Single screw extruder working principle

- Apr 13, 2020-

The single screw extruder now is popular used in the meltblown cloth production equipment which is the heart of a medical mask. 

The single screw is generally divided into three sections in terms of effective length, and the effective length of the three sections is determined according to the screw diameter and pitch.

The last thread of the feed port starts to be called the conveying section: the material needs to be plasticized here, but it needs to be preheated and compacted under pressure. In the past, the old extrusion theory believed that the material here was loose, and later proved that the material is actually Solid plug, that is to say, the material is a solid like a plug after being squeezed, so as long as the conveying task is completed, it is its function.

The second section is called the compression section. At this time, the volume of the screw groove is gradually reduced from large to large, and the temperature has to reach the degree of plasticization of the material. The compression occurs here from the conveying section three, where it is compressed to one. 3 ﹕ 1, some machines are also changed, and the plasticized material enters the third stage.

The third section is the metering section, where the material maintains the plasticizing temperature, but just like the metering pump, the melt material is accurately and quantitatively delivered to the machine head. At this time, the temperature cannot be lower than the plasticizing temperature, which is generally slightly higher.