Finished mucous membrane (difficult demolding) refers to a phenomenon in which the molded product of a plastic mold cannot be completely or quickly removed from the mold during production. This phenomenon will greatly increase the failure rate of products, increase costs, and reduce customer satisfaction, so it is urgent to solve it. Let's first analyze the reasons for the difficulty in removing the mucous membrane/demolding of plastic mold products:

Analysis of the reasons for poor demolding of plastic molds:

1. According to the size and temperature of the molded product, an increase in demolding resistance will result in poor demolding:

Although it may also be affected by resin properties and molding conditions, the main reason still lies in the shape of the molded product and the structure of the mold. Special attention should be paid to the situation when accompanied by slender reinforcing ribs, wheel hubs, and plastic hole bolts tightly;

2. When the molding shrinkage around the plastic hole plug is too large, the clamping force on the plastic hole plug will increase, which can easily lead to poor demolding:

In terms of molding conditions, low mold temperature and excessive holding pressure can easily cause poor demolding;

3. When long reinforcing ribs or wheel hubs are filled in vertically formed products, these reinforcing ribs or wheel hubs will become difficult to detach, resulting in poor demolding:

In terms of molding conditions, low mold temperature and excessive holding pressure can easily cause poor demolding. This is exactly the opposite of holding the plastic hole bolt tightly;

4. When the demolding slope of the cavity product department is too small, due to the high demolding resistance, demolding defects are prone to occur:

The position of the ejector pin also has a significant impact (fortunately, ejector pins are set up in areas with high demolding resistance). In addition, the smoothness or damage of the mold cavity surface also affects the demolding resistance, resulting in poor demolding.

Analysis of Reasons for Plastic Mold Finished Mucosa:

1. During injection molding, there may be mucous membrane formation in the finished product, and the first thing to consider is whether the injection pressure or holding pressure is too high:

Excessive injection pressure can cause over saturation of the finished product, causing the plastic to be filled into other gaps and making it difficult to remove the product from the mold cavity. It is also prone to mucous membrane formation during removal;

2. When the temperature of the material tube is too high, two phenomena usually occur:

One is that high temperature causes plastic to decompose and deteriorate, losing its original characteristics: and during the demolding process, it breaks or tears, causing mucous membranes;

The second reason is that the rubber material is not easy to cool after being filled into the mold cavity, and the cycle time needs to be extended, which is not cost-effective. So it is necessary to adjust the operating temperature moderately according to the characteristics of the rubber material;

3. In terms of molds, if the feeding port is unbalanced, it will easily cause mucosal phenomenon when demolding the finished product. In this case, improvement measures need to be taken on the mold.

Possible causes and treatment strategies for finished mucous membranes:

1. Excessive filling reduces the injection dose, time, and speed;

2. Reduce the injection pressure or barrel temperature when the injection pressure or barrel temperature is too high;

3. Reduce the holding time if the holding time is too long;

4. The shooting speed is too fast, which reduces the shooting speed;

5. Uneven feeding causes partial overfilling and changes in the size or position of the overflow port;

6. Insufficient cooling time increases cooling time;

7. Adjust the mold temperature and the relative temperature on both sides if the mold temperature is too high or too low;

8. There is an under cut in the mold to remove the chamfer during mold repair;

9. Unbalanced feeding ports in multi cavity molds, or unbalanced feeding ports in single cavity molds, limit the flow of plastic as close as possible to the main channel;

10. The poor design of the demolding exhaust system for the probe provides sufficient air escape channels;

11. The screw advance time is too long, which reduces the screw advance time;

12. Adjust the misalignment of the mold center and lock it with a "pullback" angle;

13. The surface of the mold is too rough, the surface of the mold cavity is polished, and release agent is sprayed;

Reasons for difficulties in sticking/demolding the sprue mold and troubleshooting methods:

1. Modify the mold if the sprue is too large;

2. Insufficient cooling of the sprue can prolong the cooling time or lower the temperature of the material pipe;

3. Insufficient demolding angle of the sprue, modify the mold to increase the angle;

4. Adjust and match the concave arc of the sprue and the nozzle again if they do not match properly;

5. The inner surface of the sprue is not smooth or has demoulding chamfers for mold maintenance;

6. The outer hole of the sprue is damaged and the mold needs to be repaired;

7. No sprue grab lock added with grab lock;

8. When the demolding resistance is too high due to the tightness of the plastic hole bolt, it is also effective to suppress the molding shrinkage by increasing the holding pressure and mold temperature;

9. If the size increases and is embedded in the mold cavity due to overfilling, the holding pressure and mold temperature should be reduced to increase the molding shrinkage;

10. When the demolding resistance is too high due to the tightness of the plastic hole bolt, it is also effective to suppress the molding shrinkage by increasing the holding pressure and mold temperature;

11. Increase the demolding slope around the mold cavity, hub, and reinforcement ribs;

12. In the case where components such as the mold cavity and wheel hub have been firmly embedded, ejector pins should be added to the parts that require increased ejector strength.