The function of the rear end of the screw on the plastic extruder
2025-7-28
There are many types of plastics used for extrusion molding in plastic extruders, and one screw cannot shape all plastics. Screw design should be based on the characteristics of raw materials and consider the commonalities of various raw materials as much as possible, so that a single screw can extrude several plastics at the same time, which is economically meaningful in industrial production.
The reverse thread at the back end of the screw serves to prevent material leakage.
The length to diameter ratio of the screw is L/D, and the screw diameter D refers to the outer diameter of the screw thread. The effective length L of the screw refers to the length of the working part of the screw. The effective length and the total length of the screw are different. The aspect ratio is the ratio of the effective length to the diameter of a screw. The length and diameter of the screw in early splicing machines were relatively small, only 12-16. With the development of the plastic molding industry, the aspect ratio of extruder screws has gradually increased, with commonly used values of 15, 20, and 25, and a maximum of 43.