The temperature control system of injection mold needs cooling and heating functions. Commonly used as temperature regulating transmission medium are water, oil and other liquids and vapors, as well as electric heating devices. Cooling or heating the mold processing depends on the material performance, the structural shape and size of the parts, the productivity and the requirements of the molding process. The general principles are as follows.

(1) Plastics with high drillability and good fluidity (such as PP, PS, PE, PA, etc.) usually use warm water to cool the injection mold because the molding temperature is not too high, and control the mold processing temperature by adjusting the flow. When the productivity requirements are very high (the accuracy of the workpiece allows), cold water can also be used to control the mold temperature.

(2) Plastics with high drillability and poor fluidity (such as PC, PPC, PSU and hard PVC) need high mold temperature for mold filling, so injection molds are often heated

(3) For plastics with low private flow temperature or melting point, generally use warm water or cold water to cool the injection mold; For plastics with high private flow temperature or high melting point, controlling the mold temperature with warm water will be more conducive to uniform mold temperature distribution.

4) Local heating and cooling measures can be adopted for the mold cavity with special shape; Adopt proper heating method for long process and large-area molding cavity to improve the temperature distribution (it will not be difficult to flow due to the temperature drop during mold filling).