Products with PC pepper balls with a diameter of more than 15mm are easy to shrink and produce blowholes. The main reason is that the injection temperature of PC plastic is too high. During the cooling process, after the surface of plastic pepper ball is cooled, the internal plastic needs to be cooled slowly, and it will continue to shrink during the cooling process, resulting in the phenomenon that the surface of plastic pepper ball shrinks or shrinks into a small hole.The improvement method of PC plastic pepper ball shrinkage is mainly adjusted from the aspects of mold temperature, injection pressure, injection temperature, etc. First, the mold temperature should be raised as much as possible, and the mold temperature can be raised to about 150 degrees. This mold is helpful for molding, the injection pressure should be increased, and the pressure holding time should be long. The glue position that shrinks during the internal cooling process of the plastic pepper ball can be replenished by the injection molding machine, which can ensure that the plastic pepper ball will not be affected by the internal shrinkage.