Additive manufacturing modified material with wave absorbing function and manufacturing method thereof

Abstract

The invention provides an additive manufacturing modified material with a wave absorbing function and a manufacturing method thereof.The manufacturing method of the additive manufacturing modified material with the wave absorbing function comprises the steps that low-viscosity semi-crystalline thermoplastic resin, a wave absorbing agent and a nucleating agent are evenly mixed at a high speed according to a certain proportion; feeding the mixed powder into a double-screw extruder through a hopper, heating to a molten state, and pelletizing at an outlet to obtain master batch particles; feeding the master batch particles, high-viscosity semi-crystalline thermoplastic resin and reinforced fibers into a double-screw extruder according to a certain proportion, heating to a molten state, and pelletizing at an outlet; granules are directly used as fused deposition modeling additive manufacturing raw materials, or filaments are further prepared through a single-screw extruder and traction and rolling equipment. The problems that in the printing process of a high-temperature cavity (above the glass transition temperature), a model is prone to collapse and deformation, the surface is rough, and the electromagnetic performance of a printed product has anisotropy can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of additive manufacturing, in particular to an additive manufacturing modified material with wave-absorbing function and a manufacturing method thereof. BACKGROUND

[0002] The wave-absorbing structure usually has a relatively complex configuration, and can realize the low RCS effect of the component in cooperation with the wave-absorbing material. Fused deposition modeling is a 3D printing process based on material extrusion. The thermoplastic resin filament or particles are sent into a heated printing nozzle for melting through gear driving. The molten material is deposited layer by layer according to the printing path. The fused deposition modeling process of the wave-absorbing thermoplastic polymer can realize the manufacturing of the wave-absorbing structure with high design freedom. CN118755231A provides a 3D printing carbonyl iron powder / polyether ether ketone composite material filament, so that the printed structure has a wave-absorbing function. However, the printed structure has serious electromagnetic anisotropy, that is, the electromagnetic properties of the product in different directions are different, and the electromagnetic properties in the Z direction are more than 3 times different from those in the X and Y directions. This is mainly due to the principle of the traditional fused deposition modeling process. The poor fluidity of the material leads to poor interlayer fusion and obvious condensed state difference between layers. The poor dispersibility of the wave-absorbing agent in the high-viscosity resin material leads to uneven dispersion, causing electromagnetic anisotropy of the 3D printed product. In addition, when the cavity temperature is high during the printing process, the model needs to have high strength at high temperature to prevent the model from collapsing and deforming. CN119155978A provides a method for preparing a 3D printed product with anisotropic electromagnetic properties, which discloses the problem of large difference in electromagnetic properties in different directions of the 3D printed product. SUMMARY

[0003] The present application provides an additive manufacturing modified material with wave-absorbing function and a manufacturing method thereof, which improves the problems of easy collapse, deformation, surface roughness of the model during the printing process in the high-temperature cavity (above the glass transition temperature), and electromagnetic anisotropy of the printed product.

[0004] In a first aspect, the present application provides a manufacturing method of an additive manufacturing modified material with wave-absorbing function, comprising: mixing a low-viscosity semi-crystalline thermoplastic resin, a wave-absorbing agent and a nucleating agent uniformly at a certain proportion at a high speed; feeding the mixed powder into a double-screw extruder through a hopper, heating to a molten state, and cutting at the outlet to obtain masterbatch particles; feeding the masterbatch particles, a high-viscosity semi-crystalline thermoplastic resin and reinforcing fibers into a double-screw extruder at a certain proportion, heating to a molten state, and cutting at the outlet; using the granules directly as raw materials for fused deposition modeling additive manufacturing, or further preparing long filaments through a single-screw extruder and traction and winding equipment.

[0005] Further, the high-viscosity semi-crystalline thermoplastic resin has a melt index of 1-10 g / 10 min, and the low-viscosity semi-crystalline thermoplastic resin has a melt index of 15-30 g / 10 min.

[0006] Further, the high-viscosity semi-crystalline thermoplastic resin and the low-viscosity semi-crystalline thermoplastic resin have the same molecular monomer structure.

[0007] Further, the semi-crystalline thermoplastic resin is any one or more of polypropylene, polylactic acid, nylon, polyformaldehyde, polyphenylene sulfide, polyether ether ketone, polyether ketone ketone, and polyaryletherketone.

[0008] Further, the high-viscosity semi-crystalline thermoplastic resin and the low-viscosity semi-crystalline thermoplastic resin have the same molecular monomer structure.

