Preparation method and application of integral solid supporting rod

Abstract

The invention relates to a preparation method and application of an integral solid supporting rod, and relates to the technical field of carbon fiber composites.The preparation method of the integral solid supporting rod comprises the steps that carbon fiber cloth and a chopped carbon fiber net tire are needled into composite cloth, and after the composite cloth is rolled to the diameter of 30 mm, an anti-scattering tool is installed; the rod core is formed by first needling and then re-needling, then the rod core is wrapped with composite cloth, and staged gradient needling is conducted according to the diameter, specifically, the needling depth of the section of 30-50 mm is 14-15 mm, the needling density is 26-32 stitches / cm, the needling depth of the section of 50-80 mm is 14-18 mm, the needling density is 23-32 stitches / cm, the needling depth of the section larger than 80 mm is 14-19 mm, and the needling density is 23-32 stitches / cm; and finally, heating and curing to obtain the integral solid support rod. The prepared integral solid supporting rod has the advantages of being excellent in mechanical property, adaptive to different sizes and capable of being produced on a large scale.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of carbon fiber composite materials, in particular to a preparation method and application of a whole solid support rod. BACKGROUND

[0002] With the continuous rise of the demand for lightweight, high-strength and high-modulus materials in the high-end manufacturing field, the preparation technology of carbon fiber support rods, as the core framework of composite materials, has become a key link restricting the upgrading of the downstream industry. The demand in the fields of aerospace, new energy vehicles, high-end equipment manufacturing and the like accounts for more than 70%, which promotes the development of carbon fiber support rod preparation technology towards high efficiency, precision and integration. In the common production process, carbon fiber weaving and resin impregnation process, chopped fiber molding process and 3D printing forming technology are the three most widely used preparation methods, but they all have inherent defects that are difficult to overcome.

[0003] As the most mature technology path, the carbon fiber weaving + resin impregnation process interweaves carbon fiber tows into a blank body according to a specific texture (such as plain weave, twill weave and satin weave) through a weaving machine, and then impregnates and solidifies the resin to form a product. The advantage of this process is that the fiber orientation is controllable, and it is suitable for preparing complex-shaped parts. However, the core problem of this process is that the production efficiency is extremely low. On the one hand, the weaving process relies on manual or semi-automatic equipment. For example, it takes 8-12 hours to weave a single carbon fiber support rod with a diameter of 200 mm, which is difficult to meet the demand of large-scale production. On the other hand, the resin impregnation process is prone to uneven impregnation, which causes bubbles or dry spots inside the support rod, and stress concentration is easy to occur after subsequent solidification.

[0004] The short fiber molding process cuts the carbon fiber into short fibers, mixes them with the resin matrix to make a prepreg, and then places it in a mold for pressure and heat curing. The characteristics of this process are fast forming speed and low equipment investment, and it is widely used in batch production scenes such as automobile parts. However, this process faces serious delamination problems when preparing large-diameter products. Since the length of the chopped fiber is usually 3-10 mm, the bridging effect between the fibers is weak, and during the molding process, the fiber-rich area and the resin-rich area are easy to form a delamination interface due to uneven pressure transmission inside the large-diameter blank. When the product diameter exceeds 300 mm, the delamination defect rate is as high as 40-50% or more, which causes the mechanical properties of the product to drop sharply, such as the axial compression strength being reduced by 25%-30% compared with the designed value, which cannot meet the use requirements of load-bearing structures such as wind power main shafts and large storage tanks.

[0005] 3D printing, a relatively new technology that has emerged in recent years, uses fused deposition modeling (FDM) and photopolymerization to deposit carbon fiber composite materials layer by layer. It offers advantages such as high design freedom, no need for molds, and rapid iteration, making it suitable for small-batch customized products. However, its fatal flaw lies in the low interlayer bonding strength. Due to the layer-by-layer deposition characteristic of 3D printing, the layers are only connected by the adhesive effect of resin, resulting in poor fiber continuity. The interlayer shear strength is typically only 40%-50% of that of traditional weaving processes. 3D-printed carbon fiber support rods have a high probability of interlayer delamination failure under lateral loads, and carbon fibers are prone to agglomeration during the printing process, leading to uneven fiber distribution within the support rod and further exacerbating performance fluctuations. While the three existing mainstream processes each have their own strengths, they all have significant shortcomings in efficiency, performance stability, and structural adaptability, making it difficult to meet the comprehensive requirements of high-end manufacturing for carbon fiber support rods. Summary of the Invention

[0006] The purpose of this application is to provide a method for manufacturing a solid integral support rod and its application. This method can improve the mechanical properties of the support rod and increase its applicability. At the same time, it can also be adapted to the manufacturing of support rods of different sizes, making it suitable for mass production.

