Some problems of compound thread rubber extruder

The beginning of the screw of the convergent primary and secondary compound thread cold feed rubber extruder machine is symmetrically distributed with double threads. One main thread in the plasticizing section of the screw is disconnected, and a secondary thread is added at the same time. The lead of the secondary thread is relatively small. Large, relatively small top diameter. There are also the following problems with this screw rod:

(1) The quality of rubber mixing is not ideal: because its mechanism of action is similar to the thin pass operation of the rubber by the open mill, the rubber can not be mixed evenly after 1 or 2 times of thin pass, and objectively there are still small local rubber. The phenomenon of uneven mixing will affect the quality of semi-finished products;

(2) Since the auxiliary thread spans the groove of the main thread, the flow of the rubber material is only a narrow slit, and the resistance is very large, so the energy consumption is large and the unit consumption is high;

(3) In the process of processing, the strong shearing effect of the screw on the rubber leads to a high discharge temperature, and some rubber materials that are sensitive to temperature are difficult to process. At the same time, because high-speed production is restricted by the discharge temperature, it is difficult for the screw to Meet high production capacity requirements;

(4) Since the thread pitch in the secondary thread section is variable and closed at the beginning and end, the self-cleaning property is poor and processing is difficult.

Despite the above shortcomings, it is still widely used in some cold feed extruders, especially for small and medium-sized cold feed extruders (such as φ45 and 065 cold feed extruders, etc.).