Method for coating carbon fibers on the surface of a three-dimensionally printed carbon fiber composite material

Abstract

The application provides a carbon fiber coating method for a three-dimensional printing carbon fiber composite material surface, through simultaneously coating a metal net and a carbon fiber cloth layer on the three-dimensional printing carbon fiber composite material surface, and adding a process step of a separation film and vacuum compression, the mechanical properties and the heat conduction properties of the coated part are obviously improved, so that the working load and the service life of the part can be greatly improved, and the part surface also plays a decorative role, has the characteristics of simple preparation process, low manufacturing cost and the like, and has high implementability in industrialized production, has great market potential and broad application prospect, and plays an important role in popularization and application of carbon fiber composite materials in robot lightweight.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new material processing technology, and particularly relates to a carbon fiber coating method for the surface of three-dimensional printing carbon fiber composite material. BACKGROUND

[0002] The carbon fiber composite material is commonly used to replace part of metal material due to its advantages of high specific strength, high specific modulus, fatigue resistance, corrosion resistance, low expansion coefficient, vibration resistance, strong designability, easy large-area integral forming, and wear resistance, and has been widely applied in the fields of aerospace, military and civil. The three-dimensional printing technology has the advantages of low cost, high productivity, short research and development cycle, and easy processing of complex models. The combination of the carbon fiber composite material and the three-dimensional printing technology can simultaneously exert the advantages of the material properties and the forming method, and solve the problems of complicated forming process of the carbon fiber composite material and difficulty in manufacturing complex structure models.

[0003] With the development trend of robot lightweight, material lightweight has greater weight reduction potential and broader application range than structural lightweight. The three-dimensional printing carbon fiber composite material can replace the aluminum alloy to manufacture the mechanical arm joint, so that the overall weight can be greatly reduced, and the mechanical inertia, the accuracy and the energy consumption can be reduced. However, the mechanical arm cannot work under heavy load, because the forming pressure in the three-dimensional printing process is small, the fiber impregnation is insufficient, the porosity of the formed carbon fiber composite material is high, the fiber volume content is low, and the mechanical properties need to be improved. In addition, the thermal conductivity of the carbon fiber composite material is far lower than that of metal materials such as aluminum alloy, and the local part of the mechanical arm joint will overheat during long-term work. Since the heat resistance of the resin matrix is not high, the resin layer in the thickness direction will be damaged first, thereby greatly shortening the service life of the mechanical arm.

[0004] Therefore, in order to enable the three-dimensional printing carbon fiber composite material to be more widely applied in the field of robots, how to simultaneously improve the mechanical properties and the thermal conductivity of the three-dimensional printing carbon fiber composite material becomes a difficult problem to be solved. SUMMARY

[0005] The present application provides a carbon fiber coating method for the surface of three-dimensional printing carbon fiber composite material, which is used to solve the defects of insufficient mechanical properties and thermal conductivity of the three-dimensional printing carbon fiber composite material in the prior art. The method simultaneously coats a metal mesh and a carbon fiber cloth layer on the surface of the three-dimensional printing carbon fiber composite material, and increases the process steps of the isolation film and the vacuum compression, so that the thermal conductivity and the mechanical properties of the three-dimensional printing short carbon fiber composite material are greatly improved, and the three-dimensional printing carbon fiber composite material can be more widely applied in the field of robots.

[0006] The present application provides a carbon fiber coating method for the surface of three-dimensional printing carbon fiber composite material, which comprises:

[0007] S1, polishing and wiping the surface of the component to be coated clean;

[0008] S2, after mixing and stirring the primer evenly, evenly applying the primer on the surface of the component treated in S1;

[0009] S3, laying the metal mesh cut to a predetermined size on the surface of the component obtained in S2;

[0010] S4, laying the carbon fiber cloth cut to a predetermined size on the surface of the metal mesh;

[0011] S5, covering the surface of the component treated in S4 with a layer of release film;

[0012] S6, placing the component treated in S5 into a vacuum bag, sealing and vacuumizing;

