Why is there often gas discharge from injection molds?

(1) Air in the casting system and mold cavity.

(2) Some raw materials contain water that has not been dried out, and they will vaporize into water vapor at high temperature.

(3) Due to the high temperature in the injection molding, some unstable plastic will decompose and produce gas.

(4) Some additives in the plastic raw materials volatilization or mutual chemical reaction generated gas.