Plastic mold processing from plastic into the mold in addition to through the heat radiation, the heat flow out of the mold. Most of the heat is carried out of the mold by means of heat conduction by circulating heat transfer medium. Heat transfer medium includes water, oil, etc.

The temperature of plastic mold is generally controlled by adjusting the temperature of heat transfer medium, adding heat insulation board and heating rod.

To reduce the temperature of the mold, it is generally realized by using the fixed mold with warm water (about 25 degrees) and the moving mold with "frozen water" (about 4 degrees). When the channel of heat transfer medium, namely the cooling channel, cannot pass through other parts, materials with better heat transfer efficiency should be used to transfer heat to the heat transfer medium.

To increase the temperature of the mold, it is generally realized by feeding hot water into the cooling channel and heating by the hot water machine. When the temperature of the mold is high, an electric heating rod can be used to heat it. For the mold that needs to be heated, in order to prevent heat loss from heat conduction, a resin heat insulation board should be added to the mold panel.

In the hot runner mold, the temperature requirement of the hot runner plate is higher, and it must be heated by the heating rod. In order to avoid the heat transfer from the hot runner plate to the fixed die, it is difficult to cool the fixed die. Therefore, the contact surface of the fixed die should be reduced as far as possible in the design, and the heat insulation piece is used for heat insulation.