After the printed parts such as signs are made, a layer of high-tension paint is poured on the surface, and the height of the paint can reach1.3 mm. Because of its arc appearance, it is called dome technology abroad. Because of its high fullness, high transparency, crystal-like texture, and at the same time because of its image characteristics, China is used to calling this "crystal" glue dropping process, and its commodity material is called crystal glue, and the symbol combined with this process is called the crystal glue dropping symbol. Initially, crystal glue was developed by Wuxi Chemical Research and Design Institute, and was the first to provide practical goods.