How to Prevent Hot Runner Internal Oxidation and Rust

Thermocouple mounting holes, heating outer walls, and hot runner metal flow channels are all vulnerable to oxidation rust in prolonged high-temperature, humid, alternating work environments. In addition to obstructing small flow channels and affecting melt flow, rust particles can harm the fitting gap between thermocouple probes and mounting holes, which can lead to poor heat conduction and imprecise temperature readings. The rate at which hot runner interior components oxidize and rust can be significantly reduced by taking effective daily precautions.

Prior to production, tightly regulate the raw materials' moisture level. After being heated and melted, wet plastic particles will release a lot of hot water vapor. These water vapors will remain in the closed hot runner flow channel for a considerable amount of time, stick to the inner wall of the metal, and eventually create rust spots. All plastic raw materials should undergo adequate drying before injection molding production in order to minimize internal moisture volatilization, significantly lower the production of high-temperature water vapor inside the hot runner, and eliminate the primary cause of metal oxidation and rust formation.

When the equipment is turned off for standby, perform an excellent job of providing daily moisture-proof sealing protection. After production is complete and the machine is stopped, completely remove any remaining melt from the flow channel. Then, use special high-temperature sealing plugs to cover the manifold feeding port and nozzle glue outlet to keep outside moist air, dust, and other debris out of the interior. To maintain the interior environment dry, sprinkle desiccant around the hot runner installation point on a regular basis and store molds that are not in use for an extended period of time in a dry, well-ventilated area.

Apply heat-conducting and high-temperature anti-rust grease to important fitting locations on a regular basis. Coat the thermocouple probe outer wall, heating component contact surface, and hot runner assembly joint gaps with a special high-temperature resistant anti-rust grease. This protective grease layer can prevent moisture and air from coming into touch with metal surfaces, help prevent oxidation and rust, and increase heat conduction efficiency to guaranty that thermocouples record temperature more precisely. To prevent deterioration and carbonization during high temperatures, grease specifically designed for hot runners must be chosen.

Clean up the rust spots as soon as they appear. In order to prevent the rust layer from thickening and expanding, use professional high-efficiency metal cleaning agents to remove any minor rust from the inner wall of the flow channel and the wall of the temperature measuring holes during routine disassembly and cleaning operations. Then, polish the area smooth once more. Additionally, avoid long-term ultra-limit high-temperature operation that accelerates the oxidation aging of metal materials by controlling the hot runner working temperature range suitably. The interior structure of the hot runner can be kept intact and smooth, and temperature monitoring and heating accessories can continue to operate steadily over time with multifaceted protection from raw material processing, shutdown storage, and routine maintenance.