The structure of the hot runner system
The hot runner system is generally composed of hot nozzles, manifolds, temperature control boxes and accessories.
The edge of the hot nozzle adopts elasticity instead of rigid design. The elastic edge provides preload under cooling conditions and prevents system damage. If it is overheated accidentally, it can also absorb thermal expansion and expand the operating range to ±110°C. Thermal nozzles generally include two types: open thermal nozzles and needle valve thermal nozzles. Since the form of the hot nozzle directly determines the selection of the hot runner system and the manufacture of the mold, the hot runner system is often divided into an open hot runner system and a needle valve hot runner system accordingly. The splitter plate is used when one mold is multi-cavity or multi-point feeding, single-point feeding but the material level is offset. The material is usually P20 or H13. The manifold is generally divided into two categories: standard and non-standard, and its structure is mainly determined by the distribution of the cavity on the mold, the arrangement of the nozzles and the position of the gate. The temperature control box includes the host, cables, connectors and wiring male and female sockets. Hot runner accessories usually include: heaters and thermocouples, runner seals, connectors and junction boxes.
1. The back of the hot nozzle is fixed on the manifold; the high temperature bolts that fix the hot nozzle on the manifold can prevent leakage under cooling conditions. This kind of system still needs cold clearance, because the rigid edge needs a certain expansion space at normal temperature. Although this method can actively prevent leakage from the hot nozzle to the manifold, it cannot prevent the thermal expansion of components under overheating conditions.
2. The hot nozzle fixed on the manifold by bolts moves together with the manifold. This design has a minimum length requirement for the hot nozzle and also a limitation on the cavity spacing. It is an economical and effective way to prevent leakage between the hot nozzle and the manifold, and is suitable for systems with fewer cavities.
3. The edge of the hot nozzle adopts elasticity instead of rigid design. The elastic edge provides preload under cooling conditions and prevents system damage. If it is overheated accidentally, it can also absorb thermal expansion and expand the operating range to ±110°C. Thermal nozzles generally include two types: open thermal nozzles and needle valve thermal nozzles. Since the form of the hot nozzle directly determines the selection of the hot runner system and the manufacture of the mold, the hot runner system is often divided into an open hot runner system and a needle valve hot runner system accordingly. The splitter plate is used when one mold is multi-cavity or multi-point feeding, single-point feeding but the material level is offset. The material is usually P20 or H13. The manifold is generally divided into two categories: standard and non-standard, and its structure is mainly determined by the distribution of the cavity on the mold, the arrangement of the nozzles and the position of the gate. The temperature control box includes the host, cables, connectors and wiring male and female sockets. Hot runner accessories usually include: heaters and thermocouples, runner seals, connectors and junction boxes.
