Domestic composite materials have been applied to the automobile industry since the late 1950s, but the overall development speed is slow, and the production process is mainly hand lay-up. In the 1990s, due to the introduction and development of mechanized production processes such as SMC, BMC, and RTM, the amount of composite materials gradually increased and the scope of application was also expanded. However, due to the barriers between industries and the limitation of technical level, composite materials have not received the recognition and attention they deserve in the automotive industry, and the hand lay-up process still occupies a dominant position.
FRP products are rationally combined by resin, reinforcing materials and various auxiliary components, with a wide variety of manufacturing processes.
Sheet Molding Comp (SMC) and Bulk Molding Compoun (BMC) are a type of sheet molding compound made of resin paste impregnated fiber or chopped fiber mat, covered with polyethylene film on both sides , Belongs to the range of prepreg material. When in use, the films on both sides are torn off, cut and laminated according to the size of the product, and placed in a metal mold to heat and pressurize to obtain the desired product. It is currently one of the most widely used molding materials in the world.
The main advantages of the SMC/BMC molding process are: high production efficiency, short molding cycle, easy to achieve professional and automated production; high product dimensional accuracy, good repeatability; smooth surface without secondary modification; low production cost.
The disadvantage of SMC/BMC is that the mold manufacturing is complicated and the initial investment is large.