A 3D printing method, 3D printing filament and components

Abstract

This invention relates to the field of 3D printing technology, and discloses a 3D printing method, 3D printing filament, and component. The 3D printing method includes: providing a filament body made of a thermoplastic composite material; conformally coating the surface of the filament body with at least one layer of graphene oxide film to form a 3D printing filament; using the 3D printing filament to perform 3D printing to form a 3D printed component; and placing the 3D printed component in a vacuum oven for heating and drying to establish covalent bonds between the graphene oxide film and the surface of the filament body. This invention is applicable to any FDM filament with or without fiber reinforcement. By forming high-strength covalent bonds between the graphene oxide material and the filament body surface, the adhesion between the 3D printed filaments is enhanced, resulting in a significant increase in the mechanical strength and ultimate bending strength of the 3D printed component. It has broad commercial value and brings new application opportunities for 3D printing technology in aerospace, automotive, and other fields.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and more particularly to a 3D printing method, 3D printing filament, and components. Background Technology

[0002] 3D printing, or additive manufacturing, enables the creation of a wide variety of complex 3D structures with unprecedented flexibility and capability. Customization, rapid prototyping, automation, and rapid manufacturing, along with the flexibility to design complex geometries at relatively low cost and in a short time due to a simple process that eliminates the need for expensive molds or tooling, have led to incredible advancements in the field of 3D printing. Therefore, 3D printing has the potential to revolutionize component manufacturing. Several 3D printing technologies have been developed, including Fused Deposition Modeling (FDM), Direct Ink Writing (DIW), Selective Laser Sintering (SLS), and Stereolithography (SLA). Due to its low cost and simplicity, FDM, which uses thermoplastics, is considered the most widely used technology among all types of 3D printing.

[0003] However, due to the inherently low mechanical strength of thermoplastics, 3D-printed parts using traditional FDM technology exhibit poor mechanical properties. Although extensive research has been conducted to optimize processing parameters, such as lamination orientation and laminate thickness, to improve the mechanical properties of 3D-printed thermoplastic structures, the improvements have not been significant. Therefore, 3D-printed parts are primarily used for prototyping or toys and cannot be used as structural components in the aerospace or automotive sectors. Thus, achieving high-strength 3D-printed parts is crucial for expanding the applicability of 3D printing in the aerospace and automotive fields, a primary goal of industrial manufacturing.

[0004] Reinforcing materials, such as carbon, glass, and Kevlar fibers, have been added to thermoplastic composites to enhance their mechanical properties. High-performance fiber-reinforced composites (FRCs) possess high strength-to-weight ratios, low coefficients of thermal expansion, good corrosion resistance, and high thermal conductivity. They play a crucial role in various industries vital to our economy, including aerospace, construction, automotive, sports, and energy. The prototype principle has been applied to FDM 3D printing. Different reinforcing materials, such as carbon black, lamellar fibers, chopped fibers, polymer fibrils, and continuous fibers, are mixed with thermoplastics to create fiber-reinforced filaments, which are extruded during the filament printing process. Despite significant improvements in mechanical properties, they still fall short compared to conventional FRCs.

[0005] The performance of these 3D-printed FRCs largely depends on the fiber orientation and fiber volume fraction (FVF) in the plastic. Using continuous fiber reinforcement allows for excellent alignment of fiber orientation, and the FVF can be easily controlled by the amount of fiber reinforcement. Traditional FRC manufacturing processes apply high temperatures and pressure to ensure strong interfacial bonding between different materials by forming macromolecular chains of thermoplastics. In contrast, 3D printing technology suffers from relatively weak interfacial bonding between filaments and layers due to the weaker bonding forces based on van der Waals molecular interactions, resulting in incomplete adhesion of fiber reinforcement. Therefore, the mechanical properties of 3D-printed FRCs are still far inferior to those of conventional FRCs with the same FVF (only 50% of the ultimate flexural strength). Therefore, improving interfacial bonding is key to further enhancing the mechanical properties of 3D-printed FRCs. Currently, there is no method to further improve the interfacial bonding of 3D-printed FRCs, thus a technological breakthrough is urgently needed.

