Description of several factors in the mechanical properties of PVC-U pipe

1. The die section design is unreasonable
In particular, the distribution of the internal ribs and the treatment of the interface angle. This will cause stress concentration, and it is necessary to improve the design and eliminate the right angle and acute angle at the interface.
2. The die pressure is insufficient
The pressure at the die is directly determined by the compression ratio of the mold, especially the length of the straight section of the mold. If the compression ratio of the die is too small or the straight section is too short, the product will not be dense and affect the physical properties. On the one hand, the change of the die pressure can adjust the flow resistance by changing the length of the flat section of the die; on the other hand, different compression ratios can be selected to change the extrusion pressure during the mold design stage, but it must be noted that the compression ratio of the head should be The compression ratio of the extruder screw is adapted; the melt pressure can also be changed by changing the formulation, adjusting the extrusion process parameters, and increasing the perforated plate. .
3. The shunt merging is poor
For the performance degradation caused by the poor convergence of the split ribs, the length of the ribs and the outer surface, the ribs and the ribs at the confluence should be appropriately increased, or the compression ratio should be increased to solve. .
4. The die discharge is uneven
The die discharge is uneven, resulting in inconsistent wall thickness of the profile or inconsistent compactness. This also caused a difference in the mechanical properties between the two faces of the profile. We sometimes failed to pass the test on the side of the test, which is just proof of this. As for non-standard profiles such as thin walls, I won’t say more here.