into the 3D printing system The 3D printing ink prepared in step (2) is transferred to a dedicated printing syringe, and the pneumatic control system inside the 3D printing device of the ink writing 3D printing technology is activated.

[0066] (4) Setting of printing parameters After installation is complete, control the printing accuracy by adjusting the following printing parameters.

[0067] Print speed: 5 mm / s; Extrusion pressure: 0.5 MPa; Platform temperature: 25℃; Initial distance between needle and receiving platform: 0.7 mm; Distance between adjacent wires: 0.6 mm (The diameter of the wire strip is 0.6 mm, so after printing, the spacing between the wire strips is 0 and they are close to each other).

[0068] (5) Design of printing structure Print an electromagnetic shielding workpiece with a parallel orientation structure, that is, the laying direction of the printed wire strips of each planar unit is parallel to the same base plane, and the wire strips of each planar unit are also parallel. The planar units of this embodiment have a total of 4 layers.

[0069] Example 2 A direct writing 3D printing preparation method for an electromagnetic shielding component with a multi-axis orientation structure, comprising: (1) Dispersion of carbon-based functional fillers At room temperature, 70 parts of carbon-based functional fillers, 30 parts of carbon fibers, 20 parts of carboxylated nanocellulose and 8 parts of PVP were added to excess water and mixed, and dispersed for 120 minutes using an ultrasonic cell disruptor with an ultrasonic power of 1500 W to obtain a suspension. The aspect ratio of the carbon fibers used was 8 to 10:1.

[0070] (2) Preparation of printing ink The suspension obtained in step (1) was concentrated in a water bath at 80° C., with constant stirring during the process, and the water was concentrated to 550 parts, and the prepared 3D printing ink was transferred to a sealed container.

[0071] (3) Loading ink into the 3D printing system The ink prepared in step (2) is transferred to a dedicated printing syringe, and the pneumatic control system inside the 3D printing device of the ink writing 3D printing technology is activated.

[0072] (4) Setting of printing parameters After installation is complete, control the printing accuracy by adjusting the following printing parameters.

[0073] Printing speed: 10 mm / s; Extrusion pressure: 0.5 MPa; Platform temperature: 25℃; Initial distance between needle and receiving platform: 0.5 mm; Distance between adjacent wires: 0.6 mm. (The diameter of the wire strip is 0.6 mm, so after printing, the spacing between the wire strips is 0 and they are close to each other).

[0074] (5) Design of printing structure like Figure 3 As shown, the shielding workpiece of the printed multi-axis oriented structure, that is, the laying direction of the wire strips of each layer of the plane unit is arranged at 45° in space, but they are all parallel to the same reference plane unit in space. There are a total of 4 layers of plane units in this embodiment. It should be noted that the parallel orientation structure of Example 1 is actually a special multi-axis orientation structure. Printing a multi-axis orientation structure can adapt to a more complex electromagnetic wave environment and achieve all-round protection.

[0075] The above-mentioned Embodiment 1 and Embodiment 2 only provide two achievable orientation structure electromagnetic shielding parts. Those skilled in the art can easily think of various orientation structures similar to multi-layer crossing (such as crossing angles of 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, etc.) or crossing at intervals of several layers (such as crossing once every two layers, such as two parallel layers and two crossed layers, etc.) based on the parallel orientation and multi-axis orientation, and apply them to specific environments as long as all planar units are parallel to the same reference plane.

[0076] Example 3 A direct writing 3D printing preparation method for an electromagnetic shielding component with a parallel orientation structure is different from Example 1 in that the aspect ratio of the carbon fiber used is 66 to 200:1.

[0077] Example 4 A direct writing 3D printing preparation method for an electromagnetic shielding component with an axially oriented structure is different from Example 2 in that the aspect ratio of the carbon fiber used is 66 to 200:1.

[0078] Comparative Example 1 A method for preparing an electromagnetic shielding component with a vertical orientation structure, comprising: (1) Dispersion of carbon-based functional fillers At room temperature, 70 parts of carbon-based functional fillers, 30 parts of carbon fibers, 20 parts of carboxylated nanocellulose and 8 parts of PVP were added to excess water and mixed, and dispersed for 90 minutes using an ultrasonic cell disruptor with an ultrasonic power of 1500 W to obtain a suspension. The aspect ratio of the carbon fibers used was 8 to 10:1.

[0079] (2) Preparation of printing ink The suspension obtained in step (1) was concentrated in a water bath at 80° C., with constant stirring during the process, and the water was concentrated to 550 parts, and the prepared 3D printing ink was transferred to a sealed container.

[0080] (3) Loading ink into the 3D printing system The ink prepared in step (2) is transferred to a dedicated printing syringe, and the pneumatic control system inside the 3D printing device of the ink writing 3D printing technology is activated.

[0081] (4) Setting of printing parameters After installation is complete, control the printing accuracy by adjusting the following printing parameters.