[0006] The above information is provided as background information only to aid in understanding this disclosure and does not constitute an assertion or admission that any of the above content can be used as prior art relative to this disclosure. Summary of the Invention

[0007] The purpose of this invention is to provide a 3D printing method, 3D printing filament, and components to improve the mechanical strength of components manufactured using fused deposition modeling (FDM) 3D printing technology.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] A 3D printing method, comprising:

[0010] Provides wire bodies made of thermoplastic composite materials;

[0011] At least one layer of graphene oxide film is conformally coated onto the surface of the filament body to form a 3D printed filament;

[0012] The 3D printing filament is used to 3D print parts.

[0013] The 3D printed part is placed in a vacuum oven for heating and drying to establish covalent bonds between the graphene oxide film and the surface of the filament body.

[0014] Optionally, the method of conformally coating the surface of the wire body with a graphene oxide film includes:

[0015] First, the wire body is placed in a positively charged polymer material solution, soaked for a first preset time, then taken out, washed with deionized water and dried.

[0016] The wire body is then placed in a graphene oxide solution and soaked for a second preset time before being removed, rinsed with deionized water, and then dried.

[0017] Optionally, a graphene oxide film can be conformally coated onto the surface of the wire body using a droplet method.

[0018] Optionally, 3D printing can be performed using the 3D printing filament under preset low humidity conditions; the humidity control range under the low humidity conditions is 1% to 5%.

[0019] Optionally, the polymer material solution is a polydiallyldimethylammonium chloride (PDDA) solution or a polyethylene adipate (PEA) solution, and the range of the first preset time and the second preset time is 15s-1min.

[0020] Optionally, during the 3D printing process using the 3D printing filament, low humidity can be achieved by filling the cavity of the 3D printer with gas, including nitrogen or argon.

[0021] Optionally, the temperature control range inside the vacuum oven is 60℃-140℃.

[0022] A 3D printing filament, comprising:

[0023] The wire body is made of a thermoplastic composite material;

[0024] A graphene oxide film, wherein the graphene oxide film covers at least a portion of the surface of the wire body.

[0025] Optionally, the thermoplastic composite material is specifically a fiber-reinforced composite material (FRC).

[0026] A 3D printed part, said 3D printed part being manufactured according to any one of the above-described 3D printing methods.

[0027] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0028] This invention is universally applicable to any FDM filament, with or without fiber reinforcement. By forming high-strength covalent bonds between the coated graphene oxide material and the filament body surface, the adhesion between 3D printed filaments is significantly enhanced, thereby achieving a significant increase in the mechanical strength of 3D printed parts.

[0029] Experimental results show that the mechanical strength of 3D printed parts made from 3D printing filaments coated with graphene oxide film is more than 70% higher than that of 3D printed parts made from 3D printing filaments without graphene oxide film coating.

[0030] More importantly, its ultimate flexural strength is even better than that of 3D-printed glass fiber reinforced composites, approaching the average value of conventional FRC, making this material very promising for aerospace and automotive applications.

[0031] Furthermore, this invention requires only a single layer of graphene oxide film to achieve significant enhancements in mechanical strength and ultimate flexural strength, saving materials and allowing the coating process to be carried out in solution, eliminating the need for a high-temperature, high-vacuum coating environment and resulting in low coating costs. Therefore, this invention offers extremely high cost-effectiveness, significantly improves the load-to-weight ratio of structures, has broad commercial value, is conducive to industrial promotion, and will bring new application opportunities for 3D printing technology in aerospace, automotive, and other fields. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart of the 3D printing method provided in the embodiments of the present invention;

[0034] Figure 2 This is a conceptual design drawing of a graphene oxide coating to enhance the strength of 3D printing.

[0035] Figure 3 This is a schematic diagram of the roll-to-roll self-assembly method for graphene oxide coating.

[0036] Figure 4 These are photographs of 3D printing filaments with and without coating; where (a) is a photograph of 3D printing filaments coated with graphene oxide film, and (b) is a photograph of 3D printing filaments without coating.

[0037] Figure 5 This is a schematic diagram of a 3D printed structure with fiber reinforcement.

