Although there are many hot runner manufacturers and a variety of hot runner products in the world, a typical hot runner system consists of the following: (1) hot runner plate (2) nozzle (3) temperature controller (5) Auxiliary part one, hot runner plate: splitter plate: connected with the nozzle and the injection molding machine, the molten molten processing of plastic products plastic melt is evenly distributed to each nozzle through the heated splitter plate pressure. Second, the hot runner system is generally divided into two categories according to the heating method of the heat flow guide: (1) Insulation: The insulated runner mold has an excessive flow passage composed of a template. The flow channel is not heated, but the size of the flow channel is large enough to be combined with the heat generated by the plastic that is condensed on the flow channel wall under working conditions to maintain the melt in the flow channel. Unblocked. This kind of system is earlier and simpler in two categories. The advantage is that the design is not so complicated and the manufacturing cost is low.
The disadvantage is that condensation sometimes forms at the gate; in order to maintain the molten state, a very fast duty cycle is required; in order to achieve a stable melting temperature, a long preparation time is required. Another major problem is that it is difficult to achieve consistency in injection molding, or it cannot be guaranteed. Also, because there is no heating in the system, a high injection pressure is required, which often causes deformation or bending of the cavity plate. (2) Heating type: The heating channel system also has two designs: an inner heating channel and an outer heating channel: 1. an inner heating channel: the inner heating channel is characterized by an internally heated annular channel. Heating is provided by a probe in the flow channel and a heating shuttle (also known as a distributor tube). This system utilizes the insulating effect of molten plastic to reduce heat transfer and loss elsewhere in the mold. Despite the annular heater in the distributor tube, there is still a condensation of material between the heating shuttle and the flow channel wall.
The material must flow between the insulation wall and the heating shuttle, which, combined with the annual flow effect, causes a drop in pressure within the system, so the importance of balance is critical. In view of this problem, the internal heating system is most suitable for processing a wide range of materials and equidistant flow paths to the gates. This system is not suitable for the use of heat sensitive plastics. Internal heating provides improved heat distribution relative to the insulation system, but the system is more costly and more complex to design. Such systems require careful balancing and complex thermal control. 2, external heating system: Another design of the hot runner is the external heating system. This design consists of an annular heating header with internal flow channels. The header is designed with a variety of insulation configurations that are isolated from the rest of the mold. The advantage of this system is better temperature control, but the cost is higher and the equipment is complicated. The latest technology development has reduced the size of the header and made the installation easier. The external heating system can also be balanced by diameter rather than by length.
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