Carbon fiber is widely used in aerospace, infrastructure, electromagnetic shielding, automobile manufacturing, oil exploitation and other fields because of its fatigue resistance, high temperature resistance, high strength, high modulus, conductivity, radiation resistance, small coefficient of thermal expansion and light weight. It has strong designability and various molding methods, including winding, pultrusion, injection, hand paste, molding, etc. This article introduces the molding process of carbon fiber.
Carbon fiber molding steps:
1. Mold cleaning. Clean the mold to avoid the residue of dust and sundries.
2. Apply release agent. After ensuring that the mold is clean and smooth, apply release agent to prevent the product from sticking with the mold after molding.
3. Material preparation. Prepare the required carbon fiber prepreg according to the shape and size of the product.
4. Stack. The carbon fiber prepreg is stacked layer by layer and preloaded to form a dense entity with regular shape and certain quality.
5. Molding. Put the stacked raw materials into the mold, close the mold, set the pressure, time and temperature, and press at high temperature.
6. Cooling and demoulding. After hot pressing, cool for a period of time, and then open the mold to take out the product.
7. Post processing. The products taken out from the mold are rough, and have to go through a series of post-treatment processes such as trimming, grinding and painting.
Molding process is the oldest and most dynamic molding method in the production of composite materials. Compared with the traditional hand paste process, the molding process is more advanced and has high dimensional accuracy. It is suitable for mass production, but molding is not without shortcomings, It still needs to decide whether to choose the molding process according to the final carbon fiber parts and the real demand.
Main advantages of carbon fiber composite molding:
1. High production efficiency, easy to realize professional and automatic production
2. The product has high dimensional accuracy and good repeatability
3. The surface is smooth without secondary modification
4. It can form products with complex structure at one time
5. Because of mass production, the price is relatively low.
Disadvantages of carbon fiber composite molding:
The disadvantage of molding is that the mold manufacturing is complex, the investment is large, and limited by the press, it is most suitable for mass production of small and medium-sized composite products. With the continuous improvement and development of metal processing technology, press manufacturing level and synthetic resin process performance, the tonnage and table size of the press are increasing, and the molding temperature and pressure of the molding material are also relatively reduced, which makes the size of the molded products gradually develop to large-scale. At present, it has been able to produce large automobile parts, bathtub, integral toilet components, etc.
In the molding process, special attention should be paid to the three elements of temperature, pressure and time. Temperature has a decisive influence on the melting, flow and solidification of materials; Pressure can make a layer of carbon fiber prepreg bond more closely; Time can make the product in the mold cavity have enough time to cure.
