Hot runner technology uses a high-pressure and high-temperature nozzle extension of the injection molding machine to install the nozzle and hot runner metal plate inside the plastic injection mold. Temperature sensors adjust the temperature inside the runner to ensure that the plastic in the runner is heated to a molten state, maintains a constant temperature, and ensures that no solidification occurs during the injection molding process. Especially during demolding, there is no water droplet carried out with the molded product, ensuring that the entire runner is smoother.
When using hot runner technology, the pouring method directly determines the selection of hot runner system components and mold manufacturing. Therefore, the hot runner must be divided into three types according to the pouring method. The first type is a hot tip hot runner system, the second type is a bushing hot runner system, and the third type is a valve or valve pin hot runner system. Each type of hot runner system has its own application characteristics and scope.
The hot tip hot runner system, as the most common hot runner system in use, can accurately control the molding and processing temperature of plastic at the pour gate by combining the Hot Tip of the nozzle with the cooling system. The bushing hot runner system is very suitable for injection molding of parts with medium size and weight above because the plastic flow pressure loss at the pour gate is small. The valve hot runner system is currently the most important hot runner system offered by international hot runner suppliers. With the action of the valve pin control device, the pouring gate can be opened or closed mechanically at a predetermined time, which can artificially control the switch time of the pouring gate and ensure the smoother pouring gate.
The function of the hot runner manifold plate is to separately deliver the molten plastic configured by the injection molding machine to different injection ports, and can ensure that the temperature of the melt is constant. In this process, since the amount of melt at each injection port is completely the same, it can ensure that the flow length of the runner melt at each accommodation point is consistent, so that the mold can be evenly filled with melted material. The overall structure of the hot runner manifold plate is closely related to the internal structure of the accommodation object itself, the arrangement of the injection ports, and the position of the glue inlet. By controlling the temperature inside the runner, the thermocouple can also be used to adjust the temperature of the heating element everywhere to ensure that the plastic product is always in a molten state.
Miniaturization, standardization, and serialization of components
Component miniaturization can effectively reduce the molding time of injection molding products, improve the overall precision of products, and is therefore an important direction for the future development of mold injection industries. By applying component miniaturization technology, production efficiency can be greatly improved, and hot runner injection nozzles can be made smaller to achieve the effect of multiple mold cavities or multiple pouring gates.
Expand the scope of materials and improve overall reliability
Since the cost of hot runner molds is very expensive, and the internal structure of the mold is very complex, the standardization and unification of machine parts can not only increase the service life of components but also effectively reduces maintenance costs. By using standardized production and manufacturing of components, it is also more convenient to replace components and reduce maintenance costs. In addition, standardized components can also be combined with computer software to ensure the automation of the design and structure of plastic injection molds, and improve the standardization of components.