There are basically two major categories, namely wet contact type and dry pressure forming. According to the characteristics of the process, there are hand lay-up, lamination, RTM, pultrusion, compression molding, and winding molding. Hand lay-up includes hand lay-up, bag press, spray, wet paste low pressure and moldless paste.
There are currently four types of molding methods that are most used in the world.
1. Hand paste method: the main countries used are Norway, Japan, the United Kingdom, Denmark and so on.
2. Injection method: the main countries used are Sweden, the United States, Norway and so on.
3. Molding method: the main use of the country is Germany.
4RTM method (resin transfer molding): The main countries used are Europe and the United States, Japan.
Also: filament winding method, pultrusion method, hot potting method, etc.
More than 90% of FRP products in China are produced by hand-paste method, and others have molding methods, winding methods, lamination methods, and the like. Japan’s hand-paste method still accounts for 50%. From the perspective of countries around the world, the hand-paste method still accounts for a considerable proportion, indicating that it still has vitality. The hand-paste method is characterized by molding with a wet resin, simple equipment, low cost, and an overall product that can be pasteed for more than 10 m at a time. The shortcomings are low degree of mechanization, long production cycle and unstable quality. China has introduced process equipment such as squeezing, spraying and winding from abroad. With the development of FRP industry, new process methods will continue to emerge.