[0009] Further, the wave-absorbing agent is any one or both of a magnetic loss wave-absorbing agent and an electric loss wave-absorbing agent. The magnetic loss wave-absorbing agent is any one or more of iron powder, nickel powder, cobalt powder, ferrite, and carbonyl iron, and the electric loss wave-absorbing agent is any one or more of carbon powder, carbon black, carbon nanotube, carbon fiber, graphite, graphene, and silicon carbide. The content of the wave-absorbing agent is 1-10% by weight of the additive manufacturing modified material.

[0010] Further, the nucleating agent is any one or both of dibenzyl sorbitol and its derivatives and aromatic phosphate salt. The content of the nucleating agent is 0.1-20% by weight of the additive manufacturing modified material.

[0011] Further, the reinforcing fiber is any one or more of carbon fiber, glass fiber, quartz fiber, mullite fiber, basalt fiber, lignin fiber, natural fiber, carbon nanotube fiber, ceramic fiber, boron fiber, aramid fiber, Kevlar fiber, ultra-high molecular weight polyethylene fiber, liquid crystal polymer, optical fiber, polyaryletherketone fiber, nylon fiber, and polyimide fiber. The content of the reinforcing fiber is 0-20% by weight of the additive manufacturing modified material.

[0012] In a second aspect, the present application provides an additive manufacturing modified material with wave-absorbing function, which is obtained based on the manufacturing method of the additive manufacturing modified material with wave-absorbing function as described above.

[0013] In a third aspect, the present application provides the use of the additive manufacturing modified material with wave-absorbing function as described above in the field of additive manufacturing.

[0014] The above technical solutions of the present application have the following advantages: The manufacturing method of the additive manufacturing modified material with wave-absorbing function provided in the first aspect of the present application comprises the following steps: uniformly mixing low-viscosity semi-crystalline thermoplastic resin, wave-absorbing agent and nucleating agent at a certain proportion at a high speed, feeding the mixed powder into a double-screw extruder through a hopper, heating to a molten state, and cutting at the outlet to obtain master batch particles; feeding the master batch particles, high-viscosity semi-crystalline thermoplastic resin and reinforcing fibers into the double-screw extruder at a certain proportion, heating to a molten state, and cutting at the outlet to obtain granules; and directly using the granules as a raw material for fused deposition modeling additive manufacturing, or further preparing a filament through a single-screw extruder and traction and winding equipment. The two-step method is used to prepare the material, the low-viscosity material disperses the wave-absorbing agent to make the master batch, and then the master batch is mixed with the high-viscosity resin to provide high-temperature strength, thereby avoiding the problems that the wave-absorbing agent is difficult to mix uniformly in different flowability blended resins and the wave-absorbing agent is difficult to disperse in high-viscosity resin materials, and improving the electromagnetic anisotropy and shape roughness of the 3D printing product.

[0015] It can be understood that the beneficial effects of the second aspect and the third aspect described above can be referred to the related description in the first aspect described above, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the specific embodiments or prior art in the present application, the drawings needed to be used in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.

[0017] Figure 1 The flow chart of the manufacturing method of the additive manufacturing modified material with wave-absorbing function provided in the present application. DETAILED DESCRIPTION

[0018] In order to make the technical problems, technical solutions and beneficial effects of the present application more clearly understood, the present application will be further described in detail below with examples. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0019] In the present application, "at least one" means one or more, and "multiple" means two or more. "At least one of the following" or similar expressions means any combination of these items, including any combination of single item or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can represent a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, wherein a, b, and c can be single or multiple.

[0020] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0021] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0022] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a well-known unit of mass in the chemical industry, such as µg, mg, g, or kg.

[0023] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0024] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application.

[0025] Modified 3D printing materials mainly include high-viscosity semi-crystalline thermoplastic resin, low-viscosity semi-crystalline thermoplastic resin, microwave absorber, nucleating agent and reinforcing fiber.

[0026] like Figure 1 As shown, this application provides a method for manufacturing an additively modified material with wave-absorbing function, comprising the following steps: (1) Mix the low-viscosity semi-crystalline thermoplastic resin, microwave absorber and nucleating agent in a certain proportion using a high-speed mixer until homogeneous.

[0027] (2) The powder mixed in step (1) is fed into a twin-screw extruder through a hopper and heated until the resin is fully mixed in a molten state. The powder is then granulated at the outlet to obtain masterbatch granules.