[0007] Firstly, the method for manufacturing an integral solid support rod provided in this application adopts the following technical solution: A method for manufacturing a solid integral support rod includes the following steps: S1. Composite fabric is obtained by combining carbon fiber cloth and short-cut carbon fiber mesh. S2. Roll up the composite fabric from step S1, cut it after it reaches the reference diameter, install the anti-scattering fixture, and obtain the rolled rod core. S3. Perform the first needle piercing on the rod core in step S2, and then perform a second needle piercing to obtain a needle-pierced rod core; S4. Lay a composite fabric on the outside of the needle-punched rod core from step S3, and continue needle-punching to obtain a semi-finished product; wherein when the diameter of the semi-finished product is 30-50mm, use a needle-punching depth of 14-15mm and a needle-punching rate of 26-32 needles / cm. 2 Needling is performed to determine the needle density; when the diameter of the semi-finished product is 50-80mm, a needle depth of 14-18mm and a needle density of 23-32 needles / cm are used. 2 Needling is performed to determine the needle density; when the diameter of the semi-finished product is greater than 80mm, a needle depth of 14-19mm and a needle density of 23-32 needles / cm are used. 2 Acupuncture was performed to determine the acupuncture density; S5. Curing treatment: The semi-finished product is heated, kept at a certain temperature, and then cooled naturally before being taken out of the furnace to obtain a solid support rod.

[0008] By adopting the above technical solution, a composite structure of carbon fiber cloth and chopped carbon fiber mesh is used. This structure ensures the overall mechanical strength and tensile properties of the support rod by relying on the carbon fiber cloth, while the chopped carbon fiber mesh increases the internal fiber interweaving density, enhancing structural integrity and reducing the risk of delamination. The core component of the rod undergoes a double-ring needle-punching process, consisting of one initial ring and one secondary ring, to improve core density and build a stable core for subsequent gradient needle-punching. Furthermore, this application allows for differentiated gradient needle-punching parameters based on the different diameters of the support rod. Smaller diameters utilize a more concentrated needle-punching depth and density, while larger diameters adjust the needle-punching depth and density. This avoids excessive needle-punching that could damage fibers at small diameters, while ensuring that needle-punching effectively targets deep fibers at larger diameters, guaranteeing a uniform and dense overall structure. The curing process prevents excessively rapid heating that could cause internal stress and defects, and segmented curing ensures full cross-linking of the carbon fiber material, further strengthening the structural stability and mechanical properties of the support rod.

[0009] Optionally, the diameter of the semi-finished product is 30-45 mm, the needle-punching depth is 14-14.5 mm, and the needle-punching density is 26-30 needles / cm. 2 .

[0010] By adopting the above technical solution, for semi-finished products with a diameter of 30-45mm, a needle penetration depth of 14-14.5mm and a needle penetration rate of 26-30 needles / cm are selected. 2 The needle-punching density is precisely tailored to the structural requirements of this diameter range. This needle-punching depth ensures that the needles penetrate the outer composite fabric and act on the core, avoiding both insufficient depth leading to weak bonding between the inner and outer fibers, and excessive depth damaging the already formed core structure; while 26-30 needles / cm 2 The density ensures that the carbon fibers are fully interwoven to improve the compactness of the support rod and enhance the overall mechanical strength, while preventing the carbon fibers from breaking due to excessive density. Ultimately, this allows the support rod to have a uniform internal structure and reliable performance within this size.

[0011] Optionally, the diameter of the semi-finished product is 50-60 mm, the needle-punching depth is 14-16 mm, and the needle-punching density is 26-32 needles / cm. 2 .

[0012] By adopting the above technical solution, for semi-finished products with a diameter of 50-60mm, a needle penetration depth of 14-16mm and a needle penetration rate of 26-32 needles / cm are used. 2 The needle-punching density precisely matches the structural reinforcement requirements for this size. This diameter range is thicker than smaller support rods, and the 14-16mm needle-punching depth penetrates the outer composite fabric to reach the inner layer, ensuring full interweaving of fibers between the inner and outer layers; 26-32 needles / cm. 2The needle-punching density ensures that the carbon fibers are tightly bonded to improve the overall rigidity of the support rod, while avoiding excessive density that could cause the carbon fibers to break. The combination of these two factors gives the support rod, at this diameter, both a uniform and dense internal structure and reliable mechanical properties, meeting the requirements for deformation resistance and delamination resistance in subsequent high-temperature applications.

