There are many types of molding materials, including pre impregnated materials, pre mixed materials, and raw materials. At that time, the main types of molding materials used were prepreg, fiber premix, BMC, DMC, HMC, SMC, XMC, TMC, and ZMC.

Skills and strengths

① High production efficiency, easy to complete specialized and automated production; ② High precision in product scale and good repeatability; ③ Smooth appearance, no need for secondary polishing; ④ Can produce products with messy layouts in one go; ⑤ Due to mass production, the quotation is relatively low.

The shortcomings of compression molding are that the mold production is messy, the investment is large, and coupled with the constraints of the press machine, it is suitable for mass production of small and medium-sized composite material products. With the continuous improvement and development of metal processing skills, the level of press production, and the functionality of synthetic resin skills, the tonnage and table size of press machines continue to increase, and the molding temperature and pressure of molded materials also relatively decrease, making the scale of molded products gradually move towards large-scale production. Currently, it is possible to produce large automotive parts, bathtubs, and all bathroom components.

Data selection

(1) Synthetic resin

The molding material required for composite material molded products is synthetic resin, which has: ① excellent moisturizing function for reinforcing materials, so as to form outstanding adhesion at the interface between synthetic resin and reinforcing materials; ② With appropriate viscosity and outstanding fluidity, it can uniformly fill the entire mold cavity together with the reinforcement material under limited conditions; ③ Under limited conditions, it has a suitable curing speed, and there are no by-products or few by-products during the curing process, resulting in a small volume reduction rate Can meet the specific functional requirements of the molded products. According to the above material selection requirements, commonly used synthetic resins include unsaturated polyester resin, epoxy resin, phenolic resin, vinyl resin, furan resin, organosilicon resin, polybutadiene resin, allyl ester, melamine resin, polyimide resin, etc. In order to achieve specific functional indicators for molded products, corresponding auxiliary materials, fillers, and pigments should also be selected after selecting the resin type and trademark.

(2) Enhance data

The commonly used reinforcement materials in molding guessing mainly include glass fiber cutting wire, untwisted yarn, twisted yarn, continuous glass fiber bundles, glass fiber cloth, glass fiber felt, etc. There are also a few special products that use asbestos felt, asbestos fabric (cloth) and asbestos paper, as well as high silica fiber, carbon fiber, organic fiber (such as aramid fiber, nylon fiber, etc.) and natural fiber (such as linen cloth, cotton cloth, boiled cloth, non boiled cloth, etc.). Sometimes two or more types of fibrous viscous materials are also used as reinforcement materials.

(3) Auxiliary materials

It usually contains auxiliary materials such as curing agents (initiators), accelerators, diluents, surface treatment agents, low shortening additives, release agents, coloring agents (pigments), and fillers.
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