Please note: Five precautions in the production process of PVC pipesPlease note: Five precautions in the production process of PVC pipes
PVC pipe is one of the most widely used pipes in the pipe industry. It is used frequently in construction and decoration. Therefore, the quality of PVC pipe is very strict, and there are many precautions in the production process. PVC pipe manufacturer Peida Plastics will tell you in detail today what matters need to be paid attention to in the production process of PVC pipe. There are five specific points:
In the production process, since PVC is a heat-sensitive material, even adding a heat stabilizer can only increase the decomposition temperature and prolong the stability time without decomposition. This requires that the molding temperature of PVC should be strictly controlled. Especially RPVC, because its processing temperature is very close to the decomposition temperature, often due to improper temperature control caused decomposition. Therefore, the extrusion temperature should be determined according to factors such as the formula, the characteristics of the extruder, the structure of the head, the screw speed, the position of the temperature measuring point, the error of the temperature measuring instrument and the depth of the temperature measuring point.
1. Temperature control
Temperature control is an important control factor in extrusion operations. The temperature control factors required for extrusion molding are barrel temperature, diameter temperature, and die temperature. The temperature is too low, the plasticization is poor, the appearance of the pipe is matt, the mechanical properties are poor, and the product quality does not meet the requirements: the temperature is too high, the material will decompose, and the product will become discolored.
2. Screw speed
The screw speed increases and the extrusion volume increases, which can increase the output, but it is easy to cause the phenomenon of poor plasticization, which causes the roughness of the inner wall of the pipe and the strength to decrease. At this time, the head pressure should be adjusted to achieve the best output and quality. The temperature control of the screw affects the material delivery rate, material plasticization, melting quality, etc. Extruded tubing needs cooling water to reduce the screw temperature, which is conducive to improving the quality of plasticization. The screw cooling water temperature is about 50 ~ 70.
3. Traction speed
The adjustment of the traction speed in the re-extrusion operation is very important. The material is melted and plasticized by extrusion, and is continuously extruded from the head and then pulled, so as to enter the shaping device, cooling device, traction device, etc. The traction speed should be comparable to the extrusion speed match. Generally, in normal production, the traction speed should be about 1% ~ 10% faster than the extrusion speed of the pipe.
4. Compressed air and pressure
Compressed air can inflate the pipe to keep the pipe round. The pressure should be appropriate. The pressure is too small, the pipe is not round, the pressure is too large, the core mold is cooled, the inner wall of the pipe is cracked, not smooth, and the quality of the pipe is reduced. At the same time, the pressure needs to be stable. If the pressure suddenly increases or decreases, the pipe is prone to slub status.
5. Temperature of sizing device and cooling device
Extruding different plastic products, using different sizing methods and cooling methods, the cooling medium can be air, water or other types of liquids, the temperature needs to be controlled, and its temperature is mainly related to production efficiency and product internal stress.
The above five points are the points that general manufacturers should pay attention to when producing PVC pipes. As long as the above five points are done, I believe that the PVC pipes made will definitely ensure better quality.If you want to know more about it please do not hesitate to contact me. WhatsApp:+86-15966835076.