[0013] Optionally, the diameter of the semi-finished product is 60-80 mm, the needle-punching depth is 14-18 mm, and the needle-punching density is 23-32 needles / cm. 2 .

[0014] By adopting the above technical solution, for semi-finished products with a diameter of 60-80mm, a needle penetration depth of 14-18mm and a needle density of 23-32 needles / cm are selected. 2 The needle-punching density can be precisely adapted to the structural characteristics and performance requirements of this size. Within this diameter range, the support body thickness increases, and a needle-punching depth of 14-18mm effectively penetrates the outer composite fabric, preventing loose bonding between the inner and outer fibers; 23-32 needles / cm. 2 The needle-punching density ensures that the fibers are fully interwoven to improve the compactness and overall rigidity of the support rod, while avoiding carbon fiber breakage and damage due to excessive density.

[0015] Optionally, the diameter of the semi-finished product is 80-125 mm, the needle-punching depth is 14-17 mm, and the needle-punching density is 26-30 needles / cm. 2 .

[0016] By adopting the above technical solution, within this diameter range, the support rod can be thicker, and with a needle-punching depth of 14-17mm, it can completely penetrate the outer composite fabric, allowing the needle-punching effect to extend to the inner layer, thereby ensuring the continuity of the overall structure; while 26-30 needles / cm 2 The needle-punching density can both improve the tightness of the support rod through appropriate fiber interlacing and enhance the rod's resistance to deformation, and prevent carbon fiber breakage caused by excessive density, thus avoiding affecting the material properties.

[0017] Optionally, the diameter of the semi-finished product is 125-140 mm, the needle-punching depth is 14-17 mm, and the needle-punching density is 26-32 needles / cm. 2 .

[0018] By adopting the above technical solution, for semi-finished products with a diameter of 125-140mm, a needle penetration depth of 14-17mm and a needle penetration rate of 26-32 needles / cm are used. 2 The needle-punching density is adaptable to the structural reinforcement requirements of large-sized support rods. For rods in this diameter range that are relatively thick, a needle-punching depth of 14-17mm ensures that the needles penetrate multiple layers of composite fabric, promoting tight interweaving of inner and outer fibers and preventing loose bonding between the core and outer layers; 26-32 needles / cm. 2The density can enhance the degree of fiber entanglement, improve the overall compactness and structural stiffness, and at the same time avoid fiber damage caused by excessive needle punching.

[0019] Optionally, the diameter of the semi-finished product is greater than 140 mm, the needle-punching depth is 14-18 mm, and the needle-punching density is 26-32 needles / cm. 2 .

[0020] By adopting the above technical solution, the thickness of the rod body with this diameter is significantly increased, and the needle-punching depth of 14-18mm can penetrate multiple layers of composite fabric and act on the inner layer, allowing the fibers of the inner and outer layers to fully intertwine and bond, effectively avoiding the problem of separation between the inner and outer layers; 26-32 needles / cm 2 The appropriate density can improve the overall tightness and structural strength of the support rod through the proper interweaving of fibers, while preventing carbon fiber breakage and damage caused by excessive density.

[0021] Optionally, the areal density of the carbon fiber cloth is 300-400 g / m². 2 The tread density of the chopped carbon fiber mesh is 50-100 g / m². 2 .

[0022] By adopting the above technical solution, 300-400g / m 2 The carbon fiber cloth has a sufficient amount of continuous fibers, which can serve as the skeleton of the composite structure, providing core mechanical support for the support rod and ensuring the required strength, tensile strength, and deformation resistance of the support rod; 50-100g / m 2 Short-cut carbon fiber mesh fills the gaps between carbon fiber fabrics, increasing the overall fiber weaving density of the material and preventing looseness or voids in the structure. The balanced ratio of the two ensures that there are no mechanical performance deficiencies due to insufficient carbon fiber fabric surface density, nor material redundancy or structural heaviness due to excessive mesh surface density, providing an easy-to-process and stable composite substrate for subsequent winding and needle punching.

[0023] Optionally, the heating temperature in S5 is 280-300℃.

