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The principle of the mold temperature machine is:

A mold temperature machine is used to adjust the equilibrium mold temperature, which can be heated or cooled. The mold temperature machine utilizes a highly thermally conductive medium to quickly dissipate excess heat inside the mold. After setting the thermal equilibrium temperature, it can automatically control its temperature within a very small error and maintain a constant value.

The working principle of the mold temperature machine consists of a water tank, a heating and cooling system, a power transmission system, a liquid level control system, as well as temperature sensors, injection ports, and other components. Normally, pumps in power transmission systems transport hot fluid from a water tank equipped with built-in heaters and coolers to the mold, and then from the mold back to the water tank; The temperature sensor measures the temperature of the hot fluid and transmits the data to the controller of the control section; The controller adjusts the temperature of the hot fluid, thereby indirectly regulating the temperature of the mold. If the temperature of the mold exceeds the set value of the controller during production, the controller will open the solenoid valve and connect the inlet pipe until the temperature of the hot fluid, that is, the temperature of the mold, returns to the set value. If the mold temperature is lower than the set value, the controller will turn on the heater.

The types of mold temperature machines are classified according to the heat transfer fluid (water or heat transfer oil) used. The mold temperature machine that uses water usually has an outlet temperature of 90 ℃, while the mold temperature machine that uses oil is used in situations where the working temperature is ≥ 200 ℃. Under normal circumstances, mold temperature machines with open water tanks for heating are suitable for water or oil, with outlet temperatures ranging from 90 ℃ to ≥ 150 ℃. The main features of this mold temperature machine are simple design and economical price. On the basis of this machine, a mold temperature machine using pressurized water has been derived, which can allow an outlet temperature of 160 ℃ or higher. Due to the much better thermal conductivity of water than oil at the same temperature above 90 ℃, this machine has outstanding high-temperature working ability. In addition to this, there is also a type of forced flow mold temperature machine. For safety reasons, this mold temperature machine is designed to work at temperatures above 150 ℃ and uses thermal oil. In order to prevent the oil in the mold temperature machine heater from overheating, the machine uses a forced flow pumping system, and the heater is composed of a certain number of stacked tubes with finned heating elements for flow guidance.

The uneven temperature control within the mold is also related to the timing of the injection cycle. After injection, the temperature of the mold cavity increases, and the hot melt hits the cold wall of the mold cavity. When the part is removed, the temperature decreases. The function of the mold temperature machine is to maintain a constant temperature between θ 2min and θ 2max, which means to prevent the temperature difference △ θ w from fluctuating up and down during the production process or gap. The following control methods are suitable for controlling the temperature of molds: controlling fluid temperature is a 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 temperature fluctuation of the mold is quite large because the thermal factors affecting the mold are not directly measured and compensated for (including changes in injection cycle, injection speed, melting temperature, and room temperature). Next is the direct control of mold temperature. This method involves installing temperature sensors inside the mold, which is only adopted when the precision of mold temperature control is relatively high. The main characteristics of mold temperature control include: the temperature set by the controller is consistent with the mold temperature; The thermal factors affecting the mold can be directly measured and compensated for. In general, the stability of mold temperature is better than controlling fluid temperature. In addition, the mold temperature control has good repeatability in the production process control. The third is joint control. Joint control is a combination of the above methods, which can simultaneously control the temperature of the fluid and the mold. In joint control, the position of the temperature sensor in the mold is very important. When placing the temperature sensor, the shape, structure, and position of the cooling channel must be considered. In addition, temperature sensors should be placed in a location that plays a decisive role in the quality of injection molded parts. There are many ways to connect one or more mold temperature machines to the injection molding machine controller. Prioritize the use of digital interfaces, such as RS 485 communication, from the perspectives of operability, reliability, and anti-interference. Information can be transmitted between the control unit and the injection molding machine through software. The mold temperature machine can also be automatically controlled.