Method for improving surface roughness of reflecting surface of composite material antenna

Abstract

According to the method for improving the surface roughness of the reflecting surface of the composite material antenna, a composite material component is trimmed to be below 10m for resin layer spraying, the thickness uniformity of a resin-rich layer is improved, then the thickness of the resin-rich layer is further ground, the thickness of the resin-rich layer is controlled to be about 40m, and the surface roughness of the reflecting surface of the composite material antenna is improved. And the possibility of cracking and deformation risks of the resin in high and low temperature environments is reduced. By adopting the method for improving the surface roughness of the reflecting surface of the composite material antenna, the surface roughness of the reflecting surface of the antenna is reduced to about 130nm by using parameters such as water-sand mixed liquid with different particle sizes, the diameter of the polishing disk, the pressure of the polishing disk, the revolution speed of polishing, the polishing time and the like, and then the surface roughness is improved; therefore, the surface roughness is controlled within a certain range, and the optimal state of the solar absorptivity and reflectivity is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of composite material antenna reflector surface roughness, and particularly relates to a method for improving the surface roughness of a composite material antenna reflector. BACKGROUND

[0002] An antenna reflector is a core component of a surface antenna, and its function is to concentrate and reflect the electromagnetic waves emitted by a feed source in a specific direction according to specific requirements. With the improvement of technical indicators of antenna performance in modern communication, radar and space technology, and in order to balance the light weight and the shape accuracy of an air antenna, a composite material antenna reflector becomes a selection for balancing light weight and high performance. However, defects such as lines, pinholes, bubbles and uneven thickness are easily generated in the resin spraying and curing process, which increases the surface roughness, affects the metallization process, and further affects the electromagnetic performance.

[0003] The pretreatment of the resin-rich layer on the surface of the composite material antenna reflector is an extremely important process in the processing technology of the antenna reflector. Due to the characteristics and use requirements of the resin material, and in combination with the current research status of resin polishing processing, the surface roughness of the resin layer is improved through polishing process. However, the surface roughness of the resin layer is difficult to control within a certain range by simply polishing the surface roughness. Excessive improvement of the surface roughness of the resin layer will cause the reflectivity to increase significantly, and the reflected light will be concentrated in a specific direction, and the solar absorption ratio will decrease. Therefore, in order to achieve the optimal state of the solar absorption ratio and the reflectivity, the polishing process of the surface roughness of the composite material antenna reflector needs to be further improved.

[0004] Patent document CN111390654A discloses a treatment method for the surface of a carbon fiber resin-based composite material, which comprises the following steps: (1) coarsely polishing the carbon fiber resin-based composite material with sandpaper having a mesh number of 200-799; (2) finely polishing the surface of the carbon fiber resin-based composite material 1-n times with sandpaper having a mesh number of 800-6999 until the surface roughness Ra is less than or equal to 0.8 microns, a different sandpaper is used each time, the mesh number of the sandpaper is increased, and the polishing direction angle of the sandpaper is changed to remove the traces of the previous polishing; and (3) finely polishing the surface of the carbon fiber resin-based composite material 1-m times with sandpaper having a mesh number of more than 7000, a different sandpaper is used each time, the mesh number of the sandpaper is increased, and the polishing direction angle of the sandpaper is changed to remove the traces of the previous polishing.

[0005] However, the patent document CN111390654A does not solve the technical problem of improving the uniformity of the surface roughness first and then improving the surface roughness to achieve the optimal state of the solar absorption ratio and the reflectivity. SUMMARY

[0006] In view of the defects in the prior art, the purpose of the present application is to provide a method for improving the surface roughness of a composite material antenna reflector.

