The working principles of different hot runner systems vary, and the following mainly introduces the working principles of two plastic molds with hot runner systems:

1. The working principle of the plastic mold for the valve rubber port hot runner system.

The plastic mold structure of the valve rubber port hot runner system is the most complex, which has the same structure as the ordinary multi head hot runner system plastic mold. In addition, there is an additional set of valve needle transmission device to control the opening and closing movement of the valve needle. This transmission device is equivalent to a hydraulic cylinder, which is connected to the mold using the hydraulic device of the injection machine to form a hydraulic circuit, achieving the opening and closing movement of the valve needle, and controlling the injection of molten plastic into the mold cavity.

2. The working principle of a plastic mold with a single hot runner system.

The single head hot runner system mainly consists of a single nozzle, nozzle head, nozzle connecting plate, temperature control box system, etc. The plastic mold structure of the single head hot runner system is relatively simple. Inject molten plastic from the injection molding machine into the nozzle connecting plate, and after reaching the nozzle head through the nozzle, inject it into the mold cavity.

It is necessary to control the dimensions d, D, L, and adjust the thickness of the nozzle connecting plate to make the fixed mold fixed plate compress the end face of the nozzle connecting plate, control the axial displacement of the nozzle, or directly use the injection molding machine nozzle to support the end face of the nozzle connecting plate, which can also achieve the same goal. Install a lead slot at a suitable position on the fixed plate of the mold, allowing the power cord to be led out of the mold and connected to the wiring base installed on the mold.