The injection mold cooling water leakage failure is mainly in the following aspects.
Injection Mold Cooling Water Leakage Failure 1. The most occurring in the mold cooling water pipe joints, such as found leaking, should be wound on the threads of the pipe joints sealing tape, and then tighten.
Injection Mold Cooling Water Leakage Failure 2. Due to the long-term molding conditions, the waterproof ring inside the mold will be broken, in the O-shaped waterproof rubber ring is easy to harden and crack, resulting in water leakage.
Some poor installation of the waterproof ring can also cause seal failure. Generally need to regularly check the installation position and sealing performance of the seal ring.
Injection Mold Cooling Water Leakage Failure 3. The whole wall of the cooling water hole is broken.
This often happens when trying out a new mold, where the designed wall thickness is adequate, but the whole wall is worn through due to machining errors or post-processing. In most cases, the leaking water hole can not be used again.
Injection Mold Cooling Water Leakage Failure 4. Cooling water hole maintenance.
The cooling water hole is easy to scale, impedes heat transfer, serious when the water circuit does not work, and the need for regular maintenance. For straight water holes, insert a steel rod with a diameter of 0.5mm smaller than that of the cooling water hole, and hit it with a hammer to remove scale and rust. For the cooling water pipe buried in the mold, the mold should be decomposed to remove the rust.
After inspection and repair should be carried out a leak test, using a hand pump to fill the water hole, keep 5min under 2MPa pressure, and judge whether the water hole is leaking by observing whether the water pressure is reduced.
Leakage can be used with rubber, cork, and other elastic materials for mechanical fastening method of blocking, but also can try room temperature curing type silica gel as a sealing material.
Injection Mold Cooling Water Leakage Failure 5. Regular maintenance of the heating pipe and decompression pump with the use of.
The heating tube is an effective heat transfer element and is very effective in cooling the core of the fine and deep structure. In the part where cooling water can easily pass, setting a one-way heating tube can reduce leakage. In addition, the use of a reduced pressure pump to suck cooling water is also a way to prevent cooling water leakage.
Common failures and solutions of injection molds
1. Difficulty in the sprue release.
In the process of injection molding, the sprue is stuck in the sprue bushing, and it is not easy to get out. When the mold is opened, the product will be cracked and damaged. In addition, the operator must use the tip of the copper rod to knock out from the nozzle to make it loose before the mold can be released, which seriously affects the production efficiency.
The main cause of this failure is the poor finish of the conical hole of the gate and the knife marks in the circumference of the inner hole.
Secondly, the material is too soft, the small end of the cone hole is deformed or damaged after use for a period of time, and the curvature of the nozzle sphere is too small, which causes the riveting head of the sprue material here.
Solution.
The tapered hole of the sprue is difficult to process, so standard parts should be used as far as possible, if you need to process it by yourself, you should also make your own or buy a special reamer. The tapered hole should be ground to Ra0.4 or more. In addition, a sprue guide pin or sprue ejector sleeve must be set.
2. Damage to the guide column.
In the following cases, the moving and fixed mold will produce a huge lateral deflection force during injection:
(1). When the wall thickness of the plastic part is not uniform, the material flow through the thick wall at a large rate, generating a large pressure here;
(2). The side of the plastic part is not symmetrical, such as the step-shaped parting surface of the mold on both sides of the opposite side of the counter pressure is not equal.
Solution.
The guide bushing in the mold mainly plays a guiding role to ensure that the core and cavity molding surface in any case do not touch each other, and cannot be used as a guide pin force or positioning parts.
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