When the plastic mold is processed, the plastic is brought into the mold except by heat radiation and heat flow out of the mold. Most of the heat is carried out of the mold by the circulating heat transfer medium through heat conduction. The heat transfer medium includes water, oil, etc.

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

To reduce the temperature of the mold, it is generally achieved by passing the fixed mold through warm water (about 25 degrees) and the moving mold through "frozen water" (about 4 degrees). When the channel of the heat transfer medium, that is, the cooling water 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 pouring hot water into the cooling water channel and heating it by a hot water machine. When the mold temperature is required to be high, an electric heating rod can be used to heat the mold. For the mold that needs to be heated, in order to prevent the loss of heat by heat conduction, a resin insulation board should be added to the mold panel.

In the hot runner mold, the temperature of the hot runner plate is relatively high, and it must be heated by a heating rod. In order to prevent the heat of the hot runner plate from being transferred to the fixed die, it is difficult to cool the fixed die. Therefore, the contact surface with the fixed die should be minimized in the design. And insulate with heat shield.