Plastic PP pepper balls are transparent, and it is easy to see bubbles in the middle. Some customers have high quality requirements and do not accept plastic PP pepper balls with bubbles in the middle. The reason for the bubbles in plastic PP pepper balls is mainly formed in the injection molding process, so the improvement direction is to improve the design method of the mold besides the injection molding process.

Bubble caused by material: The material contains moisture. When it is used as an ordinary plastic product, it is thinner than the product and will not produce bubbles. However, the wall thickness of plastic PP pepper balls is generally more than 5mm, and the cavity is large, so the gas can not be discharged at all. Therefore, the material must be dried before injection molding.

Bubble caused by mold: The main reason for the bubble of plastic PP pepper ball caused by mold is that the air in the mold cavity cannot be exhausted. The improvement method is to exhaust the mold, which solves the problem of plastic PP pepper ball bubble caused by poor exhaust.

Bubbles caused by the temperature of the injection molding machine: During the injection molding process, the temperature of the injection molding machine is too high, the PP material decomposes and gasifies, and some gas enters the mold with the rubber compound to form bubbles. The improvement method is to lower the temperature of the injection molding machine, generally below 215 degrees. After the temperature is lowered, the problem of plastic PP pepper ball bubbles caused by material gasification can be basically solved.