[0028] (3) The masterbatch granules prepared in step (2), high viscosity semi-crystalline thermoplastic resin with the same molecular structure, and reinforcing fiber are fed into a twin-screw extruder in a certain proportion and heated until the resin is fully mixed in the molten state, and then granulated at the outlet.

[0029] (4) The granules in step (3) can be used directly as raw materials for fused deposition modeling additive manufacturing, or filaments can be prepared by a single screw extruder and traction and winding equipment.

[0030] The high-viscosity semi-crystalline thermoplastic resin has a melt index of 1-10 g / 10 min. During the printing process at high-temperature chamber temperature (above the glass transition temperature), the material has high high-temperature strength, high zero-shear viscosity, poor fluidity, and certain strength under nozzle extrusion. The overall shape retention of the product is good, and the surface is less affected by dragging force during nozzle movement, resulting in low roughness.

[0031] Low-viscosity semi-crystalline thermoplastic resins have a melt index of 15-30 g / 10min. During high-temperature chamber printing (above the glass transition temperature), they exhibit good material flow between layers, which is beneficial for interlayer fusion. High-viscosity and low-viscosity semi-crystalline thermoplastic resins have the same molecular monomer structure; the difference lies in their molecular weight and molecular weight distribution. Semi-crystalline thermoplastic resins refer to resin materials whose polymer chains are arranged in a certain regular sequence, possessing a certain degree of crystallinity, and can be processed when heated to a certain temperature. These include, but are not limited to, polypropylene, polylactic acid, nylon, polyoxymethylene, polyphenylene sulfide, polyetheretherketone, polyetherketoneketone, and polyaryletherketone. The combined content of high-viscosity and low-viscosity semi-crystalline thermoplastic resins in modified 3D printing materials ranges from 75% to 99% by weight.

[0032] Microwave absorbing agents mainly include two types: magnetic loss absorbing agents and electrical loss absorbing agents. Magnetic loss absorbing agents mainly include various magnetic metal powders and their compounds, such as iron powder, nickel powder, cobalt powder, ferrite, and iron carbonyl. Electrical loss absorbing agents mainly include carbon powder, carbon black, carbon nanotubes, carbon fibers, graphite, graphene, and silicon carbide. Their content is 1-10% by weight.

[0033] Nucleating agents are additives that promote the formation of crystal nuclei. Their main function is to alter the crystallization behavior of polymers, increase the crystallization rate, and enhance crystal density and crystallinity. The primary role of nucleating agents during printing is that, during the extrusion and deposition of material from a high-temperature nozzle (above the melting temperature) into the printing cavity, the material undergoes a rapid crystallization process, transitioning from above the melting temperature to below the melting temperature but above the glass transition temperature. This is a relatively short, non-isothermal crystallization process. To ensure the product maintains high strength at the high cavity temperature, a high degree of crystallinity is required. Therefore, nucleating agents are added to promote rapid crystallization during the non-isothermal crystallization stage of extrusion. Adding nucleating agents can effectively prevent product collapse and deformation during printing and improve surface roughness. Nucleating agents mainly include, but are not limited to, dimethicone (DBS) and its derivatives, aromatic phosphate salts, substituted benzoates, mica, calcium carbonate, silica, POSS, carbon nanotubes, etc. Their content ranges from 0.1% to 20% by weight.

[0034] Reinforcing fibers mainly include organic fibers, inorganic fibers, or metal wires, including carbon fiber, glass fiber, quartz fiber, mullite fiber, basalt fiber, lignin fiber, natural fiber, carbon nanotube fiber, ceramic fiber, boron fiber, aramid fiber, Kevlar fiber, ultra-high molecular weight polyethylene fiber, liquid crystal polymer (LCP), optical fiber, polyaryletherketone fiber, nylon fiber, polyimide fiber, etc. Their content, by weight, ranges from 0-20%.

[0035] The technical solution of this application will be further described below with reference to specific embodiments.

[0036] Example 1 In this embodiment, polyetheretherketone (PEEK) is selected as the resin matrix, and the synergistic effect of high-viscosity and low-viscosity resins is achieved through molecular weight control. The high-viscosity PEEK has a molecular weight of 500,000 (melt index 5 g / 10 min) and accounts for 70% of the total mass; the low-viscosity PEEK has a molecular weight of 200,000 (melt index 20 g / 10 min) and accounts for 20% of the total mass. The microwave absorber is carbonyl iron powder with a particle size ≤ 5 μm, accounting for 5% of the total mass; the nucleating agent is dimethicone (DBS), accounting for 2% of the total mass; and the reinforcing fiber is short-cut carbon fiber with a length of 3 mm, accounting for 3% of the total mass.

