Due to the low temperature of the material, the plasticization of PVC pipe parts is poor, which is generally called cold material spot. The method of eliminating cold material spot of PVC pipe parts is introduced below.
The elimination of cold spots and the generation of cold spots are both caused by excessive raw materials. The reason is: the temperature of the material is low and the plasticization is poor. It can be achieved in the following ways: (1) heating up, mainly by raising the temperature of each zone by 2 to 4 degrees each time; A large amount of heat is used to achieve the purpose of increasing the temperature of the material. Note: There are pros and cons to both heating methods. Although the material is well plasticized by heat, it is easy to decompose at a higher temperature, resulting in bubbles, silver threads, red lines, etc. Once this defect occurs, it is difficult to lower the temperature, and increasing the preforming pressure and flow can keep the temperature constant, thereby increasing the operating space
