What is the purpose of adding a screen changer to an extruder?
An extruder screen changer is a piece of equipment used in the plastics processing industry whose main function is to filter impurities from the melt while also allowing the filter screen to be changed without stopping the machine. This design increases productivity, reduces energy consumption, and decreases scrap and mold wear. Specifically, the addition of a screen changer to an extruder serves the following purposes:
1, filter out impurities in the raw material, improve the quality of the product, and at the same time reduce the loss brought about by the screen changer; energy saving and reduce consumption, not only improve the output but also reduce labor intensity.
2, the addition of screen changer to increase the back pressure of the machine head, greatly improving the plasticization of raw materials and homogenization effect, the product texture is more uniform, better finish, the product pressure resistance value will be enhanced. This is the reason why the screen changer is installed for new raw materials without impurities. Adding a screen changer has an additional static mixer.
3、After installing the screen changer, the rheological behavior of the material is changed from rotating flow to linear flow, avoiding the appearance of “winding pattern” of the products. Porous plate and screen at the same time have the role of “damping”, so that the entire cross-section of the melt flow rate as consistent as possible, to avoid the phenomenon of “polymer orientation” and laminar flow, so that the longitudinal strength of the product increases while the transverse strength of the product decreases, thereby affecting the quality of the product, because the melt The flow rate of the ring wall and the middle of the flow rate is very different.
4、Adding screen changer to increase the back pressure of the machine head is conducive to the elimination of water vapor and volatiles in the raw materials.
5、Placing the screen changer reduces the wear and tear of impurities on the mold, which helps to extend the service life of the mold.
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