Post-ejection cooling behavior of injection molded parts

The quantity of heat and its distribution in an injection molded part at the time of ejection has bearing upon part quality. A method for accurate measurement of part surface temperature from soon after ejection and during cooling has been created. It is found that-following ejection, the mold part's surface quickly heats to approximately the bulk mean temperature. The entire part then cools gradually at nearly uniform temperature. Measured results compare well with predicted behavior. This approach can be used to assess the effectiveness of active die cooling and verify the appropriateness of the selected in-die cooling time.