Analysis of the Reasons of Unstable PVC Pipe Extrusion

Extrusion instability refers to the fact that PVC pipes are produced in a rapid and slow manner, which affects the quality of pipes. I have analyzed the following reasons for PVC pipe extrusion line, which are roughly in the following aspects:

1. The screw speed control is not accurate. Due to the continuous progress of frequency control technology, this situation is not common at present;

2. If the heating system is not controlled accurately, the barrel temperature will fluctuate from high to low;

3. The instability of material transportation and the bridge of biological material in the hopper lead to the uneven discharge, which is the most common problem at present;

4. Insufficient plasticizing capacity will also cause unstable discharge;

5. Instability caused by blocking during cutting;

6. The instability of PVC pipe extrusion production is mainly caused by the addition of more calcium and the uneven cutting of raw materials. The only solution is to add more grinding materials;

7. Uneven heating will not cause fluctuation, which is reflected in the difference in the appearance of pipes. I think the fluctuation is mainly due to the different flow rate of mixture blanking, more calcium powder, resulting in the difference in plasticization. You can think of ways on calcium carbonate. The above mentioned addition of grinding material is also a good way;

8. Uneven internal and external lubrication will also cause uneven discharge;

9. Die sticking is caused by insufficient external sliding or stabilizer. The poor toughness of pipe is also related to the insufficient stabilizer. If the stabilizer is enough, more impact modifier can be added to improve it;

10. The use of light calcium powder is too high, resulting in uneven mixing and fluffy mixing. The result is uneven cutting speed, and bridge erection is also the main reason in serious cases! The use of heavy calcium will greatly improve;

11. Too much lubricant, especially too much external lubrication, will cause the material to slip between the barrel and the screw, which will not form a strong solid plug, and will also cause fast and slow discharging.