Publish Time: 2025-04-03 Origin: Site
The carbon fiber prepreg is laid onto the mold according to the required ply orientation and then sealed within a vacuum bag before being placed into the autoclave. Under vacuum conditions, the autoclave undergoes a sequence of heating, pressurization, holding, cooling, and depressurization. The uniform temperature and distributed pressure inside the autoclave facilitate curing, resulting in high-quality surface and internal structure, as well as complex-shaped and large-area carbon fiber composite parts.
The autoclave process was developed in the 1940s for the production of second-generation composite materials. It was not widely adopted until the 1960s, after which it became extensively used in high-tech industries such as aerospace, composite materials, electronics, weaponry, transportation, sports equipment, and new energy. The process has played a crucial role, especially in the production of skin-like components, and has now become a mature technology. Products manufactured using the autoclave process account for more than 50% of all composite material production, with a proportion exceeding 80% in the aerospace industry. Today, the autoclave process remains one of the primary forming methods for carbon fiber composite components and is widely employed by many carbon fiber composite parts manufacturers.
The autoclave process for carbon fiber relies on carbon fiber prepreg as its primary material. Carbon fiber prepreg consists of carbon fiber tow, epoxy resin, release paper, and other materials, processed through coating, hot pressing, cooling, laminating, and winding. Also known as carbon fiber prepreg fabric, it features high strength, low density, and exceptional durability. Its strength is 6–12 times that of steel, while its density is only one-fourth of steel. The material can be molded into any shape according to the mold, making it easy to process, highly resistant to corrosion, and long-lasting.
Molds used in the carbon fiber autoclave process must exhibit rapid thermal conductivity, low specific heat capacity, high rigidity, light weight, low thermal expansion coefficient, heat resistance, excellent thermal stability, long service life, low manufacturing cost, ease of use and maintenance, and convenient transportation. In particular, good thermal conductivity, rigidity at high temperatures, and airtightness are crucial. The following are the most commonly used mold materials in the production of carbon fiber composite parts:
Aluminum: Good thermal conductivity and ease of processing, lightweight, but relatively high thermal expansion coefficient. Its low hardness makes it prone to damage, limiting its application in certain cases.
Steel: High precision, excellent strength and hardness, long service life, and suitable for most products. However, it has a high mass and heat capacity.
Cast Steel or Cast Iron: A cost-effective alternative to steel, but with larger temperature variations at different points on the mold surface, and prone to surface defects such as sand holes.