Thermoplastic hot runner and thermosetting cold runner can be injected with anhydrous material after final molding due to different characteristics of thermoplastic and thermosetting plastics, as well as different heating parts of injection plastics.

In an injection mold, the plastic in the runner is heated to a molten high temperature and then injected into the mold cavity for cooling and solidification, and the injection method that needs to prevent the high heat transfer from the runner to the mold is called thermoplastic hot runner injection. The hot runner system is generally composed of several parts, including a hot nozzle, a splitter plate, a temperature controller, and accessories. The hot nozzle and splitter plate mainly serve to transport molten high-temperature plastic, while the temperature controller is a device installed on the periphery of the mold to control the heating temperature of the hot nozzle and splitter plate. There are generally two types of hot nozzles according to the gate type: open type hot nozzles and needle valve type hot nozzles. Due to the fact that the form of the hot nozzle directly determines the selection of the hot runner system and the manufacturing of the mold, the hot runner system is often divided into an open hot runner system and a needle valve hot runner system accordingly.

In injection molds, the injection method of injecting low temperature plastic into the heated mold cavity to harden and prevent heat transfer from the mold to the runner is called thermosetting cold runner injection.

Traditional thermoplastic injection, on the other hand, cools both the flow channel and mold cavity of the mold, with the cooled flow channel and product taken out each time the mold is opened. This causes a large amount of waste of raw materials during multi cavity and single cavity multi gate injection molding, and of course, seriously damages the profit space of plastic product injection molding. The advantage of this type of injection molding is that the mold manufacturing is simple, and it can also meet the aesthetic needs of certain plastic products well. For example, it can reduce the injection into transparent acrylic or polycarbonate parts used for light transmission, and avoid the visible banded effect caused by injection in certain parts.

For the drawbacks of traditional thermoplastic injection, in addition to waste of raw materials, it adds steps to the entire automated or manual process. Removing the cooled runner from the mold requires robots or workers to separate these parts from the product. In the case of multiple cavities, the amount of plastic in the runners and gates will exceed the total amount of injection molded products, and the cooling time of the runners and gates will also exceed the cooling time of the injection molding part, resulting in a longer injection cycle of the mold. Especially for transparent and expensive material injection molding, the runner is almost unusable, which will cause great waste. And the hot runner can precisely solve these problems.