[0024] By adopting the above technical solution, the temperature does not exceed the upper limit of carbon fiber's tolerance and will not cause damage to the carbon fiber's microstructure. While ensuring the curing effect, it can retain the material's own strength and high temperature resistance to the greatest extent, so that the bracket has excellent structural stability and resistance to high temperature deformation after molding, making it suitable for subsequent high temperature scenarios.

[0025] Secondly, the integral solid support rod provided in this application has the following applications: Application of a solid support rod in the photovoltaic and semiconductor fields.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. Compared with the prior art, this application prepares a composite fabric by combining carbon fiber cloth and carbon fiber mesh, and uses double-ring needle punching in the preparation of the rod core. According to the actual production needs, different sizes of support rods are needle punched using a gradient needle punching method, which effectively increases the applicability of the support rod and is conducive to mass production. At the same time, the gradient needle punching method helps to increase the interlayer shear strength of the support rod, thereby improving the service life of the support rod. 2. Compared with the prior art, this application uses a gradient needle punching method to prepare the support rod by integral needle punching, which increases the compressive strength of the support rod compared with the splicing process, and is beneficial to increase the load-bearing capacity of the support rod. Detailed Implementation

[0027] Unless otherwise specified, the parameters and sources of the specific chemical substances used in the preparation examples, embodiments, and comparative examples of this application, and all raw materials used are commercially available products: Carbon fiber cloth, model: UT70-30, Toray Industries, Inc., Japan.

[0028] Example 1 A method for manufacturing a solid integral support rod includes the following steps: First, prepare the composite fabric: a fabric with a surface density of 300 g / m² is used. 2 The carbon fiber cloth was laid flat for inspection, and surface fuzz and wrinkles were removed; then the surface density was 100g / m². 2 The chopped carbon fiber mesh is stretched out using a flattening device. Then, the needle-punching laminating machine is adjusted, with carbon fiber cloth as the bottom layer and the chopped carbon fiber mesh as the top layer. The layers are passed through the unwinding mechanism of the needle-punching laminating machine, and the laminating speed is controlled at 6 m / min to prepare the composite fabric. Next, the rod core is rolled: the prepared composite fabric is pre-treated and output smoothly through the unwinding device, while the initial tension of the winding machine is adjusted to 10N; after starting the winding machine, the mandrel is rotated at a constant speed of 5r / min, and the composite fabric is tightly wound spirally along the mandrel. The diameter of the rod core is monitored in real time by a laser diameter gauge. The machine pauses every 3 layers and uses a micrometer to select 3 measuring points evenly in the circumference of the rod core to verify the diameter. When the diameter reaches 30mm, the winding machine automatically stops and the rod core is cut perpendicular to the axis of the rod core; then, a semi-circular anti-scattering clamp suitable for a 30mm diameter rod core is selected, and the clamp is symmetrically fastened to both ends of the rod core. The bolts are tightened at a uniform speed to complete the installation of the anti-scattering tooling; the rolled rod core is thus obtained. Then, the rod core is needle-punched: First, the rolled rod core with the anti-scattering fixture installed is fixed on the rotating clamp of the needle-punching machine; before the first needle-punching, the needle plate depth of the needle-punching machine is calibrated to 14mm, and the needle density is set to 20 needles / cm. 2After starting the acupuncture machine, the needle plate vertically punctures the needle core at a frequency of 20 times / second, while the core rotates at a speed of 5 rpm. After the first round of acupuncture, maintaining the puncture depth at 14 mm, the needle density is increased to 25 needles / cm. 2 Perform a second puncture, adjusting the rod core rotation speed to 5 r / min during the second puncture, so that the puncture points are staggered with the initial puncture points, resulting in a dense puncture rod core.

[0029] Next, gradient needle punching is performed: First, the needle core is fixed in the rotating position of the needle punching machine. Then, the composite fabric prepared in the above steps is taken out and wrapped around the core along its circumference. Subsequently, the needle punching machine is started, and the needle punching depth is calibrated to 14mm and the needle punching density is set to 28 needles / cm. 2 The rod core rotates at 5 rpm. After needling, the diameter is monitored using a laser diameter gauge until the rod diameter reaches 35 mm. The needling machine is then paused, and the needling depth is calibrated to 14.5 mm and the needling density is set to 30 needles / cm. 2 The rod core rotates at a speed of 5 r / min until the diameter of the support rod reaches 37.5 mm, then the needle punching ends, and the gradient needle punching semi-finished product is obtained.

