1. Improve the mold temperature, reduce the injection time and cycle. Because PP bubbles are formed due to internal shrinkage formed by too long cooling time.
2. Increase the back pressure, extend the injection time, with high pressure and low speed.
The PP injection moulding materials generally do not have bubbles (due to small moisture absorption), may be the pp granulation filling problems. If the solution in the process is: 1. Add standby material post drying material. 2. Injection molding back pressure increases, and injection molding speed slows down. 3. The temperature of the barrel should not be too high.
Originally PP injection moulding material is very easy to deal with the material.1. First, consider your mold structure, where the bubble is formed. 2.The bubble temperature should not be too high. 3. Thickness of the product.4.No glue or less glue. In fact, injection molding efficiency should not only look at the parameters, more analysis of the problem is the most important.
1. The material storage speed is too fast,it is appropriate to add some back pressure.
2. The raw material is not dry enough, containing moisture
3. The residence time of plastic in the barrel is too long.
4. The screw shot amount is too long.
5. The mold exhaust is poor.
6. The PP injection pressure is too high and injection speed is too quickly.
7. The melt temperature is too high and the mold temperature is too low.