Autoclave forming process, also known as vacuum bag-autoclave forming process, is the main method to produce high-strength components of high-fiber reinforced thermosetting plastics for aerospace. The basic technological process is to combine prepreg with other accessories to form a vacuum bag combination system, which is cured in an autoclave at a certain pressure (including vacuum negative pressure in the vacuum bag and positive pressure outside the bag) and temperature to make parts with various shapes.

As the bag is vacuumized, volatile substances in air and materials can be eliminated. If the parts need to be bonded twice, the autoclave method can be used. The main equipment for autoclave molding is autoclave and vacuum pumping system. The inner cavity of the autoclave should be large enough to control the temperature and raise the temperature as required and bear enough pressure, and a system for automatically recording the temperature and pressure should be attached. The vacuum system provides suitable bags before and after the parts are cured.

When the vacuum.

The mold for autoclave molding depends on the shape of the product. Female die is often used for parts with smooth outer surface; On the other hand, a male mold is used. According to the number of parts, resin type of fiber reinforced composite parts, curing temperature and surface roughness requirements, the mold material can be made of steel, aluminum or fiber reinforced composite materials. When choosing the mold material, we should also consider its linear expansion performance.

Autoclave forming process;

(1) Prepare the mold, gently wipe it clean with soft materials, and check whether there is air leakage. Then coating a mold release agent on the mold;

(2) Cutting and stacking: cutting the prepreg with protective film according to the sample, paying attention to the fiber direction when cutting, then removing the protective film from the cut prepreg, stacking it in the specified order and direction, and pressing the prepreg with rubber rollers and other tools on each layer to expel air;

(3) combined bagging: the prepreg and various auxiliary materials are combined and bagged in a mold, and whether the vacuum bag and the surrounding seals are intact is checked;

(4) hot pressing curing: combining the vacuum bag system into an autoclave, connecting a vacuum pipeline, closing the autoclave, and then vacuumizing/heating/pressurizing curing according to the determined process conditions;

(5) demoulding, cooling to room temperature after curing, taking out the vacuum bag system from the autoclave, taking out various auxiliary materials, and taking out parts for trimming.