What Is a Pressure Bag?

Thermosetting molding method for bag moulding composite materials. Use suction to remove trapped air, voids, and excess resin from the composite structure. Divided into pressure bag method, vacuum bag method and autoclave method. (1) Pressure bag method: Put a rubber bag on the surface of the uncured product after hand lay-up, fix the upper cover or dense rope net to prevent the rubber bag from expanding indefinitely, and then use compressed air or steam to make the material surface bear Pressure, and at the same time cured by heat to obtain products. (2) A vacuum bag method, in which an uncured product formed on a mold is put into a vacuum forming apparatus, evacuated, and cured by atmospheric pressure. (3) Hot pressing method. Similar to the vacuum bag method, the difference is that the former uses a special autoclave, filled with a high-pressure elastic medium, and heated to make the product solidify. The advantages of the bag pressing method are that both sides of the product are smooth, can be used for polyester, epoxy and phenolic polyester, and the product has high quality and short molding cycle. Products suitable for bag pressing include: various components, products with small output, complex products that cannot be produced by molding, and small and medium-sized products that require smooth sides. ^[1]