[0030] Finally, a curing process is performed: the gradient needle-punched semi-finished product is first placed in an oven, the initial temperature is set to 0℃, then the heating program is started, the heating rate is set to 1℃ / min, until 280℃ is reached, then it is kept at 280℃ for 6 hours, and then naturally cooled to 30℃ and taken out of the oven to obtain an integral solid support rod.

[0031] Example 2 The difference between Embodiment 2 and Embodiment 1 in this application lies in gradient needle punching.

[0032] The gradient needle punching process in Embodiment 2 of this application is as follows: First, fix the needle core in the rotating position of the needle punching machine, then take out the composite fabric prepared in the above process and wrap it around the circumference of the core; then start the needle punching machine, calibrate the needle depth to 14mm and the needle density to 28 needles / cm. 2 The rod core rotates at 5 r / min. After needling, the diameter is monitored using a laser diameter gauge until it reaches 40 mm. The needling machine is then paused, and the needling depth is calibrated to 15 mm and the needling density is set to 26 needles / cm. 2 The rod core rotates at 5 r / min until the rod diameter reaches 50 mm. Then, pause the acupuncture machine, calibrate the acupuncture depth to 16 mm, and set the acupuncture density to 32 needles / cm². 2 The rod core is rotated at a speed of 5 r / min, and the diameter is monitored with a laser diameter gauge until it reaches 52.5 mm. The needling ends, and the gradient needling semi-finished product is obtained.

[0033] Example 3 The difference between Embodiment 3 and Embodiment 1 in this application lies in gradient needle punching.

[0034] The gradient needle punching process in Embodiment 3 of this application is as follows: First, fix the needle core in the rotating position of the needle punching machine, then take out the composite fabric prepared in the above process and wrap it around the circumference of the core; then start the needle punching machine, calibrate the needle depth to 14mm and the needle density to 28 needles / cm. 2 The rod core rotates at 5 r / min. After needling, the diameter is monitored using a laser diameter gauge until it reaches 40 mm. The needling machine is then paused, and the needling depth is calibrated to 15 mm and the needling density is set to 26 needles / cm. 2 The rod core rotates at 5 r / min until the rod diameter reaches 50 mm. Then, pause the acupuncture machine, calibrate the acupuncture depth to 16 mm, and set the acupuncture density to 32 needles / cm². 2 The rod core rotates at 5 r / min until the rod diameter reaches 60 mm. The needle penetration depth is then calibrated to 17 mm and the needle penetration density is set to 26 needles / cm. 2 The rod core is rotated at a speed of 5 r / min, and the diameter is monitored with a laser diameter gauge until it reaches 67.5 mm. The needle punching ends, and the gradient needle punching semi-finished product is obtained.

[0035] Example 4 The difference between Embodiment 4 and Embodiment 1 in this application lies in gradient needle punching.

[0036] The gradient needle punching process in Embodiment 4 of this application is as follows: First, fix the needle core in the rotating position of the needle punching machine, then take out the composite fabric prepared in the above steps and wrap it around the circumference of the core; then start the needle punching machine, calibrate the needle depth to 14mm and the needle density to 26 needles / cm. 2 The rod core rotates at 5 r / min. After needling, the diameter is monitored using a laser diameter gauge until it reaches 40 mm. The needling machine is then paused, and the needling depth is calibrated to 14 mm and the needling density is set to 30 needles / cm². 2 The rod core rotates at 5 r / min until the rod diameter reaches 50 mm. Then, pause the acupuncture machine, calibrate the acupuncture depth to 15 mm, and set the acupuncture density to 28 needles / cm². 2 The rod core rotates at 5 r / min until the rod diameter reaches 65 mm. The needle penetration depth is then calibrated to 15 mm and the needle penetration density is set to 26 needles / cm. 2 The rod core rotates at 5 r / min until the rod diameter reaches 80 mm. Then, pause the acupuncture machine, calibrate the acupuncture depth to 16 mm, and set the acupuncture density to 30 needles / cm². 2The rod core rotates at a speed of 5 r / min, and the diameter is monitored with a laser diameter gauge until it reaches 82.5 mm. The needling ends, and the gradient needling semi-finished product is obtained.

[0037] Example 5 The difference between Embodiment 5 and Embodiment 1 in this application lies in gradient needle punching.

