The temperature inside the injection mold is uneven, and it is also related to the point in time during the injection cycle. The function of the mold warmer is to keep the temperature constant between 2 min and 2 max, that is to prevent the temperature difference from fluctuating above and below the production process or gap.
The following several control methods are suitable for controlling the temperature of the mold: controlling the fluid temperature is the most common method, and the control accuracy can meet most of the requirements. Using this control method, the temperature displayed in the controller does not agree with the mold temperature; the mold temperature fluctuations are considerable because the thermal factors affecting the mold do not directly measure and compensate for these factors including changes in the injection cycle, injection speed, melting temperature, and Room temperature. The second is the direct control of the mold temperature.
The method is to install a temperature sensor inside the mold, which will be used when the mold temperature control accuracy requirements are relatively high. The main features of the mold temperature control include: the temperature set by the controller is consistent with the mold temperature; the thermal factors that affect the mold can be directly measured and compensated. In general, mold temperature stability is better than by controlling fluid temperature. In addition, mold temperature control is more reproducible in production process control.
The third is joint control. Joint control is a combination of the above methods, it can control the temperature of the fluid and mold at the same time. In joint control, the position of the temperature sensor in the mold is extremely important. When placing the temperature sensor, the shape, structure, and position of the cooling channel must be considered. In addition, the temperature sensor should be placed in a place that is decisive for the quality of the injection molded part. There are many ways to connect one or more mold temperature controllers to the injection molding machine controller. It is best to use a digital interface in terms of operability, reliability, and anti-jamming.