The shear performance of the extruder is determined by […]
The shear performance of the extruder is determined by the screw structure of the extruder. However, the quality of extrusion and the efficiency of extrusion are also due to the compatibility of the extrusion process with the shear performance of the extruder. Otherwise, the low-shear extruder uses an excessively high extrusion speed to extrude, and it is difficult to produce extruded high-quality profile products, and the high-shear extruder runs at an excessively low extrusion speed, which makes it difficult to effectively exert the extrusion efficiency. Extruders with different shear properties have a certain process control range, which is limited. The extrusion process advocated in the industry is "saddle type", that is, the set temperature of the heating zone should be higher, the set temperature of the constant temperature zone should be lower, and the set temperature of the heat preservation zone should be higher. But with different shear performance extruders running at different extrusion speeds, the height of the "saddle" and the "seat" of the "saddle type" are completely different.
When extruding plastic profiles, it is necessary to maximize the extrusion efficiency of the extruder with different shear properties, and establish the required heat and heat for the screw heating zone (feeding section, compression section) and constant temperature zone (melting section, metering section). The balance of the heat supplied is the key. According to the shear performance characteristics of the extruder, different shear performance extruders, extruding different specifications of plastic profiles, should adopt different extrusion processes to meet the requirements of product quality and performance.extruder screw barrel is on sale ,why not to take a look !
Plastic profile extrusion, the material is transformed from glass state to molten state. There are two heat sources, one is external heating provided by electric heater, and the other is produced by rolling, friction, and shearing of the material during the rotation of the screw. The heat. When starting production, the melting of the material is mainly external heating. In the normal production stage, the melting of the material is mainly the internal heat generated by the screw rolling, friction, and shearing of the material. Relevant data indicate that: in profile extrusion, the proportion of internal heat to the heat supplied by the extruder is roughly above 65%.