[0013] S7, placing the component treated in S6 into a heating device and heating for 1-2 hours or at least 12 hours at room temperature, until the glue layer on the surface of the component is completely cured, and the heating temperature is set at 40-60 degrees;

[0014] S8, taking out the component treated in S7 from the heating device, removing the release film covering the surface of the component, trimming the excess laying layer on the edge of the component, and polishing the surface of the component flat;

[0015] S9, mixing and slowly stirring the top glue evenly, standing for 5-10 minutes, then evenly applying a thin layer of top glue on the surface of the component treated in S8, heating the component with top glue in a heating device for 1-3 hours or at least 3 hours at room temperature, setting the heating temperature at 40-60 degrees, waiting for the top glue on the surface of the component to complete solidification, then applying a thin layer of top glue again, then heating the component in the heating device again, repeating the operation until 3-4 layers of top glue are applied;

[0016] S10, after the glue layer on the surface of the component treated in S9 is completely cured, polishing and polishing the surface of the component, and spraying paint to obtain a carbon fiber coated component finished product;

[0017] The primer is an epoxy resin carbon fiber primer, which is divided into main agent A and curing agent B, and the mass ratio is 1:1;

[0018] The top glue is a carbon fiber coated epoxy resin top glue, which is divided into main agent A and curing agent B, and the mass ratio is 2:1;

[0019] The heating device is an intelligent digital electric heating oven or a heating furnace.

[0020] According to the carbon fiber covering method for the surface of the three-dimensional printing carbon fiber composite material provided by the application, the part to be covered is preferably a three-dimensional printing carbon fiber composite material.

[0021] According to the carbon fiber covering method for the surface of the three-dimensional printing carbon fiber composite material provided by the application, the metal mesh is preferably a 20-mesh to 100-mesh red copper mesh, the number of covering layers is 1-2 layers, and the carbon fiber cloth is preferably 3K plain weave or twill carbon fiber cloth, and the number of covering layers is 1-2 layers.

[0022] According to the carbon fiber covering method for the surface of the three-dimensional printing carbon fiber composite material provided by the application, the isolation film is preferably a preservative film, and the material of the vacuum bag is preferably polyamide and polyethylene.

[0023] According to the carbon fiber covering method for the surface of the three-dimensional printing carbon fiber composite material provided by the application, by simultaneously covering the metal mesh and the carbon fiber cloth on the surface of the three-dimensional printing carbon fiber composite material, and adding the process steps of the isolation film and the vacuum compression, the mechanical properties and the heat conduction properties of the covered part are obviously improved, so that the working load and the service life of the part can be greatly improved, and the part surface also plays a decorative role. The preparation process is simple, the manufacturing cost is low, the implementability is high in industrial production, has great market potential and broad application prospect, and plays an important role in the popularization and application of carbon fiber composite materials in robot lightweight. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0025] Figure 1 It is a process route map of the carbon fiber covering method for the surface of the three-dimensional printing carbon fiber composite material provided by the application;

[0026] Figure 2 It is a mechanical arm part effect drawing provided by the application.

[0027] Reference signs:

[0028] 1: mechanical arm joint body; 2: inner layer copper mesh composite layer; 3: outer layer carbon fiber cloth composite layer. DETAILED DESCRIPTION

[0029] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below in combination with the drawings in the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the protection scope of the present application.

[0030] The present application provides a carbon fiber coating method for the surface of a three-dimensional printed carbon fiber composite material. Figures 1-2 The present application provides a carbon fiber coating method for the surface of a three-dimensional printed carbon fiber composite material.

[0031] The present application provides a carbon fiber coating method for the surface of a three-dimensional printed carbon fiber composite material. Figure 1 , Figure 1 The present application provides a carbon fiber coating method for the surface of a three-dimensional printed carbon fiber composite material.

