What are the main aspects of cooling water leakage in injection molds?
Cooling water leakage of injection molds often occurs for many reasons, mainly in the following aspects:
① It occurs mostly at the joints of the mold cooling water pipe. If leakage is found, the sealing tape should be wound around the thread of the pipe joint and then tightened.
② Under the condition of long-term molding, the waterproof ring in the mold will be damaged, and the O-shaped waterproof rubber ring is easy to harden and crack, resulting in water leakage. Poor installation of some waterproof rings can also cause seal failure. Generally, the installation position and sealing performance of the seal ring need to be checked regularly.
③ The wall of the cooling water hole is damaged. This often happens when trying new molds. The designed wall thickness is sufficient, but the hole wall is broken due to processing errors or post-processing. In most cases, leaking holes can no longer be used.
④ Maintenance of cooling water holes. The scale in the cooling water hole is easy to form scale, hinder heat transfer, and in severe cases make the waterway inaccessible, requiring regular maintenance. For straight water holes, you can insert a steel rod 0.5mm smaller than the diameter of the cooling water hole and strike with a hammer to remove scale and rust. For the cooling water pipe buried in the mold, the mold should be disassembled to remove rust.
⑤ Regularly repair and use heating pipes and pressure reducing pumps. The heating tube is an effective heat transfer element, which is very effective for the core cooling of fine and deep structures. In places where cooling water can easily pass, setting a one-way heating pipe can reduce water leakage. In addition, using a decompression pump to suck cooling water is also a method to prevent cooling water leakage.
After maintenance, a water leakage test should be performed. Use a hand pressure pump to fill the water hole with water, hold it at 2MPa for 5 minutes, and determine whether the water hole is leaking by observing whether the water pressure decreases. The leaking place can be blocked by mechanical fastening with elastic materials such as rubber and cork, and room temperature curing silicone can also be used as the blocking material.