Functions of the installation of screen changer for extruded plastic products

The installation of screen changer for extruded plastic products has the following functions: 

(1) First filter out the impurities in the raw materials, improve the quality of the products, and at the same time reduce the loss caused by changing the screen, also save energy and reduce consumption, increase the output and reduce the labor intensity. 

(2) The installation of screen changer increases the back pressure of the extruder die head, which greatly improves the plasticizing and homogenizing effect of raw materials, the product texture is more uniform, the finish is better, and the pressure resistance value of the product will be improved. This is also the reason why the new raw material is equipped with screen changer without impurities. The installation of the screen changer seems to have added a static mixer. 

(3) After installing the screen changer, the rheological behavior of the material is changed from rotational flow to linear flow, so as to avoid the appearance of "winding lines" of products. The porous plate and the filter screen have the function of "damping" at the same time, which makes the cross-sectional velocity of the whole melt consistent as far as possible, avoids the phenomenon of "polymer orientation" and laminar flow, and increases the longitudinal strength of the product while the transverse strength decreases, thus affecting the quality of the product, because the velocity of the melt ring wall is very different from that in the middle.

 (4) The installation of the screen changer increases the back pressure of the machine head, which is beneficial to the elimination of water vapor and volatiles in the raw materials.