1. When the spiral double-layer cup blank falls into the initial mold, it cannot accurately enter the initial mold, and the friction with the mold wall is too large, forming a crease. After blowing, the crease expands and expands, forming a crease in the spiral double-layer cup.

2. The shear marks of some feeders are too large, and some spiral double-layer cups have shear marks on the bottle body after forming.

3. The initial mold and molding materials of the spiral double-layer cup are poor, and the density is not good. After high temperature, the oxidation is rapid, and the surface of the mold forms small pits, resulting in the surface of the spiral double-layer cup after molding is not shiny.

4. The initial mold plan is unreasonable, the mold cavity is large or small, and the material droplets are blown and spread unevenly after entering the molding mold, which will cause spots on the spiral double-layer cup body.

5. The dripping speed of the machine is not uniform, and the improper adjustment of the nozzle will make the temperature of the spiral double-layer cup preliminary mold and the mold temperature inconsistent. Simply create cold spots on the spiral double-layer cup bottle body, which directly affects the brightness.