[0032] The three-dimensional printed carbon fiber composite material is applied in the field of robots, such as multiple mechanical arm joints formed by the three-dimensional printed carbon fiber composite material. When the mechanical arm is working, it cannot work continuously for a long time, because the carbon fiber composite material has poor thermal conductivity, and overheating phenomenon occurs locally. Since the heat resistance of the resin matrix is not high, the resin layer in the thickness direction will be damaged first, greatly shortening the service life of the mechanical arm. At the same time, it cannot work under heavy load, because the mechanical properties of the parts formed by this technology need to be improved. In summary, especially for parts with complex curved surface structures, the mechanical properties and thermal conductivity of the three-dimensional printed carbon fiber composite material need to be improved.

[0033] Currently, there is no three-dimensional printed carbon fiber composite material that can overcome the above problems at the same time. Therefore, the surface of the part can be treated to solve the problem. For example, the surface carbon fiber coating process and the thermal conductive coating method can be used. For example, the carbon fiber cloth and epoxy resin glue are coated on the surface of the helmet to improve the mechanical properties of the helmet. The thermal conductive material is applied on the surface of the part to improve the heat dissipation capacity and thermal conductivity of the part. Neither of the two technologies can overcome the above two problems at the same time.

[0034] In order to solve the technical problems in the prior art, the present application provides a carbon fiber coating method for the surface of a three-dimensional printed carbon fiber composite material. The part to be coated is a three-dimensional printed carbon fiber composite material PA12-CF. The specific carbon fiber coating steps of the carbon fiber composite part are as follows:

[0035] S1, surface pretreatment: polishing and wiping the surface of the part to be coated clean.

[0036] Specifically, first, the surface of the part is roughened with 150 mesh sandpaper until the printed texture on the surface disappears, then the surface is polished again with 400 mesh sandpaper, and finally the surface is wiped clean with alcohol and dried.

[0037] S2, primer: after the primer is uniformly mixed and stirred, the surface of the part treated in S1 is uniformly coated with the primer.

[0038] Specifically, the epoxy resin carbon fiber primer AB component (A main agent and B curing agent) is mixed and stirred uniformly at a mass ratio of 1:1, and then a thick layer of primer is uniformly coated on the surface of the part treated in S1 using a nylon brush. The primer has good adhesion to the carbon fiber cloth.

[0039] S3, surface layer: cut the metal mesh to the desired size and lay it on the surface of the part obtained in S2, then cut the carbon fiber cloth to the desired size and lay it on the surface of the metal mesh.

[0040] Specifically, first, cut the 60 mesh red copper mesh to the appropriate size and lay it on the surface of the part obtained in S2, then cut the 3K twill carbon fiber cloth to the appropriate size and lay it on the surface of the red copper mesh; the 60 mesh red copper mesh has good electrical conductivity and thermal conductivity, is a soft metal, is easy to attach to a curved surface, has appropriate pores, and can penetrate the epoxy resin primer to better bond the carbon fiber cloth; the 3K twill carbon fiber cloth has appropriate mechanical properties and is relatively soft, making it easy to attach to a curved surface.

[0041] S4, cover the isolation film: completely cover the surface of the part treated in S3 with an isolation film.

[0042] Specifically, cut the cling film to the appropriate size and completely cover the surface of the part treated in S3, ensuring that the surface is flat and smooth; the cling film can be easily separated from the glue layer and can be flattened under negative pressure, and has the characteristics of simple preparation process, low manufacturing cost, and high implementability in industrial production.

[0043] S5, put into vacuum bag: put the part treated in S4 into a vacuum bag, seal it and vacuum it.

[0044] Specifically, place the part treated in S4 into a food vacuum bag, seal it, and then use a food vacuum pump to vacuum it, ensuring that the vacuum bag does not leak and that the primer completely wets the layers and tightly adheres to the surface of the part; the cling film can isolate the part from direct contact with the vacuum bag, protecting the vacuum bag for normal use.

[0045] The material of the vacuum bag is polyamide and polyethylene (PA+PE), which is green and environmentally friendly, greatly reducing the process cost.

[0046] S6, curing: the parts treated in S5 are placed in a heating device for 1-2 hours or at room temperature for at least 12 hours until the glue layer on the surface of the parts is completely cured, and the heating temperature is set at 40-60 degrees.

