The temperature in the injection mold is uneven, and it is related to the point in time of the injection cycle. The role of the mold temperature machine is to maintain a constant temperature between 2min and 2max, that is to prevent the temperature difference in the production process or gap fluctuation. The following control methods are suitable for controlling the temperature of the mold: the control fluid temperature is the most common method, and the control precision can meet the requirements of most cases. Using this control method, the temperature of 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 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 installed in the mold temperature sensor, which in the mold temperature control accuracy requirements are relatively high in the case will be used. The main features of mold temperature control include: the temperature of the controller is consistent with the mold temperature, and the thermal factors affecting the mold can be directly measured and compensated. Typically, the mold temperature is more stable than by controlling the fluid temperature. In addition, the mold temperature control in the production process Control repeatability is better. The third is joint control. Joint control is the synthesis of the above method, 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 extremely important and the position of the shape, structure and cooling channel must be taken into account when placing the temperature sensor. In addition, the temperature sensor should be placed where the quality of the molded part plays a decisive role. There are many ways to connect one or more die temperature machines to the injection moulding machine controller.
The digital interface is best used in terms of operability, reliability, and anti-jamming considerations. The heat balance of injection molds is the key to the production of injection molded parts by controlling the thermal conduction of injection moulding machines and molds. Inside the mold, the heat from the plastic (such as thermoplastic) is passed through the heat radiation to the material and the mold of the steel, passing through the flow to the heat conduction. In addition, heat is passed through the heat radiation to the atmosphere and the mold frame. The heat absorbed by the heat conduction body is taken away by the mold temperature machine. The heat balance of the mold can be described as: P=pm-ps. In the formula P is the heat taken away by the mold temperature; PM the heat introduced into the plastic; PS is the heat that the mold emits to the atmosphere. The purpose of controlling mold temperature and the influence of mold temperature on the injection molding process, the main purpose of controlling the mold temperature is to heat the mold to the operating temperature, and the second is to keep the mold temperature constant at the operating temperature. The success of the above two points, the cycle time can be optimized to ensure that the molded parts stable high-quality. Mold temperature affects surface quality, fluidity, shrinkage, injection cycle and deformation. High or low mold temperatures can have different effects on different materials. For thermoplastics, a higher mold temperature typically improves surface quality and fluidity, but increases cooling time and injection cycle. A lower mold temperature will reduce shrinkage in the mold, but will increase the shrinkage of the molded parts after demoulding. For Thermoset plastics, a higher mold temperature usually reduces the cycle time, and time is determined by the time it takes for the part to cool. In addition, in the plastic processing, the higher the mold temperature will reduce plasticizing time, reduce cycle times.