The last thread of the material mouth starts to call th […]
The last thread of the material mouth starts to call the conveying section. The material here cannot be plasticized, but it must be preheated and compacted. In the past, the old extrusion theory believed that the material was loose. Later, it was proved that the material is solid Stopper, that is to say, the material here is a solid like a stopper after being squeezed, so as long as it completes the transportation task, it is its function. When the second section is called the compression section, the volume of the screw groove gradually decreases from large to large, and the temperature must reach the degree of plasticization of the material. Here, the compression is generated by the conveying section three, and here it is compressed to one. This is called the compression ratio of the screw -3: 1. Some machines also have changes, and the plasticized material enters the third stage. The third section is the metering section. Here the material maintains the plasticizing temperature, but it is just like the metering pump to accurately and quantitatively transfer the melt material to the machine head. At this time, the temperature cannot be lower than the plasticizing temperature, which is generally slightly higher.