[0007] The application provides a composite material antenna reflector surface roughness improving method, which comprises the following steps: The antenna reflector surface with an average resin layer thickness of less than 40 µm is polished by using a water-sand mixed solution with different grit sizes to reduce the surface roughness of the antenna reflector surface; The surface roughness of the antenna reflector surface is repeatedly reduced until the surface roughness of the antenna reflector surface is within the range of 90-110 nm; Then, the surface roughness of the antenna reflector surface is adjusted to increase the surface roughness again, so that the set state of the solar absorption ratio and the reflectivity is achieved.

[0008] Preferably, the surface roughness of the antenna reflector surface is adjusted to increase the surface roughness again to the range of 150-180 nm.

[0009] Preferably, the surface roughness is the surface roughness of a resin-rich layer on the surface of the antenna reflector surface.

[0010] Preferably, the water-sand mixed solution is prepared by mixing deionized water and different grit sizes of corundum at a mass ratio of 2:1.

[0011] Preferably, the polishing disc has a diameter of 30 mm, the polishing disc pressure is 3.5-30 N, the polishing public rotation speed is 300 rpm, and the public rotation speed is 200 rpm.

[0012] Preferably, the composite material antenna reflector surface mainly comprises carbon fiber as a main reinforcing material and a medium-temperature curing resin as a base material.

[0013] Preferably, after the antenna reflector surface is cured and formed, the antenna reflector surface is ground and trimmed to have a precision RMS of less than 10 µm; a resin layer is sprayed on the surface of the reflector surface, and after high-temperature post-processing at 180 °C, the antenna reflector surface is ground again to have a resin layer thickness of less than 40 µm.

[0014] Preferably, the different grit sizes of corundum include W40, W20, W10, W7 and W5.

[0015] Preferably, the polishing time is calculated according to the path of a 30 mm diameter polishing disc passing through the workpiece area and the running distance of 300 mm per minute.

[0016] The application further provides a composite material antenna, wherein the surface of the antenna reflector is processed by using the composite material antenna reflector surface roughness improving method.

[0017] Compared with the prior art, the application has the following beneficial effects: 1. This invention applies resin layer spraying to high-precision composite material surface components with a thickness of less than 10µm, which improves the overall uniformity of the resin-rich layer thickness of the composite material antenna reflector. Furthermore, through high-precision grinding, the resin-rich layer thickness is controlled to around 40µm, effectively reducing the possibility of cracking or deformation of the resin-rich layer in high and low temperature environments.

[0018] 2. This invention reduces the roughness of the antenna reflector surface to about 130nm by using parameters such as water-sand mixtures with different particle sizes, polishing disc diameter, polishing disc pressure, polishing rotation speed, and polishing time. This allows the surface roughness of the composite material antenna reflector surface to be improved after removing scratches, bubbles, textures, and other issues that affect the uniformity of surface roughness left in the early stage. In this way, the surface roughness is controlled within a certain range to achieve the optimal state of solar absorptivity and reflectivity. Attached Figure Description

[0019] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 It is one of the curved surface components in the reflector surface of a composite material antenna; Figure 2 The light reflected by the resin-rich layer from a white light source in the range of 150–180 nm has a surface roughness Ra of 0.164 μm. Figure 3 The light reflected by a white light source when the surface roughness of the resin-rich layer is below 30 nm, with a surface roughness Ra of 0.009 μm. Detailed Implementation

[0020] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0021] This invention provides a method for improving the surface roughness of the reflector surface of a composite material antenna. For antenna reflectors with an average resin layer thickness of less than 40µm after high-precision grinding and spraying, the surface roughness is reduced using parameters such as water-sand mixtures with different particle sizes, polishing disc diameter, polishing disc pressure, polishing rotation speed, and polishing time. Specifically, the water-sand mixture is prepared by mixing deionized water and diamond abrasive of different particle sizes in a 2:1 mass ratio; the polishing disc diameter is 30mm; the polishing disc pressure is 3.5–30N; the polishing rotation speed is 300rpm on its own axis and -200rpm on its revolution; and the polishing time depends on the workpiece area at the set speed. Repeatedly reduce the surface roughness of the antenna reflector until it reaches approximately 100 nm. Then, adjust the parameters to increase the surface roughness of the antenna reflector again, achieving the optimal balance between solar absorptivity and reflectivity.

