The temperature in the injection mold is uneven at various points, which is also related to the time point in the injection cycle. The function of the mold temperature machine is to keep the temperature constant between 2min and 2max, which means to prevent the temperature difference from fluctuating up and down during the production process or the gap. The following control methods are suitable for controlling the temperature of the mold: Controlling the temperature of the fluid is the most commonly used method, and the control accuracy can meet the requirements of most situations. Using this control method, the temperature displayed on the controller is not consistent with the mold temperature; the mold temperature fluctuates considerably, because the thermal factors affecting the mold are not directly measured and compensated. These factors include changes in the injection cycle, injection speed, melting temperature and Room temperature. The second is the direct control of mold temperature. This method is to install a temperature sensor inside the mold, which is only used when the mold temperature control accuracy is relatively high.