What are the common problems and solutions for BMC injection molding?


Problems that are prone to occur in the molding of BMC […]

Problems that are prone to occur in the molding of BMC injection products:
1. During the whole molding process of BMC injection products, the gas is not released immediately, and the gas accumulates;
2. The temperature of the mold is too high, causing the raw material to not fill the mold core to be suspicious of glue;
3. The injection rate is too slow, so the raw materials are solidified without fluidity;
4. Insufficient supply of raw materials;
5. The mold gap is too large.

The countermeasures adopted are:
1. Select the processing technology of vacuum pump forming;
2. Do a good job of vent hole design plan in advance;
3. The mold is provided with ejector pins, etc., and also has air holes;
4. Effectively control the injection rate;
5. Reduce the mold temperature;
6. Check the metrological verification status;
7. Change the mold.

The second, more common problem is having some air bubbles on top of the finished product. The key reasons for such a problem are:
1. The temperature is too high, butadiene vapor evaporates;
2. Short curing time and slow internal curing;
3. The mold temperature is low and the curing is poor.

The countermeasures that should be taken to solve this problem are:
1. Moderately reduce the mold temperature of BMC injection products;
2. Moderately increase the curing time;
3. Increase the mold temperature;
4. Improve pe powder.
In addition, a more common problem is the expansion and contraction of the surface layer, which includes two reasons, one is because of the problem of post-folding, and the other is the poor positioning of chemical fibers. The countermeasures to be taken are:
1. Adjust the whole process of refrigeration again; 2. Renovate and design the product again; 3. Select refrigeration fixtures; 4. Adjust the nozzle part again; 5. Use injection to reduce molding.

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