If there is any operation error in the production of PVC pipe, there will be serious quality problems. Normally these problems can be bubble, uneven wall thickness and pitting. This time, let’s talk about the reason of pitting problem and how to deal with it.
If there is any impurity that hard to plastify, there will be pitting. We can see the content of impurity if the pitting is large enough. While the crystal content can also cause pitting. Besides, if the raw material is wet, it may cause small bubble and form pitting after moulding. You can see clearly that there is small tail against the extruding direction.
As we all know, the raw material is the most important factor for the product quality. Therefore, we have to guarantee the raw material are high quality. Moreover, we can increase the process temperature and dry up the raw material.
Large amount of water cause pitting
This is mainly occurs in hole type sizing sleeves. Because the inner space doesn’t zone, the bottom of pipe has great pressure. While the top section has small amount of water. Therefore, pitting appears in the high water pressure places.
Besides, the sizing sleeve block and cause uneven water. This also cause pitting distribute regularly. Sometimes they line on the surface of the pipe. On such occasion, we should adjust and keep the cooling water tunnel smooth.
The uneven cooling water amount also cause pitting
Many sizes of pipes have such problem, especially the pipes whose diameter is over 315mm. That’s because with the size larger, the gravity will be large. Then the amount of cooling water will be large. For this, we can adjust the water amount of every inlet pipes and increase the top water amount properly.
OrientFlex has been in hoses over 16 years and we become a powerful supplier in the world. If you have any questions during the production and process, welcome to contact us. We will offer you the best solutions.