FRP is basically divided into two categories, namely wet contact type and dry pressure forming. For example, according to the characteristics of the process, there are hand lay-up molding, lamination molding, RTM method, extrusion method, compression molding, winding molding, etc. Hand lay-up includes hand lay-up, bag press, spraying, wet paste low pressure and no-mold hand lay-up.
There are the following four most used molding methods in the world.
①Hand lay-up method: The main countries where it is used are Norway, Japan, the United Kingdom, Denmark, etc.
②Spray method: The main countries used are Sweden, the United States, Norway, etc.
③ Molding method: The main countries used are Germany and so on.
④RTM method (resin transfer molding): The main countries used are Europe, America and Japan.
There are also: filament winding molding method, pultrusion molding method and hot pressure filling molding method and so on.
More than 90% of FRP products in my country are produced by hand lay-up, and others include molding, winding, and lamination. Japan's hand paste method still accounts for 50%. From the point of view of countries in the world, the hand paste method still accounts for a considerable proportion, indicating that it still has vitality. The characteristic of the hand lay-up method is that it is formed by wet resin, the equipment is simple, the cost is low, and the overall product of more than 10m can be pasted at one time. The disadvantage is that the degree of mechanization is low, the production cycle is long, and the quality is unstable. my country has introduced process equipment such as extrusion, spraying, and winding from abroad. With the development of the FRP industry, new process methods will continue to appear.