[0037] Preparation method First, low-viscosity PEEK, carbonyl iron powder, and DBS are placed in a high-speed mixer in a specific ratio and mixed at 3000 rpm for 10 minutes to ensure the microwave absorber is initially and evenly dispersed in the low-viscosity resin. Then, the mixed powder is added to the hopper of a twin-screw extruder. The extruder temperature is set to 300℃ for the front section, 340℃ for the middle section, and 380℃ for the rear section, with a screw speed of 180 rpm, allowing the materials to be fully mixed in a molten state. The molten material is then cut into 6mm diameter masterbatch granules by a pelletizer at the twin-screw extruder outlet. Next, the masterbatch granules and high-viscosity PEEK are added back to the twin-screw extruder in a specific ratio. The temperature is adjusted to 280℃ to 380℃, and the screw speed is 220 rpm. This melt blending further optimizes the uniformity of the material system, and the final pelletized product is the printed granule material.

[0038] Example 2 In this embodiment, polyaryletherketone (PAEK) is used as the resin matrix. The high-viscosity PAEK has a molecular weight of 600,000 (melt index 6 g / 10 min) and accounts for 40% of the total mass; the low-viscosity PAEK has a molecular weight of 180,000 (melt index 25 g / 10 min) and accounts for 37% of the total mass. The microwave absorber is a composite powder of graphene (3 wt%) and carbonyl iron powder (7 wt%), accounting for 10% of the total mass; the nucleating agent is polysiloxane-modified nanoparticles (POSS), accounting for 3% of the total mass; and the reinforcing fiber is 10 μm diameter glass fiber, accounting for 10% of the total mass. Preparation method First, low-viscosity PAEK and graphene / carbonyl iron powder composite powder are added to a high-speed mixer in a specific ratio and mixed at 5000 rpm for 20 minutes to ensure uniform dispersion of the microwave absorber in the low-viscosity resin. Then, the mixture and POSS nucleating agent are added to a twin-screw extruder. The extruder temperature is set to 320℃ in the front section, 360℃ in the middle section, and 400℃ in the rear section, with a screw speed of 180 rpm. This allows the materials to fully melt and undergo initial blending under gradient heating conditions. After pelletizing, masterbatch granules are obtained. Next, the masterbatch granules are added to a twin-screw extruder with high-viscosity PAEK and glass fiber for secondary blending. The extruder temperature is set to 320℃ in the front section, 360℃ in the middle section, and 400℃ in the rear section, with a screw speed of 200 rpm. The material is directionally drawn at the outlet to obtain a finished printing filament material with a diameter of 1.75 mm.

[0039] Example 3 In this embodiment, polyphenylene sulfide (PPS) is used as the resin matrix. The high-viscosity PPS has a molecular weight of 400,000 (melt index 5 g / 10 min) and accounts for 40% of the total mass; the low-viscosity PPS has a molecular weight of 150,000 (melt index 30 g / 10 min) and accounts for 40% of the total mass. The microwave absorber and nucleating agent are carbon nanotubes (5 wt%), and the reinforcing fiber is carbon fiber, accounting for 15% of the total mass.

[0040] Preparation method First, low-viscosity PPS and carbon nanotubes are added to a high-speed mixer and mixed at 3000 rpm for 15 minutes to ensure the microwave absorber is evenly dispersed on the surface of the low-viscosity resin. Then, the mixture is added to a twin-screw extruder, with the extruder temperature set to 290℃ in the front section, 310℃ in the middle section, and 320℃ in the rear section, and the screw speed set to 220 rpm. Initial blending is achieved through the shearing action of the screw. The molten material is then pelletized to obtain masterbatch granules. These masterbatch granules are then added to a twin-screw extruder with high-viscosity PPS and carbon fibers for secondary blending. The extruder temperature is set to 290℃ in the front section, 310℃ in the middle section, and 330℃ in the rear section, and the screw speed is increased to 200 rpm. Finished printing filament material with a diameter of 1.75 mm is then produced using a traction device.

[0041] This application provides a method for manufacturing additive manufacturing modified materials with microwave absorption function. It proposes a two-step method: first, a low-viscosity material is used to disperse the microwave absorbing agent to create a masterbatch, which is then mixed with a high-viscosity resin to provide high-temperature strength. This avoids the problems of uneven mixing of the microwave absorbing agent in resins with different flowability and poor dispersion of the microwave absorbing agent in high-viscosity resin materials. This improves the electromagnetic anisotropy and surface roughness of 3D printed products. It also improves the electromagnetic anisotropy caused by poor interlayer flowability during 3D printing and addresses the problems of model collapse, deformation, and poor surface roughness caused by insufficient material strength at high temperatures during printing.