[0022] Furthermore, the composite material antenna reflector is composed of carbon fiber as the main reinforcing material and medium-temperature curing resin as the matrix material. The surface roughness refers to the surface roughness of the resin-rich layer on the antenna reflector surface. Specifically, the process of achieving an antenna reflector surface with an average resin layer thickness of less than 40µm after high-precision grinding and spraying involves grinding the cured antenna reflector surface to a precision RMS better than 10µm; spraying a resin layer onto the reflector surface; post-treatment at 180℃; and then grinding the surface again to a resin layer thickness of less than 40µm. The different particle sizes of the diamond abrasive include five particle sizes: W40, W20, W10, W7, and W5. The polishing time is calculated based on the workpiece area, the path traveled by a 30mm diameter polishing disc, and a travel rate of 300mm per minute. The goal is to improve the surface roughness of the antenna reflector surface to the range of 150–180nm.

[0023] The present invention will now be described in more detail.

[0024] like Figure 1 The image shows a portion of a curved surface in a composite material antenna reflector component. The method includes the following steps: (1) The surface accuracy of the molded composite material antenna reflector component is measured. Based on the cloud map of the measurement results, the grinding program of the composite material antenna reflector is programmed. The grinding head diameter is set to 30mm, the grinding time is controlled to be about 6 hours, W40 diamond abrasive is used, the water-abrasive mass ratio is 1:2, and the grinding disc pressure is controlled within the range of 0.1 to 0.2 MPa for surface trimming. (2) Repeat step (1) until the surface accuracy is better than 10µm, then spray a layer of resin onto the reflective surface of the composite antenna. After curing at room temperature, perform high-temperature post-treatment at 180℃, and repeat step (1) until the surface accuracy is better than 10µm and the resin layer thickness is less than 40µm after the difference between the two, then start surface roughness polishing; (3) Use W20 diamond abrasive, with a water-to-abrasive mass ratio of 2:1, a polishing disc diameter of 30mm, a polishing disc pressure of 20N, and a polishing rotation speed of 300rpm and -200rpm. The polishing time is set to approximately 13 hours with a rotation speed of 300mm per minute. Polish repeatedly until the surface roughness is stable and difficult to reduce further, then stop polishing with the current settings. (5) Use W5 diamond abrasive with a water-to-abrasive ratio of 2:1. The polishing disc diameter is 30mm. The polishing disc pressure is set from high to low by 10 to 3.5N. The polishing rotation speed is 300rpm for rotation and -200rpm for revolution. The polishing time is set at 300mm per minute for approximately 13 hours. Polish repeatedly until the surface roughness is about 130nm. Although the surface roughness can continue to decrease under the current settings, polishing must be stopped immediately. Otherwise, it will be difficult to achieve the desired surface roughness during the subsequent process of increasing the surface roughness of the composite material antenna reflector. (5) Use W7 diamond abrasive, with a water-to-abrasive mass ratio of 2:1, a polishing disc diameter of 30mm, a polishing disc pressure setting from high to low of 7 to 3.5N, a polishing rotation speed of 300rpm and -200rpm, and a polishing time of approximately 13 hours with a rotation speed of 300mm per minute. Repeat polishing until the surface roughness of the antenna reflector returns to approximately 150nm, then stop polishing. (6) Based on the surface roughness test results, W10 diamond abrasive was used, with a water-to-abrasive mass ratio of 2:1. The polishing disc diameter was 30 mm, the polishing disc pressure was set to 7-3.5 N, and the polishing rotation speed was 300 rpm for rotation and -200 rpm for revolution. The polishing time was set to approximately 13 hours with a rotation speed of 300 mm per minute. The polishing was repeated 2-3 times to achieve a surface roughness of 150-180 nm for the antenna reflector. The surface roughness polishing of the composite material antenna reflector was completed.