[0038] Figure 6 It is the humidity curve of the 3D printing process;

[0039] Figure 7 These are photos of 3D printed test samples with and without graphene oxide coating; (a) is a 3D printed test sample without coating; (b) is a 3D printed sample with graphene oxide film coating.

[0040] Figure 8These are Raman spectra of 3D printed test samples with and without graphene oxide coating; where (a) is the Raman spectrum of the 3D printed test sample without coating; and (b) is the Raman spectrum of the 3D printed sample with graphene oxide film.

[0041] Figure 9 The X-ray photoelectron spectroscopy (XPS) curves of the 3D-printed test sample with graphene oxide coating are shown; (a) is the XPS broadband scan curve; (b) is the C1s peak; and (c) is the O1s peak.

[0042] Figure 10 These are stress curves of 3D-printed test samples with and without graphene oxide coating. Detailed Implementation

[0043] To enable those skilled in the art to better understand the embodiments of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0044] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or device.

[0045] To improve the mechanical strength of 3D printed parts, this invention provides a 3D printing method, the principle of which is as follows: Figure 2 As shown, due to the abundance of oxygen-containing functional groups on the surface of graphene oxide, some of these functional groups can be broken through a weak reduction method involving heating, forming free dangling bonds. These bonds can then form covalent bonds with the surface of another filament of graphene oxide, or between the surface of the filament and the coated graphene oxide film, achieving ultra-high surface adhesion and significantly improving the mechanical strength of the 3D printed model. Please refer to [link / reference]. Figure 1 The method specifically includes:

[0046] S101. A filament body made of thermoplastic composite material is provided, and at least one layer of graphene oxide film is conformally coated on the surface of the filament body to form a 3D printed filament.

[0047] In one alternative implementation, a method of layer-by-layer self-assembly stacking electropositive polymers and graphene oxide films can be used to conformally coat the surface of a 3D-printed filament with a graphene oxide film.

[0048] The specific steps of layer-by-layer self-assembly stacking include: first, immersing the wire body in a positively charged polymer material solution for a first preset time, then removing it, rinsing it with deionized water, and then drying it; then immersing the wire body in a graphene oxide solution for a second preset time, then removing it, rinsing it with deionized water, and then drying it.

[0049] Among them, the positively charged polymer material solution can be polydiallyldimethylammonium chloride (PDDA) or polyethylene adipate (PEA), and the range of the first preset time and the second preset time can be selected from 15s to 1min; after the soaking is completed, the wire body can be dried by blowing gas, and the gas can be compressed air or nitrogen.

[0050] It should be noted that completing the above steps will deposit one layer of graphene oxide film; repeating the above steps will achieve the deposition of multiple layers of graphene oxide film. In practical applications, the number of graphene oxide film layers can be selected according to actual needs, and the embodiments of the present invention do not impose specific limitations on this.

[0051] In another alternative implementation, a graphene oxide film can be conformally coated onto the surface of the wire body using a droplet method.

[0052] Compared with the droplet method, the layer-by-layer self-assembly stacking method is more likely to achieve uniform conformal coating and easier to control the thickness of a single layer of coating.

[0053] To meet the demand for continuous coating of large quantities of graphene oxide films, this invention designs and manufactures a roll-to-roll continuous coating machine, as shown in the schematic diagram below. Figure 3 As shown. The coating time T is determined by the length L of the wire during the coating process and the winding speed v of the wire, satisfying the following equation:

[0054] T = L / v

[0055] The length L of the wire is determined by the size of the container and the number of wire reversals. The number of wire reversals is controlled by adjusting the position, diameter, and number of pulleys. To increase production, both the winding speed and the running length can be increased. Increasing the running length can be achieved by using a larger container and increasing the number of pulleys, thereby increasing the number of reversals.

[0056] An exemplary photograph of a 3D printed filament coated with a graphene oxide film is shown below. Figure 4 As shown in (a), a photograph of the uncoated 3D printing filament is shown. Figure 4As shown in (b), the uncoated 3D printing filament is pure white, the color of glass fiber. The 3D printing filament with a graphene oxide film is significantly darker in color than the uncoated filament, due to the color of the graphene oxide.