[0042] This application also provides an additive manufacturing modified material with wave-absorbing function, which is obtained based on the manufacturing method of the additive manufacturing modified material with wave-absorbing function as described above.

[0043] This application also provides the application of the additive manufacturing modified material with wave-absorbing function as described above in the field of additive manufacturing.

[0044] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. This application is not limited to the specific methods described above and shown in the figures. Furthermore, for the sake of brevity, detailed descriptions of known methods and techniques are omitted here.

[0045] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application 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 this application, and should all be included within the protection scope of this application.

Claims

1. A method for manufacturing an additive manufacturing modified material having a wave-absorbing function, characterized by, The application relates to a method for manufacturing an additive manufacturing modified material with a wave-absorbing function. The low-viscosity semi-crystalline thermoplastic resin, the wave-absorbing agent and the nucleating agent are uniformly mixed at a certain proportion at high speed; The mixed powder is sent into a double-screw extruder through a hopper and heated to a molten state, and then pelletized at the outlet to obtain a master batch particle; The master batch particle, the high-viscosity semi-crystalline thermoplastic resin and the reinforcing fiber are sent into a double-screw extruder at a certain proportion and heated to a molten state, and then pelletized at the outlet; The granules are directly used as a raw material for fused deposition modeling additive manufacturing, or further prepared into a filament through a single-screw extruder and traction and winding equipment.

2. The method of claim 1, wherein the material is a material for additive manufacturing. The high-viscosity semi-crystalline thermoplastic resin has a melt index of 1-10 g / 10 min; and the low-viscosity semi-crystalline thermoplastic resin has a melt index of 15-30 g / 10 min.

3. The method of claim 1, wherein the material is a material for additive manufacturing modified to have a wave-absorbing function. The high-viscosity semi-crystalline thermoplastic resin and the low-viscosity semi-crystalline thermoplastic resin have the same molecular monomer structure.

4. The method of claim 1, wherein the material is a material for additive manufacturing. The semi-crystalline thermoplastic resin is any one or more of polypropylene, polylactic acid, nylon, polyformaldehyde, polyphenylene sulfide, polyether ether ketone, polyether ketone ketone and polyaryletherketone.

5. The method of claim 1, wherein the material is a material for additive manufacturing. The content of the high-viscosity semi-crystalline thermoplastic resin and the low-viscosity semi-crystalline thermoplastic resin is 75%-99% of the weight of the additive manufacturing modified material.

6. The method of claim 1, wherein the material is a material for additive manufacturing modified with a wave-absorbing function. The wave-absorbing agent is any one or both of a magnetic loss wave-absorbing agent and an electric loss wave-absorbing agent; The magnetic loss wave-absorbing agent is any one or more of iron powder, nickel powder, cobalt powder, ferrite and carbonyl iron; the electric loss wave-absorbing agent is any one or more of carbon powder, carbon black, carbon nanotube, carbon fiber, graphite, graphene and silicon carbide; and the content of the wave-absorbing agent is 1-10% of the weight of the additive manufacturing modified material.

7. The method of claim 1, wherein the material is a material for additive manufacturing. The nucleating agent is any one or both of dibenzyl sorbitol and its derivative and aromatic phosphate salt; and the content of the nucleating agent is 0.1-20% of the weight of the additive manufacturing modified material.

8. The method of claim 1, wherein the material is a material for additive manufacturing modified with a wave-absorbing function. The reinforcing fiber is any one or more of carbon fiber, glass fiber, quartz fiber, mullite fiber, basalt fiber, lignin fiber, natural fiber, carbon nanotube fiber, ceramic fiber, boron fiber, aramid fiber, Kevlar fiber, ultra-high molecular weight polyethylene fiber, liquid crystal polymer, optical fiber, polyaryletherketone fiber, nylon fiber and polyimide fiber; and the content of the reinforcing fiber is 0-20% of the weight of the additive manufacturing modified material.

9. An additive manufacturing modified material with wave-absorbing function, characterized in that, The method for manufacturing the additive manufacturing modified material with the wave-absorbing function is based on any one of claims 1 to 8.

10. The additive manufacturing modified material with the wave-absorbing function according to claim 9 is applied in the field of additive manufacturing.

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