[0025] The method for improving the surface roughness of the composite material antenna reflector provided by this invention can visually demonstrate, as shown in the following figure. Figure 2 As shown, when the surface roughness of the composite material antenna reflector is in the range of 150–180 nm, the light reflected from the white light source appears as a soft yellow light. If the surface roughness of the antenna reflector is low, the reflected light appears white, such as… Figure 3 As shown.

[0026] Table 1. Performance comparison of antenna reflectors with different surface roughnesses of different composite materials

[0027] As shown in Table 1, by comparing the solar absorptivity and diffuse reflection test results within different surface roughness ranges, the smaller the surface roughness, the lower the diffuse reflection and the relatively smaller the solar absorptivity. Since surface roughness testing is based on points, while solar absorptivity and diffuse reflection are based on surfaces, the uniformity of surface roughness will have a certain impact on solar absorptivity and diffuse reflection. In this invention, different particle sizes of abrasive grains are used to polish the surface roughness of the composite material antenna reflector to a relatively stable state. Then, by adjusting parameters such as abrasive grain size and polishing disc pressure, the surface roughness is increased to the range of 150-180 nm, resulting in a solar absorptivity close to 0.25 and a diffuse reflectivity greater than 90%.

[0028] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0029] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for improving the surface roughness of a composite antenna reflector surface, comprising: The application relates to a composite material antenna reflector surface roughness improving method. The antenna reflector surface with a resin layer with an average thickness less than 40 microns is polished by using water-sand mixed liquid with different grit sizes to reduce the surface roughness of the antenna reflector surface. The surface roughness of the antenna reflector surface is repeatedly reduced until the surface roughness of the antenna reflector surface is within the range of 90-110 nm. Then, the surface roughness of the antenna reflector surface is adjusted to be increased again to reach the set state of the solar absorption ratio and reflectivity.

2. The method of claim 1, wherein the composite antenna reflector surface roughness is increased by, The surface roughness of the antenna reflector surface is adjusted to be increased again to be within the range of 150-180 nm.

3. The method of claim 1, wherein the composite antenna reflector surface roughness is increased by, The surface roughness is the surface roughness of the resin-rich layer on the surface of the antenna reflector surface.

4. The method of claim 1, wherein the composite antenna reflector surface roughness is increased by, The water-sand mixed liquid is prepared by mixing deionized water and different grit sizes of corundum at a mass ratio of 2:

1.

5. The method of claim 1, wherein the composite antenna reflector surface roughness is increased by a factor of 2 to 5. The polishing disc has a diameter of 30 mm, the polishing disc pressure is 3.5-30 N, the polishing disc rotation speed is 300 rpm, and the rotation speed is 200 rpm.

6. The method of claim 1, wherein the composite antenna reflector surface roughness is increased by a factor of 2 to 10. The composite material antenna reflector surface is mainly composed of carbon fiber as the main reinforcing material and medium-temperature curing resin as the matrix material.

7. The method of claim 1, wherein the composite antenna reflector surface roughness is increased by a factor of 2 to 10. The antenna reflector surface after curing and forming is ground and trimmed to have a precision RMS better than 10 microns. The antenna reflector surface is sprayed with a resin layer, and after high-temperature post-processing at 180 DEG C, the antenna reflector surface is ground again to have a resin layer thickness less than 40 microns.

8. The method of claim 1, wherein the composite antenna reflector surface roughness is increased by a factor of 2 to 10. The different grit sizes of corundum include W40, W20, W10, W7 and W5.

9. The method of claim 1, wherein the composite antenna reflector surface roughness is increased by a factor of 2 to 10. The polishing time is calculated according to the path of the 30 mm diameter polishing disc and the running speed of 300 mm per minute.

10. A composite antenna, characterized by The antenna reflector surface is processed by using the composite material antenna reflector surface roughness improving method in any one of claims 1 to 9.

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