Principle of single screw extruder

Single screw is generally divided into three sections on the effective length. The effective length of the three sections is determined according to the diameter of the screw, the pitch of the screw and the depth of the screw.
The last thread of the material port begins to call the conveying section: the material here is not plasticized, but to preheat, compressed compaction, the old extrusion theory that the material here is loose body, later by proving that the movement of the material here is similar to the solid piston, so as long as the completion of the conveying task is its function.
The second section is called the compression section, at this time, the volume of the screw tank gradually decreases from large, and the temperature to reach the degree of plasticization of the material, here produced compression by the delivery section three, here compressed to a, this is called the compression ratio of the screw -3:1, some machines also have changes, complete the plasticized material into the third section.
The third section is the metering section, here the material to maintain the plasticization temperature, just like the metering pump accurate, quantitative transport of melt materials, to supply the head, at this time the temperature can not be lower than the plasticization temperature, generally slightly higher.