[0047] Specifically, the parts treated in S5 are placed in an electric oven, and the temperature is set at 60 degrees for 1 hour until the glue layer on the surface of the parts is completely cured.

[0048] Of course, the heating device can be an intelligent digital electric oven or a heating furnace.

[0049] S7, surface pretreatment: the parts treated in S6 are taken out of the heating device, the isolation film covering the surface of the parts is removed, the excess layer on the edge of the parts is cut off, and the surface of the parts is polished flat.

[0050] Specifically, the parts treated in S6 are taken out of the heating device, the plastic wrap is removed, the excess layer on the edge is cut off, and the surface is polished flat with 400 grit sandpaper;

[0051] S8, surface glue coating: mix the surface glue slowly and uniformly, stand for 5-10 minutes, then evenly coat a thin layer of surface glue on the surface of the parts treated in S7, after coating, the parts coated with surface glue are heated in a heating device for 1-3 hours or at room temperature for at least 3 hours, the heating temperature is set at 40-60 degrees, after the surface glue on the surface of the parts is completely solidified, a thin layer of surface glue is coated again, then the parts are heated in the heating device again, and the operation is repeated until 3-4 layers of surface glue are coated.

[0052] Specifically, the carbon fiber coated epoxy resin surface glue AB component is mixed slowly and uniformly at a mass ratio of 2:1, and after standing for 10 minutes, a thin layer of surface glue is evenly coated on the surface of the parts treated in S7 with a nylon brush, and then placed in an electric oven with a temperature setting of 60 degrees for 1 hour. After the first layer of glue layer is solidified, a thin layer of surface glue is coated again, and then the parts are heated in the heating device again. Repeat the operation until 3 layers of surface glue are coated. The curing effect of the surface glue is good, which can protect the surface of the parts and play a decorative role.

[0053] S9, surface post-treatment: after the surface glue layer of the parts treated in S8 is completely cured, the surface is polished and painted to obtain the carbon fiber coated part product.

[0054] After the carbon fiber coated part product obtained by the embodiment of the application and the carbon fiber cloth coated part product are subjected to heat conduction performance and mechanical property experiments, the data obtained are shown in Table 1.

[0055] Table 1

[0056]

[0057]

[0058] The difference from the existing carbon fiber coating process is that the existing carbon fiber coating process is mainly applied to simple curved surface plastic parts such as automobile steering wheels, bicycle frames and helmets, and only carbon fiber cloth layers are coated, which can improve the mechanical properties of the plastic parts and play a decorative role on the surface. The present application can be used on the surface of a three-dimensional printed carbon fiber composite part with a complex curved structure, such as a mechanical arm joint, and simultaneously coats a metal mesh and a carbon fiber cloth layer, and adds a process step of a separation film and vacuum compression. Compared with coating only carbon fiber cloth layers on the surface of a three-dimensional printed carbon fiber composite material, the mechanical properties and thermal conductivity of the coated part are significantly improved, the bending strength is increased by 28%, reaching 176.76 MPa, the elastic modulus is increased by 22%, reaching 11.14 GPa, and the thermal conductivity is increased by 31%, reaching 0.388 W / m·K, thereby greatly improving the working load and service life of the part, and also playing a decorative role on the surface of the part.

[0059] In addition, in related technical research, such as using copper mesh for the skin surface of an airplane to play a lightning protection role, because the skin mainly uses carbon fiber composite materials, the carbon fiber composite material has low electrical conductivity and anisotropy, and a large resistivity, and after being affected by lightning, ablation occurs to cause damage to the skin. Here, the copper mesh is attached to the outermost layer of the woven carbon fiber cloth, and a laminated plate of carbon fiber composite material with a copper mesh protective layer on the surface is made by molding, and then the laminated plate with a certain rigidity is fixed to the skin with rivets. Therefore, the copper mesh is indirectly attached to the outermost surface of the skin. Since copper has good electrical conductivity, it can reduce the resistivity of the skin surface of the airplane, so that the current can be easily dissipated, thereby protecting the skin of the airplane from damage caused by lightning.

