​Needle valve hot runner hot nozzle What to pay attention to? Valve needle hot nozzle, good color change performance, suitable for most plastics, good flow performance, very fine gate marks. Valve gate hot runner system plastic mold structure is the most complex. It has the same structure as the common multi-head hot runner system plastic mold, and there is also a set of valve needle transmission device to control the opening and closing movement of the valve needle。

The transmission device is equivalent to a hydraulic cylinder, and the hydraulic device of the injection machine is connected with the mold to form a hydraulic circuit to realize the opening and closing movement of the valve needle and control the molten plastic injection cavity.

As with the application requirements of hot tip and jacket hot runner systems, if the temperature control at the valve gate is not good, it will also cause serious production difficulties. For example, if the temperature at the gate is too high, there is a danger that the plastic will stick to the valve needle when opening the mold. On the contrary, if the temperature at the gate is too low, the gate plastic is too cold, causing the valve needle to close difficult.

The price of the valve gate hot runner mold is more expensive than the hot tip and pouring jacket hot runner mold. If the valve hot runner system and the valve needle control device themselves are not well designed, problems will occur such as the formation of a flow dead Angle behind the valve needle, or the overflow phenomenon on the sliding mating surface between the valve needle and other parts.

In addition, if the valve needle is not made well and the operation control of the closing action is improper, there will also be serious consequences of damaging the gate. Therefore, although the valve hot runner system has many advantages that the other two types of hot runner systems do not have, it also increases the complexity of the mold.