[0057] S102. Use the 3D printing filament to perform 3D printing to produce a 3D printed part.

[0058] In this step, FDM technology is specifically applied for 3D printing, including: First, a roll of 3D printing filament is loaded into the 3D printer. Once the nozzle reaches the required temperature, the 3D printing filament is fed into the extruder head and melts in the nozzle. Second, the molten material is extruded into thin strips and deposited layer by layer at predetermined locations, where it cools and solidifies. Then, after one layer is printed, the stage descends one layer thickness along the Z-axis in predetermined increments. The material is extruded and deposited on the previously solidified material. The final 3D printed part is formed by the gradual accumulation of material layer by layer.

[0059] For ease of testing, this invention employs a design that alternates between layers of onyx (a fusion material of engineered nylon and chopped carbon fiber) and printed layers coated with graphene oxide. A schematic diagram of this design is shown below. Figure 5 As shown. In actual use, the printing order can be defined as needed.

[0060] Preferably, 3D printing is performed using 3D printing filament under preset low humidity conditions. Because the hydrophilic surface of graphene oxide easily attracts water vapor, during the printing heating process, the presence of water vapor means that most of the heating energy is used for water vapor evaporation, preventing the printing filament from heating to the preset height and affecting print quality. Therefore, this embodiment of the invention achieves low humidity by filling the 3D printer cavity with a gas, such as nitrogen or argon, controlling it between 1% and 5% to ensure print quality. The humidity change over time curve is shown below. Figure 6 As shown.

[0061] S103. The 3D printed part is placed in a vacuum oven for further heating and drying to establish covalent bonds between the graphene oxide and the filament surface.

[0062] In this step, graphene oxide is further weakly reduced by heating. This removes oxygen-containing functional groups to create dangling bonds, which ultimately form covalent bonds, enhancing the mechanical properties of the 3D printed parts. Heating and reducing graphene oxide in the presence of oxygen would directly oxidize the dangling bonds, preventing effective covalent bond formation. Therefore, an oxygen-free reduction environment is essential. The best way to create this environment is to run a post-processing cycle in a vacuum oven. When the vacuum oven is running, the internal pressure is maintained at a negative value.

[0063] The heating serves several purposes: firstly, to reduce graphene oxide and create covalent bonds. Secondly, it aims to determine how to improve the flexural stiffness and strength of the fabricated sample through heat treatment. Furthermore, to ensure the results are applicable to practical applications, the geometry of the specimen should not be significantly altered. Therefore, the selected heating temperature range is 60°C (the temperature at which graphene oxide begins to be reduced by heat) to 210°C (the glass transition point of PA6), with dimensional accuracy occurring outside this range.

[0064] For example, printed test samples such as Figure 7 As shown, the uncoated 3D-printed test sample appears transparent white, as... Figure 7 As shown in (a), the test sample with the graphene oxide coating on its surface appears brown, as... Figure 7 As shown in (b), brown represents the color of graphene oxide. The color indicates that graphene oxide successfully adheres to the surface of the printing filament and is successfully retained during the printing process. Therefore, this method is fundamentally different from the traditional method of adding graphene oxide solution during printing, which cannot achieve conformal coating.

[0065] To further confirm the successful attachment of graphene oxide to the surface of the printed filament, Raman spectroscopy was used to determine the Raman spectrum of the printed filament. Raman spectroscopy is a high-resolution, non-invasive characterization technique, well-suited for analyzing nanostructured carbon materials. Laser-induced excitation of surface molecular vibrational modes reveals information about electronic and phonon behavior. Graphene and graphene oxide exhibit distinct Raman characteristics, which is why Raman spectroscopy was chosen as the characterization technique in this embodiment of the invention. The most prominent features in the Raman spectrum of graphene oxide are the first-order D and G bands, which are generated by the vibrations of sp2 carbon. The D and G bands appear at 1344 cm⁻¹, respectively. -1 and 1597cm -1 nearby. Figure 7 Raman spectra of the uncoated sample and the graphene oxide coated sample are shown. Figure 8 The spectrum in (a) shows no correlation with the characteristic peaks of graphene oxide. However, Figure 8 The coating sample in (b) was at 1330 cm⁻¹ -1 and 1595cm -1 The peak value was found at a point less than 1% different from the published value, which strongly proves that the graphene oxide film was successfully deposited on the surface of the wire body.

