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The role of hot runner in plastic mold design

The role of hot runner in plastic mold design Hot runner (HRS) is also called a hot water nozzle, which turns a solidified nozzle into a molten nozzle. Its composition is relatively simple and mainly includes a manifold, a hot nozzle, a temperature controller, etc. Among them, the manifold can be divided into I-shaped, The methods can be divided into watch core type, plug-in card type and computer centralized control type. ​
In injection molding processing, hot runner is used in conjunction with the mold and plays a very important role. For example, in the injection molding production of ultra-thin parts (such as mobile phone battery covers), high-precision, high-quality products can be easily produced by using hot runners; for injection molding raw materials with poor fluidity (such as LCP), by using hot runners It can significantly improve the fluidity of raw materials and ensure the smooth progress of injection molding production; for some large injection molded parts, such as car bumpers and door panels, TV rear casings, air conditioner casings, etc., the use of hot runners makes very difficult injection molding easy. Relatively simple.

In multi-cavity mold injection molding, molding cannot be achieved without a hot runner. It can be said that hot runner is the best technology to ensure the balance of runner. Due to the shear force of the plastic in the runner, no matter how reasonable the geometric balance of the mold is, the weight of the molded product is difficult to be consistent. Especially for multi-cavity molds, if hot runners are not used, the molded product will be The outside of the product will be lighter than the inside. For plastic processors, as long as there is a certain batch of injection molding production, it is quite economical to use hot runner. This is because hot runner helps companies eliminate nozzles in injection molding production. In most cases, the spout cannot be reused. Sometimes, the weight of the nozzle is almost the same as the weight of the product. If the traditional nozzle injection molding method is used, it means that as much raw material is wasted as the raw material used in the product. Based on this calculation, 30% to 50% of raw materials can be saved by using hot runner.https://solidcomould.com/product/fitting-pipe-mould2/

In addition, hot runners also help reduce mold wear and extend the life of the mold. Generally speaking, the service life of hot runner mold is 2 times that of fine nozzle mold.
Although the composition of the hot runner is relatively simple, each component plays an important role. Generally, a good-quality hot runner has very high requirements on structural design and materials. As far as Xianrui hot runner is concerned, the heaters and temperature sensing wires selected are all imported from South Korea, and the steel materials used are all imported from Japan. These are the prerequisites for ensuring the quality of the hot runner. In addition, hot runner suppliers also need to help customers design and install suitable hot runner systems based on their plastic products and molds used. Xianrui has senior hot runner experts from South Korea who can design reasonable solutions based on the customer’s product conditions to ensure that the hot runner system can maximize efficiency in injection molding processing.

For example, in the design of hot runner for door panel injection molding of Shanghai General Motors, the relevant components of the hot runner were selected based on full consideration of the materials used in the door panel.https://doi.org/10.1016/j.polymertesting.2014.05.009

If the door panel is made of PP material, a three-point hot runner is usually sufficient, that is, a Y-shaped manifold and three hot nozzles. This solution greatly reduces the manufacturing cost while ensuring the molding quality of the product; if the door panel uses fireproof ABS When using materials, a 5-point hot runner must be used, that is, a special manifold and 5 hot nozzles to ensure the smooth molding of the product. When installing the hot runner, you need to pay attention to the following points: ● Fully inspect the hot runner, including all sizes, resistances, and quantities; ● Fully inspect the dimensions of the relevant parts of the mold and hot runner; ● Before installing the panel, you must use a thermostat to carefully Ground inspection of the hot runner must be carried out to confirm that it is working properly before the machine can be operated; ● Before production, a multimeter must be used to conduct a final inspection of the hot runner, otherwise the machine is not allowed to be started; ● Air firing must be carried out before mold closing, and cardboard handle B should be used during air firing The plate mold is covered, and then the mold is closed to try out the mold. In order to help customers use hot runner correctly, hot runner suppliers should train customers. The training content should include: ● Basic principles of hot runner. The hot runner uses electric heating to keep the plastic in the runner in a molten state. Here, it is particularly important to emphasize to customers that when the hot runner is working in the mold, it needs to have good insulation measures. For this reason, square iron cannot be used as a substitute when making the manifold cavity. This is very important in injection molding. of. ●Learn to correctly install and disassemble hot runner. First of all, customers must understand the sealing position of the hot runner, which includes the sealing of the hot nozzle and the manifold plate, the sealing of the hot nozzle and the mold A plate, the sealing of the main nozzle and the panel, and the sealing of the valve needle and valve needle guide. Sealing glue and sealing glue between main nozzle and hot flow plate. ● Maintenance and maintenance of hot runner. The customer must realize that once there is a problem with the hot runner, it must be removed from the mold for repair, a process that takes at least 8 hours. For customers, the cost of loss is approximately 10 times that of the hot runner supplier. Therefore, it is very important to have dedicated full-time or part-time personnel to maintain the hot runner.

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