Structural form of hot runner

1) Extended nozzle
It is a special nozzle that lengthens the nozzle of the ordinary injection machine to make it directly contact with the mold gate. It is heated by an electric heating coil and has a temperature measurement and control system. The nozzle temperature is required to be 15~20 ℃ higher than the barrel. The nozzle mouth is actually the gate of the mold cavity, and the point gate with a diameter of 0.8~1.2 mm is commonly used.
As the high temperature nozzle directly (or indirectly) forms plastic parts, the mold must be insulated to prevent the high temperature of the nozzle from affecting the curing of plastic parts. Commonly used air gap and plastic skin insulation. After injection and pressure maintaining, the nozzle should be separated from the mold to minimize the contact area between the nozzle and the mold.
The extended nozzle has a simple structure and is often used in single-cavity molds. Commonly used are spherical, conical and other forms.
(a) Spherical nozzle (b) conical nozzle
(c) Forming nozzle (d) adiabatic nozzle
Structure of extension nozzle
Figure (a) The nozzle extends into the gate sleeve, the nozzle is positioned against the shoulder and bears the force, and there is an increase between the nozzle and the gate sleeve
Bushing for air gap.
Figure (b) The nozzle end face is a part of the mold cavity, with an intermediate bushing, an air gap groove, and cooling water.
Figure (c) The nozzle must be positioned on the injection base to withstand pressure. The nozzle front end fits with the hole, and thermal expansion must be considered
Bulging and flash.
Figure (d) shows the adiabatic nozzle, a bowl-shaped plastic thermal insulation cover, with a central thickness of 0.4 ～ 0.5 mm and a lateral thickness of 1.2 ～ 1.5 mm. The pressure shoulder is embedded with PTFE sealing gasket. Ensure the strong rigidity of the bottom of the gating cup.
2) Multi-cavity hot runner injection mold
It has many structural forms and is widely used. The utility model is characterized by having a runner plate heated by a heater. It is connected to the main flow channel, and is equipped with a diversion channel and multiple nozzles.