Type of Hot Runner Nozzle System

Hot runner applied to the injection mold during the production of the TZM alloy is the assembly of heating components that put the melting plastic into the cavity.

Generally, the hot runner systems can be divided into single-headed hot runner system, multi-headed hot runner system and valve-regulated hot runner system. The single-headed hot runner system includes one nozzle, the nozzle head, temperature controller and so on. 

Single-headed hot runner system:

The structure of its injection molds is relatively simple. During the production of TZM alloy, the molten plastic is poured into the nozzle connecting plate from the nozzle to the nozzle head and then injected into the mold cavity. It is necessary to control the sizes (d, D, L) and adjust the thickness of the nozzle connecting plate so that the fixing plate of fixed mold can press the end of the nozzle connecting plate to control the axial displacement. The same purpose can be achieved by directly using the nozzle of the injection machine against the end of the nozzle connecting plate.

TZM picture

Multi-headed hot runner system:

The structure of its injection molds is relatively complicated. During the production of TZM alloy, the molten plastic is poured into the nozzle connecting plate from the nozzle to the nozzle head and then injected into the mold cavity. The nozzles and fixed mold plates have matching requirements for radial dimension D1 and axial dimensional limit requirements. The nozzle head and the fixed mold insert have a matching requirement for radial dimension d to ensure that the molten plastic does not overflow to the non-cavity part, and the hardness of the fixed mold insert is required to be hardened by about 50HRC.

Valve-regulated hot runner system:

Compared with other normal hot runner systems, the plastic mold structure of this system is the most complicated because it has an additional valve needle transmission device which controls the opening and closing movement of the valve needle. The transmission device is equivalent to a hydraulic cylinder, which is connected with the mold by the hydraulic device of the injection machine to form a hydraulic circuit. As a result, it realizes the opening and closing movement of the valve needle and controls the molten plastic injection into the cavity.

 

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