The Process and Usage Considerations of Double Screw Extruder

Double screw extruder has a similar overall structure to a single screw extruder unit, consisting of a main unit, a head, and an auxiliary unit. The main unit is usually called the double screw extruder. In practical applications, a double screw extruder must be equipped with a head and an auxiliary unit, also known as a double screw extruder unit. Let's take a look at the process and considerations for using a double screw extruder!


Process of double screw extruder


  • During the extrusion process, the material of the double screw extruder changes from a glass state to a molten state. The melt pressure is also a very critical control index, in addition to stabilizing the balance of the heat required for material plasticization and the heat supplied to make the material achieve ideal plasticization. Considering the influence of the mold resistance on the material during the extrusion process, the compression ratio of the screw does not exist under normal pressure. For different molds, the compression ratio of the screw is basically balanced and stable, and does not change.

  • Under the premise of constant extrusion speed, the material capacity of the screw in the feeding section changes, while the material capacity in the exhaust section remains unchanged. Therefore, the melting pressure in the feeding section increases or decreases with changes in the compression ratio; under the premise of constant feeding speed, the material capacity of the screw in the feeding section also changes.


Considerations for using the double screw extruder


The surface is too rough


The surface of the impeller blade is too rough, resulting in excessive friction between the mud and the blade. Therefore, when welding the impeller blade, do not weld it. It should be replaced all at once and replaced gradually to ensure the smooth completion of the brick.


The lining of the mud cylinder is severely worn


The gap between the impeller blade and the lining of the mud cylinder is too large, causing too much rotation of the mud in the mud cylinder and the mud cannot enter. At this time, a new lining of the mud cylinder should be replaced or several parallel or inclined ribs should be installed on the inner wall of the lining to replace the worn groove, prevent ineffective rotation of the mud, and increase effective extrusion.


The clearance is too large


The clearance between the mud plate and the impeller blade is too large, and the mud cannot be pressed down. At this time, adjustments or welding should be carried out. Updating the blade is the technical key point and problem analysis of the double screw extruder.


Nanjing KY Chemical Machinery Co., Ltd. not only provides customers with first-class quality extruders, but also helps customers optimize the entire production system. From material storage, drying, transportation, metering, mixing, to final product packaging, we provide a factory-level intelligent control system to provide customers with a set of highly reliable and cost-effective solutions.


The application of twin screws will also be extended to industries such as fibers, films, and reaction extrusion, creating higher value. Welcome to inquire.

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