What is the role of the screw and barrel of the injection molding machine?


When the screw rotates and pushes the extruded raw mate […]

When the screw rotates and pushes the extruded raw material to move forward, the heat is transferred from the outside of the barrel to the raw material, and the volume of the screw thread groove is gradually reduced, so that the raw material is squeezed, turned and sheared while being pushed forward. After the action of various forces, it is uniformly mixed and plasticized into a molten state to complete the plasticization of the plastic.

Classification of Injection Molding Machine Screw and Barrel
The structure of the barrel is more divided into: monolithic, segmented, bushing, casting, and bimetallic barrels.
Integral barrel: In injection molding machines and extruders, most applications are integral barrels, especially small and medium-sized models, which basically adopt this structure. The barrel is generally used for 38CrMoALA. Moreover, the temperature control is accurate and easy, and the processing accuracy is relatively easy to guarantee.
Segmented barrel: Mainly used in larger extruders and vented extruders. Since the total length of the barrel is composed of several sections, the machining of each section of the barrel is much more convenient, and the temperature control of heating and cooling has relatively large errors.
Rubber screw barrel classification
The barrel is generally designed as an integral type, and nowadays, multi-stage combined barrels are rarely used.
In the solids conveying theory, how to increase the solids conveying capacity has been discussed, mainly from the rational selection of the screw structure and technical parameters, but the improvement of the solids conveying capacity is not significant, and the efficiency is only 20%-40%.