[0038] The gradient needle punching process in Embodiment 5 of this application is as follows: First, fix the needle core in the rotating position of the needle punching machine, then take out the composite fabric prepared in the above steps and wrap it around the circumference of the core; then start the needle punching machine, calibrate the needle depth to 14mm and the needle density to 26 needles / cm. 2 The rod core rotates at 5 r / min. After needling, the diameter is monitored using a laser diameter gauge until it reaches 40 mm. The needling machine is then paused, and the needling depth is calibrated to 14 mm and the needling density is set to 30 needles / cm². 2 The rod core rotates at 5 r / min until the rod diameter reaches 50 mm. The acupuncture machine is then paused, and the acupuncture depth is calibrated to 15 mm and the acupuncture density is set to 28 needles / cm². 2 The rod core rotates at 5 rpm until the rod diameter reaches 65 mm. The acupuncture machine is then paused, and the acupuncture depth is calibrated to 15 mm and the acupuncture density is set to 26 needles / cm². 2 The rod core rotates at 5 rpm until the rod diameter reaches 80 mm. The acupuncture machine is then paused, and the acupuncture depth is calibrated to 16 mm and the acupuncture density is set to 30 needles / cm². 2 The rod core rotates at 5 r / min, and the diameter is monitored using a laser diameter gauge until it reaches 95 mm. The acupuncture machine is then paused, and the acupuncture depth is calibrated to 16 mm and the acupuncture density is set to 26 needles / cm². 2 The rod core rotates at 5 rpm until the rod diameter reaches 110 mm. The acupuncture machine is then paused, and the acupuncture depth is calibrated to 17 mm and the acupuncture density is set to 30 needles / cm². 2 The rod core rotates at 5 r / min, and the diameter is monitored using a laser diameter gauge until it reaches 125 mm. The acupuncture machine is then paused, and the acupuncture depth is calibrated to 17 mm and the acupuncture density is set to 32 needles / cm². 2 The rod core is rotated at a speed of 5 r / min, and the diameter is monitored with a laser diameter gauge until it reaches 130 mm to end the needle punching process, thus obtaining the gradient needle punching semi-finished product.

[0039] Example 6 The difference between Embodiment 6 and Embodiment 1 in this application lies in gradient needle punching.

[0040] The gradient needle punching process in Embodiment 6 of this application is as follows: First, fix the needle core in the rotating position of the needle punching machine, then take out the composite fabric prepared in the above steps and wrap it around the circumference of the core; then start the needle punching machine, calibrate the needle depth to 14mm and the needle density to 26 needles / cm. 2 The rod core rotates at 5 r / min. After needling, the diameter is monitored using a laser diameter gauge until it reaches 40 mm. The needling machine is then paused, and the needling depth is calibrated to 14 mm and the needling density is set to 30 needles / cm². 2 The rod core rotates at 5 r / min until the rod diameter reaches 50 mm. The acupuncture machine is then paused, and the acupuncture depth is calibrated to 15 mm and the acupuncture density is set to 28 needles / cm². 2 The rod core rotates at 5 rpm until the rod diameter reaches 65 mm. The acupuncture machine is then paused, and the acupuncture depth is calibrated to 15 mm and the acupuncture density is set to 26 needles / cm². 2 The rod core rotates at 5 rpm until the rod diameter reaches 80 mm. The acupuncture machine is then paused, and the acupuncture depth is calibrated to 16 mm and the acupuncture density is set to 30 needles / cm². 2 The rod core rotates at 5 r / min, and the diameter is monitored using a laser diameter gauge until it reaches 95 mm. The acupuncture machine is then paused, and the acupuncture depth is calibrated to 16 mm and the acupuncture density is set to 26 needles / cm². 2 The rod core rotates at 5 rpm until the rod diameter reaches 110 mm. The acupuncture machine is then paused, and the acupuncture depth is calibrated to 17 mm and the acupuncture density is set to 30 needles / cm². 2 The rod core rotates at 5 rpm until the rod diameter reaches 125 mm. The acupuncture machine is then paused, and the acupuncture depth is calibrated to 17 mm and the acupuncture density is set to 32 needles / cm². 2 The rod core rotates at 5 r / min until the rod diameter reaches 140 mm. Stop the acupuncture machine, calibrate the acupuncture depth to 18 mm, and set the acupuncture density to 28 needles / cm². 2 The rod core rotates at a speed of 5 r / min, and the diameter is monitored with a laser diameter gauge until it reaches 150 mm to end the needle punching process, thus obtaining the gradient needle punching semi-finished product.

[0041] Comparative Example 1 The difference between Comparative Example 1 and Example 5 lies in gradient needle punching.

