Hot runner systems fall into two categories:
Insulated and heated.
Heat insulation
The insulated runner mold has an oversized flow path 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 the two categories. The advantage of the electric heating tube 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
The heated runner system has two designs: the inner heated and the outer heated system. The heated runner is characterized by an internally heated annular runner. Heating is provided by a probe in the flow channel and a heating shuttle (also known as a distributor tube). This system uses the thermal insulation effect of molten plastic to reduce heat transfer and
Loss elsewhere in the mold. Despite the "+" shaped heating manifold/explosion-proof electric heating tube/hose heater in the distributor tube, there is still 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.
1. The structure of carbon steel coil heater: carbon steel electric heating element is made of metal pipe as the outer casing, and the spiral electric heating alloy wire (nickel chrome, iron chrome alloy) is evenly distributed along the center of the pipe. The gap filling compaction has good insulation and thermal conductivity. Magnesia oxide sand, sealed at both ends with silicone or ceramic, this metal armored heating element can heat air, metal molds and various liquids.
2. Use of carbon steel hot coil heater: Carbon steel electric heating element is an electrical component that converts electrical energy into heat energy. Because of its low price, convenient use, convenient installation and no pollution, it is widely used in various heating occasions. The service life is very long, and the general design life is more than 10,000 hours.
3. Performance of carbon steel coil heater: Carbon steel electric heating element is a kind of crystalline magnesium oxide powder which is placed in a metal pipe and is closely filled with a good heat resistance, thermal conductivity and insulation in the void portion. Processed. The utility model has the advantages of simple structure, high mechanical strength, high thermal efficiency, safety and reliability, simple installation and long service life.