Injection molding of crosslinking polymers

A method for determining whether an expanding crosslinking polymer part is ready to be ejected from a mold cavity during an injection molding cycle, the method comprising:

• during the injection molding cycle, injecting molten expanding crosslinking polymer into a mold cavity;
• during the injection molding cycle, measuring at least one non-time dependent variable during the injection mold cycle;
• during the injection molding cycle and upon the at least one non-time dependent variables reaching a first threshold value, commencing a hold profile for the expanding crosslinking polymer part, the hold profile comprising:
• restricting additional molten expanding crosslinking polymer from being injected into the mold cavity, and
• upon the measured at least one non-time dependent variables reaching a second threshold value, terminating the hold profile,
• during the injection molding cycle and upon completing the hold profile, ejecting the molded part from the mold cavity;
• and
• during the injection molding cycle and upon ejecting the molded part, commencing a cure profile for the molded part whereby the molded part expands to a final form, the cure profile comprising:
• measuring a different non-time dependent variable,
• upon the measured different non-time dependent variable reaching a third threshold value, transferring the molded part to a stabilization tunnel in which the molded part cools for a duration dependent on the third threshold value,
• wherein the at least one non-time dependent variable and the different non-time dependent variable is selected from the group consisting of a pressure value, a temperature value, a rate of change in pressure values, or a hardness value.