[0066] Furthermore, this embodiment uses X-ray photoelectron spectroscopy (XPS) to analyze the chemical composition of the wire surface coated with graphene oxide. XPS is a technique for analyzing the chemical composition of material surfaces (1-10 nm). The characteristic XPS peaks of graphene oxide are fully documented in the literature and will be used as indicators for comparing our spectra. Figure 9 (a) shows the C1s and O1s peaks located at 284.6 eV and 532.6 eV, respectively, in broad scan spectra. One way to quantify the oxygen content of graphene oxide is to measure the carbon-oxygen (C / O) atomic ratio. This is done by comparing the areas of the C1s and O1s spectra determined from XPS. Typically, the C / O ratio of graphene oxide ranges from 1.5 to 2.5. Our nanomaterial has a C / O ratio of 2.31, which is well within the known range for graphene oxide. The binding energies of the C1s peaks are 284.27, 285.59, 286.96, and 288.65 eV. Figure 9 (b) represents C=C (32.03%), CO (24.75%), C=O (31.58%), and OC=O (7.42%) bonds, respectively. The peaks with O1s binding energies of 531.43, 533.54, and 534.1 eV ( Figure 9 (c) represents OC=O (64.82%), C-OH (28.24%), and COO (6.94%) bonds, respectively. The peak positions are consistent with those in the literature. Using this characterization method, it is possible to demonstrate the presence of graphene oxide on the surface and determine the percentage of oxygen-containing functional groups after deposition.

[0067] Quasi-static bending tests were conducted on a universal testing machine (Instron model 5965) equipped with a 10 kN load cell and a crosshead speed of 1.5 mm / min. According to the aforementioned standards, the radii of the loading head and the two support rollers (bending die) were all 5.0 mm, and the test specimens were guaranteed a minimum span-to-thickness ratio (L / t) of 16:1 to a maximum of 40:1 L / t. Historical force and displacement records were documented during the bending tests, and the specimens behaved as simply supported beams, with the nominal bending stress σ... f Use the following formula to calculate.

[0068]

[0069] Where F is the load applied in the middle of the specimen (N), L is the span length (mm), and b and d are the width and thickness of the specimen (mm), respectively. The load is applied until the maximum strain on the outer surface of the specimen reaches 5% of the deformation, or if fracture occurs before reaching the maximum strain, the load is applied at fracture. The nominal strain can be calculated using the following equation.

[0070]

[0071] Where D is the corresponding mid-span deflection, which in this example is the machine displacement.

[0072] Here, uncoated samples are used as a benchmark to compare the improvements in mechanical strength resulting from graphene oxide coating and post-treatment. The results are as follows: Figure 10 As shown, the maximum stress of the 3D-printed sample without graphene oxide coating was 206±1N, while the maximum stress of the sample with graphene oxide coating and post-processing was 351±1N, with an overall improvement of 70%. All measurements were averaged from multiple measurements, ensuring their accuracy and reliability.

[0073] This invention also provides a 3D printing filament, comprising: a filament body made of a thermoplastic composite material; and a graphene oxide film covering at least a portion of the surface of the filament body.

[0074] The wire body can be any FDM wire with or without fiber reinforcement, or it can be a fiber-reinforced composite material (FRC).

[0075] Based on the same inventive concept, this embodiment of the invention also provides a 3D printed part, which is manufactured according to the 3D printing method described above.

[0076] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A 3D printing method, characterized by, The application relates to a 3D printing method and a 3D printing component. A wire body made of a thermoplastic composite material is provided. A graphene oxide film is conformally coated on the surface of the wire body to form a 3D printing wire. The 3D printing wire is used for 3D printing to form a 3D printing component. The 3D printing component is placed in a vacuum oven for warm drying treatment to form a covalent bond between the graphene oxide film and the surface of the wire body.

