Heating mode of nozzle

① Externally heated nozzle
The heat source comes from the heating ring around the nozzle. The melt flow resistance in the nozzle is small and the length is not limited. Due to structural constraints, the temperature at the front gate of the nozzle is low. Due to the temperature difference, the heat balance is not easy to control. The heat utilization rate of the externally heated nozzle is low, and there should be an adiabatic air gap of 3-5 mm around the heating ring.
Multi-cavity hot runner injection mold with contact nozzle
1 - Fixed mold floor; 2 - Cushion block; 3 - Stop pin; 4 - Plug; 5 - Heater; 6 - Hot runner plate; 7 - Side support plate; 8 - Direct contact nozzle; 9 - Heating ring; 10-fixed model cavity plate; 11 - Moving formwork
② Internally heated nozzle
The heat comes from the heating rod in the center of the split shuttle. The power of heating rod can be adjusted by voltage. The melt channel clearance around the shunting shuttle is generally 3-5 mm. Small clearance, large flow resistance, fast heat dissipation; Large gap and large radial temperature difference of melt. If the nozzle is long, use electric heating coil to assist external heating.
The temperature of the internally heated nozzle can be effectively controlled because the high temperature conical tip extends into the gate.