[0060] For example, the layered structure resin-based pantograph slide plate is made of a composite material and a layered copper mesh by hot pressing, and multiple layers of copper mesh are laid in the slide plate structure, which mainly utilizes the good electrical conductivity of the copper mesh, which is a soft metal, as the main conductive component of the slide plate, and also improves the toughness of the slide plate.

[0061] Please refer to Figure 2 , Figure 2 The mechanical arm part effect drawing provided by the present application.

[0062] The mechanical part comprises a mechanical arm joint body 1, a copper mesh inner layer composite layer 2 and an outer layer carbon fiber cloth composite layer 3. In the application, the carbon fiber cloth is at the top layer, and the copper mesh is below the carbon fiber cloth. The main use is that the copper mesh has good heat conductivity and belongs to a soft metal. In the structure, the epoxy resin primer can partially penetrate the pores of the copper mesh, and is well combined with the carbon fiber cloth, so that the copper mesh is coated to form a stable coating film, which is directly attached to the surface of the three-dimensional printing carbon fiber composite material part with a complex curved surface structure, so as to improve the mechanical properties and heat conductivity of the part, the film thickness is small, no mold is needed, and the part can be made at room temperature, the process is simple, the cycle is short, the efficiency is high, and the cost is low.

[0063] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of carbon fiber coating for a surface of a three-dimensional printed carbon fiber composite material, characterized by, The application relates to a carbon fiber coating method and a carbon fiber coating part. S1, polishing and cleaning the surface of a part to be coated; The part to be coated is a three-dimensional printing carbon fiber composite material; The three-dimensional printing carbon fiber composite material is applied to a mechanical arm of a robot; S2, uniformly mixing and stirring a primer, and uniformly applying the primer on the surface of the part treated in S1; S3, laying a metal mesh cut to a preset size on the surface of the part obtained in S2, and then laying a carbon fiber cloth cut to a preset size on the surface of the metal mesh; the specific method comprises the following steps: cutting a 60-mesh red copper mesh, laying one layer of the red copper mesh on the surface of the part obtained in S2, and then laying one layer of a 3K twill carbon fiber cloth on the surface of the red copper mesh; the 60-mesh red copper mesh and the 3K twill carbon fiber cloth can be attached to a curved surface; S4, covering the surface of the part treated in S3 with an isolation film; S5, placing the part treated in S4 into a vacuum bag, sealing the vacuum bag, and then vacuumizing the vacuum bag; S6, placing the part treated in S5 into a heating device and heating the part for 1-2 hours or at least 12 hours at normal temperature until the glue layer on the surface of the part is completely solidified; the heating temperature is set to be 40-60 DEG C; S7, taking out the part treated in S6 from the heating device, removing the isolation film covering the surface of the part, cutting off the excess laying layer at the edge of the part, and polishing the surface of the part with a 400-mesh water sandpaper; S8, uniformly mixing and slowly stirring a top glue, standing for 5-10 minutes, uniformly applying a thin layer of the top glue on the surface of the part treated in S7, heating the part coated with the top glue in the heating device for 1-3 hours or at least 3 hours at normal temperature, setting the heating temperature to be 40-60 DEG C, waiting for the top glue on the surface of the part to be completely solidified, again applying a thin layer of the top glue, and then again heating the part in the heating device, repeating the operation until 3-4 layers of the top glue are applied; S9, after the glue layer on the surface of the part treated in S8 is completely solidified, polishing and polishing the surface of the part, and then spraying paint to obtain a carbon fiber coated part product; The primer is an epoxy resin carbon fiber primer, which is divided into a main agent A and a curing agent B, and the mass ratio is 1:1; The top glue is a carbon fiber coating epoxy resin top glue, which is divided into a main agent A and a curing agent B, and the mass ratio is 2:1; The heating device is an intelligent digital electric heating oven or a heating furnace.

2. The carbon fiber coating method of a three-dimensional printed carbon fiber composite material surface according to claim 1, characterized by, The isolation film is a preservative film, and the material of the vacuum bag is polyamide and polyethylene.

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