2. The 3D printing method according to claim 1, characterized in that, The method for conformally coating the graphene oxide film on the surface of the wire body comprises the following steps: The wire body is first placed in a solution of a positively charged polymer material, soaked for a first preset time, taken out, washed with deionized water and dried. Then the wire body is placed in a graphene oxide solution, soaked for a second preset time, taken out, washed with deionized water and dried.

3. The 3D printing method of claim 1, wherein, The graphene oxide film is conformally coated on the surface of the wire body in a dropwise manner.

4. The 3D printing method of claim 1, wherein, The 3D printing wire is used for 3D printing under a preset low humidity condition, and the humidity control range is 1% to 5% under the low humidity condition.

5. The 3D printing method of claim 2, wherein, The solution of the polymer material is a polydiallyldimethylammonium chloride (PDDA) solution or a polyethylene adipate (PEA) solution, and the first preset time and the second preset time are 15 seconds to 1 minute.

6. The 3D printing method of claim 4, wherein, During the 3D printing process of the 3D printing wire, the low humidity is realized by filling a gas into the cavity of a 3D printer, and the gas includes nitrogen or argon.

7. The 3D printing method of claim 1, wherein, The temperature control range in the vacuum oven is 60 DEG C to 140 DEG C.

8. A 3D-printed wire made by the 3D-printing method according to any one of claims 1 to 7, characterized in that The application relates to a 3D printing method and a 3D printing component. A wire body made of a thermoplastic composite material is provided. A graphene oxide film is conformally coated on the surface of the wire body to form a 3D printing wire.

9. The 3D printing filament of claim 8, wherein, The 3D printing wire is used for 3D printing to form a 3D printing component.

10. A 3D printed part, characterized in that, The 3D printing component is placed in a vacuum oven for warm drying treatment to form a covalent bond between the graphene oxide film and the surface of the wire body. The method for conformally coating the graphene oxide film on the surface of the wire body comprises the following steps: The wire body is first placed in a solution of a positively charged polymer material, soaked for a first preset time, taken out, washed with deionized water and dried. Then the wire body is placed in a graphene oxide solution, soaked for a second preset time, taken out, washed with deionized water and dried. The graphene oxide film is conformally coated on the surface of the wire body in a dropwise manner. The 3D printing wire is used for 3D printing under a preset low humidity condition, and the humidity control range is 1% to 5% under the low humidity condition. The solution of the polymer material is a polydiallyldimethylammonium chloride (PDDA) solution or a polyethylene adipate (PEA) solution, and the first preset time and the second preset time are 15 seconds to 1 minute. During the 3D printing process of the 3D printing wire, the low humidity is realized by filling a gas into the cavity of a 3D printer, and the gas includes nitrogen or argon. The temperature control range in the vacuum oven is 60 DEG C to 140 DEG C. The application relates to a 3D printing method and a 3D printing component. A wire body made of a thermoplastic composite material is provided. A graphene oxide film is conformally coated on the surface of the wire body to form a 3D printing wire. The 3D printing wire is used for 3D printing to form a 3D printing component. The 3D printing component is placed in a vacuum oven for warm drying treatment to form a covalent bond between the graphene oxide film and the surface of the wire body. The method for conformally coating the graphene oxide film on the surface of the wire body comprises the following steps: The wire body is first placed in a solution of a positively charged polymer material, soaked for a first preset time, taken out, washed with deionized water and dried. Then the wire body is placed in a graphene oxide solution, soaked for a second preset time, taken out, washed with deionized water and dried. The graphene oxide film is conformally coated on the surface of the wire body in a dropwise manner. The 3D printing wire is used for 3D printing under a preset low humidity condition, and the humidity control range is 1% to 5% under the low humidity condition. The solution of the polymer material is a polydiallyldimethylammonium chloride (PDDA) solution or a polyethylene adipate (PEA) solution, and the first preset time and the second preset time are 15 seconds to 1 minute. During the 3D printing process of the 3D printing wire, the low humidity is realized by filling a gas into the cavity of a 3D printer, and the gas includes nitrogen or argon. The temperature control range in the vacuum oven is 60 DEG C to 140 DEG C.

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