[0042] The needle-punching process in Comparative Example 1 is as follows: First, fix the needle core in the rotating position of the needle punching machine, then take out the composite fabric prepared in the above process and wrap it around the circumference of the core; then start the needle punching machine, calibrate the needle depth to 14mm and the needle density to 28 needles / cm. 2 The rod core rotates at a speed of 5 r / min until the diameter of the support rod reaches 130 mm, at which point the needle piercing ends and the needle piercing semi-finished product is obtained.

[0043] Comparative Example 2 A method for preparing a splicing bracket includes the following steps: With a surface density of 300 g / m 2 The carbon fiber cloth was laid flat for inspection, and surface fuzz and wrinkles were removed; then the surface density was 100g / m². 2 The chopped carbon fiber mesh is stretched using a flattening device. Next, the base plate support is fabricated using a layering method of one layer of carbon fiber cloth layered with one layer of chopped carbon fiber mesh, with a needle-punching density of 15 needles / cm. 2 A needle-punching process with a depth of 15mm is used to ensure tight bonding between the material layers, forming a flat support rod. The conical head is then prepared based on this flat support rod, which is needle-punched at a density of 15 needles / cm. 2 The rod is further needle-punched to a depth of 15mm, resulting in a thickness of 130mm. A CNC thread milling machine specifically designed for carbon fiber support rods is used to precision machine one end of the flat support rod, creating a threaded structure that meets assembly requirements, thus completing the fabrication of the cone-shaped component. The rod body is also initially made from the flat support rod, with a needle-punching density of 15 needles / cm². 2 The core blank is further processed by hand-punching to a depth of 15mm to a thickness of 130mm, resulting in a preliminary core blank. Then, based on the final diameter specification of 130mm, the core blank is machined on a lathe to produce a smooth surface and precise diameter core. Next, a core with a surface density of 300g / m³ will be used. 2 The carbon fiber cloth has a surface density of 100 g / m³. 2 The composite fabric, composed of short-cut carbon fiber mesh, is cut to the initial dimensions of the rod core and tightly wrapped around the surface of the rod core, using a needle-punching density of 15 needles / cm. 2 The composite fabric is firmly bonded to the rod core using a 15m needle-punching method. After the manual punching process is completed, one end of the rod is machined to create a threaded opening that matches the tapered head thread, thus completing the preparation of the rod component. Finally, the machined tapered head and the rod are precisely aligned using the pre-reserved threaded structure and then tightened until they fit tightly, completing the preparation of the entire spliced ​​support rod.

[0044] Test case The compressive strength was tested according to the test methods in GB / T 1448-2005 "Test Method for Compression Properties of Fiber Reinforced Plastics"; the interlaminar shear strength was tested according to GB / T 40388-2021 "Test Method for Shear Strength of Carbon / Carbon Composites". The test results are shown in Table 1. Table 1 Comprehensive Performance Test Observing the compressive strength and interlaminar strength test data of Examples 1-6 and Comparative Examples 1-2 in Table 1, it can be found that the compressive strength and interlaminar strength values ​​of Examples 1-6 are higher, while the values ​​among Examples 1-6 are generally similar. The compressive strength and interlaminar shear strength of Examples 1-6 are better than those of Comparative Examples 1 and 2. Comparing Example 6 with the Comparative Examples, Example 6 has better mechanical properties, possibly because the gradient needle punching and overall preparation process optimize the interfacial interaction and structural integrity of the carbon fiber. Compared with the single-parameter needle punching of Comparative Example 1, the gradient needle punching of Examples 1-6 constructs a more reasonable three-dimensional fiber network by dynamically adjusting the needle punching depth and needle punching density: in the early stage of support rod forming, a depth of 14 mm and a needle density of 26-28 needles / cm are used. 2 High-density needle punching ensures initial bonding between the composite fabric and the core while avoiding fiber damage from excessive density. As the diameter increases, the needle punching depth is gradually increased to 14.5-18mm, and the needle punching density to 30-32 needles / cm. 2 This process encourages the outer fibers to interweave deeper into the inner layers, and the staggered needle-punching points significantly increase the number of fiber entanglement points, resulting in a substantial enhancement of interlayer bonding. The gradient carbon fiber entanglement structure used in this application not only allows stress to be rapidly transferred between layers, reducing the problem of local stress concentration, but also enhances the support rod's ability to resist interlayer delamination. In contrast, single-parameter needle punching in Comparative Example 1 makes it difficult to achieve uniform entanglement of carbon fibers across layers, easily forming weak surfaces between layers. Therefore, the compressive strength and interlayer strength values ​​of Examples 1-6 are higher.

