In the field of injection molding, injection molds serve as the core “equipment” and are mostly crafted from tool steel. However, during the injection molding process, molds inevitably come into contact with substances that can cause rusting, such as corrosive gases and water. Once a mold rusts, the plastic parts it produces will suffer from quality issues, including surface defects and dimensional deviations, which severely impact product performance and market competitiveness. Therefore, delving deep into the causes of injection mold rusting and finding effective solutions have become critical challenges that the industry urgently needs to overcome. Below, let’s uncover the mysteries behind injection mold rusting and explore targeted solutions.
Corrosive Gases from Plastic Melt Decomposition: Precautions for Mold Rust Prevention
Some plastic raw materials release volatile gases during the heating process, especially when overheated. These gases, like invisible “corrosion killers,” are highly corrosive and permeate the surrounding area of the machine. When the injection mold is in a shutdown state, it becomes the prime target for these gases, gradually eroding the mold surface and leading to rusting.
To address this issue, meticulous protective measures are required. When the machine stops operating, be sure to use a soft cloth to carefully wipe the injection mold clean, ensuring no residue remains. Then, close the mold to form a protective barrier. If the mold is expected to remain idle for an extended period, spray an appropriate amount of anti-rust agent into the mold cavity to provide an extra layer of protection. Additionally, when closing the mold, apply a layer of grease and plug the gate to further isolate external corrosive factors and safeguard the mold comprehensively.
Carbonaceous Compounds “Wreaking Havoc”: Timely Cleaning to Protect the Mold
After prolonged continuous operation, certain components in the molding material will precipitate and decompose under high-temperature and high-pressure conditions, generating carbonaceous compounds. These compounds act like tiny “sandpapers,” continuously wearing down the mold surface while their corrosive nature gradually erodes the mold material, causing rusting. Once carbonaceous compounds are detected on the mold surface, immediate action is necessary. Use a dry cloth to promptly wipe them off and clean the area to prevent further spread and more severe damage to the mold.
Cooling Water “Causing Trouble”: Drying Treatment is the Key
To achieve rapid cooling and improve production efficiency, cooling water is typically circulated through injection molds. However, this also leads to a high humidity environment around the machine, with water vapor permeating the air. When the injection mold is cooled to a certain degree, water vapor in the air condenses into water droplets on the mold surface. If these droplets are not wiped off promptly, they become a breeding ground for rust, accelerating the rusting process of the mold.
Especially when the injection mold stops working, condensation water forms rapidly, further increasing the risk of rusting. Therefore, in actual production, it is advisable to avoid stopping the injection molding operation lightly. If a shutdown is necessary due to special circumstances, be sure to turn off the cooling water system in advance and use a dry cloth to thoroughly dry the injection mold, ensuring the mold surface is completely free of moisture and eliminating rusting hazards at the source.
Although the issue of injection mold rusting may seem daunting, by gaining a deep understanding of its causes and implementing scientific and reasonable solutions, we can effectively prevent and control mold rusting. This ensures the smooth progress of injection molding production and improves product quality and production efficiency. It is hoped that the above content can provide valuable references and insights for professionals in the injection molding industry.
