A method for injection molding an expanding crosslinking polymer part in an injection molding system, the method comprising: injecting molten expanding crosslinking polymer into a mold cavity; measuring strain at the mold cavity or at another location within the injection molding system during the injection molding cycle; calculating from the measured strain at least one non-time dependent variable during the injection mold cycle, wherein the non-time dependent variable is a variable that is independent from a fixed or specified hold time; commencing a hold profile for the expanding crosslinking polymer part; upon completing the hold profile, commencing a cure profile for the molded part, and ejecting the part from the mold cavity; wherein commencing the hold profile comprises: upon the calculated at least one non-time dependent variables reaching a first threshold value, commencing the hold profile; restricting additional molten expanding crosslinking polymer from being injected into the mold cavity; and upon the calculated at least one non-time dependent variables reaching a second threshold value, terminating the hold profile wherein the first threshold value is indicative of the mold cavity being substantially full of molten expanding cross linking polymer; wherein the second threshold value is indicative of the part being structurally sound; commencing the cure profile comprises: upon the at least one calculated non-time dependent variable reaching a third threshold value, terminating the cure profile, wherein the third threshold value is a predetermined rate of change in a cavity pressure value. injecting molten expanding crosslinking polymer into a mold cavity; measuring strain at the mold cavity or at another location within the injection molding system during the injection molding cycle; calculating from the measured strain at least one non-time dependent variable during the injection mold cycle, wherein the non-time dependent variable is a variable that is independent from a fixed or specified hold time; commencing a hold profile for the expanding crosslinking polymer part; upon completing the hold profile, commencing a cure profile for the molded part, and ejecting the part from the mold cavity; wherein commencing the hold profile comprises: upon the calculated at least one non-time dependent variables reaching a first threshold value, commencing the hold profile; restricting additional molten expanding crosslinking polymer from being injected into the mold cavity; and upon the calculated at least one non-time dependent variables reaching a second threshold value, terminating the hold profile wherein the first threshold value is indicative of the mold cavity being substantially full of molten expanding cross linking polymer; wherein the second threshold value is indicative of the part being structurally sound; commencing the cure profile comprises: upon the at least one calculated non-time dependent variable reaching a third threshold value, terminating the cure profile, wherein the third threshold value is a predetermined rate of change in a cavity pressure value. upon the calculated at least one non-time dependent variables reaching a first threshold value, commencing the hold profile; restricting additional molten expanding crosslinking polymer from being injected into the mold cavity; and upon the calculated at least one non-time dependent variables reaching a second threshold value, terminating the hold profile wherein the first threshold value is indicative of the mold cavity being substantially full of molten expanding cross linking polymer; wherein the second threshold value is indicative of the part being structurally sound; commencing the cure profile comprises: upon the at least one calculated non-time dependent variable reaching a third threshold value, terminating the cure profile, wherein the third threshold value is a predetermined rate of change in a cavity pressure value.