[0045] Compared to the threaded splicing process of Comparative Example 2, the integral support rod fabrication method of Examples 1-6 fundamentally eliminates the performance shortcomings caused by the discontinuity of the spliced ​​structure. In Comparative Example 2, the interface gaps created by the threaded splicing can become stress concentration sources, and under compressive loads, the splice is prone to shear failure due to stress concentration. In contrast, the integral support rod fabrication method of Examples 1-6, through continuous rolling and gradient needle punching, allows the carbon fiber network to run through the entire support rod. The carbon fiber entanglement from the core to the surface exhibits a gradient transition with no obvious interface defects. During curing, the material shrinks uniformly, further ensuring structural density. Ultimately, when subjected to compressive force, the stress in the support rods prepared in Examples 1-6 can be evenly distributed along the continuous carbon fiber network, and the interlayer shear force can be effectively transferred through the abundant fiber entanglement points, thus exhibiting superior mechanical properties, while the mechanical properties in Comparative Example 2 are worse. In Examples 1-6, gradient needle punching was used to increase the needle punching depth and density in stages radially, so that the outer layer first formed a high-density in-plane interweaving and locking shear, and then a stepped bridging was constructed in the inner layer; the core fiber bundles were penetrated layer by layer as the diameter increased, forming a multi-level structure. Crack propagation required continuous tearing of bridging zones at different depths, which significantly increased the fracture energy. At the same time, the gradient parameters avoided repeated piercing on the same layer, reduced fiber cutting, and maintained in-plane strength, so that the interlaminar shear force of the support rods prepared in Examples 1-6 was significantly higher than that of Comparative Example 1.

[0046] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made to the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method of making a unitary solid support rod, characterized by, It comprises the following steps: S1, carbon fiber cloth, chopped carbon fiber tire composite, get composite cloth; S2, the composite cloth in step S1 is rolled to the specified diameter, then cut, and installed with anti-scattering tooling to obtain a rolled rod core; S3, the rod core in step S2 is first needled, and then re-needled to obtain a needled rod core; S4, the needled rod core in step S3 is laid with composite cloth on the outside, and then needled to obtain a semi-finished product; when the diameter of the semi-finished product is 30-50 mm, the needling depth is 14-15 mm, and the needling density is 26-32 needles / cm2; when the diameter of the semi-finished product is 50-80 mm, the needling depth is 14-18 mm, and the needling density is 23-32 needles / cm2; when the diameter of the semi-finished product is greater than 80 mm, the needling depth is 14-19 mm, and the needling density is 23-32 needles / cm2; S5, curing treatment: the semi-finished product is heated, kept warm, naturally cooled, and then discharged to obtain a whole solid support rod.

2. The method of making a unitary solid stem as defined in claim 1, wherein, The diameter of the semi-finished product is 30-45 mm, the needle punching depth is 14-14.5 mm, and the needle punching density is 26-30 needles / cm 2 .

3. The method of making a unitary solid stem as defined in claim 1, wherein, The diameter of the semi-finished product is 50-60 mm, the needle punching depth is 14-16 mm, and the needle punching density is 26-32 needles / cm 2 .

4. The method of making a unitary solid stem as defined in claim 1, wherein, The diameter of the semi-finished product is 60-80 mm, the needle punching depth is 14-18 mm, and the needle punching density is 23-32 needles / cm 2 .

5. The method of making a unitary solid stem as defined in claim 1, wherein, The diameter of the semi-finished product is 80-125 mm, the needle punching depth is 14-17 mm, and the needle punching density is 26-30 needles / cm 2 .

6. The method of making a unitary solid stem as defined in claim 1, wherein, The diameter of the semi-finished product is 125-140 mm, the needle punching depth is 14-17 mm, and the needle punching density is 26-32 needles / cm 2 .

7. The method of making a unitary solid stem as defined in claim 1, wherein, The semi-finished product has a diameter greater than 140 mm, a needle punching depth of 14-18 mm and a needle punching density of 26-32 needles / cm 2 .

8. The method of making a unitary solid stem as defined in claim 1, wherein, The carbon fiber cloth has a surface density of 300-400 g / m 2 The short-cut carbon fiber web has a surface density of 50-100 g / m 2 .

9. The method of making a unitary solid stem as defined in claim 1, wherein, The heating temperature in S5 is 280-300℃.

10. Use of the whole solid support rod according to any one of claims 1-9 in the fields of photovoltaics and semiconductors.

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