[0082] Print speed: 8 mm / s; Extrusion pressure: 0.5 Mpa; Platform temperature: 25℃; Initial distance between needle and receiving platform: 0.7 mm; Distance between adjacent wires: 0.6 mm. (The diameter of the wire strip is 0.6 mm, so after printing, the spacing between the wire strips is 0 and they are close to each other) (5) Design of printing structure Printing shielding workpieces with vertically oriented structures, that is, structures where the wire strips of the planar units are laid perpendicular to the same reference plane ( Figure 3 ).

[0083] Comparative Example 2 A method for preparing a non-oriented electromagnetic shielding component, wherein the printing ink prepared in Example 1 is loaded into a mold by a mold pressing method, and then directly pressed to form a non-oriented electric shielding component, the structural schematic diagram of which is shown in FIG. Figure 4As shown in the microscopic diagram Figure 5 shown.

[0084] Effect test According to the above test method, the electromagnetic properties of the electromagnetic shielding components of each embodiment and comparative example were tested. The thickness of the electromagnetic shielding components was the same. The results are shown in Table 1 below: Table 1 Electromagnetic properties of electromagnetic shielding components of various embodiments Figure 1 In the table, no orientation corresponds to comparative example 2, vertical orientation corresponds to comparative example 1, parallel orientation corresponds to example 1, and multi-axis orientation corresponds to example 2. Figure 1 It can be seen that the electromagnetic shielding performance of the parallel oriented structure electromagnetic shielding component and the multi-axial oriented structure electromagnetic shielding component of Example 1 and Example 2 is significantly improved compared with the electromagnetic shielding component of the vertical oriented structure of Comparative Example 1 and the electromagnetic shielding component of the non-oriented structure of Comparative Example 2. After the aspect ratio of the carbon fiber is further increased from 8 to 10:1 to 66 to 200:1, the shielding performance of the electromagnetic shielding components prepared in Examples 3 and 4 is better than that of Examples 1 and 2.

[0085] like Figure 7 As shown, the electromagnetic shielding device of the present invention is further described for the application environment. In this application environment, the base, the sensitive element, and the customized electromagnetic shielding device constitute an electromagnetic shielding system, and the laying direction of the wire strips of the plane unit in the customized electromagnetic shielding device is perpendicular to the incident direction of the electromagnetic wave, so as to achieve the best electromagnetic shielding effect.

[0086] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and the embodiments. They can be applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily realized.

Claims

1. An anisotropic reinforced electromagnetic shielding component with an oriented structure, characterized in that: The planar units are stacked layer by layer, and the laying direction of the filamentary materials extruded by 3D printing is parallel to the same base plane. The shielding effect is best along the normal direction of the base plane.

2. The anisotropic reinforced electromagnetic shielding component with an oriented structure according to claim 1, characterized in that: According to the application environment, the laying direction is set to be perpendicular to the incident direction of the electromagnetic wave, so as to meet the shielding reinforcement of the electromagnetic waves incident in a specific direction, thereby forming an electromagnetic shielding component customized for the application environment.

3. A 3D printing preparation method for the electromagnetic shielding component according to claim 1, characterized in that: By utilizing the extrusion process in the 3D printing process, the filamentary material is arranged in an orderly manner along the flow field direction to form a macro-oriented structure, and by adding high-length-diameter rigid materials to assist the 3D printing unidirectional flow field to induce the orderly arrangement of microscopic nanoparticles to form a micro-oriented structure. The synergistic effect of the two orientation structures from micro to macro can obtain functional parts with multi-level orientation structures and anisotropic electromagnetic shielding properties.

4. The 3D printing preparation method of the electromagnetic shielding component according to claim 3, characterized in that: Specifically include: Recording 3D printing ink to the 3D printing system; Set the printing parameters of the 3D printing system to: Printing speed: 1~20 mm / s; Extrusion pressure: 0.1~0.5 MPa; Platform temperature: -20~25℃; Initial distance between needle and receiving platform: 0.5~1.5 mm; Distance between adjacent wires: 0.3~2 mm; The filament material extruded by the 3D printing system is precisely deposited in a pre-set direction and pattern: A reference plane is established. In the first layer of the basic structure, the filamentary material is laid along the set direction, turns 180° at the edge of the printing layer, and continues to advance in the adjacent but opposite parallel direction, and repeats this process until the first layer is completed to form a basic structure with consistent directionality, which is a plane unit. The second layer of stacking strictly follows the set directional pattern to lay the filaments. This process repeats this process until the top layer is reached, and the electromagnetic shielding component having several layers of basic structures and all basic structures are parallel to the same reference plane is obtained.

5. A 3D printing ink used in the preparation method of claim 3, characterized in that: The composition comprises the following components in parts by weight: Surfactant <10 parts Carbon fiber 10~50 parts Other carbon-based functional fillers 60~100 parts; 20-25 parts of viscosity regulator; 300~550 parts of water.

6. The 3D printing ink according to claim 5, characterized in that: The aspect ratio of the carbon fiber is 8 to 500:

1.

7. The 3D printing preparation method of the electromagnetic shielding component according to claim 3, characterized in that: The 3D printing ink according to claim 6 is loaded into a 3D printing system to print the electromagnetic shielding component.

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