To produce high-quality PVC pipes, the PVC plastic pipe extrusion line must strictly control all links in the processing of PVC pipes, such as raw material selection, temperature, screw speed, compressed air, traction speed, traction cooling, etc., which are all very important factors affecting the quality of PVC pipes.
The first factor that affects the quality of plastic pipes is of course the raw materials. The selection of raw materials plays a crucial role in the quality of pipes made by PVC pipe production lines. There are many specifications and grades of PVC raw materials. Raw materials that can be used to produce PVC corrugated pipes cannot produce PVC water supply pipes. Here, manufacturers still need to do a lot of experiments and choose materials suitable for their own production of pipes in the extrusion production line.
Temperature is the main factor affecting the plasticization and production of plastic pipes. If the temperature is too low, the plasticization is not good, and if the temperature is too high, the material is easy to decompose. The temperature control should be determined according to the original formula, extruder and head structure, screw speed and other factors. When we are processing hard PVC pipes, since the processing temperature is quite close to the decomposition temperature, the material temperature at each point should be strictly controlled during production. At the same time, pay attention to the error of the temperature measuring instrument and the position of the measuring point.
The choice of screw speed directly affects the output and quality. The screw speed depends not only on the size of the extruder, but also on the size of the upper pipe. When the rotation speed increases, the extrusion volume increases, and the shear force on the material is large, which is helpful for the plasticization of the material, but the residence time of the material in the screw is short, and the excessive friction heat makes the inner wall of the pipe relatively rough and the strength of the pipe decreases. Therefore, the control of screw speed should be fully balanced according to the requirements of output, product appearance and physical and mechanical properties.
The traction speed directly affects the wall thickness of product. The traction speed should be matched with the extrusion speed, and usually the traction speed is 1% to 10% higher than the extrusion speed of the pipe.
If the cooling is not enough, the extruded material will stick and cannot be shaped. The pipe extrusion production line adopts the high-efficiency extruder of special HDPE and PE pipe, the screw adopts the structure with barrier and mixing head, and the barrel adopts the new slotted barrel, which has good plasticizing and mixing effect, large and stable extrusion. It is best to use air cooling combined with water cooling, and the cooling water temperature should be maintained at about 15°.
In addition, compressed air is also an influence on the quality of pipes made by PVC pipe production line. Compressed air shapes the pipe and maintains a certain roundness. The pressure is generally 0.02 to 0.05mpa.
The above points are all very important factors that affect the pipe production of the PVC pipe production line. Only by strictly selecting materials and controlling the production and processing process can we produce high-quality PVC pipes that meet the national standards.