Hot runnerIt is a cyclic injection molding production process used on molds to help melt plastic. It can also control our material temperature, consistency, and injection pressure, allowing technicians to freely adjust the machine and achieve the desired product. Due to the long-term exposure of the hot runner to high temperatures, it is inevitable to encounter problems such as abnormal temperature rise and glue filling, which is also unavoidable for all hot runners, Moreover, dealing with these issues requires professional personnel to complete. Among many hot runner manufacturers, which one can provide strong after-sales service? What is the cause of material leakage in the hot runner
In most cases, material leakage in the hot runner system is not caused by poor planning, but rather by failure to operate according to planning parameters. Generally, leakage occurs at the sealing area between the hot nozzle and the splitter plate. According to the general planning specifications for hot runner, there is a steel edge at the hot nozzle, which ensures that the height of the hot nozzle component is less than the practical groove depth on the hot runner plate. The reason for planning this scale difference (commonly referred to as cold gap) is to avoid damaging components due to thermal expansion when the system is at operating temperature. For example, regarding a 60mm thick splitter plate and a 40mm hot nozzle assembly (with a total height of 100mm), when the temperature rises to an operating temperature of 230 ℃, it generally expands by 0.26mm. If there is no cold gap, thermal expansion often forms damage to the edge of the hot nozzle. Therefore, the lack of effective sealing under cooling conditions is generally the main cause of material leakage in the hot runner. In order to ensure the sealing of the system (hot nozzle and splitter plate), it is necessary to heat the system to operating temperature so that the force generated is sufficient to offset the injection pressure, and then avoid the injection pressure from pushing the two components apart. Generally, inexperienced operators often do not wait for the system to reach operating temperature, and even worse, they may forget to turn on the heating system. In this way, the pressure on the surface of the hot runner with cold voids cannot avoid material leakage before reaching its operating temperature.
In addition, material leakage may also occur under excessive heating. Due to the poor adaptability of hot nozzles with steel edges to thermal expansion, once the system is overheated and drops to operating temperature again, the sealing pressure that occurs cannot avoid leakage due to the influence of steel deformation. In this case, in addition to material leakage causing system damage, there will also be irreparable damage to the hot nozzle due to excessive pressure, and then the hot nozzle needs to be replaced. Because the preload of the hot nozzle and splitter plate is very important, it is necessary to strictly comply with the scale and service requirements provided by the hot runner supplier in order to effectively avoid material leakage in the system. Therefore, for mold manufacturers, they should carefully check the height and groove dimensions of all hot nozzle components according to the drawing requirements of the hot runner supplier. If there are any problems, they should also communicate with the hot runner supplier in a timely manner.