The winding technology of carbon fiber composite materials is a key process of obtaining high-strength and high stiffness products by winding carbon fibers impregnated with resin on a core mold at a specific angle and tension rule, and then curing and forming them. Products produced by carbon fiber winding technology are widely used. The core advantage of its technology lies in the ability to fully utilize the axial strength of carbon fiber (up to 3000MPa or more), and the high fiber volume content (typically 60% -70%) and strong structural integrity of the product, making it one of the mainstream forming methods for high-end composite material products.
1、 Technical principles and core elements
The essence of carbon fiber winding technology is "directional fiber reinforcement", which precisely controls the angle, tension, and path of fiber winding to achieve the optimal arrangement of fibers in the direction of force, thereby matching the mechanical requirements of the usage scenario (such as the circumferential/axial strength balance of internal pressure vessels). So its key parameters mainly include, firstly, the core parameter that determines the mechanical properties of the product, the winding angle (circumferential angle, axial angle, and helical angle); Secondly, high-precision tension control of reinforcing fibers that determine product quality; Thirdly, the fiber impregnation method that determines the microscopic performance of the product.
2、 Core processes and technical procedures
The entire process of carbon fiber winding technology can be divided into four stages: "design preparation molding testing", and the technical details of each stage directly affect the performance of the product.
Firstly, preliminary design and simulation: Based on the product's stress requirements (such as internal pressure, tension, and bending), the winding path is designed using CAD/CAE software (such as CATIA, ANSYS) to simulate fiber arrangement, tension distribution, and stress state after curing.
Secondly, product based core mold design: customized according to the shape of the product (metal, composite material, or soluble core mold), requiring a smooth surface (roughness Ra ≤ 0.8 μ m) to ensure the quality of the inner wall of the product.
Thirdly, raw material selection and matching: carbon fiber (commonly T700, T800 grade (high-strength type) or M40J, M55J grade (high modulus type), choose fiber bundle specifications (12K, 24K, etc.) according to product requirements) and resin system (epoxy, phenolic, bismaleimide (BMI), etc., need to be matched with curing process)
Fourth, winding forming equipment and process: Equipment types only need to include CNC winding machines (multi axis linkage can achieve complex path winding, with positioning accuracy of ± 0.1mm) and robot winding systems (more flexible, suitable for large shaped parts). The winding methods mainly include dry winding and wet winding.
Fifth, curing and post-treatment: Choose the curing method according to the resin type, such as hot press tank (high-pressure environment, suitable for aviation grade products), oven (atmospheric pressure, suitable for civilian products), or microwave curing (high-efficiency and energy-saving, reducing curing time by 50%). Post treatment mainly involves removing burrs and drilling holes after demolding, and if necessary, surface spraying (such as anti-corrosion coating) or machining (accuracy requirement ± 0.05mm).
Sixth, quality inspection: Non destructive testing: ultrasonic testing (detecting delamination and bubbles), X-ray (detecting fiber arrangement defects), CT scanning (three-dimensional structural analysis); Mechanical performance testing: tensile strength (≥ 2000MPa), burst pressure (e.g. 45MPa hydrogen cylinder needs to pass 1.5 times the working pressure burst test), fatigue life (≥ 100000 cycles)
3、 Typical products of Huitong winding technology
1. Standard carbon fiber lightweight structural pipes: mainly including round pipes, square pipes, patterned pipes, etc.
2. Various lightweight carbon fiber shaped pipes: mainly including irregular cross-section pipes (hexagonal, octagonal, elliptical), variable diameter pipes (conical), curved pipes, etc.
3. Advanced carbon fiber high-strength winding shaft: mainly includes inflatable shaft, transmission shaft, coupling, etc.
4. Advanced carbon fiber lightweight hydraulic cylinders: mainly including piston rods, hydraulic cylinders, etc.
5. Advanced carbon fiber lightweight gas storage tanks: mainly including hydrogen storage cylinders, oxygen cylinders, liquefied oil and gas cylinders, etc.